Sample records for memory perceptual speed

  1. Perceptual Simulations and Linguistic Representations Have Differential Effects on Speeded Relatedness Judgments and Recognition Memory

    PubMed Central

    Tse, Chi-Shing; Kurby, Christopher A.; Du, Feng

    2010-01-01

    We examined the effect of spatial iconicity (a perceptual simulation of canonical locations of objects) and word-order frequency on language processing and episodic memory of orientation. Participants made speeded relatedness judgments to pairs of words presented in locations typical to their real world arrangements (e.g., ceiling on top and floor on bottom). They then engaged in a surprise orientation recognition task for the word pairs. We replicated Louwerse’s finding (2008) that word-order frequency has a stronger effect on semantic relatedness judgments than spatial iconicity. This is consistent with recent suggestions that linguistic representations have a stronger impact on immediate decisions about verbal materials than perceptual simulations. In contrast, spatial iconicity enhanced episodic memory of orientation to a greater extent than word-order frequency did. This new finding indicates that perceptual simulations have an important role in episodic memory. Results are discussed with respect to theories of perceptual representation and linguistic processing. PMID:19742388

  2. Perceptual Countermeasures to Speeding

    PubMed Central

    Fildes, Brian; Corben, Bruce; Newstead, Stuart; Macaulay, Jemima; Gunatillake, Thanuja; Tziotis, Michael

    2005-01-01

    An on-road evaluation of two perceptual countermeasure treatments (an enhanced curve post treatment and peripheral transverse edgelines on the approach to an intersection) was conducted over one year to indicate potential for reducing travel speed. Measures included speed and deceleration profiles, braking, and lateral placement observations taken from video recordings at each site. Data were collected before treatment, immediately after treatment, and 12 months after treatment. The results obtained were quite variable across sites and treatments. At curves, speed effects were mixed with both speed reductions and increases observed immediately after and 12-months later. Braking results tended to support travel speed findings and some improvement in lateral placement were also observed at these locations. At intersections, the results were more stable where speed reductions were more common both immediately after treatment as well as longer-term. There were no differences in braking and lateral placement at these straight-road locations. The findings seem to have been unduly influenced to some degree by misadventure and wear and tear at these sites. It is argued that while the effectiveness of these treatments may be site specific to some degree, they do offer a low-cost solution to reducing travel speed at hazardous locations. PMID:16179136

  3. Semantic and perceptual effects on recognition memory: Evidence from ERP

    Microsoft Academic Search

    Erika Nyhus; Tim Curran

    2009-01-01

    The present experiments examined how semantic vs. perceptual encoding and perceptual match affect the processes involved in recognition memory. Experiment 1 examined the effects of encoding task and perceptual match between study and test fonts on recognition discrimination for words. Font fan was used to determine the effect of distinctiveness on perceptual match. The semantic encoding task and perceptual match

  4. Perceptual and memory constraints on language acquisition

    E-print Network

    Mehler, Jacques

    Perceptual and memory constraints on language acquisition Ansgar D. Endress1,*, Marina Nespor2 and symbolic accounts of cognitive processes could be bridged. Specialized mechanisms in language acquisition for language acquisition [3,4]. Here, we suggest a different (and complementary) approach to language

  5. On the relationship between autobiographical memory and perceptual learning

    Microsoft Academic Search

    Larry L. Jacoby; Mark Dallas

    1981-01-01

    Reports experiments designed to explore the relationship between the more aware autobiographical form of memory that is measured by a recognition memory test and the less aware form of memory that is expressed in perceptual learning. Ss were 247 undergraduates. Variables such as the level of processing of words during study influenced recognition memory, but not subsequent perceptual recognition. In

  6. The spatial scale of perceptual memory in ambiguous figure perception

    E-print Network

    Ambiguous visual stimuli highlight the constructive nature of vision: perception alternates between two plausible interpretations of unchanging input. However, when a previously viewed ambiguous stimulus reappears, its earlier perception almost entirely determines the new interpretation; memory disambiguates the input. Here, we investigate the spatial properties of this perceptual memory, taking into account strong anisotropies in percept preference across the visual field. Countering previous findings, we show that perceptual memory is not confined to the location in which it was instilled. Rather, it spreads to noncontiguous regions of the visual field, falling off at larger distances. Furthermore, this spread of perceptual memory takes place in a frame of reference that is tied to the surface of the retina. These results place the neural locus of perceptual memory in retinotopically organized sensory cortical areas, with implications for the wider function of perceptual memory in facilitating stable vision in natural, dynamic environments.

  7. Human middle temporal cortex, perceptual bias, and perceptual memory for ambiguous three-dimensional motion.

    PubMed

    Brascamp, Jan W; Kanai, Ryota; Walsh, Vincent; van Ee, Raymond

    2010-01-13

    When faced with inconclusive or conflicting visual input human observers experience one of multiple possible perceptions. One factor that determines perception of such an ambiguous stimulus is how the same stimulus was perceived on previous occasions, a phenomenon called perceptual memory. We examined perceptual memory of an ambiguous motion stimulus while applying transcranial magnetic stimulation (TMS) to the motion-sensitive areas of the middle temporal cortex (hMT+). TMS increased the predominance of whichever perceptual interpretation was most commonly reported by a given observer at baseline, with reduced perception of the less favored interpretation. This increased incidence of the preferred percept indicates impaired long-term buildup of perceptual memory traces that normally act against individual percept biases. We observed no effect on short-term memory traces acting from one presentation to the next. Our results indicate that hMT+ is important for the long-term buildup of perceptual memory for ambiguous motion stimuli. PMID:20071541

  8. Lipreading, Processing Speed, and Working Memory in Younger and Older Adults

    ERIC Educational Resources Information Center

    Feld, Julia E.; Sommers, Mitchell S.

    2009-01-01

    Purpose: To examine several cognitive and perceptual abilities--including working memory (WM), information processing speed (PS), perceptual closure, and perceptual disembedding skill--as factors contributing to individual differences in lipreading performance and to examine how patterns in predictor variables change across age groups. Method:…

  9. Memory: Enduring Traces of Perceptual and Reflective Attention

    PubMed Central

    Chun, Marvin M.; Johnson, Marcia K.

    2011-01-01

    Attention and memory are typically studied as separate topics, but they are highly intertwined. Here we discuss the relation between memory and two fundamental types of attention: perceptual and reflective. Memory is the persisting consequence of cognitive activities initiated by and/or focused on external information from the environment (perceptual attention) and initiated by and/or focused on internal mental representations (reflective attention). We consider three key questions for advancing a cognitive neuroscience of attention and memory: To what extent do perception and reflection share representational areas? To what extent are the control processes that select, maintain, and manipulate perceptual and reflective information subserved by common areas and networks? During perception and reflection, to what extent are common areas responsible for binding features together to create complex, episodic memories and for reviving them later? Considering similarities and differences in perceptual and reflective attention helps integrate a broad range of findings and raises important unresolved issues. PMID:22099456

  10. Great Expectations: Temporal Expectation Modulates Perceptual Processing Speed

    ERIC Educational Resources Information Center

    Vangkilde, Signe; Coull, Jennifer T.; Bundesen, Claus

    2012-01-01

    In a crowded dynamic world, temporal expectations guide our attention in time. Prior investigations have consistently demonstrated that temporal expectations speed motor behavior. We explore effects of temporal expectation on "perceptual" speed in three nonspeeded, cued recognition paradigms. Different hazard rate functions for the cue-stimulus…

  11. The effects of attention on perceptual implicit memory.

    PubMed

    Rajaram, S; Srinivas, K; Travers, S

    2001-10-01

    Reports on the effects of dividing attention at study on subsequent perceptual priming suggest that perceptual priming is generally unaffected by attentional manipulations as long as word identity is processed. We tested this hypothesis in three experiments by using the implicit word fragment completion and word stem completion tasks. Division of attention was instantiated with the Stroop task in order to ensure the processing of word identity even when the participant's attention was directed to a stimulus attribute other than the word itself. Under these conditions, we found that even though perceptual priming was significant, it was significantly reduced in magnitude. A stem cued recall test in Experiment 2 confirmed a more deleterious effect of divided attention on explicit memory. Taken together, our findings delineate the relative contributions of perceptual analysis and attentional processes in mediating perceptual priming on two ubiquitously used tasks of word fragment completion and word stem completion. PMID:11820751

  12. The Effects of Perceptual Interference at Encoding on Implicit Memory, Explicit Memory, and Memory for Source

    Microsoft Academic Search

    Neil W. Mulligan

    1996-01-01

    Interfering with stimulus identification can enhance later explicit memory performance. This counterintuitive (and theoretically unexpected) phenomenon was investigated in 5 experiments. Perceptual interference enhanced category-cued recall (a conceptually driven explicit test) but had no effect on a comparable implicit memory test, category-exemplar production. This dissociation was obtained across higher levels of priming and with high-frequency as well as low-frequency exemplars.

  13. Subthreshold membrane depolarization as memory trace for perceptual learning.

    PubMed

    Hoshino, Osamu

    2011-12-01

    Experience-dependent synaptic plasticity characterizes the adaptable brain and is believed to be the cellular substrate for perceptual learning. A chemical agent such as gamma-aminobutyric acid (GABA) is known to affect synaptic alteration, perhaps gating perceptual learning. We examined whether and how ambient (extrasynaptic) GABA affects experience-dependent synaptic alteration. A cortical neural network model was simulated. Transporters on GABAergic interneurons regulate ambient GABA levels around their axonal target neurons by removing GABA from (forward transport) or releasing it into (reverse transport) the extracellular space. The ambient GABA provides neurons with tonic inhibitory currents by activating extrasynaptic GABA(a) receptors. During repeated exposures to the same stimulus, we modified the synaptic connection strength between principal cells in a spike-timing-dependent manner. This modulated the activity of GABAergic interneurons, and reduced or augmented ambient GABA concentration. Reduction in ambient GABA concentration led to slight depolarization (less than several millivolts) in ongoing-spontaneous membrane potential. This was a subthreshold neuronal behavior because ongoing-spontaneous spiking activity remained almost unchanged. The ongoing-spontaneous subthreshold depolarization improved a suprathreshold neuronal response. If the stimulus was long absent for perceptual learning, augmentation of ambient GABA concentration took place and the ongoing-spontaneous subthreshold depolarization was depressed. We suggest that a perceptual memory trace could be left in neuronal circuitry as an ongoing-spontaneous subthreshold membrane depolarization, which would allow that memory to be accessed easily afterward, whereas a trace of a memory that has not recently been retrieved fades away when the ongoing-spontaneous subthreshold membrane depolarization built by previous perceptual learning is depressed. This would lead that memory to be accessed with some difficulty. In the brain, ambient GABA, whose level could be regulated by transporter may have an important role in leaving memory trace for perceptual learning. PMID:21919783

  14. Differential Effects of Intelligence, Perceptual Speed and Age on Growth in Attentional Speed and Accuracy

    ERIC Educational Resources Information Center

    Goldhammer, Frank; Rauch, Wolfgang A.; Schweizer, Karl; Moosbrugger, Helfried

    2010-01-01

    The study investigates the effects of intelligence, perceptual speed and age on intraindividual growth in attentional speed and attentional accuracy over the course of a 6-minute testing session. A sample of 193 subjects completed the Advanced Progressive Matrices and the Vienna Matrices Test representing intelligence, the tests Alertness and…

  15. Evidence for Working Memory Storage Operations in Perceptual Cortex

    PubMed Central

    Sreenivasan, Kartik K.; Gratton, Caterina; Vytlacil, Jason; D’Esposito, Mark

    2014-01-01

    Isolating the short-term storage component of working memory (WM) from the myriad of associated executive processes has been an enduring challenge. Recent efforts have identified patterns of activity in visual regions that contain information about items being held in WM. However, it remains unclear (i) whether these representations withstand intervening sensory input and (ii) how communication between multimodal association cortex and unimodal perceptual regions supporting WM representations is involved in WM storage. We present evidence that the features of a face held in WM are stored within face processing regions, that these representations persist across subsequent sensory input, and that information about the match between sensory input and memory representation is relayed forward from perceptual to prefrontal regions. Participants were presented with a series of probe faces and indicated whether each probe matched a Target face held in WM. We parametrically varied the feature similarity between probe and Target faces. Activity within face processing regions scaled linearly with the degree of feature similarity between the probe face and the features of the Target face, suggesting that the features of the Target face were stored in these regions. Furthermore, directed connectivity measures revealed that the direction of information flow that was optimal for performance was from sensory regions that stored the features of the Target face to dorsal prefrontal regions, supporting the notion that sensory input is compared to representations stored within perceptual regions and relayed forward. Together, these findings indicate that WM storage operations are carried out within perceptual cortex. PMID:24436009

  16. Variability in visual working memory ability limits the efficiency of perceptual decision making

    PubMed Central

    Ester, Edward F.; Ho, Tiffany C.; Brown, Scott D.; Serences, John T.

    2014-01-01

    The ability to make rapid and accurate decisions based on limited sensory information is a critical component of visual cognition. Available evidence suggests that simple perceptual discriminations are based on the accumulation and integration of sensory evidence over time. However, the memory system(s) mediating this accumulation are unclear. One candidate system is working memory (WM), which enables the temporary maintenance of information in a readily accessible state. Here, we show that individual variability in WM capacity is strongly correlated with the speed of evidence accumulation in speeded two-alternative forced choice tasks. This relationship generalized across different decision-making tasks, and could not be easily explained by variability in general arousal or vigilance. Moreover, we show that performing a difficult discrimination task while maintaining a concurrent memory load has a deleterious effect on the latter, suggesting that WM storage and decision making are directly linked. PMID:24695991

  17. When Does Modality Matter? Perceptual versus Conceptual Fluency-Based Illusions in Recognition Memory

    ERIC Educational Resources Information Center

    Miller, Jeremy K.; Lloyd, Marianne E.; Westerman, Deanne L.

    2008-01-01

    Previous research has shown that illusions of recognition memory based on enhanced perceptual fluency are sensitive to the perceptual match between the study and test phases of an experiment. The results of the current study strengthen that conclusion, as they show that participants will not interpret enhanced perceptual fluency as a sign of…

  18. Teaching memory-impaired people to touch type: the acquisition of a useful complex perceptual-motor skill.

    PubMed

    Todd, Mary; Barrow, Corinne

    2008-08-01

    This study provides ecological validity for laboratory findings that people with memory difficulties following brain injury can learn new skills. This was done by testing the acquisition of a useful real-world perceptual-motor skill. Using a conventional computer software training package supplemented by one-to-one coaching, a woman with severely impaired memory and a man with poor memory learned to touch type. They achieved the initial criterion of 20 wpm with over 90% accuracy; reached a top speed of 30 wpm and retained their skill a year later. The memory-impaired participants received short sessions of distributed practice and as far as possible were taught under error-free learning conditions. Their performance was broadly comparable with that of two non-memory-impaired comparison participants in terms of acquisition, consolidation and transfer, speed and accuracy, and retention. PMID:18576273

  19. Revisiting a Cognitive Framework for Test Design: Applications for a Computerized Perceptual Speed Test.

    ERIC Educational Resources Information Center

    Alderton, David L.

    This paper highlights the need for a systematic, content aware, and theoretically-based approach to test design. The cognitive components approach is endorsed, and is applied to the development of a computerized perceptual speed test. Psychometric literature is reviewed and shows that: every major multi-factor theory includes a clerical/perceptual

  20. Working memory effects in speeded RSVP tasks.

    PubMed

    Gil-Gómez de Liaño, Beatriz; Potter, Mary C; Rodríguez, Carmen

    2014-01-01

    The present paper examines the effects of memory contents and memory load in rapid serial visual presentation (RSVP) speeded tasks, trying to explain previous inconsistent results. We used a one target (Experiment 1) and a two-target (Experiment 2) RSVP task with a concurrent memory load of one or four items, in a dual-task paradigm. A relation between material in working memory and the target in the RSVP impaired the identification of the target. In Experiments 3 and 4, the single task was to determine whether any information in memory matched the target in the RSVP, while varying the memory load. A match was detected faster than a non-match, although only when there was some distance between targets in the RSVP (Experiment 4). The results suggest that memory contents automatically capture attention, slowing processing when the memory contents are irrelevant to the task, and speeding processing when they are relevant. PMID:23397260

  1. Bias Effects in Perceptual Identification: A Neuropsychological Investigation of the Role of Explicit Memory

    Microsoft Academic Search

    Margaret M Keane; Mieke Verfaellie; John D. E Gabrieli; Bonnie M Wong

    2000-01-01

    Identification of perceptually degraded words can be enhanced by prior exposure to those words. One theory proposes that such perceptual priming is due to a bias mechanism that induces costs as well as benefits in performance. Inherent in this theory is the critical assumption that bias effects observed in normal cognition reflect the operation of implicit rather than explicit memory

  2. Executive Functioning and Processing Speed in Age-Related Differences in Memory: Contribution of a Coding Task

    ERIC Educational Resources Information Center

    Baudouin, Alexia; Clarys, David; Vanneste, Sandrine; Isingrini, Michel

    2009-01-01

    The aim of the present study was to examine executive dysfunctioning and decreased processing speed as potential mediators of age-related differences in episodic memory. We compared the performances of young and elderly adults in a free-recall task. Participants were also given tests to measure executive functions and perceptual processing speed

  3. Poor anchoring limits dyslexics' perceptual, memory, and reading skills.

    PubMed

    Oganian, Yulia; Ahissar, Merav

    2012-07-01

    The basic deficits underlying the severe and persistent reading difficulties in dyslexia are still highly debated. One of the major topics of debate is whether these deficits are language specific, or affect both verbal and non-verbal stimuli. Recently, Ahissar and colleagues proposed the "anchoring-deficit hypothesis" (Ahissar, Lubin, Putter-Katz, & Banai, 2006), which suggests that dyslexics have a general difficulty in automatic extraction of stimulus regularities from auditory inputs. This hypothesis explained a broad range of dyslexics' verbal and non-verbal difficulties. However, it was not directly tested in the context of reading and verbal memory, which poses the main stumbling blocks to dyslexics. Here we assessed the abilities of adult dyslexics to efficiently benefit from ("anchor to") regularities embedded in repeated tones, orally presented syllables, and written words. We also compared dyslexics' performance to that of individuals with attention disorder (ADHD), but no reading disability. We found an anchoring effect in all groups: all gained from stimulus repetition. However, in line with the anchoring-deficit hypothesis, controls and ADHD participants showed a significantly larger anchoring effect in all tasks. This study is the first that directly shows that the same domain-general deficit, poor anchoring, characterizes dyslexics' performance in perceptual, working memory and reading tasks. PMID:22561890

  4. Further Explorations of Perceptual Speed Abilities in the Context of Assessment Methods, Cognitive Abilities, and Individual Differences during Skill Acquisition

    ERIC Educational Resources Information Center

    Ackerman, Phillip L.; Beier, Margaret E.

    2007-01-01

    Measures of perceptual speed ability have been shown to be an important part of assessment batteries for predicting performance on tasks and jobs that require a high level of speed and accuracy. However, traditional measures of perceptual speed ability sometimes have limited cost-effectiveness because of the requirements for administration and…

  5. Disruption of dorsolateral but not ventrolateral prefrontal cortex improves unconscious perceptual memories.

    PubMed

    Lee, Taraz G; Blumenfeld, Robert S; D'Esposito, Mark

    2013-08-01

    Attentive encoding often leads to more accurate responses in recognition memory tests. However, previous studies have described conditions under which taxing explicit memory resources by attentional distraction improved perceptual recognition memory without awareness. These findings lead to the hypothesis that explicit memory processes mediated by the prefrontal cortex (PFC) can interfere with memory processes necessary for implicit recognition memory. The present study directly tested this hypothesis by applying transcranial magnetic stimulation separately over either dorsolateral (DLPFC) or ventrolateral PFC (VLPFC) in humans before performance of a visual memory task. Disruption of DLPFC function led to improvement in recognition accuracy only in responses in which the participant's awareness of memory retrieval was absent. However, disruption of VLPFC function led to subtle shifts in recollection and familiarity accuracy. We conclude that explicit memory processes mediated by the DLPFC can indirectly interfere with implicit recognition memory. PMID:23926275

  6. Disruption of Dorsolateral But Not Ventrolateral Prefrontal Cortex Improves Unconscious Perceptual Memories

    PubMed Central

    Blumenfeld, Robert S.; D'Esposito, Mark

    2013-01-01

    Attentive encoding often leads to more accurate responses in recognition memory tests. However, previous studies have described conditions under which taxing explicit memory resources by attentional distraction improved perceptual recognition memory without awareness. These findings lead to the hypothesis that explicit memory processes mediated by the prefrontal cortex (PFC) can interfere with memory processes necessary for implicit recognition memory. The present study directly tested this hypothesis by applying transcranial magnetic stimulation separately over either dorsolateral (DLPFC) or ventrolateral PFC (VLPFC) in humans before performance of a visual memory task. Disruption of DLPFC function led to improvement in recognition accuracy only in responses in which the participant's awareness of memory retrieval was absent. However, disruption of VLPFC function led to subtle shifts in recollection and familiarity accuracy. We conclude that explicit memory processes mediated by the DLPFC can indirectly interfere with implicit recognition memory. PMID:23926275

  7. Basic perceptual changes that alter meaning and neural correlates of recognition memory.

    PubMed

    Gao, Chuanji; Hermiller, Molly S; Voss, Joel L; Guo, Chunyan

    2015-01-01

    It is difficult to pinpoint the border between perceptual and conceptual processing, despite their treatment as distinct entities in many studies of recognition memory. For instance, alteration of simple perceptual characteristics of a stimulus can radically change meaning, such as the color of bread changing from white to green. We sought to better understand the role of perceptual and conceptual processing in memory by identifying the effects of changing a basic perceptual feature (color) on behavioral and neural correlates of memory in circumstances when this change would be expected to either change the meaning of a stimulus or to have no effect on meaning (i.e., to influence conceptual processing or not). Abstract visual shapes ("squiggles") were colorized during study and presented during test in either the same color or a different color. Those squiggles that subjects found to resemble meaningful objects supported behavioral measures of conceptual priming, whereas meaningless squiggles did not. Further, changing color from study to test had a selective effect on behavioral correlates of priming for meaningful squiggles, indicating that color change altered conceptual processing. During a recognition memory test, color change altered event-related brain potential (ERP) correlates of memory for meaningful squiggles but not for meaningless squiggles. Specifically, color change reduced the amplitude of frontally distributed N400 potentials (FN400), implying that these potentials indicated conceptual processing during recognition memory that was sensitive to color change. In contrast, color change had no effect on FN400 correlates of recognition for meaningless squiggles, which were overall smaller in amplitude than for meaningful squiggles (further indicating that these potentials signal conceptual processing during recognition). Thus, merely changing the color of abstract visual shapes can alter their meaning, changing behavioral and neural correlates of memory. These findings are relevant to understanding similarities and distinctions between perceptual and conceptual processing as well as the functional interpretation of neural correlates of recognition memory. PMID:25717298

  8. Basic perceptual changes that alter meaning and neural correlates of recognition memory

    PubMed Central

    Gao, Chuanji; Hermiller, Molly S.; Voss, Joel L.; Guo, Chunyan

    2015-01-01

    It is difficult to pinpoint the border between perceptual and conceptual processing, despite their treatment as distinct entities in many studies of recognition memory. For instance, alteration of simple perceptual characteristics of a stimulus can radically change meaning, such as the color of bread changing from white to green. We sought to better understand the role of perceptual and conceptual processing in memory by identifying the effects of changing a basic perceptual feature (color) on behavioral and neural correlates of memory in circumstances when this change would be expected to either change the meaning of a stimulus or to have no effect on meaning (i.e., to influence conceptual processing or not). Abstract visual shapes (“squiggles”) were colorized during study and presented during test in either the same color or a different color. Those squiggles that subjects found to resemble meaningful objects supported behavioral measures of conceptual priming, whereas meaningless squiggles did not. Further, changing color from study to test had a selective effect on behavioral correlates of priming for meaningful squiggles, indicating that color change altered conceptual processing. During a recognition memory test, color change altered event-related brain potential (ERP) correlates of memory for meaningful squiggles but not for meaningless squiggles. Specifically, color change reduced the amplitude of frontally distributed N400 potentials (FN400), implying that these potentials indicated conceptual processing during recognition memory that was sensitive to color change. In contrast, color change had no effect on FN400 correlates of recognition for meaningless squiggles, which were overall smaller in amplitude than for meaningful squiggles (further indicating that these potentials signal conceptual processing during recognition). Thus, merely changing the color of abstract visual shapes can alter their meaning, changing behavioral and neural correlates of memory. These findings are relevant to understanding similarities and distinctions between perceptual and conceptual processing as well as the functional interpretation of neural correlates of recognition memory. PMID:25717298

  9. Selection and Storage of Perceptual Groups Is Constrained by a Discrete Resource in Working Memory

    ERIC Educational Resources Information Center

    Anderson, David E.; Vogel, Edward K.; Awh, Edward

    2013-01-01

    Perceptual grouping can lead observers to perceive a multielement scene as a smaller number of hierarchical units. Past work has shown that grouping enables more elements to be stored in visual working memory (WM). Although this may appear to contradict so-called discrete resource models that argue for fixed item limits in WM storage, it is also…

  10. MESO: Perceptual Memory to Support Online Learning in Adaptive Software

    Microsoft Academic Search

    E. P. Kasten; P. K. McKinley

    Adaptive and autonomic systems often must be able to detect and respond to errant behavior or changing condi- tions with little or no human intervention. Decision making is a critical issue in such systems, which must learn how and when to invoke corrective actions based on past experi- ence. This paper describes the design, implementation and evaluation of a perceptual

  11. Implicit perceptual memory modulates early visual processing of ambiguous images.

    PubMed

    de Jong, Maartje C; Brascamp, Jan W; Kemner, Chantal; van Ee, Raymond; Verstraten, Frans A J

    2014-07-23

    The way we perceive the present visual environment is influenced by past visual experiences. Here we investigated the neural basis of such experience dependency. We repeatedly presented human observers with an ambiguous visual stimulus (structure-from-motion) that can give rise to two distinct perceptual interpretations. Past visual experience is known to influence the perception of such stimuli. We recorded fast dynamics of neural activity shortly after stimulus onset using event-related electroencephalography. The number of previous occurrences of a certain percept modulated early posterior brain activity starting as early as 50 ms after stimulus onset. This modulation developed across hundreds of percept repetitions, reflecting several minutes of accumulating perceptual experience. Importantly, there was no such modulation when the mere number of previous stimulus presentations was considered regardless of how they were perceived. This indicates that the effect depended on previous perception rather than previous visual input. The short latency and posterior scalp location of the effect suggest that perceptual history modified bottom-up stimulus processing in early visual cortex. We propose that bottom-up neural responses to a given visual presentation are shaped, in part, by feedback modulation that occurred during previous presentations, thus allowing these responses to be biased in light of previous perceptual decisions. PMID:25057199

  12. The time course of protecting a visual memory representation from perceptual interference

    PubMed Central

    van Moorselaar, Dirk; Gunseli, Eren; Theeuwes, Jan; N. L. Olivers, Christian

    2015-01-01

    Cueing a remembered item during the delay of a visual memory task leads to enhanced recall of the cued item compared to when an item is not cued. This cueing benefit has been proposed to reflect attention within visual memory being shifted from a distributed mode to a focused mode, thus protecting the cued item against perceptual interference. Here we investigated the dynamics of building up this mnemonic protection against visual interference by systematically varying the stimulus onset asynchrony (SOA) between cue onset and a subsequent visual mask in an orientation memory task. Experiment 1 showed that a cue counteracted the deteriorating effect of pattern masks. Experiment 2 demonstrated that building up this protection is a continuous process that is completed in approximately half a second after cue onset. The similarities between shifting attention in perceptual and remembered space are discussed. PMID:25628555

  13. Action video games do not improve the speed of information processing in simple perceptual tasks.

    PubMed

    van Ravenzwaaij, Don; Boekel, Wouter; Forstmann, Birte U; Ratcliff, Roger; Wagenmakers, Eric-Jan

    2014-10-01

    Previous research suggests that playing action video games improves performance on sensory, perceptual, and attentional tasks. For instance, Green, Pouget, and Bavelier (2010) used the diffusion model to decompose data from a motion detection task and estimate the contribution of several underlying psychological processes. Their analysis indicated that playing action video games leads to faster information processing, reduced response caution, and no difference in motor responding. Because perceptual learning is generally thought to be highly context-specific, this transfer from gaming is surprising and warrants corroborative evidence from a large-scale training study. We conducted 2 experiments in which participants practiced either an action video game or a cognitive game in 5 separate, supervised sessions. Prior to each session and following the last session, participants performed a perceptual discrimination task. In the second experiment, we included a third condition in which no video games were played at all. Behavioral data and diffusion model parameters showed similar practice effects for the action gamers, the cognitive gamers, and the nongamers and suggest that, in contrast to earlier reports, playing action video games does not improve the speed of information processing in simple perceptual tasks. PMID:24933517

  14. FPGA Flash Memory High Speed Data Acquisition

    NASA Technical Reports Server (NTRS)

    Gonzalez, April

    2013-01-01

    The purpose of this research is to design and implement a VHDL ONFI Controller module for a Modular Instrumentation System. The goal of the Modular Instrumentation System will be to have a low power device that will store data and send the data at a low speed to a processor. The benefit of such a system will give an advantage over other purchased binary IP due to the capability of allowing NASA to re-use and modify the memory controller module. To accomplish the performance criteria of a low power system, an in house auxiliary board (Flash/ADC board), FPGA development kit, debug board, and modular instrumentation board will be jointly used for the data acquisition. The Flash/ADC board contains four, 1 MSPS, input channel signals and an Open NAND Flash memory module with an analog to digital converter. The ADC, data bits, and control line signals from the board are sent to an Microsemi/Actel FPGA development kit for VHDL programming of the flash memory WRITE, READ, READ STATUS, ERASE, and RESET operation waveforms using Libero software. The debug board will be used for verification of the analog input signal and be able to communicate via serial interface with the module instrumentation. The scope of the new controller module was to find and develop an ONFI controller with the debug board layout designed and completed for manufacture. Successful flash memory operation waveform test routines were completed, simulated, and tested to work on the FPGA board. Through connection of the Flash/ADC board with the FPGA, it was found that the device specifications were not being meet with Vdd reaching half of its voltage. Further testing showed that it was the manufactured Flash/ADC board that contained a misalignment with the ONFI memory module traces. The errors proved to be too great to fix in the time limit set for the project.

  15. Assessing everyday memory in patients with perceptual deficits

    Microsoft Academic Search

    Janet Cockburn; Barbara A Wilson; Alan Baddeley; Robert Hiorns

    1990-01-01

    The multidimensional nature of the deficits presented by patients referred for neurological rehabilitation poses problems for therapists in selecting appropriate assessments. Although many patients will exhibit memory problems on admission, most will also show signs of other impairment, such as visuoperceptual deficit; but few tests exist that take into account the effect of such influences. The Rivermead Behavioural Memory Test,

  16. Repetition Priming in Speeded Word Reading: Contributions of Perceptual and Conceptual Processing Episodes

    Microsoft Academic Search

    Colin M MacLeod; Michael E. J. Masson

    2000-01-01

    Five experiments investigated repetition priming on an indirect speeded word reading (naming) test, a task intended to circumvent conscious recollection. Reading a word or generating it from a semantic cue (either a phrase or an antonym) produced reliable priming of similar magnitude on this indirect test of memory. Efforts to encourage conscious recollection elevated response latencies in speeded reading and

  17. Similarity-based distortion of visual short-term memory is due to perceptual averaging.

    PubMed

    Dubé, Chad; Zhou, Feng; Kahana, Michael J; Sekuler, Robert

    2014-03-01

    A task-irrelevant stimulus can distort recall from visual short-term memory (VSTM). Specifically, reproduction of a task-relevant memory item is biased in the direction of the irrelevant memory item (Huang & Sekuler, 2010a). The present study addresses the hypothesis that such effects reflect the influence of neural averaging under conditions of uncertainty about the contents of VSTM (Alvarez, 2011; Ball & Sekuler, 1980). We manipulated subjects' attention to relevant and irrelevant study items whose similarity relationships were held constant, while varying how similar the study items were to a subsequent recognition probe. On each trial, subjects were shown one or two Gabor patches, followed by the probe; their task was to indicate whether the probe matched one of the study items. A brief cue told subjects which Gabor, first or second, would serve as that trial's target item. Critically, this cue appeared either before, between, or after the study items. A distributional analysis of the resulting mnemometric functions showed an inflation in probability density in the region spanning the spatial frequency of the average of the two memory items. This effect, due to an elevation in false alarms to probes matching the perceptual average, was diminished when cues were presented before both study items. These results suggest that (a) perceptual averages are computed obligatorily and (b) perceptual averages are relied upon to a greater extent when item representations are weakened. Implications of these results for theories of VSTM are discussed. PMID:24395020

  18. Similarity-based distortion of visual short-term memory is due to perceptual averaging

    PubMed Central

    Dubé, Chad; Zhou, Feng; Kahana, Michael J.; Sekuler, Robert

    2014-01-01

    A task-irrelevant stimulus can distort recall from visual short-term memory (VSTM). Specifically, reproduction of a task-relevant memory item is biased in the direction of the irrelevant memory item (Huang and Sekuler, 2010a). The present study addresses the hypothesis that such effects reflect the influence of neural averaging under conditions of uncertainty about the contents of VSTM (Alvarez, 2011; Ball and Sekuler, 1980). We manipulated subjects’ attention to relevant and irrelevant study items whose similarity relationships were held constant, while varying how similar the study items were to a subsequent recognition probe. On each trial, subjects were shown one or two Gabor patches, followed by the probe; their task was to indicate whether the probe matched one of the study items. A brief cue told subjects which Gabor, first or second, would serve as that trial’s target item. Critically, this cue appeared either before, between, or after the study items. A distributional analysis of the resulting mnemometric functions showed an inflation in probability density in the region spanning the spatial frequency of the average of the two memory items. This effect, due to an elevation in false alarms to probes matching the perceptual average, was diminished when cues were presented before both study items. These results suggest that a) perceptual averages are computed obligatorily and b) perceptual averages are relied upon to a greater extent when item representations are weakened. Implications of these results for theories of VSTM are discussed. PMID:24395020

  19. Comparing the benefits of Caffeine, Naps and Placebo on Verbal, Motor and Perceptual Memory

    PubMed Central

    Mednick, Sara C.; Cai, Denise J.; Kanady, Jennifer; Drummond, Sean P.A.

    2008-01-01

    Caffeine, the world’s most common psychoactive substance, is used by approximately 90% of North Americans everyday. Little is known, however, about its benefits for memory. Napping has been shown to increase alertness and promote learning on some memory tasks. We directly compared caffeine (200mg) with napping (60–90 minutes) and placebo on three distinct memory processes: declarative verbal memory, procedural motor skills, and perceptual learning. In the verbal task, recall and recognition for unassociated words were tested after a 7hr retention period (with a between-session nap or drug intervention). A second, different, word list was administered post-intervention and memory was tested after a 20min retention period. The non-declarative tasks (finger tapping task and texture discrimination task) were trained before the intervention and then retested afterwards. Naps enhanced recall of words after a 7hr and 20min retention interval relative to both caffeine and placebo. Caffeine significantly impaired motor learning compared to placebo and naps. Napping produced robust perceptual learning compared with placebo; however, naps and caffeine were not significantly different. These findings provide evidence of the limited benefits of caffeine for memory improvement compared with napping. We hypothesize that impairment from caffeine may be restricted to tasks that contain explicit information; whereas strictly implicit learning is less compromised. PMID:18554731

  20. Tachyon: Reliable, Memory Speed Storage for Cluster Computing Frameworks

    E-print Network

    Zakhor, Avideh

    Tachyon: Reliable, Memory Speed Storage for Cluster Computing Frameworks Haoyuan Li Ali Ghodsi Tachyon is a distributed file system enabling reliable data sharing at memory speed across cluster, as replication is used for fault-tolerance. Tachyon eliminates this bottleneck by pushing lineage, a well

  1. Memory for symmetry and perceptual binding in patients with schizophrenia.

    PubMed

    Cestari, Vincenzo; Saraulli, Daniele; Spataro, Pietro; Lega, Alessandro; Sciarretta, Antonio; Marques, Valéria Rezende; Rossi-Arnaud, Clelia

    2013-11-01

    The present study investigated the use of perceptual binding processes in schizophrenic (SC) patients and matched healthy controls, by examining their performance on the recall of symmetrical (vertical, horizontal and diagonal) and asymmetrical patterns varying in length between 2 and 9 items. The results showed that, although SC patients were less accurate than controls in all conditions, both groups recalled symmetrical patterns better than asymmetrical ones. The impairment of SC patients was magnified with supra-span symmetrical arrays, and they were more likely to reproduce symmetrical patterns as asymmetrical, particularly at medium and high length levels. Hierarchical regression analyses further indicated that the between-group differences in the recall of supra-span vertical and horizontal arrays, which require a greater involvement of visual pattern processes, remained significant after removing the variance associated with performance on asymmetrical patterns, which primarily reflects intrafigural spatial processes. It is proposed that schizophrenia may be associated with a specific deficit in the formation and retrieval of the global visual images of studied patterns and in the use of the on-line information about the type of symmetry being tested to guide retrieval processes. PMID:24148968

  2. Age-related effects on perceptual and semantic encoding in memory.

    PubMed

    Kuo, M C C; Liu, K P Y; Ting, K H; Chan, C C H

    2014-03-01

    This study examined the age-related subsequent memory effect (SME) in perceptual and semantic encoding using event-related potentials (ERPs). Seventeen younger adults and 17 older adults studied a series of Chinese characters either perceptually (by inspecting orthographic components) or semantically (by determining whether the depicted object makes sounds). The two tasks had similar levels of difficulty. The participants made studied or unstudied judgments during the recognition phase. Younger adults performed better in both conditions, with significant SMEs detected in the time windows of P2, N3, P550, and late positive component (LPC). In the older group, SMEs were observed in the P2 and N3 latencies in both conditions but were only detected in the P550 in the semantic condition. Between-group analyses showed larger frontal and central SMEs in the younger sample in the LPC latency regardless of encoding type. Aging effect appears to be stronger on influencing perceptual than semantic encoding processes. The effects seem to be associated with a decline in updating and maintaining representations during perceptual encoding. The age-related decline in the encoding function may be due in part to changes in frontal lobe function. PMID:24374080

  3. Can reading-specific training stimuli improve the effect of perceptual learning on peripheral reading speed?

    PubMed Central

    Bernard, Jean-Baptiste; Arunkumar, Amit; Chung, Susana T.L.

    2012-01-01

    In a previous study, Chung, Legge & Cheung (2004) showed that training using repeated presentation of trigrams (sequences of three random letters) resulted in an increase in the size of the visual span (number of letters recognized in a glance) and reading speed in the normal periphery. In this study, we asked whether we could optimize the benefit of trigram training on reading speed by using trigrams more specific to the reading task (i.e. trigrams frequently used in the English language) and presenting them according to their frequencies of occurrence in normal English usage and observers’ performance. Averaged across seven observers, our training paradigm (four days of training) increased the size of the visual span by 6.44 bits, with an accompanied 63.6% increase in the maximum reading speed, compared with the values before training. However, these benefits were not statistically different from those of Chung et al (2004) using a random-trigram training paradigm. Our findings confirm the possibility of increasing the size of the visual span and reading speed in the normal periphery with perceptual learning, and suggest that the benefits of training on letter recognition and maximum reading speed may not be linked to the types of letter strings presented during training. PMID:22750053

  4. Towards high-speed optical quantum memories

    E-print Network

    K. F. Reim; J. Nunn; V. O. Lorenz; B. J. Sussman; K. C. Lee; N. K. Langford; D. Jaksch; I. A. Walmsley

    2009-12-15

    Quantum memories, capable of controllably storing and releasing a photon, are a crucial component for quantum computers and quantum communications. So far, quantum memories have operated with bandwidths that limit data rates to MHz. Here we report the coherent storage and retrieval of sub-nanosecond low intensity light pulses with spectral bandwidths exceeding 1 GHz in cesium vapor. The novel memory interaction takes place via a far off-resonant two-photon transition in which the memory bandwidth is dynamically generated by a strong control field. This allows for an increase in data rates by a factor of almost 1000 compared to existing quantum memories. The memory works with a total efficiency of 15% and its coherence is demonstrated by directly interfering the stored and retrieved pulses. Coherence times in hot atomic vapors are on the order of microsecond - the expected storage time limit for this memory.

  5. Well-Being Affects Changes in Perceptual Speed in Advanced Old Age: Longitudinal Evidence for a Dynamic Link

    ERIC Educational Resources Information Center

    Gerstorf, Denis; Lovden, Martin; Rocke, Christina; Smith, Jacqui; Lindenberger, Ulman

    2007-01-01

    This study examined competing hypotheses about dynamic cross-domain associations between perceptual speed and well-being in advanced old age. We applied the bivariate dual change score model (J. J. McArdle & F. Hamagami, 2001) to 13-year incomplete longitudinal data from the Berlin Aging Study (P. B. Baltes & K. U. Mayer, 1999; N = 516, 70-103…

  6. The Perceptual Root of Object-Based Storage: An Interactive Model of Perception and Visual Working Memory

    ERIC Educational Resources Information Center

    Gao, Tao; Gao, Zaifeng; Li, Jie; Sun, Zhongqiang; Shen, Mowei

    2011-01-01

    Mainstream theories of visual perception assume that visual working memory (VWM) is critical for integrating online perceptual information and constructing coherent visual experiences in changing environments. Given the dynamic interaction between online perception and VWM, we propose that how visual information is processed during visual…

  7. High-speed quantum memory with thermal motion of atoms

    E-print Network

    K. Tikhonov; T. Golubeva; Yu. Golubev

    2015-02-26

    We discuss the influence of atomic thermal motion on the efficiency of multimode quantum memory in two configurations: over the free expand of atoms cooled beforehand in a magneto-optical trap, and over complete mixing of atoms in a closed cell at room temperature. We consider the high-speed quantum memory, and assume that writing and retrieval are short enough, and the displacements of atoms during these stages are negligibly small. At the same time we take in account thermal motion during the storage time, which, as well known, must be much longer than durations of all the other memory processes for successful application of memory cell in communication and computation. We will analyze this influence in terms of eigenmodes of the full memory cycle and show that distortion of the eigenmodes, caused by thermal motion, leads to the efficiency reduction. We will demonstrate, that in the multimode memory this interconnection has complicated character.

  8. Language and short-term memory: the role of perceptual-motor affordance.

    PubMed

    Macken, Bill; Taylor, John C; Jones, Dylan M

    2014-09-01

    The advantage for real words over nonwords in serial recall--the lexicality effect--is typically attributed to support for item-level phonology, either via redintegration, whereby partially degraded short-term traces are "cleaned up" via support from long-term representations of the phonological material or via the more robust temporary activation of long-term lexical phonological knowledge that derives from its combination with established lexical and semantic levels of representation. The much smaller effect of lexicality in serial recognition, where the items are re-presented in the recognition cue, is attributed either to the minimal role for redintegration from long-term memory or to the minimal role for item memory itself in such retrieval conditions. We show that the reduced lexicality effect in serial recognition is not a function of the retrieval conditions, but rather because previous demonstrations have used auditory presentation, and we demonstrate a robust lexicality effect for visual serial recognition in a setting where auditory presentation produces no such effect. Furthermore, this effect is abolished under conditions of articulatory suppression. We argue that linguistic knowledge affects the readiness with which verbal material is segmentally recoded via speech motor processes that support rehearsal and therefore affects tasks that involve recoding. On the other hand, auditory perceptual organization affords sequence matching in the absence of such a requirement for segmental recoding and therefore does not show such effects of linguistic knowledge. PMID:24797440

  9. Language and Short-Term Memory: The Role of Perceptual-Motor Affordance

    PubMed Central

    2014-01-01

    The advantage for real words over nonwords in serial recall—the lexicality effect—is typically attributed to support for item-level phonology, either via redintegration, whereby partially degraded short-term traces are “cleaned up” via support from long-term representations of the phonological material or via the more robust temporary activation of long-term lexical phonological knowledge that derives from its combination with established lexical and semantic levels of representation. The much smaller effect of lexicality in serial recognition, where the items are re-presented in the recognition cue, is attributed either to the minimal role for redintegration from long-term memory or to the minimal role for item memory itself in such retrieval conditions. We show that the reduced lexicality effect in serial recognition is not a function of the retrieval conditions, but rather because previous demonstrations have used auditory presentation, and we demonstrate a robust lexicality effect for visual serial recognition in a setting where auditory presentation produces no such effect. Furthermore, this effect is abolished under conditions of articulatory suppression. We argue that linguistic knowledge affects the readiness with which verbal material is segmentally recoded via speech motor processes that support rehearsal and therefore affects tasks that involve recoding. On the other hand, auditory perceptual organization affords sequence matching in the absence of such a requirement for segmental recoding and therefore does not show such effects of linguistic knowledge. PMID:24797440

  10. High speed magneto-resistive random access memory

    NASA Technical Reports Server (NTRS)

    Wu, Jiin-Chuan (inventor); Stadler, Henry L. (inventor); Katti, Romney R. (inventor)

    1992-01-01

    A high speed read MRAM memory element is configured from a sandwich of magnetizable, ferromagnetic film surrounding a magneto-resistive film which may be ferromagnetic or not. One outer ferromagnetic film has a higher coercive force than the other and therefore remains magnetized in one sense while the other may be switched in sense by a switching magnetic field. The magneto-resistive film is therefore sensitive to the amplitude of the resultant field between the outer ferromagnetic films and may be constructed of a high resistivity, high magneto-resistive material capable of higher sensing currents. This permits higher read voltages and therefore faster read operations. Alternate embodiments with perpendicular anisotropy, and in-plane anisotropy are shown, including an embodiment which uses high permeability guides to direct the closing flux path through the magneto-resistive material. High density, high speed, radiation hard, memory matrices may be constructed from these memory elements.

  11. Integrated, nonvolatile, high-speed analog random access memory

    NASA Technical Reports Server (NTRS)

    Katti, Romney R. (inventor); Wu, Jiin-Chuan (inventor); Stadler, Henry L. (inventor)

    1994-01-01

    This invention provides an integrated, non-volatile, high-speed random access memory. A magnetically switchable ferromagnetic or ferrimagnetic layer is sandwiched between an electrical conductor which provides the ability to magnetize the magnetically switchable layer and a magneto resistive or Hall effect material which allows sensing the magnetic field which emanates from the magnetization of the magnetically switchable layer. By using this integrated three-layer form, the writing process, which is controlled by the conductor, is separated from the storage medium in the magnetic layer and from the readback process which is controlled by the magnetoresistive layer. A circuit for implementing the memory in CMOS or the like is disclosed.

  12. Topographic amnesia: spatial memory disorder, perceptual dysfunction, or category specific semantic memory impairment?

    PubMed Central

    McCarthy, R A; Evans, J J; Hodges, J R

    1996-01-01

    A 60 year old patient, SE, who presented with a severe difficulty in finding his way around previously familiar environments and a mild prosopagnosia is described. SE had herpes simplex encephalitis resulting in selective right temporal lobe damage. He showed normal spatial learning, but was severely imparied in his ability to recognise pictures of buildings and landmarks. The disorder was not confined to the visual modality, but rather involved a loss of knowledge about famous buildings and landmarks when tested from their spoken name. SE was contrasted with a more severely prosopagnosic patient, PHD, who showed normal ability to recognise buildings and landmarks, indicating that recognition of people dissociates from recognition of buildings/landmarks. It is concluded that SE's failure of place knowledge represents a category specific supramodal semantic memory impairment. Images PMID:8609511

  13. Sparse distributed memory: understanding the speed and robustness of expert memory

    PubMed Central

    Brogliato, Marcelo S.; Chada, Daniel M.; Linhares, Alexandre

    2014-01-01

    How can experts, sometimes in exacting detail, almost immediately and very precisely recall memory items from a vast repertoire? The problem in which we will be interested concerns models of theoretical neuroscience that could explain the speed and robustness of an expert's recollection. The approach is based on Sparse Distributed Memory, which has been shown to be plausible, both in a neuroscientific and in a psychological manner, in a number of ways. A crucial characteristic concerns the limits of human recollection, the “tip-of-tongue” memory event—which is found at a non-linearity in the model. We expand the theoretical framework, deriving an optimization formula to solve this non-linearity. Numerical results demonstrate how the higher frequency of rehearsal, through work or study, immediately increases the robustness and speed associated with expert memory. PMID:24808842

  14. Granger causality analysis reveals distinct spatio-temporal connectivity patterns in motor and perceptual visuo-spatial working memory

    PubMed Central

    Protopapa, Foteini; Siettos, Constantinos I.; Evdokimidis, Ioannis; Smyrnis, Nikolaos

    2014-01-01

    We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no) change detection task with memory and non-memory conditions. On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes. Movement-memory trial types exhibited higher degree nodes during the first 2 s of the delay period, mainly at central, left frontal and right-parietal areas. Change detection-memory trial types resulted in a three-peak temporal pattern of the total degree with higher degree nodes emerging mainly at central, right frontal, and occipital areas. Functional connectivity networks resulting from non-memory trial types were characterized by more sparse structures for both tasks. The movement-memory trial types encompassed an apparent coarse flow from frontal to parietal areas while the opposite flow from occipital, parietal to central and frontal areas was evident for the change detection-memory trial types. The differences among tasks and conditions were more profound in ? (8–12 Hz) and ? (12–30 Hz) and less in ? (30–45 Hz) band. Our results favor the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations. PMID:25431557

  15. High-speed behavior of some shape memory alloys

    NASA Astrophysics Data System (ADS)

    Anatoly, Bragov; Andrey, Lomunov

    2005-07-01

    In the message the results of dynamic tests of materials with shape memory effect are submitted. The high-speed tests at tension and compression of alloys TiNi and CuTiAl were executed by using the Kolsky technique with the split Hopkinson pressure bar. As a result the dynamic deformation diagrams were obtained. On some of them the phase transitions from austenite into martensite and back are observed obviously. Within the framework of the Kolsky method its updating is offered allowing at return transition, caused by a plastic deformation, at the expense of sample heating to study kinetics of phase transition: i.e. to estimate time of transition, its energy. The complex character of high-speed deformation of the investigated materials is marked.

  16. Speed Matters: Relationship between Speed of Eye Movements and Modification of Aversive Autobiographical Memories

    PubMed Central

    van Veen, Suzanne Chantal; van Schie, Kevin; Wijngaards-de Meij, Leoniek D. N. V.; Littel, Marianne; Engelhard, Iris M.; van den Hout, Marcel A.

    2015-01-01

    Eye movement desensitization and reprocessing (EMDR) is an efficacious treatment for post-traumatic stress disorder. In EMDR, patients recall a distressing memory and simultaneously make eye movements (EM). Both tasks are considered to require limited working memory (WM) resources. Because this leaves fewer resources available for memory retrieval, the memory should become less vivid and less emotional during future recall. In EMDR analogue studies, a standardized procedure has been used, in which participants receive the same dual task manipulation of 1 EM cycle per second (1?Hz). From a WM perspective, the WM taxation of the dual task might be titrated to the WM taxation of the memory image. We hypothesized that highly vivid images are more affected by high WM taxation and less vivid images are more affected by low WM taxation. In study 1, 34 participants performed a reaction time task, and rated image vividness, and difficulty of retrieving an image, during five speeds of EM and no EM. Both a high WM taxing frequency (fast EM; 1.2?Hz) and a low WM taxing frequency (slow EM; 0.8?Hz) were selected. In study 2, 72 participants recalled three highly vivid aversive autobiographical memory images (n =?36) or three less vivid images (n =?36) under each of three conditions: recall?+?fast EM, recall?+?slow EM, or recall only. Multi-level modeling revealed a consistent pattern for all outcome measures: recall?+?fast EM led to less emotional, less vivid and more difficult to retrieve images than recall?+?slow EM and recall only, and the effects of recall?+?slow EM felt consistently in between the effects of recall?+?fast EM and recall only, but only differed significantly from recall?+?fast EM. Crucially, image vividness did not interact with condition on the decrease of emotionality over time, which was inconsistent with the prediction. Implications for understanding the mechanisms of action in memory modification and directions for future research are discussed.

  17. Your brain on speed: cognitive performance of a spatial working memory task is not affected by walking speed.

    PubMed

    Kline, Julia E; Poggensee, Katherine; Ferris, Daniel P

    2014-01-01

    When humans walk in everyday life, they typically perform a range of cognitive tasks while they are on the move. Past studies examining performance changes in dual cognitive-motor tasks during walking have produced a variety of results. These discrepancies may be related to the type of cognitive task chosen, differences in the walking speeds studied, or lack of controlling for walking speed. The goal of this study was to determine how young, healthy subjects performed a spatial working memory task over a range of walking speeds. We used high-density electroencephalography to determine if electrocortical activity mirrored changes in cognitive performance across speeds. Subjects stood (0.0 m/s) and walked (0.4, 0.8, 1.2, and 1.6 m/s) with and without performing a Brooks spatial working memory task. We hypothesized that performance of the spatial working memory task and the associated electrocortical activity would decrease significantly with walking speed. Across speeds, the spatial working memory task caused subjects to step more widely compared with walking without the task. This is typically a sign that humans are adapting their gait dynamics to increase gait stability. Several cortical areas exhibited power fluctuations time-locked to memory encoding during the cognitive task. In the somatosensory association cortex, alpha power increased prior to stimulus presentation and decreased during memory encoding. There were small significant reductions in theta power in the right superior parietal lobule and the posterior cingulate cortex around memory encoding. However, the subjects did not show a significant change in cognitive task performance or electrocortical activity with walking speed. These findings indicate that in young, healthy subjects walking speed does not affect performance of a spatial working memory task. These subjects can devote adequate cortical resources to spatial cognition when needed, regardless of walking speed. PMID:24847239

  18. Effects of Animation's Speed of Presentation on Perceptual Processing and Learning

    ERIC Educational Resources Information Center

    Meyer, Katja; Rasch, Thorsten; Schnotz, Wolfgang

    2010-01-01

    Animations presented at different speed are assumed to differentially interact with learners' perception and cognition due to the constraints imposed by learners' limited sensitivity to incoming dynamic information. To investigate the effects of high and low presentation speed of animation, two studies were conducted. In Study 1, participants were…

  19. Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memory

    Microsoft Academic Search

    Sara C. Mednick; Denise J. Cai; Jennifer Kanady; Sean P. A. Drummond

    2008-01-01

    Caffeine, the world's most common psychoactive substance, is used by approximately 90% of North Americans everyday. Little is known, however, about its benefits for memory. Napping has been shown to increase alertness and promote learning on some memory tasks. We directly compared caffeine (200mg) with napping (60–90min) and placebo on three distinct memory processes: declarative verbal memory, procedural motor skills,

  20. Cortico-striatal connections predict control over speed and accuracy in perceptual decision making

    Microsoft Academic Search

    B. U. Forstmann; A. Anwander; A. Schafer; J. Neumann; S. Brown; E.-J. Wagenmakers; R. Bogacz; R. Turner

    2010-01-01

    When people make decisions they often face opposing demands for response speed and response accuracy, a process likely mediated by response thresholds. According to the striatal hypothesis, people decrease response thresholds by increasing activation from cortex to striatum, releasing the brain from inhibition. According to the STN hypothesis, people decrease response thresholds by decreasing activation from cortex to subthalamic nucleus

  1. Monetary incentives in speeded perceptual decision: effects of penalizing errors versus slow responses.

    PubMed

    Dambacher, Michael; Hübner, Ronald; Schlösser, Jan

    2011-01-01

    The influence of monetary incentives on performance has been widely investigated among various disciplines. While the results reveal positive incentive effects only under specific conditions, the exact nature, and the contribution of mediating factors are largely unexplored. The present study examined influences of payoff schemes as one of these factors. In particular, we manipulated penalties for errors and slow responses in a speeded categorization task. The data show improved performance for monetary over symbolic incentives when (a) penalties are higher for slow responses than for errors, and (b) neither slow responses nor errors are punished. Conversely, payoff schemes with stronger punishment for errors than for slow responses resulted in worse performance under monetary incentives. The findings suggest that an emphasis of speed is favorable for positive influences of monetary incentives, whereas an emphasis of accuracy under time pressure has the opposite effect. PMID:21980316

  2. Monetary Incentives in Speeded Perceptual Decision: Effects of Penalizing Errors Versus Slow Responses

    PubMed Central

    Dambacher, Michael; Hübner, Ronald; Schlösser, Jan

    2011-01-01

    The influence of monetary incentives on performance has been widely investigated among various disciplines. While the results reveal positive incentive effects only under specific conditions, the exact nature, and the contribution of mediating factors are largely unexplored. The present study examined influences of payoff schemes as one of these factors. In particular, we manipulated penalties for errors and slow responses in a speeded categorization task. The data show improved performance for monetary over symbolic incentives when (a) penalties are higher for slow responses than for errors, and (b) neither slow responses nor errors are punished. Conversely, payoff schemes with stronger punishment for errors than for slow responses resulted in worse performance under monetary incentives. The findings suggest that an emphasis of speed is favorable for positive influences of monetary incentives, whereas an emphasis of accuracy under time pressure has the opposite effect. PMID:21980316

  3. Perceptual Filtering in L2 Lexical Memory: A Neural Network Approach to Second Language Acquisition

    ERIC Educational Resources Information Center

    Nelson, Robert

    2012-01-01

    A number of asymmetries in lexical memory emerge when monolinguals and early bilinguals are compared to (relatively) late second language (L2) learners. Their study promises to provide insight into the internal processes that both support and ultimately limit L2 learner achievement. Generally, theory building in L2 and bilingual lexical memory has…

  4. A multipage cell architecture for high-speed programming multilevel NAND flash memories

    Microsoft Academic Search

    Ken Takeuchi; Tomoharu Tanaka; Toru Tanzawa

    1998-01-01

    To realize low-cost, highly reliable, high-speed programming, and high-density multilevel flash memories, a multipage cell architecture has been proposed. This architecture enables both precise control of the Vth of a memory cell and fast programming without any area penalty. In the case of a four-level cell, a high programming speed of 236 ?s\\/512 bytes or 2.2 Mbytes\\/s can be obtained,

  5. Enabling Universal Memory by Overcoming the Contradictory Speed and Stability Nature of Phase-Change Materials

    PubMed Central

    Wang, Weijie; Loke, Desmond; Shi, Luping; Zhao, Rong; Yang, Hongxin; Law, Leong-Tat; Ng, Lung-Tat; Lim, Kian-Guan; Yeo, Yee-Chia; Chong, Tow-Chong; Lacaita, Andrea L.

    2012-01-01

    The quest for universal memory is driving the rapid development of memories with superior all-round capabilities in non-volatility, high speed, high endurance and low power. Phase-change materials are highly promising in this respect. However, their contradictory speed and stability properties present a key challenge towards this ambition. We reveal that as the device size decreases, the phase-change mechanism changes from the material inherent crystallization mechanism (either nucleation- or growth-dominated), to the hetero-crystallization mechanism, which resulted in a significant increase in PCRAM speeds. Reducing the grain size can further increase the speed of phase-change. Such grain size effect on speed becomes increasingly significant at smaller device sizes. Together with the nano-thermal and electrical effects, fast phase-change, good stability and high endurance can be achieved. These findings lead to a feasible solution to achieve a universal memory. PMID:22496956

  6. Neural Correlates of the Difference between Working Memory Speed and Simple Sensorimotor Speed: An fMRI Study

    PubMed Central

    Takeuchi, Hikaru; Sugiura, Motoaki; Sassa, Yuko; Sekiguchi, Atsushi; Yomogida, Yukihito; Taki, Yasuyuki; Kawashima, Ryuta

    2012-01-01

    The difference between the speed of simple cognitive processes and the speed of complex cognitive processes has various psychological correlates. However, the neural correlates of this difference have not yet been investigated. In this study, we focused on working memory (WM) for typical complex cognitive processes. Functional magnetic resonance imaging data were acquired during the performance of an N-back task, which is a measure of WM for typical complex cognitive processes. In our N-back task, task speed and memory load were varied to identify the neural correlates responsible for the difference between the speed of simple cognitive processes (estimated from the 0-back task) and the speed of WM. Our findings showed that this difference was characterized by the increased activation in the right dorsolateral prefrontal cortex (DLPFC) and the increased functional interaction between the right DLPFC and right superior parietal lobe. Furthermore, the local gray matter volume of the right DLPFC was correlated with participants' accuracy during fast WM tasks, which in turn correlated with a psychometric measure of participants' intelligence. Our findings indicate that the right DLPFC and its related network are responsible for the execution of the fast cognitive processes involved in WM. Identified neural bases may underlie the psychometric differences between the speed with which subjects perform simple cognitive tasks and the speed with which subjects perform more complex cognitive tasks, and explain the previous traditional psychological findings. PMID:22291992

  7. Working Memory Is Related to Perceptual Processing: A Case from Color Perception

    ERIC Educational Resources Information Center

    Allen, Elizabeth C.; Beilock, Sian L.; Shevell, Steven K.

    2011-01-01

    We explored the relation between individual differences in working memory (WM) and color constancy, the phenomenon of color perception that allows us to perceive the color of an object as relatively stable under changes in illumination. Successive color constancy (measured by first viewing a colored surface under a particular illumination and…

  8. Impaired perceptual memory of locations across gaze-shifts in patients with unilateral spatial neglect

    Microsoft Academic Search

    Patrik Vuilleumier; Claire Sergent; Sophie Schwartz; Nathalie Valenza; Michele Girardi; Masud Husain; Jon Driver

    2007-01-01

    Right hemisphere lesions often lead to severe disorders in spatial awareness and behavior, such as left hemispatial neglect. Neglect involves not only pathological biases in attention and exploration but also deficits in internal representations of space and spatial working memory. Here we designed a new paradigm to test whether one potential component may involve a failure to maintain an updated

  9. Executive and perceptual attention play different roles in visual working memory: evidence from suffix and strategy effects.

    PubMed

    Hu, Yanmei; Hitch, Graham J; Baddeley, Alan D; Zhang, Ming; Allen, Richard J

    2014-08-01

    Four experiments studied the interfering effects of a to-be-ignored "stimulus suffix" on cued recall of feature bindings for a series of objects. When each object was given equal weight (Experiment 1) or rewards favored recent items (Experiments 2 and 4), a recency effect emerged that was selectively reduced by a suffix. The reduction was greater for a "plausible" suffix with features drawn from the same set as the memory items, in which case a feature of the suffix was frequently recalled as an intrusion error. Changing payoffs to reward recall of early items led to a primacy effect alongside recency (Experiments 3 and 4). Primacy, like recency, was reduced by a suffix and the reduction was greater for a suffix with plausible features, such features often being recalled as intrusion errors. Experiment 4 revealed a tradeoff such that increased primacy came at the cost of a reduction in recency. These observations show that priority instructions and recency combine to determine a limited number of items that are the most accessible for immediate recall and yet at the same time the most vulnerable to interference. We interpret this outcome in terms of a labile, limited capacity "privileged state" controlled by both central executive processes and perceptual attention. We suggest further that this privileged state can be usefully interpreted as the focus of attention in the episodic buffer. PMID:24933616

  10. Working memory influences processing speed and reading fluency in ADHD

    Microsoft Academic Search

    Lisa A. Jacobson; Matthew Ryan; Rebecca B. Martin; Joshua Ewen; Stewart H. Mostofsky; Martha B. Denckla; E. Mark Mahone

    2011-01-01

    Processing-speed deficits affect reading efficiency, even among individuals who recognize and decode words accurately. Children with ADHD who decode words accurately can still have inefficient reading fluency, leading to a bottleneck in other cognitive processes. This “slowing” in ADHD is associated with deficits in fundamental components of executive function underlying processing speed, including response selection. The purpose of the present

  11. Perceptual Constraints in Phonotactic Learning

    ERIC Educational Resources Information Center

    Endress, Ansgar D.; Mehler, Jacques

    2010-01-01

    Structural regularities in language have often been attributed to symbolic or statistical general purpose computations, whereas perceptual factors influencing such generalizations have received less interest. Here, we use phonotactic-like constraints as a case study to ask whether the structural properties of specific perceptual and memory

  12. High speed and high density static induction transistor memory

    Microsoft Academic Search

    J. Nishizawa; T. Tamamushi; Y. Mochida; T. Nonaka

    1978-01-01

    Describes a high speed and high density dynamic RAM utilizing a static induction transistor (SIT) structure. The main conduction mechanism of an SIT is carrier injection control due to the potential hump at the intrinsic gate, where the potential hump is capacitively controlled by the gate and the drain voltage in a basic operation. The SIT forms a dynamic RAM

  13. Influence of occupational styrene exposure on memory and attention

    SciTech Connect

    Schoenhuber, R.; Gentilini, M. (Universita degli Studi, Modena (Italy))

    1989-11-01

    Short-term memory, perceptual speed, attention and psychomotor function were studied in 55 workers professionally exposed to styrene. The subjects were grouped according to their urinary styrene metabolites. Those with higher styrene exposure showed a significant impairment of short-term memory only.

  14. Executive Functioning in Schizophrenia: The Contributions of Attention, Working Memory, Processing Speed, and General Intelligence

    Microsoft Academic Search

    Cale D. Palmer; Elaine Heiby; Velma Kameoka

    2008-01-01

    The purpose of this study was to assess the degree to which executive functioning performance may be associated with indices of attention, working memory, processing speed, and general in- telligence in 45 individuals with schizophrenia from a multicultural sample. It was hypothesized that relatively higher performances on measures of these cognitive processes would be positively associated with higher executive functioning

  15. Tachyon: Reliable File Sharing at Memory-Speed Across Cluster Frameworks

    E-print Network

    California at Irvine, University of

    Tachyon: Reliable File Sharing at Memory- Speed Across Cluster Frameworks Haoyuan Li UC Berkeley is even slower. #12;Tachyon Project Outline| Motivation | Design | Results| Status| Future · Reliable file| Motivation | Design | Results | Status| Future More than 75x speedup Tachyon outperforms Spark cache because

  16. Multilevel dual-channel NAND flash memories with high-speed read and verifying program

    Microsoft Academic Search

    Jae-Ho Kim; Joung-Woo Lee; Kyung-Sik; Tae Whan Kim

    2006-01-01

    The multilevel dual channel (MLDC) NAND flash memory cell structures with asymmetrically-doped channel regions are proposed. The channel structures with a MLDC flash cell consisted of the two different doping channel regions. The technical computer aided design simulation results showed that the designed MLDC NAND flash cell provided the high-speed multilevel reading and program verifying due to the sensing of

  17. Cognitive Risk Factors for Specific Learning Disorder: Processing Speed, Temporal Processing, and Working Memory.

    PubMed

    Moll, Kristina; Göbel, Silke M; Gooch, Debbie; Landerl, Karin; Snowling, Margaret J

    2014-08-14

    High comorbidity rates between reading disorder (RD) and mathematics disorder (MD) indicate that, although the cognitive core deficits underlying these disorders are distinct, additional domain-general risk factors might be shared between the disorders. Three domain-general cognitive abilities were investigated in children with RD and MD: processing speed, temporal processing, and working memory. Since attention problems frequently co-occur with learning disorders, the study examined whether these three factors, which are known to be associated with attention problems, account for the comorbidity between these disorders. The sample comprised 99 primary school children in four groups: children with RD, children with MD, children with both disorders (RD+MD), and typically developing children (TD controls). Measures of processing speed, temporal processing, and memory were analyzed in a series of ANCOVAs including attention ratings as covariate. All three risk factors were associated with poor attention. After controlling for attention, associations with RD and MD differed: Although deficits in verbal memory were associated with both RD and MD, reduced processing speed was related to RD, but not MD; and the association with RD was restricted to processing speed for familiar nameable symbols. In contrast, impairments in temporal processing and visuospatial memory were associated with MD, but not RD. PMID:25124507

  18. A Perceptual Repetition Blindness Effect

    NASA Technical Reports Server (NTRS)

    Hochhaus, Larry; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    Before concluding Repetition Blindness is a perceptual phenomenon, alternative explanations based on memory retrieval problems and report bias must be rejected. Memory problems were minimized by requiring a judgment about only a single briefly displayed field. Bias and sensitivity effects were empirically measured with an ROC-curve analysis method based on confidence ratings. Results from five experiments support the hypothesis that Repetition Blindness can be a perceptual phenomenon.

  19. High-Speed Behavior of Some Shape Memory Alloys

    SciTech Connect

    Bragov, Anatoly M.; Lomunov, Andrey K.; Sergeichev, Ivan V. [Research Institute of Mechanics, Nizhny Novgorod State University, GSP-1000 (Russian Federation)

    2006-07-28

    The results of dynamic tests of shape memory alloys Ti-Ni and Cu-Al-Ni are given. Compressive tests of Ti-Ni alloy were carried out at temperatures 293-573K. Considerable influence of temperature on module of elasticity prior to the dislocation plastic flow and dislocation yield limit has been mentioned in temperature interval of reverse martensitic transformation. For Cu-Al-Ni alloy a strain rate influence on phase yield limit, module of elasticity prior to the phase unelastic flow, module of elasticity prior to the dislocation plastic flow was negligible. The method of determination of duration of reverse martensitic transformation has been realized by the example of Cu-Al-Ni alloy.

  20. Enhancement of Speed Margins for 16× Digital Versatile Disc-Random Access Memory

    NASA Astrophysics Data System (ADS)

    Watanabe, Koichi; Minemura, Hiroyuki; Miyamoto, Makoto; Iimura, Makoto

    2006-02-01

    We have evaluated the speed margins of write/read 16× digital versatile disc-random access memory (DVD-RAM) test discs using write strategies for 6--16× constant angular velocity (CAV) control. Our approach is to determine the writing parameters for the middle zones by interpolating the zone numbers. Using this interpolation strategy, we successfully obtained overwrite jitter values of less than 8% and bit error rates of less than 10-5 in 6--16× DVD-RAM. Moreover, we confirmed that the speed margins were ± 20% for a 6--16× CAV.

  1. Perceptual Repetition Blindness Effects

    NASA Technical Reports Server (NTRS)

    Hochhaus, Larry; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    The phenomenon of repetition blindness (RB) may reveal a new limitation on human perceptual processing. Recently, however, researchers have attributed RB to post-perceptual processes such as memory retrieval and/or reporting biases. The standard rapid serial visual presentation (RSVP) paradigm used in most RB studies is, indeed, open to such objections. Here we investigate RB using a "single-frame" paradigm introduced by Johnston and Hale (1984) in which memory demands are minimal. Subjects made only a single judgement about whether one masked target word was the same or different than a post-target probe. Confidence ratings permitted use of signal detection methods to assess sensitivity and bias effects. In the critical condition for RB a precue of the post-target word was provided prior to the target stimulus (identity precue), so that the required judgement amounted to whether the target did or did not repeat the precue word. In control treatments, the precue was either an unrelated word or a dummy (XXXX). Results of five experiments show that perceptual sensitivity is strikingly and significantly reduced in the RB condition relative to both baseline control conditions. The data show RB can be obtained under conditions in which memory problems are minimal and where perceptual sensitivity is assessed independently of biases.

  2. A 9-kbit associative memory for high-speed parallel processing applications

    NASA Astrophysics Data System (ADS)

    Jones, Simon R.; Jalowiecki, Ian P.; Hedge, Stephen J.; Lea, R. M.

    1988-04-01

    The authors discuss the design, development, and implementation of the 9-kb (256-word x 37-bit) associative memory used in the single-chip array processing element (SCAPE) chip, a CMOS VLSI associative parallel processor (APP) that integrates 256 associative processing elements (APEs) on a single 68-pad chip to achieve high-speed, cost-effective image and signal processing. It is shown that a static CMOS content-addressable memory (CAM) design is unsuited to the constraints of the SCAPE chip architecture and that a purely nMOS CAM cell provides the best compromise between the conflicting area, speed, power, and control requirements. Comprehensive details of this design are given together with an evaluation of its performance. Finally, a description of the design methodology used in the construction of the SCAPE chip is presented with a breakdown of circuit areas and operational data.

  3. Programming future architectures : dusty decks, memory walls, and the speed of light.

    SciTech Connect

    Rodrigues, Arun F.

    2005-08-01

    Due to advances in CMOS fabrication technology, high performance computing capabilities have continually grown. More capable hardware has allowed a range of complex scientific applications to be developed. However, these applications present a bottleneck to future performance. Entrenched 'legacy' codes - 'Dusty Decks' - demand that new hardware must remain compatible with existing software. Additionally, conventional architectures faces increasing challenges. Many of these challenges revolve around the growing disparity between processor and memory speed - the 'Memory Wall' - and difficulties scaling to large numbers of parallel processors. To a large extent, these limitations are inherent to the traditional computer architecture. As data is consumed more quickly, moving that data to the point of computation becomes more difficult. Barring any upward revision in the speed of light, this will continue to be a fundamental limitation on the speed of computation. This work focuses on these solving these problems in the context of Light Weight Processing (LWP). LWP is an innovative technique which combines Processing-In-Memory, short vector computation, multithreading, and extended memory semantics. It applies these techniques to try and answer the questions 'What will a next-generation supercomputer look like?' and 'How will we program it?' To that end, this work presents four contributions: (1) An implementation of MPI which uses features of LWP to substantially improve message processing throughput; (2) A technique leveraging extended memory semantics to improve message passing by overlapping computation and communication; (3) An OpenMP library modified to allow efficient partitioning of threads between a conventional CPU and LWPs - greatly improving cost/performance; and (4) An algorithm to extract very small 'threadlets' which can overcome the inherent disadvantages of a simple processor pipeline.

  4. Room-temperature high-speed nuclear-spin quantum memory in diamond

    E-print Network

    J. H. Shim; I. Niemeyer; J. Zhang; D. Suter

    2013-01-03

    Quantum memories provide intermediate storage of quantum information until it is needed for the next step of a quantum algorithm or a quantum communication process. Relevant figures of merit are therefore the fidelity with which the information can be written and retrieved, the storage time, and also the speed of the read-write process. Here, we present experimental data on a quantum memory consisting of a single $^{13}$C nuclear spin that is strongly coupled to the electron spin of a nitrogen-vacancy (NV) center in diamond. The strong hyperfine interaction of the nearest-neighbor carbon results in transfer times of 300 ns between the register qubit and the memory qubit, with an overall fidelity of 88 % for the write - storage - read cycle. The observed storage times of 3.3 ms appear to be limited by the T$_1$ relaxation of the electron spin. We discuss a possible scheme that may extend the storage time beyond this limit.

  5. Dissociable mechanisms of speed-accuracy tradeoff during visual perceptual learning are revealed by a hierarchical drift-diffusion model

    PubMed Central

    Zhang, Jiaxiang; Rowe, James B.

    2014-01-01

    Two phenomena are commonly observed in decision-making. First, there is a speed-accuracy tradeoff (SAT) such that decisions are slower and more accurate when instructions emphasize accuracy over speed, and vice versa. Second, decision performance improves with practice, as a task is learnt. The SAT and learning effects have been explained under a well-established evidence-accumulation framework for decision-making, which suggests that evidence supporting each choice is accumulated over time, and a decision is committed to when the accumulated evidence reaches a decision boundary. This framework suggests that changing the decision boundary creates the tradeoff between decision speed and accuracy, while increasing the rate of accumulation leads to more accurate and faster decisions after learning. However, recent studies challenged the view that SAT and learning are associated with changes in distinct, single decision parameters. Further, the influence of speed-accuracy instructions over the course of learning remains largely unknown. Here, we used a hierarchical drift-diffusion model to examine the SAT during learning of a coherent motion discrimination task across multiple training sessions, and a transfer test session. The influence of speed-accuracy instructions was robust over training and generalized across untrained stimulus features. Emphasizing decision accuracy rather than speed was associated with increased boundary separation, drift rate and non-decision time at the beginning of training. However, after training, an emphasis on decision accuracy was only associated with increased boundary separation. In addition, faster and more accurate decisions after learning were due to a gradual decrease in boundary separation and an increase in drift rate. The results suggest that speed-accuracy instructions and learning differentially shape decision-making processes at different time scales. PMID:24782701

  6. Comparing the Contribution of Two Tests of Working Memory to Reading in Relation to Phonological Awareness and Rapid Naming Speed

    ERIC Educational Resources Information Center

    Georgiou, George K.; Das, J. P.; Hayward, Denyse V.

    2008-01-01

    The purpose of this study was to compare the contribution of two different versions of working memory to word reading and reading comprehension in relation to phonological awareness and rapid naming speed. Fifty children were administered two measures of working memory, namely an adaptation of the Daneman and Carpenter sentence span task and…

  7. An ASIC memory buffer controller for a high speed disk system

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.; Campbell, Steve

    1993-01-01

    The need for large capacity, high speed mass memory storage devices has become increasingly evident at NASA during the past decade. High performance mass storage systems are crucial to present and future NASA systems. Spaceborne data storage system requirements have grown in response to the increasing amounts of data generated and processed by orbiting scientific experiments. Predictions indicate increases in the volume of data by orders of magnitude during the next decade. Current predictions are for storage capacities on the order of terabits (Tb), with data rates exceeding one gigabit per second (Gbps). As part of the design effort for a state of the art mass storage system, NASA Langley has designed a 144 CMOS ASIC to support high speed data transfers. This paper discusses the system architecture, ASIC design and some of the lessons learned in the development process.

  8. Menstrual Cycle Effects on Perceptual Closure Mediate Changes in Performance on a Fragmented Objects Test of Implicit Memory

    ERIC Educational Resources Information Center

    Hampson, E.; Finestone, J.M.; Levy, N.

    2005-01-01

    Healthy premenopausal women with regular menstrual cycles were assessed on a fragmented objects test of implicit memory. Testing took place at either the low estrogen (n=17) or the high estrogen (n=16) stages of the menstrual cycle. Concentrations of ovarian hormones were confirmed by saliva assays. Both groups of women exhibited a priming effect,…

  9. Memory versus Perceptual-Motor Tradeoffs in a Blocks World Task Wai-Tat Fu (wfu@gmu.edu)

    E-print Network

    Gray, Wayne

    ). If information in the external environment can be considered as an external memory store, the cost in searching's rational analysis framework. In most tasks, the information stored in the external environment from an in-the-world to an in-the-head strategy is surprisingly low. Introduction Information stored in

  10. Self-Construal Priming Affects Speed of Retrieval from Short-Term Memory

    PubMed Central

    MacDonald, Justin A.; Sandry, Joshua; Rice, Stephen

    2012-01-01

    We investigated the effects of collective or individual self-construal priming on recall in a short-term memory (STM) task. We primed participants to either their individual or their collective self-construals or a neutral control condition. Participants then completed a STM retrieval task using either random or patterned digit strings. Findings revealed that priming an individual self-construal resulted in faster retrieval of information from STM for both stimulus types. These results indicate that individual self-accessibility improves retrieval speed of digits from STM, regardless of set configuration. More broadly, the present findings extend prior research by adding further evidence of the effects of self-construal priming on cognitive information processing. PMID:23209632

  11. Memory psychophysics

    Microsoft Academic Search

    Timothy L. Hubbard

    1994-01-01

    The relationship between perceptual and cognitive processes has been a topic of increasing interest. This review focuses on the use of techniques and theory drawn from classical psychophysics and applied to the study of mental representation. Several issues including examination of the functions that relate remembered and perceived magnitude to physical intensity, the relationship of memorial to perceptual functions, the

  12. Individual differences and predictors of forgetting in old age: The role of processing speed and working memory

    Microsoft Academic Search

    Daniel Zimprich; Tanja Kurtz

    2012-01-01

    The goal of the present study was to examine whether individual differences in basic cognitive abilities, processing speed, and working memory, are reliable predictors of individual differences in forgetting rates in old age. The sample for the present study comprised 364 participants aged between 65 and 80 years from the Zurich Longitudinal Study on Cognitive Aging. The impact of basic

  13. Perceptual salience affects the contents of working memory during free-recollection of objects from natural scenes

    PubMed Central

    Pedale, Tiziana; Santangelo, Valerio

    2015-01-01

    One of the most important issues in the study of cognition is to understand which are the factors determining internal representation of the external world. Previous literature has started to highlight the impact of low-level sensory features (indexed by saliency-maps) in driving attention selection, hence increasing the probability for objects presented in complex and natural scenes to be successfully encoded into working memory (WM) and then correctly remembered. Here we asked whether the probability of retrieving high-saliency objects modulates the overall contents of WM, by decreasing the probability of retrieving other, lower-saliency objects. We presented pictures of natural scenes for 4 s. After a retention period of 8 s, we asked participants to verbally report as many objects/details as possible of the previous scenes. We then computed how many times the objects located at either the peak of maximal or minimal saliency in the scene (as indexed by a saliency-map; Itti et al., 1998) were recollected by participants. Results showed that maximal-saliency objects were recollected more often and earlier in the stream of successfully reported items than minimal-saliency objects. This indicates that bottom-up sensory salience increases the recollection probability and facilitates the access to memory representation at retrieval, respectively. Moreover, recollection of the maximal- (but not the minimal-) saliency objects predicted the overall amount of successfully recollected objects: The higher the probability of having successfully reported the most-salient object in the scene, the lower the amount of recollected objects. These findings highlight that bottom-up sensory saliency modulates the current contents of WM during recollection of objects from natural scenes, most likely by reducing available resources to encode and then retrieve other (lower saliency) objects. PMID:25741266

  14. Stochastic accumulation of feature information in perception and memory

    PubMed Central

    Kent, Christopher; Guest, Duncan; Adelman, James S.; Lamberts, Koen

    2014-01-01

    It is now well established that the time course of perceptual processing influences the first second or so of performance in a wide variety of cognitive tasks. Over the last 20 years, there has been a shift from modeling the speed at which a display is processed, to modeling the speed at which different features of the display are perceived and formalizing how this perceptual information is used in decision making. The first of these models (Lamberts, 1995) was implemented to fit the time course of performance in a speeded perceptual categorization task and assumed a simple stochastic accumulation of feature information. Subsequently, similar approaches have been used to model performance in a range of cognitive tasks including identification, absolute identification, perceptual matching, recognition, visual search, and word processing, again assuming a simple stochastic accumulation of feature information from both the stimulus and representations held in memory. These models are typically fit to data from signal-to-respond experiments whereby the effects of stimulus exposure duration on performance are examined, but response times (RTs) and RT distributions have also been modeled. In this article, we review this approach and explore the insights it has provided about the interplay between perceptual processing, memory retrieval, and decision making in a variety of tasks. In so doing, we highlight how such approaches can continue to usefully contribute to our understanding of cognition. PMID:24860530

  15. Perceptual telerobotics

    NASA Technical Reports Server (NTRS)

    Ligomenides, Panos A.

    1989-01-01

    A sensory world modeling system, congruent with a human expert's perception, is proposed. The Experiential Knowledge Base (EKB) system can provide a highly intelligible communication interface for telemonitoring and telecontrol of a real time robotic system operating in space. Paradigmatic acquisition of empirical perceptual knowledge, and real time experiential pattern recognition and knowledge integration are reviewed. The cellular architecture and operation of the EKB system are also examined.

  16. Local consumption speed of turbulent premixed flames - An analysis of ''memory effects''

    SciTech Connect

    Hemchandra, Santosh; Lieuwen, Tim [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2010-05-15

    The local turbulent flame speed of an attached flame is not only a function of the local flow and flame conditions, but also of upstream conditions - i.e., it is ''non-local'' or exhibits ''memory''. Non-locality adds an additional degree of freedom to the classic problem of a freely propagating flame propagating normally to the time averaged flow. Non-locality occurs due to mean tangential flow along the flame brush, which causes flame wrinkles to translate downstream. As such, the wrinkling of the flame at any given point is not only a function of the local velocity disturbance, but also a superposition of flame surface perturbations from locations upstream at previous times. This causes the correlation length scale of turbulent flame wrinkles to differ from that of the underlying turbulent velocity fluctuations. The objective of this paper is to provide a physical description of the key flame kinematic processes that cause these non-local effects. Two approaches are adopted in this work. First, analytical solutions of the G-equation that explicitly describe the effect of non-locality in the low turbulence limit are developed. Second, numerical computations of the G-equation are performed that demonstrate the role of non-linearity in flame surface kinematics at higher turbulence intensities. Finally, these predictions are shown to be consistent with data from a turbulent Bunsen flame. (author)

  17. A high speed programming scheme for multi-level NAND flash memory

    Microsoft Academic Search

    Young-Joon Choi; Kang-Deog Suh; Yong-Nam Koh; Jong-Wook Park; Ki-Jong Lee; Yun-Jin Cho; Byung-Hoon Suh

    1996-01-01

    A new scheme for page programming of multi-level NAND flash memory has been developed. It maintains the 528 byte page size of 32 Mb NAND flash memories with a high throughput of 0.5 MB\\/s. The circuitry has been successfully implemented into an experimental 128 Mb multi-level flash memory

  18. High speed and nonvolatile Si nanocrystal memory for scaled flash technology using highly field-sensitive tunnel barrier

    Microsoft Academic Search

    Seung Jae Baik; Siyoung Choi; U-In Chung; Joo Tae Moon

    2003-01-01

    For the first time, a nitride\\/oxide\\/nitride stacked tunnel structure is adopted as highly field-sensitive tunnel barrier to improve both program\\/erase speed and data retention of nanocrystal memory. Product-adaptive nonvolatility (>10 years at 85°C) and cycling endurance (>106) were obtained with the program time of 10 ?s at VG=8 V and the erase time of 100 ?s at VG=-8 V with

  19. Aging White Matter and Cognition: Differential Effects of Regional Variations in Diffusion Properties on Memory, Executive Functions, and Speed

    PubMed Central

    Kennedy, Kristen M.; Raz, Naftali

    2009-01-01

    Disruption of cerebral white matter has been proposed as an explanation for age-related cognitive declines. However, the role of specific regions in specific cognitive declines remains unclear. We used diffusion tensor imaging to examine the associations between regional microstructural integrity of the white matter and performance on age-sensitive cognitive tasks in a sample of healthy adults (N = 52, age 19–81 years). White matter integrity was assessed by fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in multiple regions of interest (genu and splenium of corpus callosum, internal capsule limbs, prefrontal, temporal, superior/posterior parietal, occipital white matter) and related to processing speed, working memory, inhibition, task switching, and episodic memory. We found that age and regional white matter integrity differentially influenced cognitive performance. Age-related degradation in anterior brain areas was associated with decreased processing speed and poorer working memory, whereas reduced inhibition and greater task switching costs were linked to decline in posterior areas. Poorer episodic memory was associated with age-related differences in central white matter regions. The observed multiple dissociations among specific age-sensitive cognitive skills and their putative neuroanatomical substrates support the view that age-related cognitive declines are unlikely to stem from a single cause. PMID:19166865

  20. Visual prediction and perceptual expertise

    PubMed Central

    Cheung, Olivia S.; Bar, Moshe

    2012-01-01

    Making accurate predictions about what may happen in the environment requires analogies between perceptual input and associations in memory. These elements of predictions are based on cortical representations, but little is known about how these processes can be enhanced by experience and training. On the other hand, studies on perceptual expertise have revealed that the acquisition of expertise leads to strengthened associative processing among features or objects, suggesting that predictions and expertise may be tightly connected. Here we review the behavioral and neural findings regarding the mechanisms involving prediction and expert processing, and highlight important possible overlaps between them. Future investigation should examine the relations among perception, memory and prediction skills as a function of expertise. The knowledge gained by this line of research will have implications for visual cognition research, and will advance our understanding of how the human brain can improve its ability to predict by learning from experience. PMID:22123523

  1. Novel Co-Design of NAND Flash Memory and NAND Flash Controller Circuits for Sub30 nm Low-Power High-Speed Solid-State Drives (SSD)

    Microsoft Academic Search

    Ken Takeuchi

    2009-01-01

    As the cell size of the NAND flash memory has been scaled down by 40%-50% per year and the memory capacity has been doubling every year, a solid-state drive (SSD) that uses NAND as mass storage for personal computers and enterprise servers is attracting much attention. To realize a low-power high-speed SSD, the co-design of NAND flash memory and NAND

  2. Speed and Accuracy of Accessing Information in Working Memory: An Individual Differences Investigation of Focus Switching

    ERIC Educational Resources Information Center

    Unsworth, Nash; Engle, Randall W.

    2008-01-01

    Three experiments examined the nature of individual differences in switching the focus of attention in working memory. Participants performed 3 versions of a continuous counting task that required successive updating and switching between counts. Across all 3 experiments, individual differences in working memory span and fluid intelligence were…

  3. Statistical Mechanics Model of the Speed - Accuracy Tradeoff in Spatial and Lexical Memory

    NASA Astrophysics Data System (ADS)

    Kaufman, Miron; Allen, Philip

    2000-03-01

    The molar neural network model of P. Allen, M. Kaufman, A. F. Smith, R. E. Popper, Psychology and Aging 13, 501 (1998) and Experimental Aging Research, 24, 307 (1998) is extended to incorporate reaction times. In our model the entropy associated with a particular task determines the reaction time. We use this molar neural model to directly analyze experimental data on episodic (spatial) memory and semantic (lexical) memory tasks. In particular we are interested in the effect of aging on the two types of memory. We find that there is no difference in performance levels for lexical memory tasks between younger and older adults. In the case spatial memory tasks we find that aging has a detrimental effect on the performance level. This work is supported by NIH/NIA grant AG09282-06.

  4. High speed, very large (8 megabyte) first in/first out buffer memory (FIFO)

    DOEpatents

    Baumbaugh, Alan E. (Batavia, IL); Knickerbocker, Kelly L. (Aurora, IL)

    1989-01-01

    A fast FIFO (First In First Out) memory buffer capable of storing data at rates of 100 megabytes per second. The invention includes a data packer which concatenates small bit data words into large bit data words, a memory array having individual data storage addresses adapted to store the large bit data words, a data unpacker into which large bit data words from the array can be read and reconstructed into small bit data words, and a controller to control and keep track of the individual data storage addresses in the memory array into which data from the packer is being written and data to the unpacker is being read.

  5. Animacy, perceptual load, and inattentional blindness.

    PubMed

    Calvillo, Dustin P; Jackson, Russell E

    2014-06-01

    Inattentional blindness is the failure to notice unexpected objects in a visual scene while engaging in an attention-demanding task. We examined the effects of animacy and perceptual load on inattentional blindness. Participants searched for a category exemplar under low or high perceptual load. On the last trial, the participants were exposed to an unexpected object that was either animate or inanimate. Unexpected objects were detected more frequently when they were animate rather than inanimate, and more frequently with low than with high perceptual loads. We also measured working memory capacity and found that it predicted the detection of unexpected objects, but only with high perceptual loads. The results are consistent with the animate-monitoring hypothesis, which suggests that animate objects capture attention because of the importance of the detection of animate objects in ancestral hunter-gatherer environments. PMID:24197657

  6. Cache Memories

    Microsoft Academic Search

    Alan Jay Smith

    1982-01-01

    Cache memories are used in modern, medium and high-speed CPUs to hold temporarily those portions of the contents of main memory which are {believed to be) currently in use. Since instructions and data in cache memories can usually be referenced in 10 to 25 percent of the time required to access main memory, cache memories permit the executmn rate of

  7. Placing Inspection Time, Reaction Time, and Perceptual Speed in the Broader Context of Cognitive Ability: The VPR Model in the Lothian Birth Cohort 1936

    ERIC Educational Resources Information Center

    Johnson, Wendy; Deary, Ian J.

    2011-01-01

    The idea that information processing speed is related to cognitive ability has a long history. Much evidence has been amassed in its support, with respect to both individual differences in general intelligence and developmental trajectories. Two so-called elementary cognitive tasks, reaction time and inspection time, have been used to compile this…

  8. Architecture and Evaluation of a HighSpeed Networking Subsystem for DistributedMemory Systems

    E-print Network

    Steenkiste, Peter

    use of the HIPPI bandwidth [16], interface. We perform some communication tasks on the distributed­Performance Parallel Interface interface and to minimize the amount of work that is (HIPPI) protocol [12] have become commercially available tasks on the distributed­memory system itself (bottom supercomputers have a HIPPI

  9. The Local Wavelet Transform: a memory-efficient, high-speed architecture optimized to a Region-Oriented Zero-Tree coder

    Microsoft Academic Search

    G. Lafruit; L. Nachtergaele; B. Vanhoof; F. Catthoor

    2000-01-01

    1 Abstract The memory required for the implementation of the 2D wavelet transform typically incurs relatively high power consumption and limits the speed performances. In this paper we propose an optimized architecture of the 1D\\/2D wavelet transform, that reduces the memory size cost with one order of magnitude compared to classical implementation styles. This so-called Local Wavelet Transform also minimizes

  10. Perceptual fluency, auditory generation, and metamemory: analyzing the perceptual fluency hypothesis in the auditory modality.

    PubMed

    Besken, Miri; Mulligan, Neil W

    2014-03-01

    Judgments of learning (JOLs) are sometimes influenced by factors that do not impact actual memory performance. One recent proposal is that perceptual fluency during encoding affects metamemory and is a basis of metacognitive illusions. In the present experiments, participants identified aurally presented words that contained inter-spliced silences (the generate condition) or that were intact, a manipulation analogous to visual generation manipulations. The generate condition produced lower perceptual fluency as assessed by both accuracy and identification latency. Consistent with the perceptual fluency hypothesis, the less fluent, generate condition produced lower JOLs than the intact condition. However, actual memory performance was greater in the generation than intact condition in free recall (Experiment 1) and recognition (Experiment 3). The negative effect of generation on JOLs occurred for both aggregate and item-by-item JOLs, but in the latter case, the positive generation effect in actual memory performance was reduced or eliminated (as also occurs with visual generation tasks; Experiments 2 and 4). Furthermore, the decrease in perceptual fluency produced by the generation manipulation was correlated with the decrease in JOLs for this condition (Experiment 5). The negative effect of generation on JOLs persisted even when participants were warned that the generation condition produces equal or greater memory performance compared to the intact condition (Experiment 6). The results are in accord with the perceptual fluency hypothesis and show that this metamemory illusion is related to objective measures of perceptual difficulty. With regard to actual memory performance, this novel auditory generation manipulation produces results consistent with those produced in the visual modality. PMID:24016138

  11. Low resistive tungsten dual polymetal gate process for high speed and high density memory devices

    Microsoft Academic Search

    Yong Soo Kim; Kwan-Yong Lim; Min-Gyu Sung; Soo-Hyun Kim; Hong-Seon Yang; Heung-Jae Cho; Se-Aug Jang; Jae-Geun Oh; Kwangok Kim; Young-Kyun Jung; Tae-Woo Jung; Choon-Hwan Kim; Doek-Won Lee; Won Kim; Young-Hoon Kim; Kang-Sik Choi; Tae-Kyung Oh; Yun-Taek Hwang; Seung-Ho Pyi; Ja-chun Ku; Jin-Woong Kim

    2007-01-01

    We developed ultra-low resistive tungsten dual polymetal gate memory device by using Ti-based diffusion barrier and a unique tungsten chemical vapor deposition (CVD) process with B2H6-based nucleation layer. The low resistive CVD-W (LRW) polymetal gate process not only reveals good gate oxide reliability comparable to PVD-W process, but also highly improved transistor performances such as signal delay characteristics.

  12. Genetic Variance in Processing Speed Drives Variation in Aging of Spatial and Memory Abilities

    ERIC Educational Resources Information Center

    Finkel, Deborah; Reynolds, Chandra A.; McArdle, John J.; Hamagami, Fumiaki; Pedersen, Nancy L.

    2009-01-01

    Previous analyses have identified a genetic contribution to the correlation between declines with age in processing speed and higher cognitive abilities. The goal of the current analysis was to apply the biometric dual change score model to consider the possibility of temporal dynamics underlying the genetic covariance between aging trajectories…

  13. The impact of battery capacity and memory bandwidth on CPU speed-setting: a case study

    Microsoft Academic Search

    Thomas L. Martin; Daniel P. Siewiorek

    1999-01-01

    1. ABSTRACT The purpose of this paper is to report the power and performance of an application on a real system as the CPU frequency varies. Previous work in CPU speed-setting considered only the power of the CPU and only CPU’s that vary supply voltage with frequency. This work takes a broader approach, considering total system power, battery capacity and

  14. A reward semi-Markov process with memory for wind speed modeling

    NASA Astrophysics Data System (ADS)

    Petroni, F.; D'Amico, G.; Prattico, F.

    2012-04-01

    The increasing interest in renewable energy leads scientific research to find a better way to recover most of the available energy. Particularly, the maximum energy recoverable from wind is equal to 59.3% of that available (Betz law) at a specific pitch angle and when the ratio between the wind speed in output and in input is equal to 1/3. The pitch angle is the angle formed between the airfoil of the blade of the wind turbine and the wind direction. Old turbine and a lot of that actually marketed, in fact, have always the same invariant geometry of the airfoil. This causes that wind turbines will work with an efficiency that is lower than 59.3%. New generation wind turbines, instead, have a system to variate the pitch angle by rotating the blades. This system able the wind turbines to recover, at different wind speed, always the maximum energy, working in Betz limit at different speed ratios. A powerful system control of the pitch angle allows the wind turbine to recover better the energy in transient regime. A good stochastic model for wind speed is then needed to help both the optimization of turbine design and to assist the system control to predict the value of the wind speed to positioning the blades quickly and correctly. The possibility to have synthetic data of wind speed is a powerful instrument to assist designer to verify the structures of the wind turbines or to estimate the energy recoverable from a specific site. To generate synthetic data, Markov chains of first or higher order are often used [1,2,3]. In particular in [1] is presented a comparison between a first-order Markov chain and a second-order Markov chain. A similar work, but only for the first-order Markov chain, is conduced by [2], presenting the probability transition matrix and comparing the energy spectral density and autocorrelation of real and synthetic wind speed data. A tentative to modeling and to join speed and direction of wind is presented in [3], by using two models, first-order Markov chain with different number of states, and Weibull distribution. All this model use Markov chains to generate synthetic wind speed time series but the search for a better model is still open. Approaching this issue, we applied new models which are generalization of Markov models. More precisely we applied semi-Markov models to generate synthetic wind speed time series. The primary goal of this analysis is the study of the time history of the wind in order to assess its reliability as a source of power and to determine the associated storage levels required. In order to assess this issue we use a probabilistic model based on indexed semi-Markov process [4] to which a reward structure is attached. Our model is used to calculate the expected energy produced by a given turbine and its variability expressed by the variance of the process. Our results can be used to compare different wind farms based on their reward and also on the risk of missed production due to the intrinsic variability of the wind speed process. The model is used to generate synthetic time series for wind speed by means of Monte Carlo simulations and backtesting procedure is used to compare results on first and second oder moments of rewards between real and synthetic data. [1] A. Shamshad, M.A. Bawadi, W.M.W. Wan Hussin, T.A. Majid, S.A.M. Sanusi, First and second order Markov chain models for synthetic gen- eration of wind speed time series, Energy 30 (2005) 693-708. [2] H. Nfaoui, H. Essiarab, A.A.M. Sayigh, A stochastic Markov chain model for simulating wind speed time series at Tangiers, Morocco, Re- newable Energy 29 (2004) 1407-1418. [3] F. Youcef Ettoumi, H. Sauvageot, A.-E.-H. Adane, Statistical bivariate modeling of wind using first-order Markov chain and Weibull distribu- tion, Renewable Energy 28 (2003) 1787-1802. [4]F. Petroni, G. D'Amico, F. Prattico, Indexed semi-Markov process for wind speed modeling. To be submitted.

  15. Novel High-Speed High Pressure Torsion Technology for Obtaining Fe-Mn-Si-Cr Shape Memory Alloy Active Elements

    NASA Astrophysics Data System (ADS)

    Gur?u, Gheorghe; Gur?u, Carmela; Poteca?u, Octavian; Alexandru, Petric?; Bujoreanu, Leandru-Gheorghe

    2014-07-01

    This paper introduces an adapted high-speed high pressure torsion (HS-HPT) method of severe plastic deformation applied for obtaining shape memory alloy (SMA) active elements with revolution symmetry, able to develop axial displacement/force. Billets with circular crown forms were cut from Fe-28Mn-6Si-5Cr (mass%) SMA ingots and, by means of HS-HPT technology, were directly turned into modules, with truncated cone shell configurations. This process was performed, during time intervals of seconds, under the effect of high pressure (up to 1 GPa) cumulated with high rotation speed (hundreds of rotations per minute) applied on the active surfaces of sintered-carbide anvils, specially designed for this purpose. Due to pressure and friction, generated by rotation, the entire sample volume is heated and simultaneously deformed to final shape. During the process, microstructure fragmentation occurred enabling to obtain (ultra)fine grains and nanocrystalline areas, in spite of the heat developed by friction, which was removed by conduction at the contact surface between sample and anvils, before the occurrence of any recrystallization phenomena. When compressed between flat surfaces, the truncated cone modules developed a superelastic-like response, unique among Fe -Mn-Si base SMAs and, when heated in compressed state, they were able to develop either axial strokes or recovery forces by either free or constrained recovery shape memory effect (SME), respectively. By means of optical (OM) and scanning electron microscopy (SEM) marked structural changes caused by HT-HPT were revealed, along with fine and ultrafine crystalline grains. The presence of stress-induced ?-hexagonal close-packed ( hcp) martensite, together with nanocrystalline areas were confirmed by x-ray diffraction.

  16. Relationship between perceptual learning in speech and statistical learning in younger and older adults

    PubMed Central

    Neger, Thordis M.; Rietveld, Toni; Janse, Esther

    2014-01-01

    Within a few sentences, listeners learn to understand severely degraded speech such as noise-vocoded speech. However, individuals vary in the amount of such perceptual learning and it is unclear what underlies these differences. The present study investigates whether perceptual learning in speech relates to statistical learning, as sensitivity to probabilistic information may aid identification of relevant cues in novel speech input. If statistical learning and perceptual learning (partly) draw on the same general mechanisms, then statistical learning in a non-auditory modality using non-linguistic sequences should predict adaptation to degraded speech. In the present study, 73 older adults (aged over 60 years) and 60 younger adults (aged between 18 and 30 years) performed a visual artificial grammar learning task and were presented with 60 meaningful noise-vocoded sentences in an auditory recall task. Within age groups, sentence recognition performance over exposure was analyzed as a function of statistical learning performance, and other variables that may predict learning (i.e., hearing, vocabulary, attention switching control, working memory, and processing speed). Younger and older adults showed similar amounts of perceptual learning, but only younger adults showed significant statistical learning. In older adults, improvement in understanding noise-vocoded speech was constrained by age. In younger adults, amount of adaptation was associated with lexical knowledge and with statistical learning ability. Thus, individual differences in general cognitive abilities explain listeners' variability in adapting to noise-vocoded speech. Results suggest that perceptual and statistical learning share mechanisms of implicit regularity detection, but that the ability to detect statistical regularities is impaired in older adults if visual sequences are presented quickly. PMID:25225475

  17. Perceptual load influences selective attention across development.

    PubMed

    Couperus, Jane W

    2011-09-01

    Research suggests that visual selective attention develops across childhood. However, there is relatively little understanding of the neurological changes that accompany this development, particularly in the context of adult theories of selective attention, such as N. Lavie's (1995) perceptual load theory of attention. This study examined visual selective attention across development from 7 years of age to adulthood. Specifically, the author examined if changes in processing as a function of selective attention are similarly influenced by perceptual load across development. Participants were asked to complete a task at either low or high perceptual load while processing of an unattended probe stimulus was examined using event related potentials. Similar to adults, children and teens showed reduced processing of the unattended stimulus as perceptual load increased at the P1 visual component. However, although there were no qualitative differences in changes in processing, there were quantitative differences, with shorter P1 latencies in teens and adults compared with children, suggesting increases in the speed of processing across development. In addition, younger children did not need as high a perceptual load to achieve the same difference in performance between low and high perceptual load as adults. Thus, this study demonstrates that although there are developmental changes in visual selective attention, the mechanisms by which visual selective attention is achieved in children may share similarities with adults. PMID:21688896

  18. ADHD Subtypes and Co-Occurring Anxiety, Depression, and Oppositional-Defiant Disorder: Differences in Gordon Diagnostic System and Wechsler Working Memory and Processing Speed Index Scores

    ERIC Educational Resources Information Center

    Mayes, Susan Dickerson; Calhoun, Susan L.; Chase, Gary A.; Mink, Danielle M.; Stagg, Ryan E.

    2009-01-01

    Objective: Wechsler Intelligence Scale for Children Freedom-from-Distractibility/Working Memory Index (FDI/WMI), Processing Speed Index (PSI), and Gordon Diagnostic System (GDS) scores in ADHD children were examined as a function of subtype and coexisting anxiety, depression, and oppositional-defiant disorder. Method: Participants were 587…

  19. Visual Working Memory and Perception Speed of 3- to 6-Year-Old Children Tested with a Matrix Film Battery Test

    ERIC Educational Resources Information Center

    Pittorf, Martin L.; Lehmann, Wolfgang; Huckauf, Anke

    2014-01-01

    In this study the visual working memory (VWM) and perception speed of 60 children between the ages of three and six years were tested with an age-based, easy-to-handle Matrix Film Battery Test (reliability R?=?0.71). It was thereby affirmed that the VWM is age dependent (correlation coefficient r?=?0.66***) as expected. Furthermore, a significant…

  20. Novel co-design of NAND flash memory and NAND flash controller circuits for sub-30nm low-power high-speed solid-state drives (SSD)

    Microsoft Academic Search

    K. Takeuchi

    2008-01-01

    Three new circuit technologies, selective bit-line precharge scheme, advanced source-line program, and intelligent interleaving are proposed. By co-designing NAND flash memory and NAND controller circuits, both NAND and NAND controllers are best optimized. At sub-30 nm generation, the SSD speed improves by 150% without a cost penalty or circuit noise.

  1. Comparison of related perceptual tests.

    PubMed

    Davis, D; Eliot, J

    1994-08-01

    117 female and 76 male undergraduates were administered the ETS Hidden Figures, ETS Gestalt Completion, Harshman Figures, and the SEK Test. Results were interpreted as indicating that the two types of perceptual tests (flexibility and speed) were not factorially independent as the SEK Test correlations did not load upon the same factor as that for the ETS Hidden Figures Test. Men scored higher on the Hidden Figures and Harshman Figures but on the Gestalt completion task left-handed men and right-handed women scored higher. PMID:7808874

  2. Non-volatile, high density, high speed, Micromagnet-Hall effect Random Access Memory (MHRAM)

    NASA Technical Reports Server (NTRS)

    Wu, Jiin C.; Katti, Romney R.; Stadler, Henry L.

    1991-01-01

    The micromagnetic Hall effect random access memory (MHRAM) has the potential of replacing ROMs, EPROMs, EEPROMs, and SRAMs because of its ability to achieve non-volatility, radiation hardness, high density, and fast access times, simultaneously. Information is stored magnetically in small magnetic elements (micromagnets), allowing unlimited data retention time, unlimited numbers of rewrite cycles, and inherent radiation hardness and SEU immunity, making the MHRAM suitable for ground based as well as spaceflight applications. The MHRAM device design is not affected by areal property fluctuations in the micromagnet, so high operating margins and high yield can be achieved in large scale integrated circuit (IC) fabrication. The MHRAM has short access times (less than 100 nsec). Write access time is short because on-chip transistors are used to gate current quickly, and magnetization reversal in the micromagnet can occur in a matter of a few nanoseconds. Read access time is short because the high electron mobility sensor (InAs or InSb) produces a large signal voltage in response to the fringing magnetic field from the micromagnet. High storage density is achieved since a unit cell consists only of two transistors and one micromagnet Hall effect element. By comparison, a DRAM unit cell has one transistor and one capacitor, and a SRAM unit cell has six transistors.

  3. Specificity of perceptual processing in rereading spatially transformed materials.

    PubMed

    Horton, K D; McKenzie, B D

    1995-05-01

    While most studies using the task of reading spatially transformed text do not reveal evidence of specific perceptual transfer, a study by Masson (1986, Experiment 3) provides clear evidence of such effects. Several experiments were designed to identify the basis for this empirical discrepancy. The only substantive evidence of specific perceptual transfer occurred when the words were presented in an unfamiliar typography, although each study suggested a trend toward perceptual specificity effects. The results are discussed in terms of Graf and Ryan's (1990) ideas about the role of distinctive memory representations. PMID:7791597

  4. Effects of load and maintenance duration on the time course of information encoding and retrieval in working memory: from perceptual analysis to post-categorization processes

    PubMed Central

    Pinal, Diego; Zurrón, Montserrat; Díaz, Fernando

    2014-01-01

    Working memory (WM) involves three cognitive events: information encoding, maintenance, and retrieval; these are supported by brain activity in a network of frontal, parietal and temporal regions. Manipulation of WM load and duration of the maintenance period can modulate this activity. Although such modulations have been widely studied using the event-related potentials (ERP) technique, a precise description of the time course of brain activity during encoding and retrieval is still required. Here, we used this technique and principal component analysis to assess the time course of brain activity during encoding and retrieval in a delayed match to sample task. We also investigated the effects of memory load and duration of the maintenance period on ERP activity. Brain activity was similar during information encoding and retrieval and comprised six temporal factors, which closely matched the latency and scalp distribution of some ERP components: P1, N1, P2, N2, P300, and a slow wave. Changes in memory load modulated task performance and yielded variations in frontal lobe activation. Moreover, the P300 amplitude was smaller in the high than in the low load condition during encoding and retrieval. Conversely, the slow wave amplitude was higher in the high than in the low load condition during encoding, and the same was true for the N2 amplitude during retrieval. Thus, during encoding, memory load appears to modulate the processing resources for context updating and post-categorization processes, and during retrieval it modulates resources for stimulus classification and context updating. Besides, despite the lack of differences in task performance related to duration of the maintenance period, larger N2 amplitude and stronger activation of the left temporal lobe after long than after short maintenance periods were found during information retrieval. Thus, results regarding the duration of maintenance period were complex, and future work is required to test the time-based decay theory predictions. PMID:24744715

  5. Frequent video game players resist perceptual interference.

    PubMed

    Berard, Aaron V; Cain, Matthew S; Watanabe, Takeo; Sasaki, Yuka

    2015-01-01

    Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT), a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning. PMID:25807394

  6. Frequent Video Game Players Resist Perceptual Interference

    PubMed Central

    Berard, Aaron V.; Cain, Matthew S.; Watanabe, Takeo; Sasaki, Yuka

    2015-01-01

    Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT), a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning. PMID:25807394

  7. Processing speed enhances model-based over model-free reinforcement learning in the presence of high working memory functioning

    PubMed Central

    Schad, Daniel J.; Jünger, Elisabeth; Sebold, Miriam; Garbusow, Maria; Bernhardt, Nadine; Javadi, Amir-Homayoun; Zimmermann, Ulrich S.; Smolka, Michael N.; Heinz, Andreas; Rapp, Michael A.; Huys, Quentin J. M.

    2014-01-01

    Theories of decision-making and its neural substrates have long assumed the existence of two distinct and competing valuation systems, variously described as goal-directed vs. habitual, or, more recently and based on statistical arguments, as model-free vs. model-based reinforcement-learning. Though both have been shown to control choices, the cognitive abilities associated with these systems are under ongoing investigation. Here we examine the link to cognitive abilities, and find that individual differences in processing speed covary with a shift from model-free to model-based choice control in the presence of above-average working memory function. This suggests shared cognitive and neural processes; provides a bridge between literatures on intelligence and valuation; and may guide the development of process models of different valuation components. Furthermore, it provides a rationale for individual differences in the tendency to deploy valuation systems, which may be important for understanding the manifold neuropsychiatric diseases associated with malfunctions of valuation. PMID:25566131

  8. Psychophysical and neural evidence for emotion-enhanced perceptual vividness.

    PubMed

    Todd, Rebecca M; Talmi, Deborah; Schmitz, Taylor W; Susskind, Josh; Anderson, Adam K

    2012-08-15

    Highly emotional events are associated with vivid "flashbulb" memories. Here we examine whether the flashbulb metaphor characterizes a previously unknown emotion-enhanced vividness (EEV) during initial perceptual experience. Using a magnitude estimation procedure, human observers estimated the relative magnitude of visual noise overlaid on scenes. After controlling for computational metrics of objective visual salience, emotional salience was associated with decreased noise, or heightened perceptual vividness, demonstrating EEV, which predicted later memory vividness. Event-related potentials revealed a posterior P2 component at ?200 ms that was associated with both increased emotional salience and decreased objective noise levels, consistent with EEV. Blood oxygenation level-dependent response in the lateral occipital complex (LOC), insula, and amygdala predicted online EEV. The LOC and insula represented complimentary influences on EEV, with the amygdala statistically mediating both. These findings indicate that the metaphorical vivid light surrounding emotional memories is embodied directly in perceptual cortices during initial experience, supported by cortico-limbic interactions. PMID:22895705

  9. Two Thirds of the Age-Based Changes in Fluid and Crystallized Intelligence, Perceptual Speed, and Memory in Adulthood Are Shared

    ERIC Educational Resources Information Center

    Ghisletta, Paolo; Rabbitt, Patrick; Lunn, Mary; Lindenberger, Ulman

    2012-01-01

    Many aspects of cognition decline from middle to late adulthood, but the dimensionality and generality of this decline have rarely been examined. We analyzed 20-year longitudinal data of 6203 middle-aged to very old adults from Greater Manchester and Newcastle-upon-Tyne, UK. Participants were assessed up to eight times on 20 tasks of fluid…

  10. Speed: 131.3G flops (4Grape6 VLSI Chips 6Pipeline per chip). Memory size: 262,144 particle. (18Mbit Burst-SRAM8)

    E-print Network

    Kissler-Patig, Markus

    · Speed: 131.3G flops (4�Grape6 VLSI Chips 6Pipeline per chip). · Memory size: 262,144 particle Power consumption : DC12V 5A, ATX power supply Grape6-BLX64 is an upgrade model of Micro Grape. It is special for built-in cluster. It is 30 percent faster than Micro GRAPE by using 64bit/100MHz PCI

  11. A capacitorless 1T-DRAM technology using gate-induced drain-leakage (GIDL) current for low-power and high-speed embedded memory

    Microsoft Academic Search

    Eiji Yoshida; Tetsu Tanaka

    2006-01-01

    A capacitorless one-transistor (1T)-dynamic random-access memory (DRAM) cell using gate-induced drain-leakage (GIDL) current for write operation was demonstrated. Compared with the conventional write operation with impact-ionization (II) current, the write operation with GIDL current achieves power consumption that is lower by four orders of magnitude and a write speed within several nanoseconds. The capacitorless 1T DRAM is the most promising

  12. Speed Enhancement of WSi2 Nanocrystal Memory with Barrier-Engineered Si3N4/HfAlO Tunnel Layer

    NASA Astrophysics Data System (ADS)

    Lee, Dong Uk; Lee, Hyo Jun; Kim, Eun Kyu; You, Hee-Wook; Cho, Won-Ju

    2012-06-01

    WSi2 nanocrystal nanofloating gate capacitors with multistacked Si3N4/HfAlO high-k tunnel layers were fabricated and their electrical properties were characterized. The thicknesses of the Si3N4 and HfAlO tunnel layers were 1.5 and 3 nm, respectively. The asymmetrical Si3N4/HfAlO tunnel layer was modulated to enhance the tunneling efficiency to improve program and erase speeds. The flat-band voltage shift of the WSi2 nanofloating gate capacitor was about 7.2 V after applied voltages swept were from -10 to 10 V and from 10 to -10 V. Then, the program/erase speeds and the memory window under programming and erasing at ±7 V were 300 µs and 1 V, respectively. As demonstrated in the results, the WSi2 nanocrystal memory with barrier-engineered Si3N4/HfAlO layers could be applied to enhance the program and erase speeds at low operating voltages for nanocrystal nonvolatile memory application.

  13. Normative perceptual estimates for 91 healthy subjects age 60–75: impact of age, education, employment, physical exercise, alcohol, and video gaming

    PubMed Central

    Wilms, Inge L.; Nielsen, Simon

    2014-01-01

    Visual perception serves as the basis for much of the higher level cognitive processing as well as human activity in general. Here we present normative estimates for the following components of visual perception: the visual perceptual threshold, the visual short-term memory (VSTM) capacity and the visual perceptual encoding/decoding speed (processing speed) of VSTM based on an assessment of 91 healthy subjects aged 60–75. The estimates were modeled from input from a whole-report assessment based on a theory of visual attention. In addition to the estimates themselves, we present correlational data, and multiple regression analyses between the estimates and self-reported demographic data and lifestyle variables. The regression statistics suggest that education level, video gaming activity, and employment status may significantly impact the encoding/decoding speed of VTSM but not the capacity of VSTM nor the visual perceptual threshold. The estimates will be useful for future studies into the effects of various types of intervention and training on cognition in general and visual attention in particular. PMID:25339932

  14. Memories.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    1998-01-01

    This theme issue of the journal "Exploring" covers the topic of "memories" and describes an exhibition at San Francisco's Exploratorium that ran from May 22, 1998 through January 1999 and that contained over 40 hands-on exhibits, demonstrations, artworks, images, sounds, smells, and tastes that demonstrated and depicted the biological,…

  15. Brief Daily Exposures to Asian Females Reverses Perceptual Narrowing for Asian Faces in Caucasian Infants

    ERIC Educational Resources Information Center

    Anzures, Gizelle; Wheeler, Andrea; Quinn, Paul C.; Pascalis, Olivier; Slater, Alan M.; Heron-Delaney, Michelle; Tanaka, James W.; Lee, Kang

    2012-01-01

    Perceptual narrowing in the visual, auditory, and multisensory domains has its developmental origins during infancy. The current study shows that experimentally induced experience can reverse the effects of perceptual narrowing on infants' visual recognition memory of other-race faces. Caucasian 8- to 10-month-olds who could not discriminate…

  16. Subjective Confidence in Perceptual Judgments: A Test of the Self-Consistency Model

    ERIC Educational Resources Information Center

    Koriat, Asher

    2011-01-01

    Two questions about subjective confidence in perceptual judgments are examined: the bases for these judgments and the reasons for their accuracy. Confidence in perceptual judgments has been claimed to rest on qualitatively different processes than confidence in memory tasks. However, predictions from a self-consistency model (SCM), which had been…

  17. Neuroanatomical and Cognitive Mediators of Age-Related Differences in Perceptual Priming and Learning

    Microsoft Academic Search

    Kristen M. Kennedy; Karen M. Rodrigue; Denise Head; Faith Gunning-Dixon; Naftali Raz

    2009-01-01

    Our objectives were to assess age differences in perceptual repetition priming and perceptual skill learning and to determine whether they are mediated by cognitive resources and regional cerebral volume differences. Fragmented picture identification paradigm allows the study of both priming and learning within the same task. The authors presented this task to 169 adults (ages 18–80), assessed working memory and

  18. Perceptually oriented hypnosis.

    PubMed

    Woodard, Fredrick J

    2003-04-01

    This theoretical article explores postulates representative of a perceptual frame of reference for a better understanding of hypnotic experiencing. This author contends that Perceptual Psychology, a theory first conceptualized by Snygg and Combs, as revised by Combs, Richards, and Richards in 1988, and Perceptually Oriented Hypnosis provide an effective way of understanding hypnosis, the therapist-client relationship, and has some implications as well for better comprehending psychopathology. Perceptually oriented hypnotic principles are shown to enhance the characeristics of the adequate personality, expand the phenomenal field, change personal meanings, and change aspects of the phenomenal self in the context of hypnosis. Implications for understanding differing views and conflicting perceptions of reality held by scientists and researchers are discussed. Implications for Dissociative Identity Disorder are also addressed. Research utilizing Giorgi's research methodology and Wasicsko's qualitative procedure for assessing educators' dispositions is suggested. PMID:12785635

  19. A 120-mm2 64Mb NAND flash memory achieving 180 ns\\/Byte effective program speed

    Microsoft Academic Search

    Jin-Ki Kim; K. Sakui; Sung-Soo Lee; Y. Itoh; Suk-Chon Kwon; K. Kanazawa; Ki-Jun Lee; H. Nakamura; Kang-Young Kim; T. Himeno; Jang-Rae Kim; K. Kanda; Tae-Sung Jung; Y. Oshima; Kang-Deog Suh; K. Hashimoto; Sung-Tae Ahn; J. Miyamoto

    1997-01-01

    Emerging application areas of mass storage flash memories require low cost, high density flash memories with enhanced device performance. This paper describes a 64 Mb NAND flash memory having improved read and program performances. A 40 MB\\/s read throughput is achieved by improving the page sensing time and employing the full-chip burst read capability. A 2-?s random access time is

  20. "The mask who wasn't there": Visual masking effect with the perceptual absence of the mask.

    PubMed

    Rey, Amandine Eve; Riou, Benoit; Muller, Dominique; Dabic, Stéphanie; Versace, Rémy

    2015-03-01

    Does a visual mask need to be perceptually present to disrupt processing? In the present research, we proposed to explore the link between perceptual and memory mechanisms by demonstrating that a typical sensory phenomenon (visual masking) can be replicated at a memory level. Experiment 1 highlighted an interference effect of a visual mask on the categorization of auditory targets and confirmed the multimodal nature of knowledge. In Experiment 2, we proposed to reactivate this mask in a categorization task on visual targets. Results showed that the sensory mask has disrupted (slower reaction times) the processing of the targets whether the mask was perceptually present or reactivated in memory. These results support a sensory-based conception of memory processing and suggest that the difference between perceptual processes and memory processes is characterized by the presence (perception) or the absence (memory) of the sensory properties involved in the activity. (PsycINFO Database Record (c) 2015 APA, all rights reserved). PMID:25133514

  1. Memory Hierarchy Configuration Analysis

    Microsoft Academic Search

    Terry A. Welch

    1978-01-01

    This paper presents an analytical study of speed-cost tradeoffs in memory hierarchy design. It develops an optimization criterion by which average access time, i. e., memory system delay, is minimized under a cost constraint for a hierarchy with given memory sizes and access probabilities. Using a power function assumption relating speed and cost of memory units, it is shown that

  2. Working Memory Capacity in a Go/No-Go Task: Age Differences in Interference, Processing Speed, and Attentional Control

    ERIC Educational Resources Information Center

    Rodríguez-Villagra, Odir Antonio; Göthe, Katrin; Oberauer, Klaus; Kliegl, Reinhold

    2013-01-01

    We tested the limits of working-memory capacity (WMC) of young adults, old adults, and children with a memory-updating task. The task consisted of mentally shifting spatial positions within a grid according to arrows, their color signaling either only go (control) or go/no-go conditions. The interference model (IM) of Oberauer and Kliegl (2006)…

  3. Perceptual Learning of Acoustic Noise by Individuals with Dyslexia

    ERIC Educational Resources Information Center

    Agus, Trevor R.; Carrión-Castillo, Amaia; Pressnitzer, Daniel; Ramus, Franck

    2014-01-01

    Purpose: A phonological deficit is thought to affect most individuals with developmental dyslexia. The present study addresses whether the phonological deficit is caused by difficulties with perceptual learning of fine acoustic details. Method: A demanding test of nonverbal auditory memory, "noise learning," was administered to both…

  4. Acetylcholine and Olfactory Perceptual Learning

    ERIC Educational Resources Information Center

    Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

    2004-01-01

    Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform…

  5. Effects of Acute Cortisol Administration on Perceptual Priming of Trauma-Related Material

    PubMed Central

    Streb, Markus; Pfaltz, Monique; Michael, Tanja

    2014-01-01

    Intrusive memories are a hallmark symptom of posttraumatic stress disorder (PTSD). They reflect excessive and uncontrolled retrieval of the traumatic memory. Acute elevations of cortisol are known to impair the retrieval of already stored memory information. Thus, continuous cortisol administration might help in reducing intrusive memories in PTSD. Strong perceptual priming for neutral stimuli associated with a “traumatic” context has been shown to be one important learning mechanism that leads to intrusive memories. However, the memory modulating effects of cortisol have only been shown for explicit declarative memory processes. Thus, in our double blind, placebo controlled study we aimed to investigate whether cortisol influences perceptual priming of neutral stimuli that appeared in a “traumatic” context. Two groups of healthy volunteers (N?=?160) watched either neutral or “traumatic” picture stories on a computer screen. Neutral objects were presented in between the pictures. Memory for these neutral objects was tested after 24 hours with a perceptual priming task and an explicit memory task. Prior to memory testing half of the participants in each group received 25 mg of cortisol, the other half received placebo. In the placebo group participants in the “traumatic” stories condition showed more perceptual priming for the neutral objects than participants in the neutral stories condition, indicating a strong perceptual priming effect for neutral stimuli presented in a “traumatic” context. In the cortisol group this effect was not present: Participants in the neutral stories and participants in the “traumatic” stories condition in the cortisol group showed comparable priming effects for the neutral objects. Our findings show that cortisol inhibits perceptual priming for neutral stimuli that appeared in a “traumatic” context. These findings indicate that cortisol influences PTSD-relevant memory processes and thus further support the idea that administration of cortisol might be an effective treatment strategy in reducing intrusive reexperiencing. PMID:25192334

  6. High-k HfAlO charge trapping layer in SONOS-type nonvolatile memory device for high speed operation

    Microsoft Academic Search

    Yan Ny Tan; Wai Kin Chim; Wee Kiong Choi; Moon Sig Joo; Tsu Hau Ng; Byung Jin Cho

    2004-01-01

    A HfAlO charge storage layer in SONOS (polysilicon-oxide-silicon nitride-oxide-silicon)-type memory with a SiO2\\/high-K\\/SiO2 (SOHOS) structure is proposed. Compared to other high-K charge storage layers, HfAlO shows the advantages of high speed program\\/erase of HfO2 as well as good charge retention of Al2O3, which makes HfAlO the most promising candidate for the charge storage layer. The charge storage and program\\/erase mechanisms

  7. The cognitive effects of listening to background music on older adults: processing speed improves with upbeat music, while memory seems to benefit from both upbeat and downbeat music

    PubMed Central

    Bottiroli, Sara; Rosi, Alessia; Russo, Riccardo; Vecchi, Tomaso; Cavallini, Elena

    2014-01-01

    Background music refers to any music played while the listener is performing another activity. Most studies on this effect have been conducted on young adults, while little attention has been paid to the presence of this effect in older adults. Hence, this study aimed to address this imbalance by assessing the impact of different types of background music on cognitive tasks tapping declarative memory and processing speed in older adults. Overall, background music tended to improve performance over no music and white noise, but not always in the same manner. The theoretical and practical implications of the empirical findings are discussed. PMID:25360112

  8. Perceptual merging contributes to cueing effects.

    PubMed

    Krüger, Hannah M; MacInnes, W Joseph; Hunt, Amelia R

    2014-01-01

    An uninformative exogenous cue speeds target detection if cue and target appear in the same location separated by a brief temporal interval. This finding is usually ascribed to the orienting of spatial attention to the cued location. Here we examine the role of perceptual merging of the two trial events in speeded target detection. That is, the cue and target may be perceived as a single event when they appear in the same location. If so, cueing effects could reflect, in part, the binding of the perceived target onset to the earlier cue onset. We observed the traditional facilitation of cued over uncued targets and asked the same observers to judge target onset time by noting the time on a clock when the target appeared. Observers consistently judged the onset time of the target as being earlier than it appeared with cued targets judged as earlier than uncued targets. When the event order is reversed so that the target precedes the cue, perceived onset is accurate in both cued and uncued locations. This pattern of results suggests that perceptual merging does occur in exogenous cueing. A modified attention account is discussed that proposes reentrant processing, evident through perceptual merging, as the underlying mechanism of reflexive orienting of attention. PMID:24961250

  9. A 120 mm2 64 Mb NAND flash memory achieving 180 ns\\/byte effective program speed

    Microsoft Academic Search

    Jin-Ki Kim; Koji Sakui; Sung-Soo Lee; J. Itoh; Suk-Chon Kwon; Kazuhisa Kanazawa; Ji-Jun Lee; Hiroshi Nakamura; Kang-Young Kim; Toshihiko Himeno; Jang-Rae Kim; Kazushige Kanda; Tae-Sung Jung; Yoichi Oshima; Kang-Deog Suh; Kazuhiko Hashimoto; Sung-Tae Ahn; Junichi Miyamoto

    1996-01-01

    Rapidly increasing solid-state mass-storage application areas are requiring low cost, high density flash memories with higher read and program throughputs. This paper describes a 3.3 V-only 64 Mb NAND flash memory fabricated using a 0.4 ?m single-metal CMOS technology. The read throughput of 40 MB\\/s is achieved by improving the random access time and by introducing a full-chip burst read.

  10. Non-Attended Representations are Perceptual Rather than Unconscious in Nature

    PubMed Central

    Fahrenfort, Johannes J.; Ambroziak, Klaudia B.; Lamme, Victor A. F.

    2012-01-01

    Introspectively we experience a phenomenally rich world. In stark contrast, many studies show that we can only report on the few items that we happen to attend to. So what happens to the unattended objects? Are these consciously processed as our first person perspective would have us believe, or are they – in fact – entirely unconscious? Here, we attempt to resolve this question by investigating the perceptual characteristics of visual sensory memory. Sensory memory is a fleeting, high-capacity form of memory that precedes attentional selection and working memory. We found that memory capacity benefits from figural information induced by the Kanizsa illusion. Importantly, this benefit was larger for sensory memory than for working memory and depended critically on the illusion, not on the stimulus configuration. This shows that pre-attentive sensory memory contains representations that have a genuinely perceptual nature, suggesting that non-attended representations are phenomenally experienced rather than unconscious. PMID:23209639

  11. Protocols from perceptual observations

    Microsoft Academic Search

    Chris J. Needham; Paulo E. Santos; Derek R. Magee; Vincent E. Devin; David C. Hogg; Anthony G. Cohn

    2005-01-01

    This paper presents a cognitive vision system capable of autonomously learning protocols from perceptual observations of dynamic scenes. The work is motivated by the aim of creating a syn- thetic agent that can observe a scene containing interactions between unknown objects and agents, and learn models of these sufficient to act in accordance with the implicit protocols present in the

  12. Perceptual-Motor Dysfunction.

    ERIC Educational Resources Information Center

    Pyfer, Jean L.

    Discussed are theoretical and treatment aspects of perceptual motor dysfunction and rehabilitation in 4- to 12-year-old academically failing children involved in a 3-year investigation at the University of Kansas. The program is said to stress increasing the amount of stimulation received by sensory receptors of the vestibular, reflex, and haptic…

  13. Perceptual Learning in Speech

    ERIC Educational Resources Information Center

    Norris, Dennis; McQueen, James M.; Cutler, Anne

    2003-01-01

    This study demonstrates that listeners use lexical knowledge in perceptual learning of speech sounds. Dutch listeners first made lexical decisions on Dutch words and nonwords. The final fricative of 20 critical words had been replaced by an ambiguous sound, between [f] and [s]. One group of listeners heard ambiguous [f]-final words (e.g.,…

  14. A perceptual pitch detector

    Microsoft Academic Search

    Malcolm Slaney; Richard F. Lyon

    1990-01-01

    A pitch detector based on Licklider's (1979) duplex theory of pitch perception was implemented and tested on a variety of stimuli from human perceptual tests. It is believed that this approach accurately models how people perceive pitch. It is shown that it correctly identifies the pitch of complex harmonic and inharmonic stimuli and that it is robust in the face

  15. 1 Memory Storage What kinds of things are in your memory?

    E-print Network

    O'Reilly, Randall C.

    1 Memory Storage What kinds of things are in your memory? Perceptual memories. Motor memories organized? What is encoded & what is not? 2 Is Your Brain a Library? How are things organized orthography phonology action oriented tactile visual auditory kinesthetic form color 3-D tele phonefoot brake

  16. Early Experience & Multisensory Perceptual Narrowing

    PubMed Central

    Lewkowicz, David J.

    2014-01-01

    Perceptual narrowing is a reflection of early experience and contributes in key ways to perceptual and cognitive development. In general, findings have shown that unisensory perceptual sensitivity in early infancy is broadly tuned such that young infants respond to, and discriminate, native as well as non-native sensory inputs, whereas older infants only respond to native inputs. Recently, my colleagues and I discovered that perceptual narrowing occurs at the multisensory processing level as well. The present article reviews this new evidence and puts it in the larger context of multisensory perceptual development and the role that perceptual experience plays in it. Together, the evidence on unisensory and multisensory narrowing shows that early experience shapes the emergence of perceptual specialization and expertise. PMID:24435505

  17. Perceptual learning and human expertise

    NASA Astrophysics Data System (ADS)

    Kellman, Philip J.; Garrigan, Patrick

    2009-06-01

    We consider perceptual learning: experience-induced changes in the way perceivers extract information. Often neglected in scientific accounts of learning and in instruction, perceptual learning is a fundamental contributor to human expertise and is crucial in domains where humans show remarkable levels of attainment, such as language, chess, music, and mathematics. In Section 2, we give a brief history and discuss the relation of perceptual learning to other forms of learning. We consider in Section 3 several specific phenomena, illustrating the scope and characteristics of perceptual learning, including both discovery and fluency effects. We describe abstract perceptual learning, in which structural relationships are discovered and recognized in novel instances that do not share constituent elements or basic features. In Section 4, we consider primary concepts that have been used to explain and model perceptual learning, including receptive field change, selection, and relational recoding. In Section 5, we consider the scope of perceptual learning, contrasting recent research, focused on simple sensory discriminations, with earlier work that emphasized extraction of invariance from varied instances in more complex tasks. Contrary to some recent views, we argue that perceptual learning should not be confined to changes in early sensory analyzers. Phenomena at various levels, we suggest, can be unified by models that emphasize discovery and selection of relevant information. In a final section, we consider the potential role of perceptual learning in educational settings. Most instruction emphasizes facts and procedures that can be verbalized, whereas expertise depends heavily on implicit pattern recognition and selective extraction skills acquired through perceptual learning. We consider reasons why perceptual learning has not been systematically addressed in traditional instruction, and we describe recent successful efforts to create a technology of perceptual learning in areas such as aviation, mathematics, and medicine. Research in perceptual learning promises to advance scientific accounts of learning, and perceptual learning technology may offer similar promise in improving education.

  18. Perceptual learning and human expertise.

    PubMed

    Kellman, Philip J; Garrigan, Patrick

    2009-06-01

    We consider perceptual learning: experience-induced changes in the way perceivers extract information. Often neglected in scientific accounts of learning and in instruction, perceptual learning is a fundamental contributor to human expertise and is crucial in domains where humans show remarkable levels of attainment, such as language, chess, music, and mathematics. In Section 2, we give a brief history and discuss the relation of perceptual learning to other forms of learning. We consider in Section 3 several specific phenomena, illustrating the scope and characteristics of perceptual learning, including both discovery and fluency effects. We describe abstract perceptual learning, in which structural relationships are discovered and recognized in novel instances that do not share constituent elements or basic features. In Section 4, we consider primary concepts that have been used to explain and model perceptual learning, including receptive field change, selection, and relational recoding. In Section 5, we consider the scope of perceptual learning, contrasting recent research, focused on simple sensory discriminations, with earlier work that emphasized extraction of invariance from varied instances in more complex tasks. Contrary to some recent views, we argue that perceptual learning should not be confined to changes in early sensory analyzers. Phenomena at various levels, we suggest, can be unified by models that emphasize discovery and selection of relevant information. In a final section, we consider the potential role of perceptual learning in educational settings. Most instruction emphasizes facts and procedures that can be verbalized, whereas expertise depends heavily on implicit pattern recognition and selective extraction skills acquired through perceptual learning. We consider reasons why perceptual learning has not been systematically addressed in traditional instruction, and we describe recent successful efforts to create a technology of perceptual learning in areas such as aviation, mathematics, and medicine. Research in perceptual learning promises to advance scientific accounts of learning, and perceptual learning technology may offer similar promise in improving education. PMID:20416846

  19. Perceptually specific and perceptually non-specific influences on rereading benefits for spatially transformed text: evidence from eye movements.

    PubMed

    Sheridan, Heather; Reingold, Eyal M

    2012-12-01

    The present study used eye tracking methodology to examine rereading benefits for spatially transformed text. Eye movements were monitored while participants read the same target word twice, in two different low-constraint sentence frames. The congruency of perceptual processing was manipulated by either applying the same type of transformation to the word during the first and second presentations (i.e., the congruent condition), or employing two different types of transformations across the two presentations of the word (i.e., the incongruent condition). Perceptual specificity effects were demonstrated such that fixation times for the second presentation of the target word were shorter for the congruent condition compared to the incongruent condition. Moreover, we demonstrated an additional perceptually non-specific effect such that second reading fixation times were shorter for the incongruent condition relative to a baseline condition that employed a normal typography (i.e., non-transformed) during the first presentation and a transformation during the second presentation. Both of these effects (i.e., perceptually specific and perceptually non-specific) were similar in magnitude for high and low frequency words, and both effects persisted across a 1 week lag between the first and second readings. We discuss the present findings in the context of the distinction between conscious and unconscious memory, and the distinction between perceptually versus conceptually driven processing. PMID:23138157

  20. Modulation of cortical activity during comprehension of familiar and unfamiliar text topics in speed reading and speed listening.

    PubMed

    Buchweitz, Augusto; Mason, Robert A; Meschyan, Gayane; Keller, Timothy A; Just, Marcel Adam

    2014-12-01

    Brain activation associated with normal and speeded comprehension of expository texts on familiar and unfamiliar topics was investigated in reading and listening. The goal was to determine how brain activation and the comprehension processes it reflects are modulated by comprehension speed and topic familiarity. Passages on more familiar topics differentially activated a set of areas in the anterior temporal lobe and medial frontal gyrus, areas often associated with text-level integration processes, which we interpret to reflect integration of previous knowledge with the passage content. Passages presented at the faster presentation resulted in more activation of a network of frontal areas associated with strategic and working-memory processes (as well as visual or auditory sensory-related regions), which we interpret to reflect maintenance of local coherence among briefly available passage segments. The implications of this research is that the brain system for text comprehension adapts to varying perceptual and knowledge conditions. PMID:25463816

  1. Modulation of cortical activity during comprehension of familiar and unfamiliar text topics in speed reading and speed listening

    PubMed Central

    Buchweitz, Augusto; Mason, Robert A.; Meschyan, Gayane; Keller, Timothy A.; Just, Marcel Adam

    2014-01-01

    Brain activation associated with normal and speeded comprehension of expository texts on familiar and unfamiliar topics was investigated in reading and listening. The goal was to determine how brain activation and the comprehension processes it reflects are modulated by comprehension speed and topic familiarity. Passages on more familiar topics differentially activated a set of areas in the anterior temporal lobe and medial frontal gyrus, areas often associated with text-level integration processes, which we interpret to reflect integration of previous knowledge with the passage content. Passages presented at the faster presentation resulted in more activation of a network of frontal areas associated with strategic and working-memory processes (as well as visual or auditory sensory-related regions), which we interpret to reflect maintenance of local coherence among briefly available passage segments. The implications of this research is to demonstrate how the brain system for text comprehension adapts to varying perceptual and knowledge conditions. PMID:25463816

  2. Are Cochlear Implant Patients Suffering From Perceptual Dissonance?

    E-print Network

    Loeb, Gerald E.

    Are Cochlear Implant Patients Suffering From Perceptual Dissonance? Gerald E. Loeb, M.D. Cochlear suggests that the place-pitch and rate-pitch theories on which cochlear implants have been designed-speed, and high-density cochlear implants may make it possi- ble to identify more efficiently the best strategy

  3. The Perceptual Illusion of Baseball's Rising Fastball and Breaking Curveball

    Microsoft Academic Search

    A. Terry Bahill; William J. Karnavas

    1993-01-01

    The rising fastball and the breaking curveball are impossible according to principles of physics and physiology, yet many baseball players claim they exist. The simulation and model presented suggest that the rising fastball and breaking curveball are perceptual illusions caused by the batter misestimating the speed of the pitch. This model uses signals from known primary visual processes only. This

  4. Societal Implicit Memory and his Speed on Tracking Extrema over Dynamic Environments using Self-Regulatory Swarms

    Microsoft Academic Search

    Vitorino Ramos; Carlos Fernandes; Agostinho C. Rosa

    2005-01-01

    In order to overcome difficult dynamic optimization and environment extrema tracking problems, we propose a Self-Regulated Swarm (SRS) algorithm which hybridizes the advantageous characteristics of Swarm Intelligence as the emergence of a societal environmental memory or cognitive map via collective pheromone laying in the landscape (properly balancing the exploration\\/exploitation nature of the search strategy), with a simple Evolutionary mechanism that

  5. Exploring Possible Neural Mechanisms of Intelligence Differences Using Processing Speed and Working Memory Tasks: An fMRI Study

    ERIC Educational Resources Information Center

    Waiter, Gordon D.; Deary, Ian J.; Staff, Roger T.; Murray, Alison D.; Fox, Helen C.; Starr, John M.; Whalley, Lawrence J.

    2009-01-01

    To explore the possible neural foundations of individual differences in intelligence test scores, we examined the associations between Raven's Matrices scores and two tasks that were administered in a functional magnetic resonance imaging (fMRI) setting. The two tasks were an n-back working memory (N = 37) task and inspection time (N = 47). The…

  6. Are there unconscious perceptual processes?

    PubMed

    Brogaard, Berit

    2011-06-01

    Blindsight and vision for action seem to be exemplars of unconscious visual processes. However, researchers have recently argued that blindsight is not really a kind of unconscious vision but is rather severely degraded conscious vision. Morten Overgaard and colleagues have recently developed new methods for measuring the visibility of visual stimuli. Studies using these methods show that reported clarity of visual stimuli correlates with accuracy in both normal individuals and blindsight patients. Vision for action has also come under scrutiny. Recent findings seem to show that information processed by the dorsal stream for online action contributes to visual awareness. Some interpret these results as showing that some dorsal stream processes are conscious visual processes (e.g., Gallese, 2007; Jacob & Jeannerod, 2003). The aim of this paper is to provide new support for the more traditional view that blindsight and vision for action are genuinely unconscious perceptual processes. I argue that individuals with blindsight do not have access to the kind of purely qualitative color and size information which normal individuals do. So, even though people with blindsight have a kind of cognitive consciousness, visual information processing in blindsight patients is not associated with a distinctly visual phenomenology. I argue further that while dorsal stream processing seems to contribute to visual awareness, only information processed by the early dorsal stream (V1, V2, and V3) is broadcast to working memory. Information processed by later parts of the dorsal stream (the parietal lobe) never reaches working memory and hence does not correlate with phenomenal awareness. I conclude that both blindsight and vision for action are genuinely unconscious visual processes. PMID:21146426

  7. The measurement of perceptual curiosity

    Microsoft Academic Search

    Robert P Collins; Jordan A Litman; Charles D Spielberger

    2004-01-01

    Perceptual curiosity, as defined by Berlyne (1954), involves interest in and giving attention to novel perceptual stimulation, and motivates visual and sensory-inspection. A 33-item questionnaire constructed to assess individual differences in perceptual curiosity was administered to 320 undergraduate students (202 females; 118 males). The participants also responded to the trait scales of the State-Trait Personality Inventory (STPI), and to selected

  8. W-Polymetal Gate with Low W\\/Poly-Si Interface Resistance for High-Speed\\/High-Density Embedded Memory

    Microsoft Academic Search

    Tomohiro Yamashita; Yukio Nishida; Kiyoshi Hayashi; Takahisa Eimori; Masahide Inuishi; Yuzuru Ohji

    2004-01-01

    A new W-polymetal gate electrode with the structure of W\\/WN\\/WSi\\/poly-Si is proposed. The W-polymetal gate is suitable for high-density memories since it has low resistance and is compatible with the self-aligned contact process. In our study, however, it is found that the interface of W and poly-Si has non-ohmic and quite high resistance in the case wherein only WN is

  9. Learning, Memory, and Synesthesia

    PubMed Central

    Witthoft, Nathan; Winawer, Jonathan

    2013-01-01

    People with color-grapheme synesthesia experience color when viewing written letters or numerals, usually with a particular color evoked by each grapheme. Here we report on 11 color-grapheme synesthetes with startlingly similar color-grapheme pairings traceable to childhood toys containing colored letters. These data are the first and only to show learned synesthesia of this kind in a group larger than a single case. While some researchers have focused on genetic and perceptual aspects of synesthesia, these results indicate that a complete explanation of synesthesia must also incorporate a central role for learning and memory. We argue that these two positions can be reconciled by thinking of synesthesia as the automatic retrieval of highly specific mnemonic associations, where perceptual contents are brought to mind, akin to mental imagery or the perceptual reinstatement effects found in the memory literature. PMID:23307940

  10. Different time scales of motion integration for anticipatory smooth pursuit and perceptual adaptation.

    PubMed

    Maus, Gerrit W; Potapchuk, Elena; Watamaniuk, Scott N J; Heinen, Stephen J

    2015-01-01

    When repeatedly exposed to moving stimuli, the oculomotor system elicits anticipatory smooth pursuit (ASP) eye movements, even before the stimulus moves. ASP is affected oppositely to perceptual speed judgments of repetitive moving stimuli: After a sequence of fast stimuli, ASP velocity increases, whereas perceived speed decreases. These two effects-perceptual adaptation and oculomotor priming-could result from adapting a single common internal speed representation that is used for perceptual comparisons and for generating ASP. Here we test this hypothesis by assessing the temporal dependence of both effects on stimulus history. Observers performed speed discriminations on moving random dot stimuli, either while pursuing the movement or maintaining steady fixation. In both cases, responses showed perceptual adaptation: Stimuli preceded by fast speeds were perceived as slower, and vice versa. To evaluate oculomotor priming, we analyzed ASP velocity as a function of average stimulus speed in preceding trials and found strong positive dependencies. Interestingly, maximal priming occurred over short stimulus histories (?two trials), whereas adaptation was maximal over longer histories (?15 trials). The temporal dissociation of adaptation and priming suggests different underlying mechanisms. It may be that perceptual adaptation integrates over a relatively long period to robustly calibrate the operating range of the motion system, thereby avoiding interference from transient changes in stimulus speed. On the other hand, the oculomotor system may rapidly prime anticipatory velocity to efficiently match it to that of the pursuit target. PMID:25761334

  11. Understanding processing speed weaknesses among pedophilic child molesters: response style vs. neuropathology.

    PubMed

    Suchy, Yana; Eastvold, Angela D; Strassberg, Donald S; Franchow, Emilie I

    2014-02-01

    Research shows that pedophilic (PED) child molesters exhibit slower performance speed and greater performance accuracy when compared to nonpedophilic (N-PED) child molesters or other criminal and noncriminal controls. The purpose of the present study was to examine whether these differences reflect a slow/deliberate response style among PEDS (as we have previously hypothesized; Eastvold, Suchy, & Strassberg, 2011; Suchy, Whittaker, Strassberg, & Eastvold, 2009a, 2009b), or a fundamental neuropathological weakness in processing speed. Data came from a larger study examining neurocognition among sex offenders. Processing speed in three different domains (motor speed, visual-perceptual speed, and visual-motor integration) was examined in 20 phallometrically identified PEDs, 20 N-PEDs, and 20 nonsexual offenders, using both clinical (Finger Tapping, Symbol Search, Digit Symbol Coding) and experimental measures (Inspection Time Task [ITT]). The ITT assessed speed of visual-perceptual processing independent of response speed. On clinical measures, PEDs exhibited slower visual perception [F(2, 57) = 5.24, p = .008] and visual-motor integration [F(2, 57) = 5.02, p = .010] than the other groups, with no differences for simple motor speed. On the ITT, PEDs performed less accurately than the other groups [F(2, 57) = 3.95, p = .025], clearly indicating that slow processing speed cannot be explained by a deliberate response style. Group differences persisted after controlling for other potential confounds (age, estimate IQ, working memory, ethnicity, and substance use). PEDs' slower performance is due to a fundamental neurocognitive weakness, rather than a slow/deliberate response style. These results are consistent with Cantor et al.'s (2008) work identifying white matter abnormalities among PEDs and provide further support for a neurodevelopmental etiology of pedophilia. PMID:24661177

  12. Perceptual Load Alters Visual Excitability

    ERIC Educational Resources Information Center

    Carmel, David; Thorne, Jeremy D.; Rees, Geraint; Lavie, Nilli

    2011-01-01

    Increasing perceptual load reduces the processing of visual stimuli outside the focus of attention, but the mechanism underlying these effects remains unclear. Here we tested an account attributing the effects of perceptual load to modulations of visual cortex excitability. In contrast to stimulus competition accounts, which propose that load…

  13. Conflict-Induced Perceptual Filtering

    ERIC Educational Resources Information Center

    Wendt, Mike; Luna-Rodriguez, Aquiles; Jacobsen, Thomas

    2012-01-01

    In a variety of conflict paradigms, target and distractor stimuli are defined in terms of perceptual features. Interference evoked by distractor stimuli tends to be reduced when the ratio of congruent to incongruent trials is decreased, suggesting conflict-induced perceptual filtering (i.e., adjusting the processing weights assigned to stimuli…

  14. Perceptual learning and human expertise

    Microsoft Academic Search

    Philip J. Kellman; Patrick Garrigan

    2009-01-01

    We consider perceptual learning: experience-induced changes in the way perceivers extract information. Often neglected in scientific accounts of learning and in instruction, perceptual learning is a fundamental contributor to human expertise and is crucial in domains where humans show remarkable levels of attainment, such as language, chess, music, and mathematics. In Section 2, we give a brief history and discuss

  15. Perceptual basis for reactive teleoperation.

    SciTech Connect

    Park, Y. S.; Ewing, T. F.; Boyle, J. M.; Yule, T. J.

    2001-08-28

    To enhance task performance in partially structured environment, enhancement of teleoperation was proposed by introducing autonomous behaviors. Such autonomy is implemented based on reactive robotic architecture, where reactive motor agents that directly couples sensory inputs and motor actions become the building blocks. To this end, presented in this paper is a perceptual basis for the motor agents. The perceptual basis consists of perceptual agents that extracts environmental information from a structured light vision system and provide action oriented perception for the corresponding motor agents. Rather than performing general scene reconstruction, a perceptual agent directly provides the motion reference for the motor behavior. Various sensory mechanisms--sensor fission, fusion, and fashion--becomes basic building blocks of the perception process. Since perception is a process deeply intertwined with the motor actions, active perception may also incorporate motor behaviors as an integral perceptual process.

  16. Synesthesia and Memory: Color Congruency, von Restorff, and False Memory Effects

    Microsoft Academic Search

    Gabriel A. Radvansky; Bradley S. Gibson; M. Windy McNerney

    2011-01-01

    In the current study, we explored the influence of synesthesia on memory for word lists. We tested 10 grapheme-color synesthetes who reported an experience of color when reading letters or words. We replicated a previous finding that memory is compromised when synesthetic color is incongruent with perceptual color. Beyond this, we found that, although their memory for word lists was

  17. Modeling Recognition Memory Using the Similarity Structure of Natural Input

    Microsoft Academic Search

    Joyca P. W. Lacroix; Jaap M. J. Murre; Eric O. Postma; H. Jaap Van Den Herik

    2006-01-01

    Abstract The Natural Input Memory,(NIM) model is a new model for recognition memory,that operates on natural visual input. A biologically-informed perceptual pre-processing method,takes local samples (eye fixations) from a natural image and translates t hese into a feature-vector representation. During recognition, the model compares incoming pre-processed natural input to stored representations. By complementing,the recognition memory,process with a perceptual front-end, the

  18. Perceptual learning in sensorimotor adaptation.

    PubMed

    Darainy, Mohammad; Vahdat, Shahabeddin; Ostry, David J

    2013-11-01

    Motor learning often involves situations in which the somatosensory targets of movement are, at least initially, poorly defined, as for example, in learning to speak or learning the feel of a proper tennis serve. Under these conditions, motor skill acquisition presumably requires perceptual as well as motor learning. That is, it engages both the progressive shaping of sensory targets and associated changes in motor performance. In the present study, we test the idea that perceptual learning alters somatosensory function and in so doing produces changes to human motor performance and sensorimotor adaptation. Subjects in these experiments undergo perceptual training in which a robotic device passively moves the subject's arm on one of a set of fan-shaped trajectories. Subjects are required to indicate whether the robot moved the limb to the right or the left and feedback is provided. Over the course of training both the perceptual boundary and acuity are altered. The perceptual learning is observed to improve both the rate and extent of learning in a subsequent sensorimotor adaptation task and the benefits persist for at least 24 h. The improvement in the present studies varies systematically with changes in perceptual acuity and is obtained regardless of whether the perceptual boundary shift serves to systematically increase or decrease error on subsequent movements. The beneficial effects of perceptual training are found to be substantially dependent on reinforced decision-making in the sensory domain. Passive-movement training on its own is less able to alter subsequent learning in the motor system. Overall, this study suggests perceptual learning plays an integral role in motor learning. PMID:23966671

  19. Perceptual learning in sensorimotor adaptation

    PubMed Central

    Darainy, Mohammad; Vahdat, Shahabeddin

    2013-01-01

    Motor learning often involves situations in which the somatosensory targets of movement are, at least initially, poorly defined, as for example, in learning to speak or learning the feel of a proper tennis serve. Under these conditions, motor skill acquisition presumably requires perceptual as well as motor learning. That is, it engages both the progressive shaping of sensory targets and associated changes in motor performance. In the present study, we test the idea that perceptual learning alters somatosensory function and in so doing produces changes to human motor performance and sensorimotor adaptation. Subjects in these experiments undergo perceptual training in which a robotic device passively moves the subject's arm on one of a set of fan-shaped trajectories. Subjects are required to indicate whether the robot moved the limb to the right or the left and feedback is provided. Over the course of training both the perceptual boundary and acuity are altered. The perceptual learning is observed to improve both the rate and extent of learning in a subsequent sensorimotor adaptation task and the benefits persist for at least 24 h. The improvement in the present studies varies systematically with changes in perceptual acuity and is obtained regardless of whether the perceptual boundary shift serves to systematically increase or decrease error on subsequent movements. The beneficial effects of perceptual training are found to be substantially dependent on reinforced decision-making in the sensory domain. Passive-movement training on its own is less able to alter subsequent learning in the motor system. Overall, this study suggests perceptual learning plays an integral role in motor learning. PMID:23966671

  20. Ferroelectric memories

    Microsoft Academic Search

    J. F. Scott; C. A. Paz de Araujo

    1989-01-01

    In the past year it has become possible to fabricate ferroelectric thin-film memories onto standard silicon integrated circuits that combine very high speed (30-nanosecond read\\/erase\\/rewrite operation), 5-volt standard silicon logic levels, very high density (2 by 2 micrometer cell size), complete nonvolatility (no standby power required), and extreme radiation hardness. These ferroelectric random-access memories are expected to replace magnetic core

  1. Sex Differences in Phonological Coding: Alphabet Transformation Speed

    ERIC Educational Resources Information Center

    Majeres, Raymond L.

    2007-01-01

    A previous explanation of the sex difference on so-called perceptual speed tests was in terms of a female advantage in accessing and using phonological name codes in making item comparisons. That explanation was extended to a task involving alphabetical transformations without the requirement for comparison of perceptually available items. A…

  2. Is random access memory random?

    NASA Technical Reports Server (NTRS)

    Denning, P. J.

    1986-01-01

    Most software is contructed on the assumption that the programs and data are stored in random access memory (RAM). Physical limitations on the relative speeds of processor and memory elements lead to a variety of memory organizations that match processor addressing rate with memory service rate. These include interleaved and cached memory. A very high fraction of a processor's address requests can be satified from the cache without reference to the main memory. The cache requests information from main memory in blocks that can be transferred at the full memory speed. Programmers who organize algorithms for locality can realize the highest performance from these computers.

  3. Perceptual Training: Misdirections and Redirections

    ERIC Educational Resources Information Center

    Mann, Lester

    1970-01-01

    An argument centered on perceptual-motor training as an educational fad and a criticism of training approaches. Paper presented at the annual meeting of the American Orthopsychiatric Association (New York, New York, 1969). (RJ)

  4. The perceptual threshold for overweight.

    PubMed

    Johnson, William G; Stewart, Regan; Pusser, Andrea T

    2012-08-01

    Normative, global overweight may play a prominent role in perpetuating the obesity epidemic via its contribution to weight-related norms that describe what is customary in a social environment. These weight-related norms include a perceptual standard determining where body weight shifts from normal to overweight. We introduce the construct of a perceptual threshold for overweight to identify this transition point. The perceptual threshold is measured on 0-100mm scales positioned below adult and child figures. This report presents three studies that evaluate the psychometric properties of this variable. Study 1explored its independence from BMI and body image in factor analyses with diverse samples (Ukrainian, Mexican and US Black, White, and Hispanic). Study 2 was a replication of this factor structure, and Study 3 investigated the reliability of the perceptual threshold using classical test (CT) and generalizability methods (GT). In Studies 1 and 2, two factors were identified (Perceptual Threshold for Overweight and Body Image/BMI) with almost identical factor structures in six analyses. In Study 3 the CT and GT procedures demonstrated adequate reliability. These results indicate that the psychometric properties of the perceptual threshold are sound, and support its use in exploring the social transmission of weight and evaluating obesity prevention and intervention programs. PMID:22664395

  5. Perceptual Anomalies in Schizophrenia: Integrating Phenomenology and Cognitive Neuroscience

    PubMed Central

    Uhlhaas, Peter J.; Mishara, Aaron L.

    2007-01-01

    From phenomenological and experimental perspectives, research in schizophrenia has emphasized deficits in “higher” cognitive functions, including attention, executive function, as well as memory. In contrast, general consensus has viewed dysfunctions in basic perceptual processes to be relatively unimportant in the explanation of more complex aspects of the disorder, including changes in self-experience and the development of symptoms such as delusions. We present evidence from phenomenology and cognitive neuroscience that changes in the perceptual field in schizophrenia may represent a core impairment. After introducing the phenomenological approach to perception (Husserl, the Gestalt School), we discuss the views of Paul Matussek, Klaus Conrad, Ludwig Binswanger, and Wolfgang Blankenburg on perception in schizophrenia. These 4 psychiatrists describe changes in perception and automatic processes that are related to the altered experience of self. The altered self-experience, in turn, may be responsible for the emergence of delusions. The phenomenological data are compatible with current research that conceptualizes dysfunctions in perceptual processing as a deficit in the ability to combine stimulus elements into coherent object representations. Relationships of deficits in perceptual organization to cognitive and social dysfunction as well as the possible neurobiological mechanisms are discussed. PMID:17118973

  6. Perceptual anomalies in schizophrenia: integrating phenomenology and cognitive neuroscience.

    PubMed

    Uhlhaas, Peter J; Mishara, Aaron L

    2007-01-01

    From phenomenological and experimental perspectives, research in schizophrenia has emphasized deficits in "higher" cognitive functions, including attention, executive function, as well as memory. In contrast, general consensus has viewed dysfunctions in basic perceptual processes to be relatively unimportant in the explanation of more complex aspects of the disorder, including changes in self-experience and the development of symptoms such as delusions. We present evidence from phenomenology and cognitive neuroscience that changes in the perceptual field in schizophrenia may represent a core impairment. After introducing the phenomenological approach to perception (Husserl, the Gestalt School), we discuss the views of Paul Matussek, Klaus Conrad, Ludwig Binswanger, and Wolfgang Blankenburg on perception in schizophrenia. These 4 psychiatrists describe changes in perception and automatic processes that are related to the altered experience of self. The altered self-experience, in turn, may be responsible for the emergence of delusions. The phenomenological data are compatible with current research that conceptualizes dysfunctions in perceptual processing as a deficit in the ability to combine stimulus elements into coherent object representations. Relationships of deficits in perceptual organization to cognitive and social dysfunction as well as the possible neurobiological mechanisms are discussed. PMID:17118973

  7. Effects of the common cold on mood, psychomotor performance, the encoding of new information, speed of working memory and semantic processing.

    PubMed

    Smith, Andrew P

    2012-10-01

    Previous research has shown that people with the common cold report a more negative mood and psychomotor slowing. Recent research suggests that memory speed may also be impaired. This was examined in the study reported here. A prospective design was used and all participants (N=200; half male, half female; mean age 21 years, range 18-30 years) carried out a baseline session when healthy. The test battery involved mood rating, simple and choice reaction time, verbal reasoning and semantic processing. Volunteers returned when they developed an upper respiratory tract illness (URTI) and repeated the test battery. If they remained healthy they were recalled as a control. One hundred and eighty-nine participants completed the study and 48 developed URTIs and 141 were in the healthy control group. Symptoms and signs suggested that those who were ill had colds rather than influenza. The results showed that those with colds reported lower alertness, a more negative mood, and psychomotor slowing. They were also slower at encoding new information and slower on the verbal reasoning and semantic processing tasks. The magnitude of the mood changes associated with being ill were correlated with symptom severity. The performance changes were not correlated with symptom severity, sleep duration or mood changes. Further research is now needed to elucidate the underlying mechanisms of the behavioral malaise associated with URTIs. PMID:22749892

  8. Mental imagery of speech: linking motor and perceptual systems through internal simulation and estimation

    PubMed Central

    Tian, Xing; Poeppel, David

    2012-01-01

    The neural basis of mental imagery has been investigated by localizing the underlying neural networks, mostly in motor and perceptual systems, separately. However, how modality-specific representations are top-down induced and how the action and perception systems interact in the context of mental imagery is not well understood. Imagined speech production (“articulation imagery”), which induces the kinesthetic feeling of articulator movement and its auditory consequences, provides a new angle because of the concurrent involvement of motor and perceptual systems. On the basis of previous findings in mental imagery of speech, we argue for the following regarding the induction mechanisms of mental imagery and the interaction between motor and perceptual systems: (1) Two distinct top-down mechanisms, memory retrieval and motor simulation, exist to induce estimation in perceptual systems. (2) Motor simulation is sufficient to internally induce the representation of perceptual changes that would be caused by actual movement (perceptual associations); however, this simulation process only has modulatory effects on the perception of external stimuli, which critically depends on context and task demands. Considering the proposed simulation-estimation processes as common mechanisms for interaction between motor and perceptual systems, we outline how mental imagery (of speech) relates to perception and production, and how these hypothesized mechanisms might underpin certain neural disorders. PMID:23226121

  9. Think Before You Speak: Pauses, Memory Search, and Trace Redintegration Processes in Verbal Memory Span

    Microsoft Academic Search

    Charles Hulme; Philip Newton; Nelson Cowan; George Stuart; Gordon Brown

    1999-01-01

    Immediate memory span and speed of memory search were assessed for words and nonwords of short and long spoken duration. Memory span was substantially greater for words than for nonwords and for short than for long items, though speed of memory search was unaffected by either length or lexicality. An analysis of the temporal pattern of responses in the memory

  10. The perceptual chunking of speech: A demonstration using ERPs.

    PubMed

    Gilbert, Annie C; Boucher, Victor J; Jemel, Boutheina

    2015-04-01

    In tasks involving the learning of verbal or non-verbal sequences, groupings are spontaneously produced. These groupings are generally marked by a lengthening of final elements and have been attributed to a domain-general perceptual chunking linked to working memory. Yet, no study has shown how this domain-general chunking applies to speech processing, partly because of the traditional view that chunking involves a conceptual recoding of meaningful verbal items like words (Miller, 1956). The present study provides a demonstration of the perceptual chunking of speech by way of two experiments using evoked Positive Shifts (PSs), which capture on-line neural responses to marks of various groups. We observed listeners? response to utterances (Experiment 1) and meaningless series of syllables (Experiment 2) containing changing intonation and temporal marks, while also examining how these marks affect the recognition of heard items. The results show that, across conditions - and irrespective of the presence of meaningful items - PSs are specifically evoked by groups marked by lengthening. Moreover, this on-line detection of marks corresponds to characteristic grouping effects on listeners' immediate recognition of heard items, which suggests chunking effects linked to working memory. These findings bear out a perceptual chunking of speech input in terms of groups marked by lengthening, which constitute the defining marks of a domain-general chunking. PMID:25636270

  11. Perceptually Lossless Wavelet Compression

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Yang, Gloria Y.; Solomon, Joshua A.; Villasenor, John

    1996-01-01

    The Discrete Wavelet Transform (DWT) decomposes an image into bands that vary in spatial frequency and orientation. It is widely used for image compression. Measures of the visibility of DWT quantization errors are required to achieve optimal compression. Uniform quantization of a single band of coefficients results in an artifact that is the sum of a lattice of random amplitude basis functions of the corresponding DWT synthesis filter, which we call DWT uniform quantization noise. We measured visual detection thresholds for samples of DWT uniform quantization noise in Y, Cb, and Cr color channels. The spatial frequency of a wavelet is r 2(exp -1), where r is display visual resolution in pixels/degree, and L is the wavelet level. Amplitude thresholds increase rapidly with spatial frequency. Thresholds also increase from Y to Cr to Cb, and with orientation from low-pass to horizontal/vertical to diagonal. We propose a mathematical model for DWT noise detection thresholds that is a function of level, orientation, and display visual resolution. This allows calculation of a 'perceptually lossless' quantization matrix for which all errors are in theory below the visual threshold. The model may also be used as the basis for adaptive quantization schemes.

  12. Is faster better? Effects of response deadline on ERP correlates of recognition memory in younger and older adults.

    PubMed

    Scheuplein, Anna-Lena; Bridger, Emma K; Mecklinger, Axel

    2014-09-25

    Aging studies generally suggest that recollection is impaired whereas familiarity-based recognition remains relatively preserved in healthy older adults. The present event-related potential (ERP) study explores whether age-related impairments in recognition memory can be reduced under conditions in which recognition decisions are primarily driven by familiarity. Old and young adults performed an item recognition task with perceptually rich visual stimuli. A response deadline procedure was employed following previous studies which have shown that limiting response times attenuates recollection but leaves familiarity relatively unaffected. Age effects on memory performance were large in the non-speeded response condition in which recollection contributes to performance. When response time was limited, performance differences between groups were negligible. In the non-speeded condition the ERP correlate of recollection was not detectable in old adults. Conversely, in the speeded condition ERP correlates of familiarity were obtained in both age groups, though attenuated for old adults. For old adults in the speeded condition a temporally extended posterior negativity was obtained which was more pronounced for low performing participants. The results suggest that even though the neural generators of the familiarity signal degrade with age, familiarity is an important contributor to recognition memory in older adults and can lead to a disproportional benefit in memory in conditions designed to specifically enhance familiarity-based responding. PMID:25064432

  13. Development of Perceptual Expertise in Emotion Recognition

    PubMed Central

    Messner, Michael; Kistler, Doris J.; Cohn, Jeffrey F.

    2009-01-01

    How do children's early social experiences influence their perception of emotion-specific information communicated by the face? To examine this question, we tested a group of abused children who had been exposed to extremely high levels of parental anger expression and physical threat. Children were presented with arrays of stimuli that depicted the unfolding of facial expressions, from neutrality to peak emotions. The abused children accurately recognized anger early in the formation of the facial expression, when few physiological cues were available. The speed of children's recognition was associated with the degree of anger/hostility reported by the child's parent. These data highlight the ways in which perceptual learning can shape the timing of emotion perception. PMID:19059585

  14. New Methodologies To Evaluate the Memory Strategies of Deaf Individuals.

    ERIC Educational Resources Information Center

    Clark, Diane

    Prior studies have often confounded linguistic and perceptual performance when evaluating deaf subjects' skills, a confusion that may be responsible for results indicating lesser recall ability among the deaf. In this series of studies this linguistic/perceptual confound was investigated in both the iconic and short term memory of deaf…

  15. The effect of haptic cues on motor and perceptual based implicit sequence learning

    PubMed Central

    Kim, Dongwon; Johnson, Brandon J.; Gillespie, R. Brent; Seidler, Rachael D.

    2014-01-01

    We introduced haptic cues to the serial reaction time (SRT) sequence learning task alongside the standard visual cues to assess the relative contributions of visual and haptic stimuli to the formation of motor and perceptual memories. We used motorized keys to deliver brief pulse-like displacements to the resting fingers, expecting that the proximity and similarity of these cues to the subsequent response motor actions (finger-activated key-presses) would strengthen the motor memory trace in particular. We adopted the experimental protocol developed by Willingham (1999) to explore whether haptic cues contribute differently than visual cues to the balance of motor and perceptual learning. We found that sequence learning occurs with haptic stimuli as well as with visual stimuli and we found that irrespective of the stimuli (visual or haptic) the SRT task leads to a greater amount of motor learning than perceptual learning. PMID:24734013

  16. The effect of haptic cues on motor and perceptual based implicit sequence learning.

    PubMed

    Kim, Dongwon; Johnson, Brandon J; Gillespie, R Brent; Seidler, Rachael D

    2014-01-01

    We introduced haptic cues to the serial reaction time (SRT) sequence learning task alongside the standard visual cues to assess the relative contributions of visual and haptic stimuli to the formation of motor and perceptual memories. We used motorized keys to deliver brief pulse-like displacements to the resting fingers, expecting that the proximity and similarity of these cues to the subsequent response motor actions (finger-activated key-presses) would strengthen the motor memory trace in particular. We adopted the experimental protocol developed by Willingham (1999) to explore whether haptic cues contribute differently than visual cues to the balance of motor and perceptual learning. We found that sequence learning occurs with haptic stimuli as well as with visual stimuli and we found that irrespective of the stimuli (visual or haptic) the SRT task leads to a greater amount of motor learning than perceptual learning. PMID:24734013

  17. An analysis of MRAM based memory technologies

    E-print Network

    Vijayaraghavan, Rangarajan, M. Eng. Massachusetts Institute of Technology

    2006-01-01

    MRAM is a memory (RAM) technology that uses electron spin to store information. Often been called "the ideal memory", it can potentially combine the density of DRAM with the speed of SRAM and non-volatility of FLASH memory ...

  18. Dimensional Implicit Memory Priming Deficits in Young ADHD Adults

    E-print Network

    Tatman, Christopher G

    2012-07-11

    The experiment explored the difference between production and identification processes and conceptual and perceptual processes in long-term implicit memory. The first phase consisted of prescreening ADHD (Attention Deficit Hyperactivity Disorder...

  19. Aging Does Not Affect Brain Patterns of Repetition Effects Associated with Perceptual Priming of Novel Objects

    Microsoft Academic Search

    Anja Soldan; Yunglin Gazes; H. John Hilton; Yaakov Stern

    2008-01-01

    This study examined how aging affects the spatial patterns of repetition effects associated with perceptual priming of unfamiliar visual objects. Healthy young (N=14) and elderly adults (N=13) viewed four repetitions of structurally possible and impossible figures while being scanned with BOLD fMRI. Although explicit recognition memory for the figures was reduced in the elder subjects, repetition priming did not differ

  20. Exploring the Perceptual Spaces of Faces, Cars and Birds in Children and Adults

    ERIC Educational Resources Information Center

    Tanaka, James W.; Meixner, Tamara L.; Kantner, Justin

    2011-01-01

    While much developmental research has focused on the strategies that children employ to recognize faces, less is known about the principles governing the organization of face exemplars in perceptual memory. In this study, we tested a novel, child-friendly paradigm for investigating the organization of face, bird and car exemplars. Children ages…

  1. Subcortical hyperintensity volumetrics in Alzheimer’s disease and normal elderly in the Sunnybrook Dementia Study: correlations with atrophy, executive function, mental processing speed, and verbal memory

    PubMed Central

    2014-01-01

    Introduction Subcortical hyperintensities (SHs) are radiological entities commonly observed on magnetic resonance imaging (MRI) of patients with Alzheimer’s disease (AD) and normal elderly controls. Although the presence of SH is believed to indicate some form of subcortical vasculopathy, pathological heterogeneity, methodological differences, and the contribution of brain atrophy associated with AD pathology have yielded inconsistent results in the literature. Methods Using the Lesion Explorer (LE) MRI processing pipeline for SH quantification and brain atrophy, this study examined SH volumes of interest and cognitive function in a sample of patients with AD (n?=?265) and normal elderly controls (n?=?100) from the Sunnybrook Dementia Study. Results Compared with healthy controls, patients with AD were found to have less gray matter, less white matter, and more sulcal and ventricular cerebrospinal fluid (all significant, P <0.0001). Additionally, patients with AD had greater volumes of whole-brain SH (P <0.01), periventricular SH (pvSH) (P <0.01), deep white SH (dwSH) (P <0.05), and lacunar lesions (P <0.0001). In patients with AD, regression analyses revealed a significant association between global atrophy and pvSH (P?=?0.02) and ventricular atrophy with whole-brain SH (P <0.0001). Regional volumes of interest revealed significant correlations with medial middle frontal SH volume and executive function (P <0.001) in normal controls but not in patients with AD, global pvSH volume and mental processing speed (P <0.01) in patients with AD, and left temporal SH volume and memory (P <0.01) in patients with AD. Conclusions These brain-behavior relationships and correlations with brain atrophy suggest that subtle, yet measurable, signs of small vessel disease may have potential clinical relevance as targets for treatment in Alzheimer’s dementia. PMID:25478020

  2. Perceptual inference and autistic traits.

    PubMed

    Skewes, Joshua C; Jegindø, Else-Marie; Gebauer, Line

    2015-04-01

    Autistic people are better at perceiving details. Major theories explain this in terms of bottom-up sensory mechanisms or in terms of top-down cognitive biases. Recently, it has become possible to link these theories within a common framework. This framework assumes that perception is implicit neural inference, combining sensory evidence with prior perceptual knowledge. Within this framework, perceptual differences may occur because of enhanced precision in how sensory evidence is represented or because sensory evidence is weighted much higher than prior perceptual knowledge. In this preliminary study, we compared these models using groups with high and low autistic trait scores (Autism-Spectrum Quotient). We found evidence supporting the cognitive bias model and no evidence for the enhanced sensory precision model. PMID:24523412

  3. Increased Signal Complexity Improves the Breadth of Generalization in Auditory Perceptual Learning

    PubMed Central

    Brown, David J.; Proulx, Michael J.

    2013-01-01

    Perceptual learning can be specific to a trained stimulus or optimally generalized to novel stimuli with the breadth of generalization being imperative for how we structure perceptual training programs. Adapting an established auditory interval discrimination paradigm to utilise complex signals, we trained human adults on a standard interval for either 2, 4, or 10 days. We then tested the standard, alternate frequency, interval, and stereo input conditions to evaluate the rapidity of specific learning and breadth of generalization over the time course. In comparison with previous research using simple stimuli, the speed of perceptual learning and breadth of generalization were more rapid and greater in magnitude, including novel generalization to an alternate temporal interval within stimulus type. We also investigated the long term maintenance of learning and found that specific and generalized learning was maintained over 3 and 6 months. We discuss these findings regarding stimulus complexity in perceptual learning and how they can inform the development of effective training protocols. PMID:24349800

  4. A perceptually motivated approach for speech enhancement

    Microsoft Academic Search

    Yi Hu; Philipos C. Loizou

    2003-01-01

    A new perceptually motivated approach is proposed for enhancement of speech corrupted by colored noise. The proposed approach takes into account the frequency masking properties of the human auditory system and reduces the perceptual effect of the residual noise. This new perceptual method is incorporated into a frequency-domain speech enhancement method and a subspace-based speech enhancement method. A better power

  5. Neurally Constrained Modeling of Perceptual Decision Making

    ERIC Educational Resources Information Center

    Purcell, Braden A.; Heitz, Richard P.; Cohen, Jeremiah Y.; Schall, Jeffrey D.; Logan, Gordon D.; Palmeri, Thomas J.

    2010-01-01

    Stochastic accumulator models account for response time in perceptual decision-making tasks by assuming that perceptual evidence accumulates to a threshold. The present investigation mapped the firing rate of frontal eye field (FEF) visual neurons onto perceptual evidence and the firing rate of FEF movement neurons onto evidence accumulation to…

  6. Neuropsychological and perceptual defects in Parkinson's disease.

    PubMed

    Bodis-Wollner, Ivan

    2003-08-01

    Neuropsychiatric, perceptual and cognitive deficits are increasingly recognized as non-motor manifestations of Parkinson's Disease (PD).The premorbid personality profile of PD patients is characterized by a number of traits which figure prominently after the disease becomes manifest. In particular, less novelty seeking is one premorbid trait providing an understanding of later cognitive deficits. Anxiety and depression have been shown to precede in some patients motor manifestations and cannot be attributed to anti-parkinsonian therapy. Some neuropsychiatric manifestations and in particular hallucinosis are linked to select perceptual and cognitive changes. Cognitive deficits are common in PD, in particular in younger onset patients. Current animal studies link genetic differences in the dopamine transporter and dopamine catabolic enzyme system to select cognitive impairments attributed to frontal lobe dysfunction.Visuo-cognitive impairment is prevalent in PD. Retinal dopaminergic deficiency has been shown in patients and in the animal model of PD. Visuo-spatial deficits, however, are not simply passive reflections of retinal deficiency. In addition to vision, saccadic eye movements are affected in PD whether they contribute to visuo-spatial dysfunction is unknown. However, recent functional Magnetic Resonance Imaging (fMRI) and electroencephalogram (EEG) studies show an essential role of the occipital cortex in saccadic eye movements and positron emission tomography (PET) studies show occipital hypometabolism in PD. Visual and eye movement studies suggest that certain neuropsychiatric and cognitive deficits in PD are linked to the visual system. Synchrony of signals are essential for the co-operation of distributed neuronal network engaged in sensory-motor coordination. Local, dopaminergic neuronal groups in the retina, basal ganglia and frontal cortical memory system are affected in PD. These connections may not primarily rely on dopamine as a neurotransmitter. It is suggested that to understand visuocognitive changes we should consider pathology affecting neuronal connections, necessary for binding parallel distributed networks. PMID:12915072

  7. Synesthesia and Memory: Color Congruency, Von Restorff, and False Memory Effects

    ERIC Educational Resources Information Center

    Radvansky, Gabriel A.; Gibson, Bradley S.; McNerney, M. Windy

    2011-01-01

    In the current study, we explored the influence of synesthesia on memory for word lists. We tested 10 grapheme-color synesthetes who reported an experience of color when reading letters or words. We replicated a previous finding that memory is compromised when synesthetic color is incongruent with perceptual color. Beyond this, we found that,…

  8. The Sensory Nature of Episodic Memory: Sensory Priming Effects Due to Memory Trace Activation

    ERIC Educational Resources Information Center

    Brunel, Lionel; Labeye, Elodie; Lesourd, Mathieu; Versace, Remy

    2009-01-01

    The aim of this study was to provide evidence that memory and perceptual processing are underpinned by the same mechanisms. Specifically, the authors conducted 3 experiments that emphasized the sensory aspect of memory traces. They examined their predictions with a short-term priming paradigm based on 2 distinct phases: a learning phase consisting…

  9. Improving pulse oximetry pitch perception with multisensory perceptual training.

    PubMed

    Schlesinger, Joseph J; Stevenson, Ryan A; Shotwell, Matthew S; Wallace, Mark T

    2014-06-01

    The pulse oximeter is a critical monitor in anesthesia practice designed to improve patient safety. Here, we present an approach to improve the ability of anesthesiologists to monitor arterial oxygen saturation via pulse oximetry through an audiovisual training process. Fifteen residents' abilities to detect auditory changes in pulse oximetry were measured before and after perceptual training. Training resulted in a 9% (95% confidence interval, 4%-14%, P = 0.0004, t(166) = 3.60) increase in detection accuracy, and a 72-millisecond (95% confidence interval, 40-103 milliseconds, P < 0.0001, t(166) = -4.52) speeding of response times in attentionally demanding and noisy conditions that were designed to simulate an operating room. This study illustrates the benefits of multisensory training and sets the stage for further work to better define the role of perceptual training in clinical anesthesiology. PMID:24846194

  10. Perceptual Fading without Retinal Adaptation

    ERIC Educational Resources Information Center

    Hsieh, Po-Jang; Colas, Jaron T.

    2012-01-01

    A retinally stabilized object readily undergoes perceptual fading and disappears from consciousness. This startling phenomenon is commonly believed to arise from local bottom-up sensory adaptation to edge information that occurs early in the visual pathway, such as in the lateral geniculate nucleus of the thalamus or retinal ganglion cells. Here…

  11. Introduction to cache memories Prof. Cristina Silvano

    E-print Network

    Silvano, Cristina

    hierarchy · Cache memories: basic concepts · Architecture of a cache memory: · Direct Mapped Cache · Fully: Memory Hierarchy · To use several levels of memory, each level with differerent size and speed at each level of the hierarchy Levels of memory hierarchy Level 2 Level 1 Level n #12;Cristina Silvano, 04

  12. Recognition Memory for Realistic Synthetic Faces

    PubMed Central

    Yotsumoto, Yuko; Kahana, Michael J.; Wilson, Hugh R.; Sekuler, Robert

    2006-01-01

    A series of experiments examined short-term recognition memory for trios of briefly-presented, synthetic human faces derived from three real human faces. The stimuli were graded series of faces, which differed by varying known amounts from the face of the average female. Faces based on each of the three real faces were transformed so as to lie along orthogonal axes in a 3-D face space. Experiment 1 showed that the synthetic faces' perceptual similarity stucture strongly influenced recognition memory. Results were fit by NEMo, a noisy exemplar model of perceptual recognition memory. The fits revealed that recognition memory was influenced both by the similarity of the probe to series items, and by the similarities among the series items themselves. Non-metric multi-dimensional scaling (MDS) showed that faces' perceptual representations largely preserved the 3-D space in which the face stimuli were arrayed. NEMo gave a better account of the results when similarity was defined as perceptual, MDS similarity rather than physical proximity of one face to another. Experiment 2 confirmed the importance of within-list homogeneity directly, without mediation of a model. We discuss the affinities and differences between visual memory for synthetic faces and memory for simpler stimuli. PMID:17948069

  13. Perceptual Segment Clustering For Music Description And Time-axis Redundancy Cancellation

    Microsoft Academic Search

    Tristan Jehan

    2004-01-01

    Repeating sounds and patterns are widely exploited throughout music. However, although analysis and mu- sic information retrieval applications are often concerned with processing speed and music description, they typi- cally discard the benefits of sound redundancy cancella- tion. We propose a perceptually grounded model for de- scribing music as a sequence of labeled sound segments, for reducing data complexity, and

  14. Effects of Perceptual and Conceptual Similarity in Lexical Priming of Young Children Who Stutter: Preliminary Findings

    ERIC Educational Resources Information Center

    Hartfield, Kia N.; Conture, Edward G.

    2006-01-01

    The purpose of this study was to investigate the influence of conceptual and perceptual properties of words on the speed and accuracy of lexical retrieval of children who do (CWS) and do not stutter (CWNS) during a picture-naming task. Participants consisted of 13 3-5-year-old CWS and the same number of CWNS. All participants had speech, language,…

  15. Learning to Control Collisions: The Role of Perceptual Attunement and Action Boundaries

    ERIC Educational Resources Information Center

    Fajen, Brett R.; Devaney, Michael C.

    2006-01-01

    The authors investigated the role of perceptual attunement in an emergency braking task in which participants waited until the last possible moment to slam on the brakes. Effects of the size of the approached object and initial speed on the initiation of braking were used to identify the optical variables on which participants relied at various…

  16. Musically Cued Gait-Training Improves Both Perceptual and Motor Timing in Parkinson’s Disease

    PubMed Central

    Benoit, Charles-Etienne; Dalla Bella, Simone; Farrugia, Nicolas; Obrig, Hellmuth; Mainka, Stefan; Kotz, Sonja A.

    2014-01-01

    It is well established that auditory cueing improves gait in patients with idiopathic Parkinson’s disease (IPD). Disease-related reductions in speed and step length can be improved by providing rhythmical auditory cues via a metronome or music. However, effects on cognitive aspects of motor control have yet to be thoroughly investigated. If synchronization of movement to an auditory cue relies on a supramodal timing system involved in perceptual, motor, and sensorimotor integration, auditory cueing can be expected to affect both motor and perceptual timing. Here, we tested this hypothesis by assessing perceptual and motor timing in 15 IPD patients before and after a 4-week music training program with rhythmic auditory cueing. Long-term effects were assessed 1?month after the end of the training. Perceptual and motor timing was evaluated with a battery for the assessment of auditory sensorimotor and timing abilities and compared to that of age-, gender-, and education-matched healthy controls. Prior to training, IPD patients exhibited impaired perceptual and motor timing. Training improved patients’ performance in tasks requiring synchronization with isochronous sequences, and enhanced their ability to adapt to durational changes in a sequence in hand tapping tasks. Benefits of cueing extended to time perception (duration discrimination and detection of misaligned beats in musical excerpts). The current results demonstrate that auditory cueing leads to benefits beyond gait and support the idea that coupling gait to rhythmic auditory cues in IPD patients relies on a neuronal network engaged in both perceptual and motor timing. PMID:25071522

  17. Perceptual Color Characterization of Cameras

    PubMed Central

    Vazquez-Corral, Javier; Connah, David; Bertalmío, Marcelo

    2014-01-01

    Color camera characterization, mapping outputs from the camera sensors to an independent color space, such as XY Z, is an important step in the camera processing pipeline. Until now, this procedure has been primarily solved by using a 3 × 3 matrix obtained via a least-squares optimization. In this paper, we propose to use the spherical sampling method, recently published by Finlayson et al., to perform a perceptual color characterization. In particular, we search for the 3 × 3 matrix that minimizes three different perceptual errors, one pixel based and two spatially based. For the pixel-based case, we minimize the CIE ?E error, while for the spatial-based case, we minimize both the S-CIELAB error and the CID error measure. Our results demonstrate an improvement of approximately 3% for the ?E error, 7% for the S-CIELAB error and 13% for the CID error measures. PMID:25490586

  18. Shared neural substrates of emotionally enhanced perceptual and mnemonic vividness.

    PubMed

    Todd, Rebecca M; Schmitz, Taylor W; Susskind, Josh; Anderson, Adam K

    2013-01-01

    It is well-known that emotionally salient events are remembered more vividly than mundane ones. Our recent research has demonstrated that such memory vividness (Mviv) is due in part to the subjective experience of emotional events as more perceptually vivid, an effect we call emotionally enhanced vividness (EEV). The present study built on previously reported research in which fMRI data were collected while participants rated relative levels of visual noise overlaid on emotionally salient and neutral images. Ratings of greater EEV were associated with greater activation in the amygdala and visual cortex. In the present study, we measured BOLD activation that predicted recognition Mviv for these same images 1?week later. Results showed that, after controlling for differences between scenes in low-level objective features, hippocampus activation uniquely predicted subsequent Mviv. In contrast, amygdala and visual cortex regions that were sensitive to EEV were also modulated by subsequent ratings of Mviv. These findings suggest shared neural substrates for the influence of emotional salience on perceptual and mnemonic vividness, with amygdala and visual cortex activation at encoding contributing to the experience of both perception and subsequent memory. PMID:23653601

  19. Visual Working Memory Contents Bias Ambiguous Structure from Motion Perception

    PubMed Central

    Scocchia, Lisa; Valsecchi, Matteo; Gegenfurtner, Karl R.; Triesch, Jochen

    2013-01-01

    The way we perceive the visual world depends crucially on the state of the observer. In the present study we show that what we are holding in working memory (WM) can bias the way we perceive ambiguous structure from motion stimuli. Holding in memory the percept of an unambiguously rotating sphere influenced the perceived direction of motion of an ambiguously rotating sphere presented shortly thereafter. In particular, we found a systematic difference between congruent dominance periods where the perceived direction of the ambiguous stimulus corresponded to the direction of the unambiguous one and incongruent dominance periods. Congruent dominance periods were more frequent when participants memorized the speed of the unambiguous sphere for delayed discrimination than when they performed an immediate judgment on a change in its speed. The analysis of dominance time-course showed that a sustained tendency to perceive the same direction of motion as the prior stimulus emerged only in the WM condition, whereas in the attention condition perceptual dominance dropped to chance levels at the end of the trial. The results are explained in terms of a direct involvement of early visual areas in the active representation of visual motion in WM. PMID:23527141

  20. Speed(s).

    ERIC Educational Resources Information Center

    Levy-Leblond, Jean-Marc

    1980-01-01

    Presents three simple distinct operational procedures for transforming the empirical notion of speed into a formal concept. The relationship between these three procedures and Galilean velocity and Einsteinian relativity is also included. (HM)

  1. Memory Hierarchy Management for Iterative Graph Structures

    Microsoft Academic Search

    Ibraheem Al-furaih; Sanjay Ranka

    1998-01-01

    The increasing gap in processor and memory speeds has forced microprocessors to rely on deep cache hierarchies to keep the processors from starving for data. For many appli- cations, this results in a wide disparity between sustained and peak achievable speed. Applications need to be tuned to processor and memory system architectures for cache lo- cality, memory layout and data

  2. Emotional target cues eliminate age differences in prospective memory

    Microsoft Academic Search

    Mareike Altgassen; Louise H. Phillips; Julie D. Henry; Peter G. Rendell; Matthias Kliegel

    2010-01-01

    Cue saliency is known to influence prospective memory performance, whereby perceptually or conceptually distinct cues facilitate remembering and attenuate adult age-related deficits. The present study investigated whether similar benefits for older adults are also seen for emotional valence. A total of 41 older and 41 younger adults performed a prospective memory task in which the emotional valence of the prospective

  3. Modeling Age-Related Differences in Immediate Memory Using SIMPLE

    ERIC Educational Resources Information Center

    Surprenant, Aimee M.; Neath, Ian; Brown, Gordon D. A.

    2006-01-01

    In the SIMPLE model (Scale Invariant Memory and Perceptual Learning), performance on memory tasks is determined by the locations of items in multidimensional space, and better performance is associated with having fewer close neighbors. Unlike most previous simulations with SIMPLE, the ones reported here used measured, rather than assumed,…

  4. Sex differences in sleep-dependent perceptual learning Elizabeth A. McDevitt a,b,1,2

    E-print Network

    Whitney, David

    17 October 2013 Keywords: Perceptual learning REM sleep Napping Memory consolidation Specificity either took a nap or remained awake. Thresholds were then reassessed for both directions of motion. We of specificity in the REM condition differed between men and women. PL for men whose naps contained REM sleep

  5. Task Specific Devices and the Perceptual Bottleneck*

    E-print Network

    -segment system, the muscular system, the circulatory system, and the nervous system. A methodological dilemma properties of four subsystems of the human action system are described. The subsystems are the link. The characteristics of the human perceptual system lead to the perceptual bottleneck. Information about the dynamics

  6. Perceptual Mapping Using Ordered Logit Analysis

    Microsoft Academic Search

    Hotaka Katahira

    1990-01-01

    This study is to present a new method for constructing a perceptual map based on logit analysis. This is an extension of the explosion logit model of an individual choice to a problem of perceptual mapping giving rise to advantages over existing methods in various aspects. Firstly, input data format is flexible and user-friendly. Unlike traditional methods which typically requires

  7. Perceptual Differences between Hippies and College Students

    ERIC Educational Resources Information Center

    Brothers, Robert; Gaines, Rosslyn

    1973-01-01

    Perceptual differences were investigated between 50 college students who were non-drug users and 50 hippies who used LSD. The major hypothesis predicted was that hippies would score differently from college students in a specific direction on each of the perceptual tasks. (Author)

  8. Awareness as a perceptual model of attention

    Microsoft Academic Search

    Michael S. A. Graziano; Sabine Kastner

    2011-01-01

    We proposed a theory of consciousness in which the machinery for social perception constructs awareness, and awareness is a perceptual model of the process of attention. One can attribute awareness to others or to oneself. Awareness of X is the brain's perceptual metaphor for the deep attentive processing of X. A set of ten comments on our hypothesis are included

  9. Transient and sustained activity in a distributed neural system for human working memory

    Microsoft Academic Search

    Susan M. Courtney; Leslie G. Ungerleider; Katrina Keil; James V. Haxby

    1997-01-01

    Working memory involves the short-term maintenance of an active representation of information so that it is available for further processing. Visual working memory tasks, in which subjects retain the memory of a stimulus over brief delays, require both the perceptual encoding of the stimulus and the subsequent maintenance of its representation after the stimulus is removed from view. Such tasks

  10. Action Control: Independent Effects of Memory and Monocular Viewing on Reaching Accuracy

    ERIC Educational Resources Information Center

    Westwood, D.A.; Robertson, C.; Heath, M.

    2005-01-01

    Evidence suggests that perceptual networks in the ventral visual pathway are necessary for action control when targets are viewed with only one eye, or when the target must be stored in memory. We tested whether memory-linked (i.e., open-loop versus memory-guided actions) and monocular-linked effects (i.e., binocular versus monocular actions) on…

  11. Repetition blindness has a perceptual locus: evidence from online processing of targets in RSVP streams

    NASA Technical Reports Server (NTRS)

    Johnston, James C.; Hochhaus, Larry; Ruthruff, Eric

    2002-01-01

    Four experiments tested whether repetition blindness (RB; reduced accuracy reporting repetitions of briefly displayed items) is a perceptual or a memory-recall phenomenon. RB was measured in rapid serial visual presentation (RSVP) streams, with the task altered to reduce memory demands. In Experiment 1 only the number of targets (1 vs. 2) was reported, eliminating the need to remember target identities. Experiment 2 segregated repeated and nonrepeated targets into separate blocks to reduce bias against repeated targets. Experiments 3 and 4 required immediate "online" buttonpress responses to targets as they occurred. All 4 experiments showed very strong RB. Furthermore, the online response data showed clearly that the 2nd of the repeated targets is the one missed. The present results show that in the RSVP paradigm, RB occurs online during initial stimulus encoding and decision making. The authors argue that RB is indeed a perceptual phenomenon.

  12. Perceptual Calibration for Immersive Display Environments

    PubMed Central

    Ponto, Kevin; Gleicher, Michael; Radwin, Robert G.; Shin, Hyun Joon

    2013-01-01

    The perception of objects, depth, and distance has been repeatedly shown to be divergent between virtual and physical environments. We hypothesize that many of these discrepancies stem from incorrect geometric viewing parameters, specifically that physical measurements of eye position are insufficiently precise to provide proper viewing parameters. In this paper, we introduce a perceptual calibration procedure derived from geometric models. While most research has used geometric models to predict perceptual errors, we instead use these models inversely to determine perceptually correct viewing parameters. We study the advantages of these new psychophysically determined viewing parameters compared to the commonly used measured viewing parameters in an experiment with 20 subjects. The perceptually calibrated viewing parameters for the subjects generally produced new virtual eye positions that were wider and deeper than standard practices would estimate. Our study shows that perceptually calibrated viewing parameters can significantly improve depth acuity, distance estimation, and the perception of shape. PMID:23428454

  13. Auditory cortex mediates the perceptual effects of acoustic temporal expectation

    PubMed Central

    Jaramillo, Santiago; Zador, Anthony M.

    2011-01-01

    When events occur at predictable instants, anticipation improves performance. Knowledge of event timing modulates motor circuits, improving response speed. By contrast, the neuronal mechanisms underlying changes in sensory perception due to expectation are not well understood. We have developed a novel behavioral paradigm for rats in which we manipulated expectations about sound timing. Valid expectations improved both the speed and the accuracy of subjects’ performance, indicating not only improved motor preparedness but also enhanced perception. Single neuron recordings in primary auditory cortex revealed enhanced representation of sounds during periods of heightened expectation. Furthermore, we found that activity in auditory cortex was causally linked to the performance of the task, and that changes in the neuronal representation of sounds predicted performance on a trial-by-trial basis. Our results indicate that changes in neuronal representation as early as primary sensory cortex mediate the perceptual advantage conferred by temporal expectation. PMID:21170056

  14. Perceptual estimation obeys Occam's razor

    PubMed Central

    Gershman, Samuel J.; Niv, Yael

    2013-01-01

    Theoretical models of unsupervised category learning postulate that humans “invent” categories to accommodate new patterns, but tend to group stimuli into a small number of categories. This “Occam's razor” principle is motivated by normative rules of statistical inference. If categories influence perception, then one should find effects of category invention on simple perceptual estimation. In a series of experiments, we tested this prediction by asking participants to estimate the number of colored circles on a computer screen, with the number of circles drawn from a color-specific distribution. When the distributions associated with each color overlapped substantially, participants' estimates were biased toward values intermediate between the two means, indicating that subjects ignored the color of the circles and grouped different-colored stimuli into one perceptual category. These data suggest that humans favor simpler explanations of sensory inputs. In contrast, when the distributions associated with each color overlapped minimally, the bias was reduced (i.e., the estimates for each color were closer to the true means), indicating that sensory evidence for more complex explanations can override the simplicity bias. We present a rational analysis of our task, showing how these qualitative patterns can arise from Bayesian computations. PMID:24137136

  15. Broad-based visual benefits from training with an integrated perceptual-learning video game.

    PubMed

    Deveau, Jenni; Lovcik, Gary; Seitz, Aaron R

    2014-06-01

    Perception is the window through which we understand all information about our environment, and therefore deficits in perception due to disease, injury, stroke or aging can have significant negative impacts on individuals' lives. Research in the field of perceptual learning has demonstrated that vision can be improved in both normally seeing and visually impaired individuals, however, a limitation of most perceptual learning approaches is their emphasis on isolating particular mechanisms. In the current study, we adopted an integrative approach where the goal is not to achieve highly specific learning but instead to achieve general improvements to vision. We combined multiple perceptual learning approaches that have individually contributed to increasing the speed, magnitude and generality of learning into a perceptual-learning based video-game. Our results demonstrate broad-based benefits of vision in a healthy adult population. Transfer from the game includes; improvements in acuity (measured with self-paced standard eye-charts), improvement along the full contrast sensitivity function, and improvements in peripheral acuity and contrast thresholds. The use of this type of this custom video game framework built up from psychophysical approaches takes advantage of the benefits found from video game training while maintaining a tight link to psychophysical designs that enable understanding of mechanisms of perceptual learning and has great potential both as a scientific tool and as therapy to help improve vision. PMID:24406157

  16. Perceptual Training Strongly Improves Visual Motion Perception in Schizophrenia

    ERIC Educational Resources Information Center

    Norton, Daniel J.; McBain, Ryan K.; Ongur, Dost; Chen, Yue

    2011-01-01

    Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients' perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it…

  17. Adaptive response-time-based category sequencing in perceptual learning.

    PubMed

    Mettler, Everett; Kellman, Philip J

    2014-06-01

    Although much recent work in perceptual learning (PL) has focused on basic sensory discriminations, recent analyses suggest that PL in a variety of tasks depends on processes that discover and select information relevant to classifications being learned (Kellman & Garrigan, 2009; Petrov, Dosher, & Lu, 2005). In complex, real-world tasks, discovery involves finding structural invariants amidst task-irrelevant variation (Gibson, 1969), allowing learners to correctly classify new stimuli. The applicability of PL methods to such tasks offers important opportunities to improve learning. It also raises questions about how learning might be optimized in complex tasks and whether variables that influence other forms of learning also apply to PL. We investigated whether an adaptive, response-time-based, category sequencing algorithm implementing laws of spacing derived from memory research would also enhance perceptual category learning and transfer to novel cases. Participants learned to classify images of 12 different butterfly genera under conditions of: (1) random presentation, (2) adaptive category sequencing, and (3) adaptive category sequencing with 'mini-blocks' (grouping 3 successive category exemplars). We found significant effects on efficiency of learning for adaptive category sequencing, reliably better than for random presentation and mini-blocking (Experiment 1). Effects persisted across a 1-week delay and were enhanced for novel items. Experiment 2 showed even greater effects of adaptive learning for perceptual categories containing lower variability. These results suggest that adaptive category sequencing increases the efficiency of PL and enhances generalization of PL to novel stimuli, key components of high-level PL and fundamental requirements of learning in many domains. PMID:24380704

  18. Using Virtual Reality to Characterize Episodic Memory Profiles in Amnestic Mild Cognitive Impairment and Alzheimer's Disease: Influence of Active and Passive Encoding

    ERIC Educational Resources Information Center

    Plancher, G.; Tirard, A.; Gyselinck, V.; Nicolas, S.; Piolino, P.

    2012-01-01

    Most neuropsychological assessments of episodic memory bear little similarity to the events that patients actually experience as memories in daily life. The first aim of this study was to use a virtual environment to characterize episodic memory profiles in an ecological fashion, which includes memory for central and perceptual details,…

  19. The future of memory

    NASA Astrophysics Data System (ADS)

    Marinella, M.

    In the not too distant future, the traditional memory and storage hierarchy of may be replaced by a single Storage Class Memory (SCM) device integrated on or near the logic processor. Traditional magnetic hard drives, NAND flash, DRAM, and higher level caches (L2 and up) will be replaced with a single high performance memory device. The Storage Class Memory paradigm will require high speed (< 100 ns read/write), excellent endurance (> 1012), nonvolatility (retention > 10 years), and low switching energies (< 10 pJ per switch). The International Technology Roadmap for Semiconductors (ITRS) has recently evaluated several potential candidates SCM technologies, including Resistive (or Redox) RAM, Spin Torque Transfer RAM (STT-MRAM), and phase change memory (PCM). All of these devices show potential well beyond that of current flash technologies and research efforts are underway to improve the endurance, write speeds, and scalabilities to be on-par with DRAM. This progress has interesting implications for space electronics: each of these emerging device technologies show excellent resistance to the types of radiation typically found in space applications. Commercially developed, high density storage class memory-based systems may include a memory that is physically radiation hard, and suitable for space applications without major shielding efforts. This paper reviews the Storage Class Memory concept, emerging memory devices, and possible applicability to radiation hardened electronics for space.

  20. Perceptually oriented hypnosis: cross-cultural perspectives.

    PubMed

    Woodard, Fredrick James

    2005-08-01

    Literature is reviewed and summarized relevant to present cross-cultural, shamanic, and spiritual aspects of hypnosis. Explanations are offered within the framework of Woodard's theory of Perceptually Oriented Hypnosis. Research on cross-cultural aspects of hypnosis could enhance understanding of phenomenological and perceptual aspects of hypnosis, increase knowledge of hypnotic phenomena, and expand understanding of perceptual awareness. A summary of the qualitative research methodologies to enhance understanding of multicultural hypnotic experiences is presented. This groundwork provides for further exploration of cross-cultural hypnosis. Surprisingly, some suggestions have remained underutilized or not published. PMID:16279318

  1. Development of Auditory-Vocal Perceptual Skills in Songbirds

    PubMed Central

    Miller-Sims, Vanessa C.; Bottjer, Sarah W.

    2012-01-01

    Songbirds are one of the few groups of animals that learn the sounds used for vocal communication during development. Like humans, songbirds memorize vocal sounds based on auditory experience with vocalizations of adult “tutors”, and then use auditory feedback of self-produced vocalizations to gradually match their motor output to the memory of tutor sounds. In humans, investigations of early vocal learning have focused mainly on perceptual skills of infants, whereas studies of songbirds have focused on measures of vocal production. In order to fully exploit songbirds as a model for human speech, understand the neural basis of learned vocal behavior, and investigate links between vocal perception and production, studies of songbirds must examine both behavioral measures of perception and neural measures of discrimination during development. Here we used behavioral and electrophysiological assays of the ability of songbirds to distinguish vocal calls of varying frequencies at different stages of vocal learning. The results show that neural tuning in auditory cortex mirrors behavioral improvements in the ability to make perceptual distinctions of vocal calls as birds are engaged in vocal learning. Thus, separate measures of neural discrimination and behavioral perception yielded highly similar trends during the course of vocal development. The timing of this improvement in the ability to distinguish vocal sounds correlates with our previous work showing substantial refinement of axonal connectivity in cortico-basal ganglia pathways necessary for vocal learning. PMID:23285011

  2. Perceptual skill in soccer: implications for talent identification and development.

    PubMed

    Williams, A M

    2000-09-01

    In this review, key components of perceptual skill in soccer are identified and implications for talent identification and development highlighted. Skilled soccer players can recall and recognize patterns of play more effectively than their less skilled counterparts. This ability to encode, retrieve and recognize sport-specific information is due to complex and discriminating long-term memory structures and is crucial to anticipation in soccer. Similarly, experts use their knowledge of situational probabilities (i.e. expectations) to anticipate future events. They have a better than average idea of what is likely to happen given a particular set of circumstances. Also, proficiency-related differences in visual search strategy are observed. Skilled players use their superior knowledge to control the eye movement patterns necessary for seeking and picking up important sources of information. The nature of the task plays an important role in constraining the type of search used. Skilled soccer players use different search strategies when viewing the whole field (i.e. 11 vs 11 situations) compared with micro-states of the game (i.e. 1 vs 1, 3 vs 3 situations). Visual search behaviour also differs between defensive and offensive plays. These observations have implications for the development of perceptual training programmes and the identification of potential elite soccer players. PMID:11043899

  3. Perceptually lossless medical image coding.

    PubMed

    Wu, David; Tan, Damian M; Baird, Marilyn; DeCampo, John; White, Chris; Wu, Hong Ren

    2006-03-01

    A novel perceptually lossless coder is presented for the compression of medical images. Built on the JPEG 2000 coding framework, the heart of the proposed coder is a visual pruning function, embedded with an advanced human vision model to identify and to remove visually insignificant/irrelevant information. The proposed coder offers the advantages of simplicity and modularity with bit-stream compliance. Current results have shown superior compression ratio gains over that of its information lossless counterparts without any visible distortion. In addition, a case study consisting of 31 medical experts has shown that no perceivable difference of statistical significance exists between the original images and the images compressed by the proposed coder. PMID:16524089

  4. Probing perceptual decisions in rodents

    PubMed Central

    Carandini, Matteo; Churchland, Anne K

    2014-01-01

    The study of perceptual decision-making offers insight into how the brain uses complex, sometimes ambiguous information to guide actions. Understanding the underlying processes and their neural bases requires that one pair recordings and manipulations of neural activity with rigorous psychophysics. Though this research has been traditionally performed in primates, it seems increasingly promising to pursue it at least partly in mice and rats. However, rigorous psychophysical methods are not yet as developed for these rodents as they are for primates. Here we give a brief overview of the sensory capabilities of rodents and of their cortical areas devoted to sensation and decision. We then review methods of psychophysics, focusing on the technical issues that arise in their implementation in rodents. These methods represent a rich set of challenges and opportunities. PMID:23799475

  5. Distortions in memory for visual displays

    NASA Technical Reports Server (NTRS)

    Tversky, Barbara

    1989-01-01

    Systematic errors in perception and memory present a challenge to theories of perception and memory and to applied psychologists interested in overcoming them as well. A number of systematic errors in memory for maps and graphs are reviewed, and they are accounted for by an analysis of the perceptual processing presumed to occur in comprehension of maps and graphs. Visual stimuli, like verbal stimuli, are organized in comprehension and memory. For visual stimuli, the organization is a consequence of perceptual processing, which is bottom-up or data-driven in its earlier stages, but top-down and affected by conceptual knowledge later on. Segregation of figure from ground is an early process, and figure recognition later; for both, symmetry is a rapidly detected and ecologically valid cue. Once isolated, figures are organized relative to one another and relative to a frame of reference. Both perceptual (e.g., salience) and conceptual factors (e.g., significance) seem likely to affect selection of a reference frame. Consistent with the analysis, subjects perceived and remembered curves in graphs and rivers in maps as more symmetric than they actually were. Symmetry, useful for detecting and recognizing figures, distorts map and graph figures alike. Top-down processes also seem to operate in that calling attention to the symmetry vs. asymmetry of a slightly asymmetric curve yielded memory errors in the direction of the description. Conceptual frame of reference effects were demonstrated in memory for lines embedded in graphs. In earlier work, the orientation of map figures was distorted in memory toward horizontal or vertical. In recent work, graph lines, but not map lines, were remembered as closer to an imaginary 45 deg line than they had been. Reference frames are determined by both perceptual and conceptual factors, leading to selection of the canonical axes as a reference frame in maps, but selection of the imaginary 45 deg as a reference frame in graphs.

  6. Interdisciplinary Adventures in Perceptual Ecology

    NASA Astrophysics Data System (ADS)

    Bocast, Christopher S.

    A portfolio dissertation that began as acoustic ecology and matured into perceptual ecology, centered on ecomusicology, bioacoustics, and translational audio-based media works with environmental perspectives. The place of music in Western eco-cosmology through time provides a basis for structuring an environmental history of human sound perception. That history suggests that music may stabilize human mental activity, and that an increased musical practice may be essential for the human project. An overview of recent antecedents preceding the emergence of acoustic ecology reveals structural foundations from 20th century culture that underpin modern sound studies. The contextual role that Aldo Leopold, Jacob von Uexkull, John Cage, Marshall McLuhan, and others played in anticipating the development of acoustic ecology as an interdiscipline is detailed. This interdisciplinary aspect of acoustic ecology is defined and defended, while new developments like soundscape ecology are addressed, though ultimately sound studies will need to embrace a broader concept of full-spectrum "sensory" or "perceptual" ecology. The bioacoustic fieldwork done on spawning sturgeon emphasized this necessity. That study yielded scientific recordings and spectrographic analyses of spawning sounds produced by lake sturgeon, Acipenser fulvescens, during reproduction in natural habitats in the Lake Winnebago watershed in Wisconsin. Recordings were made on the Wolf and Embarrass River during the 2011-2013 spawning seasons. Several specimens were dissected to investigate possible sound production mechanisms; no sonic musculature was found. Drumming sounds, ranging from 5 to 7 Hz fundamental frequency, verified the infrasonic nature of previously undocumented "sturgeon thunder". Other characteristic noises of sturgeon spawning including low-frequency rumbles and hydrodynamic sounds were identified. Intriguingly, high-frequency signals resembling electric organ discharges were discovered. These sounds create a distinctive acoustic signature of sturgeon spawning. Media files include concert performance video, sturgeon audio samples, podcasts, radio pieces, music recordings, sound design, and a time-lapse soundscape reconstructed from Aldo Leopold's notes.

  7. Sex differences in sleep-dependent perceptual learning.

    PubMed

    McDevitt, Elizabeth A; Rokem, Ariel; Silver, Michael A; Mednick, Sara C

    2014-06-01

    Sex differences in learning and memory suggest differences between men and women in mechanisms of neural plasticity. Such differences have been reported in a variety of explicit memory tasks, but implicit memory has not been studied in this context. We investigated differences between men and women in offline consolidation of perceptual learning (PL) of motion direction discrimination. Initially, discrimination thresholds were measured for two opposite directions of motion, followed by approximately 40 minutes of training on one of the directions. During a post-training consolidation period, subjects either took a nap or remained awake. Thresholds were then reassessed for both directions of motion. We found that rapid eye movement (REM) sleep facilitates consolidation of PL but that the pattern of specificity in the REM condition differed between men and women. PL for men whose naps contained REM sleep was highly specific to the trained direction of motion, whereas REM sleep in women resulted in generalized learning to the untrained direction as well as to a novel direction that was not previously tested. Moreover, for subjects in the REM condition, men exhibited greater PL than women for the trained direction. Our findings provide the first evidence of sex differences in the magnitude and specificity of PL and in the role of REM sleep in implicit learning. Our results have important implications for optimization of educational and training strategies designed for males and females. PMID:24141074

  8. Emergence and perceptual guidance of prehensile action 

    E-print Network

    Smith, Joanne

    2009-01-01

    Successful coordination of prehensile action depends upon the selection and control of appropriate reach and grasp movements. This thesis explores how prehensile actions are shaped and regulated by perceptual information. ...

  9. From perceptual to language-mediated categorization

    PubMed Central

    Westermann, Gert; Mareschal, Denis

    2014-01-01

    From at least two months onwards, infants can form perceptual categories. During the first year of life, object knowledge develops from the ability to represent individual object features to representing correlations between attributes and to integrate information from different sources. At the end of the first year, these representations are shaped by labels, opening the way to conceptual knowledge. Here, we review the development of object knowledge and object categorization over the first year of life. We then present an artificial neural network model that models the transition from early perceptual categorization to categories mediated by labels. The model informs a current debate on the role of labels in object categorization by suggesting that although labels do not act as object features they nevertheless affect perceived similarity of perceptually distinct objects sharing the same label. The model presents the first step of an integrated account from early perceptual categorization to language-based concept learning. PMID:24324235

  10. Studying real-world perceptual expertise

    PubMed Central

    Shen, Jianhong; Mack, Michael L.; Palmeri, Thomas J.

    2014-01-01

    Significant insights into visual cognition have come from studying real-world perceptual expertise. Many have previously reviewed empirical findings and theoretical developments from this work. Here we instead provide a brief perspective on approaches, considerations, and challenges to studying real-world perceptual expertise. We discuss factors like choosing to use real-world versus artificial object domains of expertise, selecting a target domain of real-world perceptual expertise, recruiting experts, evaluating their level of expertise, and experimentally testing experts in the lab and online. Throughout our perspective, we highlight expert birding (also called birdwatching) as an example, as it has been used as a target domain for over two decades in the perceptual expertise literature. PMID:25147533

  11. Robot Partners: Collaborative Perceptual Robotic Systems

    E-print Network

    Little, Jim

    Robot Partners: Collaborative Perceptual Robotic Systems Working paper Cooperative Distributed robotic systems, including remote-brained soccer players, visually guided mobile robots, and visual been supported by the the Networks of Centres of Excellence Institute for Robotics and Intelligent

  12. Cognitive Perceptual Deficits in Elderly Delirious Patients 

    E-print Network

    McGrory, Sarah

    2008-06-27

    Objectives: The aim was to examine the cognitive deficits caused by delirium, with the specific goal of investigating the prevalence of cognitive perceptual deficits. To ensure this deficit is not a result of a general cognitive impairment...

  13. Greater perceptual sensitivity to happy facial expression.

    PubMed

    Maher, Stephen; Ekstrom, Tor; Chen, Yue

    2014-01-01

    Perception of subtle facial expressions is essential for social functioning; yet it is unclear if human perceptual sensitivities differ in detecting varying types of facial emotions. Evidence diverges as to whether salient negative versus positive emotions (such as sadness versus happiness) are preferentially processed. Here, we measured perceptual thresholds for the detection of four types of emotion in faces--happiness, fear, anger, and sadness--using psychophysical methods. We also evaluated the association of the perceptual performances with facial morphological changes between neutral and respective emotion types. Human observers were highly sensitive to happiness compared with the other emotional expressions. Further, this heightened perceptual sensitivity to happy expressions can be attributed largely to the emotion-induced morphological change of a particular facial feature (end-lip raise). PMID:25669052

  14. Using a multinomial tree model for detecting mixtures in perceptual detection

    PubMed Central

    Chechile, Richard A.

    2014-01-01

    In the area of memory research there have been two rival approaches for memory measurement—signal detection theory (SDT) and multinomial processing trees (MPT). Both approaches provide measures for the quality of the memory representation, and both approaches provide for corrections for response bias. In recent years there has been a strong case advanced for the MPT approach because of the finding of stochastic mixtures on both target-present and target-absent tests. In this paper a case is made that perceptual detection, like memory recognition, involves a mixture of processes that are readily represented as a MPT model. The Chechile (2004) 6P memory measurement model is modified in order to apply to the case of perceptual detection. This new MPT model is called the Perceptual Detection (PD) model. The properties of the PD model are developed, and the model is applied to some existing data of a radiologist examining CT scans. The PD model brings out novel features that were absent from a standard SDT analysis. Also the topic of optimal parameter estimation on an individual-observer basis is explored with Monte Carlo simulations. These simulations reveal that the mean of the Bayesian posterior distribution is a more accurate estimator than the corresponding maximum likelihood estimator (MLE). Monte Carlo simulations also indicate that model estimates based on only the data from an individual observer can be improved upon (in the sense of being more accurate) by an adjustment that takes into account the parameter estimate based on the data pooled across all the observers. The adjustment of the estimate for an individual is discussed as an analogous statistical effect to the improvement over the individual MLE demonstrated by the James–Stein shrinkage estimator in the case of the multiple-group normal model. PMID:25018741

  15. Perceptual Factors Influence Visual Search for Meaningful Symbols in Individuals with Intellectual Disabilities and Down Syndrome or Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Wilkinson, Krista M.; McIlvane, William J.

    2013-01-01

    Augmentative and alternative communication (AAC) systems often supplement oral communication for individuals with intellectual and communication disabilities. Research with preschoolers without disabilities has demonstrated that two visual--perceptual factors influence speed and/or accuracy of finding a target: the internal color and spatial…

  16. Is perceptual space inherently non-Euclidean?

    PubMed

    Fernandez, Julian Martin; Farell, Bart

    2009-04-01

    It is often assumed that the space we perceive is Euclidean, although this idea has been challenged by many authors. Here we show that, if spatial cues are combined as described by Maximum Likelihood Estimation, Bayesian, or equivalent models, as appears to be the case, then Euclidean geometry cannot describe our perceptual experience. Rather, our perceptual spatial structure would be better described as belonging to an arbitrarily curved Riemannian space. PMID:20161280

  17. Short-Term Memory Affects Color Perception in Context

    PubMed Central

    Olkkonen, Maria; Allred, Sarah R.

    2014-01-01

    Color-based object selection — for instance, looking for ripe tomatoes in the market — places demands on both perceptual and memory processes: it is necessary to form a stable perceptual estimate of surface color from a variable visual signal, as well as to retain multiple perceptual estimates in memory while comparing objects. Nevertheless, perceptual and memory processes in the color domain are generally studied in separate research programs with the assumption that they are independent. Here, we demonstrate a strong failure of independence between color perception and memory: the effect of context on color appearance is substantially weakened by a short retention interval between a reference and test stimulus. This somewhat counterintuitive result is consistent with Bayesian estimation: as the precision of the representation of the reference surface and its context decays in memory, prior information gains more weight, causing the retained percepts to be drawn toward prior information about surface and context color. This interaction implies that to fully understand information processing in real-world color tasks, perception and memory need to be considered jointly. PMID:24475131

  18. Topographic generalization of tactile perceptual learning.

    PubMed

    Harrar, Vanessa; Spence, Charles; Makin, Tamar R

    2014-02-01

    Perceptual learning can improve our sensory abilities. Understanding its underlying mechanisms, in particular, when perceptual learning generalizes, has become a focus of research and controversy. Specifically, there is little consensus regarding the extent to which tactile perceptual learning generalizes across fingers. We measured tactile orientation discrimination abilities on 4 fingers (index and middle fingers of both hands), using psychophysical measures, before and after 4 training sessions on 1 finger. Given the somatotopic organization of the hand representation in the somatosensory cortex, the topography of the cortical areas underlying tactile perceptual learning can be inferred from the pattern of generalization across fingers; only fingers sharing cortical representation with the trained finger ought to improve with it. Following training, performance improved not only for the trained finger but also for its adjacent and homologous fingers. Although these fingers were not exposed to training, they nevertheless demonstrated similar levels of learning as the trained finger. Conversely, the performance of the finger that was neither adjacent nor homologous to the trained finger was unaffected by training, despite the fact that our procedure was designed to enhance generalization, as described in recent visual perceptual learning research. This pattern of improved performance is compatible with previous reports of neuronal receptive fields (RFs) in the primary somatosensory cortex (SI) spanning adjacent and homologous digits. We conclude that perceptual learning rooted in low-level cortex can still generalize, and suggest potential applications for the neurorehabilitation of syndromes associated with maladaptive plasticity in SI. PMID:23855526

  19. Common and Distinct Neural Correlates of Perceptual and Memorial Selection

    E-print Network

    Jonides, John

    demonstrate that both functions elicit largely overlapping networks within the dorsolateral prefrontal cortex preferential involvement in selective attention, whereas left ventrolateral prefrontal cortex (VLPFC of prefrontal cortex (PFC) and posterior parietal cortex (PPC) play a critical role in selecting among competing

  20. Source misattributions and false recognition errors: Examining the role of perceptual resemblance and imagery generation processes.

    PubMed

    Foley, Mary Ann; Bays, Rebecca Brooke; Foy, Jeffrey; Woodfield, Mila

    2015-07-01

    In three experiments, we examine the extent to which participants' memory errors are affected by the perceptual features of an encoding series and imagery generation processes. Perceptual features were examined by manipulating the features associated with individual items as well as the relationships among items. An encoding instruction manipulation was included to examine the effects of explicit requests to generate images. In all three experiments, participants falsely claimed to have seen pictures of items presented as words, committing picture misattribution errors. These misattribution errors were exaggerated when the perceptual resemblance between pictures and images was relatively high (Experiment 1) and when explicit requests to generate images were omitted from encoding instructions (Experiments 1 and 2). When perceptual cues made the thematic relationships among items salient, the level and pattern of misattribution errors were also affected (Experiments 2 and 3). Results address alternative views about the nature of internal representations resulting in misattribution errors and refute the idea that these errors reflect only participants' general impressions or beliefs about what was seen. PMID:24931435

  1. Changes across the psychometric function following perceptual learning of an RSVP reading task

    PubMed Central

    Coates, Daniel R.; Chung, Susana T. L.

    2014-01-01

    Several recent studies have shown that perceptual learning can result in improvements in reading speed for people with macular disease (e.g., Chung, 2011; Tarita-Nistor et al., 2014). The improvements were reported as an increase in reading speed defined by specific criteria; however, little is known about how other properties of the reading performance or the participants' perceptual responses change as a consequence of learning. In this paper, we performed detailed analyses of data following perceptual learning using an RSVP (rapid serial visual presentation) reading task, looking beyond the change in reading speed defined by the threshold at a given accuracy on a psychometric function relating response accuracy with word exposure duration. Specifically, we explored the statistical characteristics of the response data to address two specific questions: was there a change in the slope of the psychometric function and did the improvements in performance occur consistently across different word exposure durations? Our results show that there is a general steepening of the slope of the psychometric function, leading to non-uniform improvements across stimulus levels. PMID:25566119

  2. Physiologic and perceptual responses during treadmill running with ankle weights.

    PubMed

    Bhambhani, Y N; Gomes, P S; Wheeler, G

    1990-03-01

    This study examined the effects of ankle weighting on physiologic and perceptual responses during treadmill running in seven healthy, female recreational runners with a mean maximal aerobic power of 48.4 +/- 4.0 ml/kg/min. Each subject completed four experimental one-mile runs at individually selected treadmill running speeds with 0, 1.6, 3.2 and 4.8 kg weights on their ankles. The subjects selected a speed at which they would run (train) if their objectives were to significantly improve cardiovascular function and induce weight loss. Metabolic and cardiovascular responses were continuously monitored, and ratings of perceived exertion were recorded near the end of the activity. During the unweighted run, the subjects selected a running speed of 6.87 +/- 0.63 mph which resulted in a net energy expenditure of 0.153 kcal/kg/min or 1.34 +/- 0.16 kcal/kg/mile. This corresponded to a training intensity of 76.3% +/- 5.1% of maximum oxygen consumption or 88.1% +/- 9.7% of maximum heart rate. Addition of weight to the ankles caused a significant decrease (p less than .05) in the running speed selected and, therefore, did not result in any significant changes (p greater than .05) in the rate of oxygen consumption, heart rate or ratings of perceived exertion when compared to the unweighted condition. These observations are in contrast to previous studies on ankle weighting which were conducted at fixed treadmill running speeds. However, the use of ankle weights did have a tendency to increase gross and net energy expenditure of running when values were expressed in kcal/mile because of slower self-selected running speeds under these conditions. This increase in energy expenditure could be of physiologic significance if running with ankle weights was performed on a regular basis at a fixed distance. PMID:2317142

  3. Perceptual categories for spatial layout.

    PubMed

    Kersten, D

    1997-08-29

    The central problems of vision are often divided into object identification and localization. Object identification, at least at fine levels of discrimination, may require the application of top-down knowledge to resolve ambiguous image information. Utilizing top-down knowledge, however, may require the initial rapid access of abstract object categories based on low-level image cues. Does object localization require a different set of operating principles than object identification or is category determination also part of the perception of depth and spatial layout? Three-dimensional graphics movies of objects and their cast shadows are used to argue that identifying perceptual categories is important for determining the relative depths of objects. Processes that can identify the causal class (e.g. the kind of material) that generates the image data can provide information to determine the spatial relationships between surfaces. Changes in the blurriness of an edge may be characteristically associated with shadows caused by relative motion between two surfaces. The early identification of abstract events such as moving object/shadow pairs may also be important for depth from shadows. Knowledge of how correlated motion in the image relates to an object and its shadow may provide a reliable cue to access such event categories. PMID:9304683

  4. Co-occurring disorders: a possible key to visual perceptual deficits in children with developmental coordination disorder?

    PubMed

    Crawford, S G; Dewey, D

    2008-02-01

    A study was conducted to examine how visual perceptual functioning in children with DCD may be influenced by co-occurring learning problems such as reading disabilities (RD) and/or attention deficit hyperactivity disorder (ADHD). Participants included seven groups of children: 27 children with DCD only, 11 with ADHD only, 14 with RD only, 63 with DCD and at least one other disorder (i.e., DCD + ADHD, DCD + RD, DCD + ADHD + RD), and 73 typically developing controls. Visual perceptual skills were assessed using the Test of Visual Perceptual Skills (TVPS) and the Rey Osterreith Complex Figure (ROCF; copy and delayed recall). Children with DCD and at least one other disorder were found to have impairments on the TVPS compared to children with DCD only, ADHD only, and typically developing controls, particularly on subtests assessing visual memory. On the ROCF, children with DCD and at least one other disorder scored significantly lower than children with ADHD only or RD only. Children with DCD plus one other disorder were then subdivided into three groups: DCD + ADHD, DCD + RD, and DCD + ADHD + RD and compared to children with DCD only, ADHD only, and RD only. Results indicated that children with DCD + ADHD + RD had significant impairments on the TVPS compared to children with DCD only and children with ADHD only. On the ROCF, children with DCD + ADHD + RD scored significantly lower than all of the groups, except the DCD+RD group. These findings suggest that DCD on its own is not associated with visual perceptual problems; rather, it is the presence of co-occurring disorders that is a possible key to visual perceptual deficits in children with DCD. The number of co-occurring disorders present with DCD is associated with the severity of the visual perceptual dysfunction. Deficits in visual memory skills appear to be a specific area of difficulty for children with DCD and co-occurring RD and/or ADHD. PMID:18192047

  5. Reducing the vigilance decrement: The effects of perceptual variability.

    PubMed

    Thomson, David R; Smilek, Daniel; Besner, Derek

    2015-05-01

    The longer we are required to monitor for rare but critical events, the accuracy and speed with which we detect such events tend to suffer (the 'vigilance decrement') with more difficult tasks yielding larger decrements. Here, we present a striking example of a situation in which increasing the difficulty and complexity of a novel vigilance task actually decreases the vigilance decrement. In a 'Stable' condition participants monitored for the same critical target throughout the task, whereas in a 'Variable' condition, participants monitored for many possible instantiations of the critical target. Despite the fact that the Variable condition was objectively more difficult, the vigilance decrement was significantly reduced in response times relative to the Stable condition. We discuss these findings in light of 'overload' and 'underload' theories of the vigilance decrement and suggest that perceptual variability may provide bottom-up support for the maintenance of attentional resource allocation to an external task. PMID:25749256

  6. It does not look odd to me: Perceptual impairments and eye movements in amnesic patients with medial temporal lobe damage

    PubMed Central

    Erez, Jonathan; Lee, Andy C.H.; Barense, Morgan D.

    2013-01-01

    Studies of people with memory impairments have shown that a specific set of brain structures in the medial temporal lobe (MTL) is vital for memory function. However, whether these structures have a role outside of memory remains contentious. Recent studies of amnesic patients with damage to two structures within the MTL, the hippocampus and the perirhinal cortex, indicated that these patients also performed poorly on perceptual tasks. More specifically, they performed worse than controls when discriminating between objects, faces and scenes with overlapping features. In order to investigate whether these perceptual deficits are reflected in their viewing strategies, we tested a group of amnesic patients with MTL damage that included the hippocampus and perirhinal cortex on a series of oddity discrimination tasks in which they had to select an odd item from a visual array. Participants' eye movements were monitored throughout the experiment. Results revealed that patients were impaired on tasks that required them to discriminate between items that shared many features, and tasks that required processing items from different viewpoints. An analysis of their eye movements revealed that they exhibited a similar viewing pattern as controls: they fixated more on the target item on trials answered correctly, but not on trials answered incorrectly. In addition, their impaired performance was not explained by an abnormal viewing-strategy that assessed their use of working memory. These results suggest that the perceptual deficits in the MTL patients are not a consequence of abnormal viewing patterns of the objects and scenes, but instead, could involve an inability to bind information gathered from several fixations into a cohesive percept. These data also support the view that MTL structures are important not only for long-term memory, but are also involved in perceptual tasks. PMID:23154380

  7. Perceived visual speed constrained by image segmentation

    NASA Technical Reports Server (NTRS)

    Verghese, P.; Stone, L. S.

    1996-01-01

    Little is known about how or where the visual system parses the visual scene into objects or surfaces. However, it is generally assumed that the segmentation and grouping of pieces of the image into discrete entities is due to 'later' processing stages, after the 'early' processing of the visual image by local mechanisms selective for attributes such as colour, orientation, depth, and motion. Speed perception is also thought to be mediated by early mechanisms tuned for speed. Here we show that manipulating the way in which an image is parsed changes the way in which local speed information is processed. Manipulations that cause multiple stimuli to appear as parts of a single patch degrade speed discrimination, whereas manipulations that perceptually divide a single large stimulus into parts improve discrimination. These results indicate that processes as early as speed perception may be constrained by the parsing of the visual image into discrete entities.

  8. Mechanical memory

    DOEpatents

    Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Albuquerque, NM); Baker, Michael S. (Albuquerque, NM)

    2006-05-16

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  9. Mechanical memory

    DOEpatents

    Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Alburquerque, NM); Baker, Michael S. (Albuquerque, NM)

    2006-08-15

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  10. Perceptual and Motor Inhibition in Adolescents/Young Adults with Childhood-Diagnosed ADHD

    PubMed Central

    Bedard, Anne-Claude V.; Trampush, Joey W.; Newcorn, Jeffrey H.; Halperin, Jeffrey M.

    2010-01-01

    Objective This study examined perceptual and motor inhibition in a longitudinal sample of adolescents/young adults who were diagnosed with ADHD in childhood, and as a function of the relative persistence of ADHD. Method Ninety-eight participants diagnosed with ADHD in childhood were re-evaluated approximately 10 years later. Eighty-five never-ADHD controls similar in age, IQ, sociodemographic background, and gender distribution served as a comparison group. Participants were administered a psychiatric interview and the Stimulus and Response Conflict Tasks (Nassauer & Halperin, 2003). Results Participants with childhood ADHD demonstrated slower and less accurate responses to both control and conflict conditions relative to the comparison group, as well as more variable responses in both conditions of the motor inhibition task; there was no specific effect of childhood ADHD on perceptual or motor inhibition. ADHD persisters and partial remitters did not differ in overall accuracy, speed or variability in responding, but relative to partial remitters, persisters demonstrated greater slowing in response to perceptual conflict. Conclusions These findings are consistent with theories positing state regulation, but not inhibitory control deficits in the etiology of ADHD, and suggest that improved perceptual inhibition may be associated with better outcome for ADHD. PMID:20604617

  11. Capacity-Speed Relationships in Prefrontal Cortex

    E-print Network

    Prabhakaran, Vivek

    Working memory (WM) capacity and WM processing speed are simple cognitive measures that underlie human performance in complex processes such as reasoning and language comprehension. These cognitive measures have shown to ...

  12. Cultural Differences in Perceptual Reorganization in US and Pirahã Adults

    E-print Network

    Yoon, Jennifer M. D.

    Visual illusions and other perceptual phenomena can be used as tools to uncover the otherwise hidden constructive processes that give rise to perception. Although many perceptual processes are assumed to be universal, ...

  13. Perceptual Image Compression in Telemedicine

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Ahumada, Albert J., Jr.; Eckstein, Miguel; Null, Cynthia H. (Technical Monitor)

    1996-01-01

    The next era of space exploration, especially the "Mission to Planet Earth" will generate immense quantities of image data. For example, the Earth Observing System (EOS) is expected to generate in excess of one terabyte/day. NASA confronts a major technical challenge in managing this great flow of imagery: in collection, pre-processing, transmission to earth, archiving, and distribution to scientists at remote locations. Expected requirements in most of these areas clearly exceed current technology. Part of the solution to this problem lies in efficient image compression techniques. For much of this imagery, the ultimate consumer is the human eye. In this case image compression should be designed to match the visual capacities of the human observer. We have developed three techniques for optimizing image compression for the human viewer. The first consists of a formula, developed jointly with IBM and based on psychophysical measurements, that computes a DCT quantization matrix for any specified combination of viewing distance, display resolution, and display brightness. This DCT quantization matrix is used in most recent standards for digital image compression (JPEG, MPEG, CCITT H.261). The second technique optimizes the DCT quantization matrix for each individual image, based on the contents of the image. This is accomplished by means of a model of visual sensitivity to compression artifacts. The third technique extends the first two techniques to the realm of wavelet compression. Together these two techniques will allow systematic perceptual optimization of image compression in NASA imaging systems. Many of the image management challenges faced by NASA are mirrored in the field of telemedicine. Here too there are severe demands for transmission and archiving of large image databases, and the imagery is ultimately used primarily by human observers, such as radiologists. In this presentation I will describe some of our preliminary explorations of the applications of our technology to the special problems of telemedicine.

  14. Disruptive Colouration and Perceptual Grouping

    PubMed Central

    Espinosa, Irene; Cuthill, Innes C.

    2014-01-01

    Camouflage is the primary defence of many animals and includes multiple strategies that interfere with figure-ground segmentation and object recognition. While matching background colours and textures is widespread and conceptually straightforward, less well explored are the optical ‘tricks’, collectively called disruptive colouration, that exploit perceptual grouping mechanisms. Adjacent high contrast colours create false edges, but this is not sufficient for an object’s shape to be broken up; some colours must blend with the background. We test the novel hypothesis that this will be particularly effective when the colour patches on the animal appear to belong to, not merely different background colours, but different background objects. We used computer-based experiments where human participants had to find cryptic targets on artificial backgrounds. Creating what appeared to be bi-coloured foreground objects on bi-coloured backgrounds, we generated colour boundaries that had identical local contrast but either lay within or between (illusory) objects. As predicted, error rates for targets matching what appeared to be different background objects were higher than for targets which had otherwise identical local contrast to the background but appeared to belong to single background objects. This provides evidence for disruptive colouration interfering with higher-level feature integration in addition to previously demonstrated low-level effects involving contour detection. In addition, detection was impeded in treatments where targets were on or in close proximity to multiple background colour or tone boundaries. This is consistent with other studies which show a deleterious influence of visual ‘clutter’ or background complexity on search. PMID:24466337

  15. Speaker's voice as a memory cue.

    PubMed

    Campeanu, Sandra; Craik, Fergus I M; Alain, Claude

    2015-02-01

    Speaker's voice occupies a central role as the cornerstone of auditory social interaction. Here, we review the evidence suggesting that speaker's voice constitutes an integral context cue in auditory memory. Investigation into the nature of voice representation as a memory cue is essential to understanding auditory memory and the neural correlates which underlie it. Evidence from behavioral and electrophysiological studies suggest that while specific voice reinstatement (i.e., same speaker) often appears to facilitate word memory even without attention to voice at study, the presence of a partial benefit of similar voices between study and test is less clear. In terms of explicit memory experiments utilizing unfamiliar voices, encoding methods appear to play a pivotal role. Voice congruency effects have been found when voice is specifically attended at study (i.e., when relatively shallow, perceptual encoding takes place). These behavioral findings coincide with neural indices of memory performance such as the parietal old/new recollection effect and the late right frontal effect. The former distinguishes between correctly identified old words and correctly identified new words, and reflects voice congruency only when voice is attended at study. Characterization of the latter likely depends upon voice memory, rather than word memory. There is also evidence to suggest that voice effects can be found in implicit memory paradigms. However, the presence of voice effects appears to depend greatly on the task employed. Using a word identification task, perceptual similarity between study and test conditions is, like for explicit memory tests, crucial. In addition, the type of noise employed appears to have a differential effect. While voice effects have been observed when white noise is used at both study and test, using multi-talker babble does not confer the same results. In terms of neuroimaging research modulations, characterization of an implicit memory effect reflective of voice congruency is currently lacking. PMID:25173195

  16. Perceptually-Based Adaptive JPEG Coding

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Rosenholtz, Ruth; Null, Cynthia H. (Technical Monitor)

    1996-01-01

    An extension to the JPEG standard (ISO/IEC DIS 10918-3) allows spatial adaptive coding of still images. As with baseline JPEG coding, one quantization matrix applies to an entire image channel, but in addition the user may specify a multiplier for each 8 x 8 block, which multiplies the quantization matrix, yielding the new matrix for the block. MPEG 1 and 2 use much the same scheme, except there the multiplier changes only on macroblock boundaries. We propose a method for perceptual optimization of the set of multipliers. We compute the perceptual error for each block based upon DCT quantization error adjusted according to contrast sensitivity, light adaptation, and contrast masking, and pick the set of multipliers which yield maximally flat perceptual error over the blocks of the image. We investigate the bitrate savings due to this adaptive coding scheme and the relative importance of the different sorts of masking on adaptive coding.

  17. Angular relation of axes in perceptual space

    NASA Technical Reports Server (NTRS)

    Bucher, Urs

    1992-01-01

    The geometry of perceptual space needs to be known to model spatial orientation constancy or to create virtual environments. To examine one main aspect of this geometry, the angular relation between the three spatial axes was measured. Experiments were performed consisting of a perceptual task in which subjects were asked to set independently their apparent vertical and horizontal plane. The visual background provided no other stimuli to serve as optical direction cues. The task was performed in a number of different body tilt positions with pitches and rolls varied in steps of 30 degs. The results clearly show the distortion of orthogonality of the perceptual space for nonupright body positions. Large interindividual differences were found. Deviations from orthogonality up to 25 deg were detected in the pitch as well as in the roll direction. Implications of this nonorthogonality on further studies of spatial perception and on the construction of virtual environments for human interaction is also discussed.

  18. Decoding oscillatory representations and mechanisms in memory.

    PubMed

    Jafarpour, A; Horner, A J; Fuentemilla, L; Penny, W D; Duzel, E

    2013-03-01

    A fundamental goal in memory research is to understand how information is represented in distributed brain networks and what mechanisms enable its reactivation. It is evident that progress towards this goal will greatly benefit from multivariate pattern classification (MVPC) techniques that can decode representations in brain activity with high temporal resolution. Recently, progress along these lines has been achieved by applying MVPC to neural oscillations recorded with electroencephalography (EEG) and magnetoencephalography (MEG). We highlight two examples of methodological approaches for MVPC of EEG and MEG data that can be used to study memory function. The first example aims at understanding the dynamic neural mechanisms that enable reactivation of memory representations, i.e., memory replay; we discuss how MVPC can help uncover the physiological mechanisms underlying memory replay during working memory maintenance and episodic memory. The second example aims at understanding representational differences between various types of memory, such as perceptual priming and conscious recognition memory. We also highlight the conceptual and methodological differences between these two examples. Finally, we discuss potential future applications for MVPC of EEG/MEG data in studies of memory. We conclude that despite its infancy and existing methodological challenges, MVPC of EEG and MEG data is a powerful tool with which to assess mechanistic models of memory. PMID:22561180

  19. Healthy Older Observers Show Equivalent Perceptual-Cognitive Training Benefits to Young Adults for Multiple Object Tracking

    PubMed Central

    Legault, Isabelle; Allard, Rémy; Faubert, Jocelyn

    2013-01-01

    The capacity to process complex dynamic scenes is of critical importance in real life. For instance, traveling through a crowd while avoiding collisions and maintaining orientation and good motor control requires fluent and continuous perceptual-cognitive processing. It is well documented that effects of healthy aging can influence perceptual-cognitive processes (Faubert, 2002) and that the efficiency of such processes can improve with training even for older adults (Richards et al., 2006). Here we assess the capacity of older participants to improve their tracking speed thresholds in a dynamic, virtual reality environment. Results show that this capacity is significantly affected by healthy aging but that perceptual-cognitive training can significantly reduce age-related effects in older individuals, who show an identical learning function to younger healthy adults. Data support the notion that learning in healthy older persons is maintained for processing complex dynamic scenes. PMID:23761025

  20. Perceptually optimised loudspeaker selection for the creation of personal sound

    E-print Network

    Jackson, Philip JB

    Perceptually optimised loudspeaker selection for the creation of personal sound zones Jon Francombe for perceptual factors. A search procedure was used to select 5 loudspeakers for production of 2 sound zones. Perceptually optimised loudspeaker selection of multiple audio programmes [9]. The ability to model t

  1. Category and Perceptual Learning in Subjects with Treated Wilson's Disease

    Microsoft Academic Search

    Pengjing Xu; Zhong-Lin Lu; Xiaoping Wang; Barbara Dosher; Jiangning Zhou; Daren Zhang; Yifeng Zhou

    2010-01-01

    To explore the relationship between category and perceptual learning, we examined both category and perceptual learning in patients with treated Wilson's disease (WD), whose basal ganglia, known to be important in category learning, were damaged by the disease. We measured their learning rate and accuracy in rule-based and information-integration category learning, and magnitudes of perceptual learning in a wide range

  2. Effects of Categorization and Discrimination Training on Auditory Perceptual Space

    Microsoft Academic Search

    Frank H. Guenther; Fatima T. Husain; Michael A. Cohen; Barbara G. Shinn-Cunningham

    Psychophysical phenomena such as categorical perception and the perceptual magnet effect indicate that our auditory perceptual spaces are warped for some stimuli. This paper investigates the effects of two dif- ferent kinds of training on auditory perceptual space. It is first shown that categorization training using non-speech stimuli, in which subjects learn to identify stimuli within a particular frequency range

  3. Effects of Aging on True and False Memory Formation: An fMRI Study

    ERIC Educational Resources Information Center

    Dennis, Nancy A.; Kim, Hongkeun; Cabeza, Roberto

    2007-01-01

    Compared to young, older adults are more likely to forget events that occurred in the past as well as remember events that never happened. Previous studies examining false memories and aging have shown that these memories are more likely to occur when new items share perceptual or semantic similarities with those presented during encoding. It is…

  4. Effects of aging on true and false memory formation: An fMRI study

    Microsoft Academic Search

    Nancy A. Dennis; Hongkeun Kim; Roberto Cabeza

    2007-01-01

    Compared to young, older adults are more likely to forget events that occurred in the past as well as remember events that never happened. Previous studies examining false memories and aging have shown that these memories are more likely to occur when new items share perceptual or semantic similarities with those presented during encoding. It is theorized that decreased item-specific

  5. Blocking Linear Algebra Codes for Memory Hierarchies

    Microsoft Academic Search

    Steve Carr; Ken Kennedy

    1989-01-01

    . Because computation speed and memory size are both increasing, the latency of memory, in basicmachine cycles, is also increasing. As a result, recent compiler research has focused on reducing the effective latencyby restructuring programs to take more advantage of high-speed intermediate memory (or cache, as it is usuallycalled). The problem is that many real-world programs are non-trivial to restructure,

  6. Improving memory hierarchy performance for irregular applications

    Microsoft Academic Search

    John M. Mellor-Crummey; David B. Whalley; Ken Kennedy

    1999-01-01

    Abstract The gap between,CPU speed and memory,speed in modern,com- puter systems is widening,as new,generations of hardware,are introduced. Loop blocking and prefetching transformations help bridge this gap for regular applications; however, these techniques aren’t as effective for irregular applications. This paper investi- gates using data and computation,reordering to improve memory hierarchy utilization for irregular applications on,systems with multi-level memory,hierarchies. We evaluate

  7. Picture recognition without picture identification: A method for assessing the role of perceptual information in familiarity-based picture recognition

    Microsoft Academic Search

    Moses M. Langley; Anne M. Cleary; Bogdan N. Kostic; Joshua A. Woods

    2008-01-01

    The present study examined the claim that unidentifiable test-pictures are processed and recognized on a perceptual, as opposed to a conceptual, level. Using an extension of the recognition without identification paradigm (e.g., Cleary, A. M. & Greene, R. L. (2000). Recognition without identification. Journal of Experimental Psychology: Learning, Memory, and Cognition, 26, 1063–1069; Peynircioglu, Z. F. (1990). A feeling-of-recognition without

  8. Does Perceptual-Motor Calibration Generalize across Two Different Forms of Locomotion? Investigations of Walking and Wheelchairs

    PubMed Central

    Kunz, Benjamin R.; Creem-Regehr, Sarah H.; Thompson, William B.

    2013-01-01

    The relationship between biomechanical action and perception of self-motion during walking is typically consistent and well-learned but also adaptable. This perceptual-motor coupling can be recalibrated by creating a mismatch between the visual information for self-motion and walking speed. Perceptual-motor recalibration of locomotion has been demonstrated through effects on subsequent walking without vision, showing that learned perceptual-motor coupling influences a dynamic representation of one's spatial position during walking. Our present studies test whether recalibration of wheelchair locomotion, a novel form of locomotion for typically walking individuals, similarly influences subsequent wheelchair locomotion. Furthermore, we test whether adaptation to the pairing of visual information for self-motion during one form of locomotion transfers to a different locomotion modality. We find strong effects of perceptual-motor recalibration for matched locomotion modalities – walking/walking and wheeling/wheeling. Transfer across incongruent locomotion modalities showed weak recalibration effects. The results have implications both for theories of perceptual-motor calibration mechanisms and their effects on spatial orientation, as well as for practical applications in training and rehabilitation. PMID:23424615

  9. Memory Hierarchy Hardware-Software Co-design in Embedded Systems

    E-print Network

    Ge, Zhiguo

    The memory hierarchy is the main bottleneck in modern computer systems as the gap between the speed of the processor and the memory continues to grow larger. The situation in embedded systems is even worse. The memory ...

  10. Rationale for the Perceptual Analysis Kindergarten Test.

    ERIC Educational Resources Information Center

    Pender, Robert M.

    The Perceptual Analysis Kindergarten Test is based on the rationale or thesis that learning is hierarchical. The test is used to help determine the level of the child in the hierarchy so that a remedial program can be devised to bring the child up to the level where he can develop the associative conceptualization required to be able to learn in…

  11. Learning Motion Style Synthesis from Perceptual Observations

    E-print Network

    Bregler, Christoph

    mapping between animation parameters and movement styles in perceptual space. We demonstrate style denotes the particular way that action is per- formed. In computer animation, the separation sequences. Specifically, given as input a target motion style and an arbitrary animation or pre

  12. Embodied cognition, perceptual symbols, and situation models

    Microsoft Academic Search

    Rolf A. Zwaan

    1999-01-01

    It is difficult to see how current models of discourse comprehension can be “scaled up” to account for the rich situation models that may be constructed during naturalistic language comprehension, as when readers are immersed in the story world. Recent proposals about embodied cognition and perceptual symbols, such as those put forth by Glenberg and Robertson and by Roth might

  13. Using body size to predict perceptual range

    Microsoft Academic Search

    Stephen G. Mech; Patrick A. Zollner

    2002-01-01

    We examined the relationship between body size and perceptual range (the distance at which an animal can perceive landscape elements) for a group of forest-dwelling rodents. We used previously published data on orientation ability at various distances for three sciurid species (gray squirrel, fox squirrel and chipmunk) and one murid species (white-footed mouse) to build a predictive model. We found

  14. Comparison and Contrast in Perceptual Categorization

    ERIC Educational Resources Information Center

    Hampton, James A.; Estes, Zachary; Simmons, Claire L.

    2005-01-01

    People categorized pairs of perceptual stimuli that varied in both category membership and pairwise similarity. Experiments 1 and 2 showed categorization of 1 color of a pair to be reliably contrasted from that of the other. This similarity-based contrast effect occurred only when the context stimulus was relevant for the categorization of the…

  15. Perceptual crossing: the simplest online paradigm

    PubMed Central

    Auvray, Malika; Rohde, Marieke

    2012-01-01

    Researchers in social cognition increasingly realize that many phenomena cannot be understood by investigating offline situations only, focusing on individual mechanisms and an observer perspective. There are processes of dynamic emergence specific to online situations, when two or more persons are engaged in a real-time interaction that are more than just the sum of the individual capacities or behaviors, and these require the study of online social interaction. Auvray et al.'s (2009) perceptual crossing paradigm offers possibly the simplest paradigm for studying such online interactions: two persons, a one-dimensional space, one bit of information, and a yes/no answer. This study has provoked a lot of resonance in different areas of research, including experimental psychology, computer/robot modeling, philosophy, psychopathology, and even in the field of design. In this article, we review and critically assess this body of literature. We give an overview of both behavioral experimental research and simulated agent modeling done using the perceptual crossing paradigm. We discuss different contexts in which work on perceptual crossing has been cited. This includes the controversy about the possible constitutive role of perceptual crossing for social cognition. We conclude with an outlook on future research possibilities, in particular those that could elucidate the link between online interaction dynamics and individual social cognition. PMID:22723776

  16. Perceptual and Neural Olfactory Similarity in Honeybees

    E-print Network

    Menzel, Randolf - Institut für Biologie

    Perceptual and Neural Olfactory Similarity in Honeybees Fernando Guerrieri[ , Marco Schubert unanswered. To address this question, we studied olfaction in honeybees Apis mellifera using the olfactory was asymmetric; (iv) a putative olfactory space could be defined for the honeybee with functional group

  17. Late Maturation of Auditory Perceptual Learning

    ERIC Educational Resources Information Center

    Huyck, Julia Jones; Wright, Beverly A.

    2011-01-01

    Adults can improve their performance on many perceptual tasks with training, but when does the response to training become mature? To investigate this question, we trained 11-year-olds, 14-year-olds and adults on a basic auditory task (temporal-interval discrimination) using a multiple-session training regimen known to be effective for adults. The…

  18. Improving Perceptual Skills with 3-Dimensional Animations.

    ERIC Educational Resources Information Center

    Johns, Janet Faye; Brander, Julianne Marie

    1998-01-01

    Describes three-dimensional computer aided design (CAD) models for every component in a representative mechanical system; the CAD models made it easy to generate 3-D animations that are ideal for teaching perceptual skills in multimedia computer-based technical training. Fifteen illustrations are provided. (AEF)

  19. Perceptual and Neural Olfactory Similarity in Honeybees

    Microsoft Academic Search

    Fernando Guerrieri; Marco Schubert; Jean-Christophe Sandoz; Martin Giurfa

    2005-01-01

    The question of whether or not neural activity patterns recorded in the olfactory centres of the brain correspond to olfactory perceptual measures remains unanswered. To address this question, we studied olfaction in honeybees Apis mellifera using the olfactory conditioning of the proboscis extension response. We conditioned bees to odours and tested generalisation responses to different odours. Sixteen odours were used,

  20. Perceptual Learning During Action Video Game Playing

    Microsoft Academic Search

    C. Shawn Green; Renjie Li; Daphne Bavelierb

    2009-01-01

    Action video games have been shown to enhance behavioral performance on a wide variety of perceptual tasks, from those that require effective allocation of attentional resources across the visual scene, to those that demand the successful identification of fleetingly presented stimuli. Importantly, these effects have not only been shown in expert action video game players, but a causative link has

  1. Perceptual watermarks for digital images and video

    Microsoft Academic Search

    Raymond B. Wolfgang; Christine I. Podilchuk; Edward J. Delp

    1999-01-01

    The growth of new imaging technologies has created a need for techniques that can be used for copyright protection of digital images and video. One approach for copyright protection is to introduce an invisible signal, known as a digital watermark, into an image or video sequence. In this paper, we describe digital watermarking techniques, known as perceptually based watermarks, that

  2. Adaptive Criterion Setting in Perceptual Decision Making

    ERIC Educational Resources Information Center

    Stuttgen, Maik C.; Yildiz, Ali; Gunturkun, Onur

    2011-01-01

    Pigeons responded in a perceptual categorization task with six different stimuli (shades of gray), three of which were to be classified as "light" or "dark", respectively. Reinforcement probability for correct responses was varied from 0.2 to 0.6 across blocks of sessions and was unequal for correct light and dark responses. Introduction of a new…

  3. Perceptual Grouping using Hypercolumnar Relaxation Phase Labeling

    Microsoft Academic Search

    WINFRIED A. FELLENZ

    2005-01-01

    A network for the extraction of salient image structure in dot patterns is proposed which uses a phase diffusion process to label the image into holistic perceptual objects and the background. The image is processed using three successive stages, copying the design of biological visual mechanisms. The popula- tion coded direction specific edge representation generated from phase-dependent energy filters is

  4. Infants Experience Perceptual Narrowing for Nonprimate Faces

    ERIC Educational Resources Information Center

    Simpson, Elizabeth A.; Varga, Krisztina; Frick, Janet E.; Fragaszy, Dorothy

    2011-01-01

    Perceptual narrowing--a phenomenon in which perception is broad from birth, but narrows as a function of experience--has previously been tested with primate faces. In the first 6 months of life, infants can discriminate among individual human and monkey faces. Though the ability to discriminate monkey faces is lost after about 9 months, infants…

  5. Improved perceptual-motor performance measurement system

    NASA Technical Reports Server (NTRS)

    Parker, J. F., Jr.; Reilly, R. E.

    1969-01-01

    Battery of tests determines the primary dimensions of perceptual-motor performance. Eighteen basic measures range from simple tests to sophisticated electronic devices. Improved system has one unit for the subject containing test display and response elements, and one for the experimenter where test setups, programming, and scoring are accomplished.

  6. Perceptual Modeling for Behavioral Animation of Fishes

    E-print Network

    Toronto, University of

    and their motions had to be laboriously keyframed like animated cartoons. Subsequently, researchers developedPerceptual Modeling for Behavioral Animation of Fishes Xiaoyuan Tu Demetri Terzopoulos Department of Computer Science University of Toronto, Toronto, Ontario, Canada, M5S 1A4 ABSTRACT The realistic animation

  7. Perceptual Completion in Newborn Human Infants

    ERIC Educational Resources Information Center

    Valenza, Eloisa; Leo, Irene; Gava, Lucia; Simion, Francesca

    2006-01-01

    Despite decades of studies of human infants, a still open question concerns the role of visual experience in the development of the ability to perceive complete shapes over partial occlusion. Previous studies show that newborns fail to manifest this ability, either because they lack the visual experience required for perceptual completion or…

  8. Tangential Speed

    NSDL National Science Digital Library

    Michael Horton

    2009-05-30

    This lab is purely a thought experiment. Although students are given an introduction to angular speed and tangential speed, they will discover the relationship between the two in this activity. The lab is an inquiry activity in that students do not know t

  9. Generalized perceptual linear prediction features for animal vocalization analysis.

    PubMed

    Clemins, Patrick J; Johnson, Michael T

    2006-07-01

    A new feature extraction model, generalized perceptual linear prediction (gPLP), is developed to calculate a set of perceptually relevant features for digital signal analysis of animal vocalizations. The gPLP model is a generalized adaptation of the perceptual linear prediction model, popular in human speech processing, which incorporates perceptual information such as frequency warping and equal loudness normalization into the feature extraction process. Since such perceptual information is available for a number of animal species, this new approach integrates that information into a generalized model to extract perceptually relevant features for a particular species. To illustrate, qualitative and quantitative comparisons are made between the species-specific model, generalized perceptual linear prediction (gPLP), and the original PLP model using a set of vocalizations collected from captive African elephants (Loxodonta africana) and wild beluga whales (Delphinapterus leucas). The models that incorporate perceptional information outperform the original human-based models in both visualization and classification tasks. PMID:16875249

  10. [Perceptual sharpness metric for visible and infrared color fusion images].

    PubMed

    Gao, Shao-Shu; Jin, Wei-Qi; Wang, Xia; Wang, Ling-Xue; Luo, Yuan

    2012-12-01

    For visible and infrared color fusion images, objective sharpness assessment model is proposed to measure the clarity of detail and edge definition of the fusion image. Firstly, the contrast sensitivity functions (CSF) of the human visual system is used to reduce insensitive frequency components under certain viewing conditions. Secondly, perceptual contrast model, which takes human luminance masking effect into account, is proposed based on local band-limited contrast model. Finally, the perceptual contrast is calculated in the region of interest (contains image details and edges) in the fusion image to evaluate image perceptual sharpness. Experimental results show that the proposed perceptual sharpness metrics provides better predictions, which are more closely matched to human perceptual evaluations, than five existing sharpness (blur) metrics for color images. The proposed perceptual sharpness metrics can evaluate the perceptual sharpness for color fusion images effectively. PMID:23427534

  11. Forced to remember: when memory is biased by salient information.

    PubMed

    Santangelo, Valerio

    2015-04-15

    The last decades have seen a rapid growing in the attempt to understand the key factors involved in the internal memory representation of the external world. Visual salience have been found to provide a major contribution in predicting the probability for an item/object embedded in a complex setting (i.e., a natural scene) to be encoded and then remembered later on. Here I review the existing literature highlighting the impact of perceptual- (based on low-level sensory features) and semantics-related salience (based on high-level knowledge) on short-term memory representation, along with the neural mechanisms underpinning the interplay between these factors. The available evidence reveal that both perceptual- and semantics-related factors affect attention selection mechanisms during the encoding of natural scenes. Biasing internal memory representation, both perceptual and semantics factors increase the probability to remember high- to the detriment of low-saliency items. The available evidence also highlight an interplay between these factors, with a reduced impact of perceptual-related salience in biasing memory representation as a function of the increasing availability of semantics-related salient information. The neural mechanisms underpinning this interplay involve the activation of different portions of the frontoparietal attention control network. Ventral regions support the assignment of selection/encoding priorities based on high-level semantics, while the involvement of dorsal regions reflects priorities assignment based on low-level sensory features. PMID:25595422

  12. Intersensory Redundancy Enhances Memory in Bobwhite Quail Embryos

    ERIC Educational Resources Information Center

    Lickliter, Robert; Bahrick, Lorraine E.; Honeycutt, Hunter

    2004-01-01

    Information presented concurrently and redundantly to 2 or more senses (intersensory redundancy) has been shown to recruit attention and promote perceptual learning of amodal stimulus properties in animal embryos and human infants. This study examined whether the facilitative effect of intersensory redundancy also extends to the domain of memory.…

  13. Birth of projection neurons in adult avian brain may be related to perceptual or motor learning

    SciTech Connect

    Alvarez-Buylla, A.; Kirn, J.R.; Nottebohm, F. (Rockefeller Univ. Field Research Center, Millbrook, NY (USA))

    1990-09-21

    Projection neurons that form part of the motor pathway for song control continue to be produced and to replace older projection neurons in adult canaries and zebra finches. This is shown by combining (3H)thymidine, a cell birth marker, and fluorogold, a retrogradely transported tracer of neuronal connectivity. Species and seasonal comparisons suggest that this process is related to the acquisition of perceptual or motor memories. The ability of an adult brain to produce and replace projection neurons should influence our thinking on brain repair.

  14. Minimizing ALU and Memory Schedules via Partitioning and Prefetching

    E-print Network

    Sha, Edwin

    utilization. A variety of techniques , ranging from cache hierarchies to various prefetch- ing and memory hierarchy to tolerate the memory latency eÆciently. In order to increase the reference locality, the entire because of the huge gap between the processor and the memory speed. The memory hierarchy is a method

  15. Fully-Buffered DIMM Memory Architectures: Understanding Mechanisms, Overheads and Scaling

    Microsoft Academic Search

    Brinda Ganesh; Aamer Jaleel; David Wang; Bruce L. Jacob

    2007-01-01

    Performance gains in memory have traditionally been obtained by increasing memory bus widths and speeds. The diminishing returns of such techniques have led to the proposal of an alternate architecture, the Fully-Buffered DIMM. This new standard replaces the conventional memory bus with a narrow, high-speed interface between the memory controller and the DIMMs. This paper examines how traditional DDRx based

  16. Exploring the perceptual spaces of faces, cars and birds in children and adults

    PubMed Central

    Tanaka, James W.; Meixner, Tamara L.; Kantner, Justin

    2011-01-01

    While much developmental research has focused on the strategies that children employ to recognize faces, less is known about the principles governing the organization of face exemplars in perceptual memory. In this study, we tested a novel, child-friendly paradigm for investigating the organization of face, bird and car exemplars. Children ages 3–4, 5–6, 7–8, 9–10, 11–12 and adults were presented with 50/50 morphs of typical and atypical face, bird and car parent images. Participants were asked to judge whether the 50/50 morph more strongly resembled the typical or the atypical parent image. Young and older children and adults showed a systematic bias to the atypical faces and birds, but no bias toward the atypical cars. Collectively, these findings argue that by the age of 3, children encode and organize faces, birds and cars in a perceptual space that is strikingly similar to that of adults. Category organization for both children and adults follows Krumhansl’s (1978) distance-density principle in which the similarity between two exemplars is jointly determined by their physical appearance and the density of neighboring exemplars in the perceptual space. PMID:21676096

  17. Stimulus Roving and Flankers Affect Perceptual Learning of Contrast Discrimination in Macaca mulatta

    PubMed Central

    Thiele, Alexander

    2014-01-01

    ‘Stimulus roving’ refers to a paradigm in which the properties of the stimuli to be discriminated vary from trial to trial, rather than being kept constant throughout a block of trials. Rhesus monkeys have previously been shown to improve their contrast discrimination performance on a non-roving task, in which they had to report the contrast of a test stimulus relative to that of a fixed-contrast sample stimulus. Human psychophysics studies indicate that roving stimuli yield little or no perceptual learning. Here, we investigate how stimulus roving influences perceptual learning in macaque monkeys and how the addition of flankers alters performance under roving conditions. Animals were initially trained on a contrast discrimination task under non-roving conditions until their performance levels stabilized. The introduction of roving contrast conditions resulted in a pronounced drop in performance, which suggested that subjects initially failed to heed the sample contrast and performed the task using an internal memory reference. With training, significant improvements occurred, demonstrating that learning is possible under roving conditions. To investigate the notion of flanker-induced perceptual learning, flanker stimuli (30% fixed-contrast iso-oriented collinear gratings) were presented jointly with central (roving) stimuli. Presentation of flanker stimuli yielded substantial performance improvements in one subject, but deteriorations in the other. Finally, after the removal of flankers, performance levels returned to their pre-flanker state in both subjects, indicating that the flanker-induced changes were contingent upon the continued presentation of flankers. PMID:25340335

  18. Memory bandwidth and machine balance in current high performance computers

    Microsoft Academic Search

    J. D. Mccalpin

    1995-01-01

    The ratio of cpu speed to memory speed in current high-performance computers is growing rapidly, with significant implications for the design and implementation of algorithms in scientific computing. I present the results of a broad survey of memory bandwidth and machine balance for a large variety current computers, including uniprocessors, vector processors, shared-memory systems, and distributed-memory systems. The results are

  19. Age-Related Differences in Memory and Executive Functions in Healthy APOE ?4 Carriers: The Contribution of Individual Differences in Prefrontal Volumes and Systolic Blood Pressure

    PubMed Central

    Bender, Andrew R.; Raz, Naftali

    2012-01-01

    Advanced age and vascular risk are associated with declines in the volumes of multiple brain regions, especially, the prefrontal cortex, and the hippocampus. Older adults, even unencumbered by declining health, perform less well than their younger counterparts in multiple cognitive domains, such as episodic memory, executive functions, and speed of perceptual processing. Presence of a known genetic risk factor for cognitive decline and vascular disease, the ?4 allele of the apolipoprotein E (APOE) gene, accounts for some share of those declines; however, the extent of the joint contribution of genetic and physiological vascular risk factors on the aging brain and cognition is unclear. In a sample of healthy adults (age 19–77), we examined the effects of a vascular risk indicator (systolic blood pressure, SBP) and volumes of hippocampus (HC), lateral prefrontal cortex (lPFC), and prefrontal white matter (pFWM) on processing speed, working memory (WM), and recognition memory. Using path analyses, we modeled indirect effects of age, SBP, and brain volumes on processing speed, WM, and memory and compared the patterns of structural relations among those variables in APOE ?4 carriers and ?3 homozygotes. Among ?4 carriers, age differences in WM were explained by increase in SBP, reduced FWM volume, and slower processing. In contrast, lPFC and FWM volumes, but not BP, explained a share of age differnces in WM among ?3 homozygotes. Thus, even in healthy older carriers of the APOE ?4 allele, clinically unremarkable increase in vascular risk may be associated with reduced frontal volumes and impaired cognitive functions. PMID:22245009

  20. Recollection can support hybrid visual memory search.

    PubMed

    Guild, Emma B; Cripps, Jenna M; Anderson, Nicole D; Al-Aidroos, Naseem

    2014-02-01

    On a daily basis, we accomplish the task of searching our visual environment for one of a number of possible objects, like searching for any one of our friends in a crowd, and we do this with ease. Understanding how attention, perception, and long-term memory interact to accomplish this process remains an important question. Recent research (Wolfe in Psychological Science 23:698-703, 2012) has shown that increasing the number of possible targets one is searching for adds little cost to the efficiency of visual search-specifically, that response times increase logarithmically with memory set size. It is unclear, however, what type of recognition memory process (familiarity or recollection) supports a hybrid visual memory search. Previous hybrid search paradigms create conditions that allow participants to rely on the familiarity of perceptually identical targets. In two experiments, we show that hybrid search remains efficient even when the familiarity of targets is minimized (Experiment 1) and when participants are encouraged to flexibly retrieve target information that is perceptually distinct from the information previously studied (Experiment 2). We propose that such efficient and flexible performance on a hybrid search task may engage a rapid from of recollection (Moscovitch in Canadian Journal of Experimental Psychology 62:62-79, 2008). We discuss possible neural correlates supporting simultaneous perception, comparison of incoming information, and recollection of episodic memories. PMID:23884688

  1. Atypicalities in perceptual adaptation in autism do not extend to perceptual causality.

    PubMed

    Karaminis, Themelis; Turi, Marco; Neil, Louise; Badcock, Nicholas A; Burr, David; Pellicano, Elizabeth

    2015-01-01

    A recent study showed that adaptation to causal events (collisions) in adults caused subsequent events to be less likely perceived as causal. In this study, we examined if a similar negative adaptation effect for perceptual causality occurs in children, both typically developing and with autism. Previous studies have reported diminished adaptation for face identity, facial configuration and gaze direction in children with autism. To test whether diminished adaptive coding extends beyond high-level social stimuli (such as faces) and could be a general property of autistic perception, we developed a child-friendly paradigm for adaptation of perceptual causality. We compared the performance of 22 children with autism with 22 typically developing children, individually matched on age and ability (IQ scores). We found significant and equally robust adaptation aftereffects for perceptual causality in both groups. There were also no differences between the two groups in their attention, as revealed by reaction times and accuracy in a change-detection task. These findings suggest that adaptation to perceptual causality in autism is largely similar to typical development and, further, that diminished adaptive coding might not be a general characteristic of autism at low levels of the perceptual hierarchy, constraining existing theories of adaptation in autism. PMID:25774507

  2. Atypicalities in Perceptual Adaptation in Autism Do Not Extend to Perceptual Causality

    PubMed Central

    Karaminis, Themelis; Turi, Marco; Neil, Louise; Badcock, Nicholas A.; Burr, David; Pellicano, Elizabeth

    2015-01-01

    A recent study showed that adaptation to causal events (collisions) in adults caused subsequent events to be less likely perceived as causal. In this study, we examined if a similar negative adaptation effect for perceptual causality occurs in children, both typically developing and with autism. Previous studies have reported diminished adaptation for face identity, facial configuration and gaze direction in children with autism. To test whether diminished adaptive coding extends beyond high-level social stimuli (such as faces) and could be a general property of autistic perception, we developed a child-friendly paradigm for adaptation of perceptual causality. We compared the performance of 22 children with autism with 22 typically developing children, individually matched on age and ability (IQ scores). We found significant and equally robust adaptation aftereffects for perceptual causality in both groups. There were also no differences between the two groups in their attention, as revealed by reaction times and accuracy in a change-detection task. These findings suggest that adaptation to perceptual causality in autism is largely similar to typical development and, further, that diminished adaptive coding might not be a general characteristic of autism at low levels of the perceptual hierarchy, constraining existing theories of adaptation in autism. PMID:25774507

  3. Perceptual color image coding with JPEG2000.

    PubMed

    Tan, D M; Tan, C S; Wu, H R

    2010-02-01

    A perceptual color image coder (PCIC) is presented for the YC(b)C(r) color space within the framework of JPEG2000. This coder employs a vision model based perceptual distortion metric (PDM) to approximate perceived error for rate-distortion (R-D) optimization in order to maximize the visual quality of coded images. The vision model employed in the PCIC is structurally based on an existing monochromatic multichannel vision model, which is extended for color image coding. Subjective tests with 30 viewers show that the PCIC provides superior picture quality at low to intermediate bitrates in comparison with a JPEG2000 compliant coder employing the mean squared error (MSE) and the visual distortion metric (Cvis) as distortion measures, respectively. PMID:20083452

  4. Perceptual Spaces: Mathematical Structures to Neural Mechanisms

    PubMed Central

    Victor, Jonathan; McDermott, Josh; Geffen, Maria; Bensmaia, Sliman; Cleland, Thomas A.

    2013-01-01

    A central goal of neuroscience is to understand how populations of neurons build and manipulate representations of percepts that provide useful information about the environment. This symposium explores the fundamental properties of these representations and the perceptual spaces in which they are organized. Spanning the domains of color, visual texture, environmental sound, music, tactile quality, and odor, we show how the geometric structures of perceptual spaces can be determined experimentally and how these structures provide insights into the principles of neural coding and the neural mechanisms that generate the codes, and into the neural processing of complex sensory stimuli. The diversity of the neural architecture in these different sensory systems provides an opportunity to compare their different solutions to common problems: the need for dimensionality reduction, strategies for topographic or nontopographic mapping, the utility of the higher-order statistical structure inherent in natural sensory stimuli, and the constraints of neural hardware. PMID:24198350

  5. A perceptual metric for photo retouching

    PubMed Central

    Kee, Eric; Farid, Hany

    2011-01-01

    In recent years, advertisers and magazine editors have been widely criticized for taking digital photo retouching to an extreme. Impossibly thin, tall, and wrinkle- and blemish-free models are routinely splashed onto billboards, advertisements, and magazine covers. The ubiquity of these unrealistic and highly idealized images has been linked to eating disorders and body image dissatisfaction in men, women, and children. In response, several countries have considered legislating the labeling of retouched photos. We describe a quantitative and perceptually meaningful metric of photo retouching. Photographs are rated on the degree to which they have been digitally altered by explicitly modeling and estimating geometric and photometric changes. This metric correlates well with perceptual judgments of photo retouching and can be used to objectively judge by how much a retouched photo has strayed from reality. PMID:22123980

  6. A perceptual metric for photo retouching.

    PubMed

    Kee, Eric; Farid, Hany

    2011-12-13

    In recent years, advertisers and magazine editors have been widely criticized for taking digital photo retouching to an extreme. Impossibly thin, tall, and wrinkle- and blemish-free models are routinely splashed onto billboards, advertisements, and magazine covers. The ubiquity of these unrealistic and highly idealized images has been linked to eating disorders and body image dissatisfaction in men, women, and children. In response, several countries have considered legislating the labeling of retouched photos. We describe a quantitative and perceptually meaningful metric of photo retouching. Photographs are rated on the degree to which they have been digitally altered by explicitly modeling and estimating geometric and photometric changes. This metric correlates well with perceptual judgments of photo retouching and can be used to objectively judge by how much a retouched photo has strayed from reality. PMID:22123980

  7. Speeding up local correlation methods.

    PubMed

    Kats, Daniel

    2014-12-28

    We present two techniques that can substantially speed up the local correlation methods. The first one allows one to avoid the expensive transformation of the electron-repulsion integrals from atomic orbitals to virtual space. The second one introduces an algorithm for the residual equations in the local perturbative treatment that, in contrast to the standard scheme, does not require holding the amplitudes or residuals in memory. It is shown that even an interpreter-based implementation of the proposed algorithm in the context of local MP2 method is faster and requires less memory than the highly optimized variants of conventional algorithms. PMID:25554127

  8. High-Speed Scanning in Human Memory

    Microsoft Academic Search

    Saul Sternberg

    1966-01-01

    When subjects judge whether a test symbol is contained in a short memorized sequence of symbols, their mean reaction-time increases linearly with the length of the sequence. The linearity and slope of the function imply the existence of an internal serial-comparison process whose average rate is between 25 and 30 symbols per second.

  9. Statistical and perceptual updating: correlated impairments in right brain injury.

    PubMed

    Stöttinger, Elisabeth; Filipowicz, Alex; Marandi, Elahe; Quehl, Nadine; Danckert, James; Anderson, Britt

    2014-06-01

    It has been hypothesized that many of the cognitive impairments commonly seen after right brain damage (RBD) can be characterized as a failure to build or update mental models. We (Danckert et al. in Neglect as a disorder of representational updating. NOVA Open Access, New York, 2012a; Cereb Cortex 22:2745-2760, 2012b) were the first to directly assess the association between RBD and updating and found that RBD patients were unable to exploit a strongly biased play strategy in their opponent in the children's game rock, paper, scissors. Given that this game required many other cognitive capacities (i.e., working memory, sustained attention, reward processing), RBD patients could have failed this task for various reasons other than a failure to update. To assess the generality of updating deficits after RBD, we had RBD, left brain-damaged (LBD) patients and healthy controls (HCs) describe line drawings that evolved gradually from one figure (e.g., rabbit) to another (e.g., duck) in addition to the RPS updating task. RBD patients took significantly longer to alter their perceptual report from the initial object to the final object than did LBD patients and HCs. Although both patient groups performed poorly on the RPS task, only the RBD patients showed a significant correlation between the two, very different, updating tasks. We suggest these data indicate a general deficiency in the ability to update mental representations following RBD. PMID:24615155

  10. Perceptual Centering Effects in Body Orientation

    Microsoft Academic Search

    D. A. Hanes

    2006-01-01

    This study mathematically characterizes the results of DiZio and Lackner (Percept Psychphys 39(1): 39–46) on the perception\\u000a of self-orientation during circular vection induced by an optokinetic stimulus. Using the hypothesis of perceptual centering,\\u000a it is shown that five basic centering transformations can logically account for the full range of illusions reported by the\\u000a subjects. All five of these transformations center

  11. Perceptual benchmarks for automatic language identification

    Microsoft Academic Search

    Yeshwant K. Muthusamy; N. Jain; Ronald A. Cole

    1994-01-01

    There has been renewed interest in the field of automatic language identification over the past two years. The advent of a public-domain ten-language corpus of telephone speech has made the evaluation of different approaches to automatic language identification feasible. In an effort to provide benchmarks for evaluating machine performance, we conducted perceptual experiments on 1-, 2-, 4- and 6-second excerpts

  12. Perceptual uniformity of commonly used color spaces

    NASA Astrophysics Data System (ADS)

    Avanaki, Ali; Espig, Kathryn; Kimpe, Tom; Xthona, Albert; Marchessoux, Cedric; Rostang, Johan; Piepers, Bastian

    2014-03-01

    Use of color images in medical imaging has increased significantly the last few years. Color information is essential for applications such as ophthalmology, dermatology and clinical photography. Use of color at least brings benefits for other applications such as endoscopy, laparoscopy and digital pathology. Remarkably, as of today, there is no agreed standard on how color information needs to be visualized for medical applications. This lack of standardization results in large variability of how color images are visualized and it makes quality assurance a challenge. For this reason FDA and ICC recently organized a joint summit on color in medical imaging (CMI). At this summit, one of the suggestions was that modalities such as digital pathology could benefit from using a perceptually uniform color space (T. Kimpe, "Color Behavior of Medical Displays," CMI presentation, May 2013). Perceptually uniform spaces have already been used for many years in the radiology community where the DICOM GSDF standard provides linearity in luminance but not in color behavior. In this paper we quantify perceptual uniformity, using CIE's ?E2000 as a color distance metric, of several color spaces that are typically used for medical applications. We applied our method to theoretical color spaces Gamma 1.8, 2.0, & 2.2, standard sRGB, and DICOM (correction LUT for gray applied to all primaries). In addition, we also measured color spaces (i.e., native behavior) of a high-end medical display (Barco Coronis Fusion 6MP DL, MDCC-6130), and a consumer display (Dell 1907FP). Our results indicate that sRGB & the native color space on the Barco Coronis Fusion exhibit the least non-uniformity within their group. However, the remaining degree of perceptual non-uniformity is still significant and there is room for improvement.

  13. Is color “categorical perception” really perceptual?

    Microsoft Academic Search

    Michael Pilling; Alison Wiggett; Emre Özgen; Ian R. L. Davies

    2003-01-01

    Roberson and Davidoff (2000) found that colorcategorical perception (CP; better cross-category than within-category discrimination) was eliminated by verbal, but not by visual, interference\\u000a presented during the interstimulus interval (ISI) of a discrimination task. On the basis of this finding, Roberson and Davidoff\\u000a concluded that CP was mediated by verbal labels, and not by perceptual mechanisms, as is generally assumed. Experiment

  14. Perceptual asymmetries and handedness: a neglected link?

    PubMed Central

    Marzoli, Daniele; Prete, Giulia; Tommasi, Luca

    2014-01-01

    Healthy individuals tend to weigh in more the left than the right side of visual space in a variety of contexts, ranging from pseudoneglect to perceptual asymmetries for faces. Among the common explanations proposed for the attentional and perceptual advantages of the left visual field, a link with the prevalence of right-handedness in humans has never been suggested, although some evidence seems to converge in favor of a bias of spatial attention toward the region most likely coincident with another person’s right hand during a face-to-face interaction. Such a bias might imply an increased efficiency in monitoring both communicative and aggressive acts, the right limb being more used than the left in both types of behavior. Although attentional and perceptual asymmetries could be linked to right-handedness at the level of phylogeny because of the evolutionarily advantage of directing attention toward the region where others’ dominant hand usually operates, it is also legitimate to question whether, at the ontogenetic level, frequent exposure to right-handed individuals may foster leftward biases. These views are discussed in the light of extant literature, and a number of tests are proposed in order to assess our hypotheses. PMID:24592250

  15. Perceptual consequences of "hidden" hearing loss.

    PubMed

    Plack, Christopher J; Barker, Daphne; Prendergast, Garreth

    2014-01-01

    Dramatic results from recent animal experiments show that noise exposure can cause a selective loss of high-threshold auditory nerve fibers without affecting absolute sensitivity permanently. This cochlear neuropathy has been described as hidden hearing loss, as it is not thought to be detectable using standard measures of audiometric threshold. It is possible that hidden hearing loss is a common condition in humans and may underlie some of the perceptual deficits experienced by people with clinically normal hearing. There is some evidence that a history of noise exposure is associated with difficulties in speech discrimination and temporal processing, even in the absence of any audiometric loss. There is also evidence that the tinnitus experienced by listeners with clinically normal hearing is associated with cochlear neuropathy, as measured using Wave I of the auditory brainstem response. To date, however, there has been no direct link made between noise exposure, cochlear neuropathy, and perceptual difficulties. Animal experiments also reveal that the aging process itself, in the absence of significant noise exposure, is associated with loss of auditory nerve fibers. Evidence from human temporal bone studies and auditory brainstem response measures suggests that this form of hidden loss is common in humans and may have perceptual consequences, in particular, regarding the coding of the temporal aspects of sounds. Hidden hearing loss is potentially a major health issue, and investigations are ongoing to identify the causes and consequences of this troubling condition. PMID:25204468

  16. The perceptual reality of synesthetic colors

    PubMed Central

    Palmeri, Thomas J.; Blake, Randolph; Marois, René; Flanery, Marci A.; Whetsell, William

    2002-01-01

    Synesthesia is a remarkable, rare condition where an individual has multimodal perceptual experiences from a unimodal sensory event. We have studied such an individual, an adult male for whom achromatic words and alphanumeric characters are seen in vivid, reliable colors. We used a variety of perceptual tasks to document the perceptual reality of synesthetic colors and to begin to localize the stage of visual processing where this anomalous binding of externally specified form and internally generated color may take place. Synesthetic colors were elicited by forms defined solely by binocular cues or solely by motion cues, which implies a central locus of visual processing for synesthetic binding of form and color. Also included among our measurements was a difficult visual search task on which non-synesthetic subjects required an effortful search through the visual display. Our subject, in contrast to non-synesthetic subjects, accomplished the task with relative ease because the target of the search had a different synesthetic color from the distractors. Thus, synesthetic experiences appear to originate from a binding of color and form that takes place within central stages of visual processing. PMID:11904456

  17. How brain oscillations form memories--a processing based perspective on oscillatory subsequent memory effects.

    PubMed

    Hanslmayr, Simon; Staudigl, Tobias

    2014-01-15

    Brain oscillations are increasingly recognized by memory researchers as a useful tool to unravel the neural mechanisms underlying the formation of a memory trace. However, the increasing numbers of published studies paint a rather complex picture of the relation between brain oscillations and memory formation. Concerning oscillatory amplitude, for instance, increases as well as decreases in various frequency bands (theta, alpha, beta and gamma) were associated with memory formation. These results cast doubt on frameworks putting forward the idea of an oscillatory signature that is uniquely related to memory formation. In an attempt to clarify this issue we here provide an alternative perspective, derived from classic cognitive frameworks/principles of memory. On the basis of Craik's levels of processing framework and Tulving's encoding specificity principle we hypothesize that brain oscillations during encoding might primarily reflect the perceptual and cognitive processes engaged by the encoding task. These processes may then lead to later successful retrieval depending on their overlap with the processes engaged by the memory test. As a consequence, brain oscillatory correlates of memory formation could vary dramatically depending on how the memory is encoded, and on how it is being tested later. Focusing on oscillatory amplitude changes and on theta-to-gamma cross-frequency coupling, we here review recent evidence showing how brain oscillatory subsequent memory effects can be modulated, and sometimes even be reversed, by varying encoding tasks, and the contextual overlap between encoding and retrieval. PMID:23769913

  18. Causal role of dorsolateral prefrontal cortex in human perceptual decision making.

    PubMed

    Philiastides, Marios G; Auksztulewicz, Ryszard; Heekeren, Hauke R; Blankenburg, Felix

    2011-06-01

    The way that we interpret and interact with the world entails making decisions on the basis of available sensory evidence. Recent primate neurophysiology [1-6], human neuroimaging [7-13], and modeling experiments [14-19] have demonstrated that perceptual decisions are based on an integrative process in which sensory evidence accumulates over time until an internal decision bound is reached. Here we used repetitive transcranial magnetic stimulation (rTMS) to provide causal support for the role of the dorsolateral prefrontal cortex (DLPFC) in this integrative process. Specifically, we used a speeded perceptual categorization task designed to induce a time-dependent accumulation of sensory evidence through rapidly updating dynamic stimuli and found that disruption of the left DLPFC with low-frequency rTMS reduced accuracy and increased response times relative to a sham condition. Importantly, using the drift-diffusion model, we show that these behavioral effects correspond to a decrease in drift rate, a parameter describing the rate and thereby the efficiency of the sensory evidence integration in the decision process. These results provide causal evidence linking the DLPFC to the mechanism of evidence accumulation during perceptual decision making. PMID:21620706

  19. Learning to read upside-down: a study of perceptual expertise and its acquisition.

    PubMed

    Ahlén, Elsa; Hills, Charlotte S; Hanif, Hashim M; Rubino, Cristina; Barton, Jason J S

    2014-03-01

    Reading is an expert visual and ocular motor function, learned mainly in a single orientation. Characterizing the features of this expertise can be accomplished by contrasts between reading of normal and inverted text, in which perceptual but not linguistic factors are altered. Our goal was to examine this inversion effect in healthy subjects reading text, to derive behavioral and ocular motor markers of perceptual expertise in reading, and to study these parameters before and after training with inverted reading. Seven subjects engaged in a 10-week program of 30 half-hour sessions of reading inverted text. Before and after training, we assessed reading of upright and inverted single words for response time and word-length effects, as well as reading of paragraphs for time required, accuracy, and ocular motor parameters. Before training, inverted reading was characterized by long reading times and large word-length effects, with eye movements showing more and longer fixations, more and smaller forward saccades, and more regressive saccades. Training partially reversed many of these effects in single word and text reading, with the best gains occurring in reading aloud time and proportion of regressive saccades and the least change in forward saccade amplitude. We conclude that reading speed and ocular motor parameters can serve as markers of perceptual expertise during reading and that training with inverted text over 10 weeks results in significant gains of reading expertise in this unfamiliar orientation. This approach may be useful in the rehabilitation of patients with hemianopic dyslexia. PMID:24370581

  20. Computer Systems Design and Architecture Second Edition 2004 Prentice Hall Chapter 7-Memory System Design

    E-print Network

    Bezrukov, Sergei

    -level memory hierarchy The cache Virtual memory The memory as a sub-system of the computer #12;S 2/e C D will also cover­ · The memory hierarchy: from fast and expensive to slow and cheap Example: Registers->Cache­>Main Memory->Disk At first, consider just two adjacent levels in the hierarchy The Cache: High speed

  1. [Neural correlates of perceptual decisions: the role of the ventral premotor cortex].

    PubMed

    Pardo-Vázquez, José L; Acuña, Carlos

    2014-05-01

    Although the premotor cortex was initially viewed as the substrate of pure motor functions, it was soon realized that this cortical region is also involved in higher order cognitive processes. By using behavioral tasks together with electrophysiological recordings it has been possible to advance in our understanding on the functional role of this area. Given its pattern of connections, the premotor ventral cortex is well suited to participate in perceptual decisions, in which sensory information is combined with knowledge on previous outcomes and expectancies to reach a behavioral choice. The neuronal correlates of the decision process have been described in several cortical areas of primates. In this work we describe our experimental results showing that different stages or elements of perceptual decisions are encoded in the firing rate of premotor ventral cortex neurons. This provides compelling evidence suggesting that this area is involved in the use of sensory evidence -maintained in working memory or retrieved from long-term memory- to reach a decision. Furthermore, after the behavioral response the same neurons convey all the information needed to evaluate the outcome of the choice. This suggests that the premotor ventral cortex could participate in shaping future behavior as a result of this evaluation. PMID:24777768

  2. Effects of roadside memorials on traffic flow.

    PubMed

    Tay, Richard; Churchill, Anthony; de Barros, Alexandre G

    2011-01-01

    Despite their growing popularity in North America, little research has been conducted on understanding the effects of roadside memorials on drivers' behaviour. In this study, we examined the short-term effects of roadside memorials on traffic speed and headways on a high speed intercity freeway as well as its long-term effect on traffic speed on a high speed urban freeway. Our study found that the placement of roadside memorials did not have any significant effect on traffic speeds or headways, either in the short or long term. Therefore, concerns about the negative effects on driver behaviour were not supported by this research, at least with regards to speeding and following too closely. However, no positive effects on safety were found either. PMID:21094348

  3. Behavioral/Cognitive How Embodied Is Perceptual Decision Making? Evidence for

    E-print Network

    Nelson, Jonathan D.

    Behavioral/Cognitive How Embodied Is Perceptual Decision Making? Evidence for Separate Processing. Moreover, whether perceptual decisions have a single neural signature is unknown. Diffusion models increasing presaccade neural activity in saccade tasks not involving perceptual decisions (Andersen and Buneo

  4. Perceptual compensation for coarticulation by Japanese quail (Coturnix coturnix japonica)

    E-print Network

    Holt, Lori L.

    Perceptual compensation for coarticulation by Japanese quail (Coturnix coturnix japonica) Andrew J Japanese quail Coturnix coturnix japonica were trained to peck a key differentially to identify clear /da

  5. Perceptual Learning of Dysarthric Speech: A Review of Experimental Studies

    PubMed Central

    Borrie, Stephanie A.; McAuliffe, Megan J.; Liss, Julie M.

    2013-01-01

    Purpose This review article provides a theoretical overview of the characteristics of perceptual learning, reviews perceptual learning studies that pertain to dysarthric populations, and identifies directions for future research that consider the application of perceptual learning to the management of dysarthria. Method A critical review of the literature was conducted that summarized and synthesized previously published research in the area of perceptual learning with atypical speech. Literature related to perceptual learning of neurologically degraded speech was emphasized with the aim of identifying key directions for future research with this population. Conclusions Familiarization with unfamiliar or ambiguous speech signals can facilitate perceptual learning of that same speech signal. There is a small but growing body of evidence that perceptual learning also occurs for listeners familiarized with dysarthric speech. Perceptual learning of the dysarthric signal is both theoretically and clinically significant. In order to establish the efficacy of exploiting perceptual learning paradigms for rehabilitative gain in dysarthria management, research is required to build on existing empirical evidence and develop a theoretical framework for learning to better recognize neurologically degraded speech. PMID:22199185

  6. Memory for Details with Self-Referencing

    PubMed Central

    Serbun, Sarah J.; Shih, Joanne Y.; Gutchess, Angela H.

    2011-01-01

    Self-referencing benefits item memory, but little is known about the ways in which referencing the self affects memory for details. Experiment 1 assessed whether the effects of self-referencing operate only at the item, or general, level or also enhance memory for specific visual details of objects. Participants incidentally encoded objects by making judgments in reference to the self, a close other (one’s mother), or a familiar other (Bill Clinton). Results indicate that referencing the self or a close other enhances both specific and general memory. Experiments 2 and 3 assessed verbal memory for source in a task that relied on distinguishing between different mental operations (internal sources). Results indicate that self-referencing disproportionately enhances source memory, relative to conditions referencing other people, semantic, or perceptual information. We conclude that self-referencing not only enhances specific memory for both visual and verbal information, but can disproportionately improve memory for specific internal source details as well. PMID:22092106

  7. Caffeine, extraversion and working memory.

    PubMed

    Smith, Andrew P

    2013-01-01

    Research has shown that extraverts performing a working memory task benefit more from caffeine than do introverts. The present study aimed to replicate this and extend our knowledge by using a lower dose of caffeine (65 mg) and a range of tasks related to different components of working memory. In addition, tasks assessing psychomotor speed and the encoding of new information were included to determine whether caffeine-extraversion interactions were restricted to working memory tasks. A double-blind design was used, with 128 participants being randomly assigned to caffeinated or de-caffeinated coffee conditions. The results showed that caffeine interacted with extraversion in the predicted direction for serial recall and running memory tasks. Caffeine improved simple reaction time and the speed of encoding of new information, effects which were not modified by extraversion. These results suggest possible biological mechanisms underlying effects of caffeine on cognitive performance. PMID:23015541

  8. A causal role for V5/MT neurons coding motion-disparity conjunctions in resolving perceptual ambiguity.

    PubMed

    Krug, Kristine; Cicmil, Nela; Parker, Andrew J; Cumming, Bruce G

    2013-08-01

    Judgments about the perceptual appearance of visual objects require the combination of multiple parameters, like location, direction, color, speed, and depth. Our understanding of perceptual judgments has been greatly informed by studies of ambiguous figures, which take on different appearances depending upon the brain state of the observer. Here we probe the neural mechanisms hypothesized as responsible for judging the apparent direction of rotation of ambiguous structure from motion (SFM) stimuli. Resolving the rotation direction of SFM cylinders requires the conjoint decoding of direction of motion and binocular depth signals [1, 2]. Within cortical visual area V5/MT of two macaque monkeys, we applied electrical stimulation at sites with consistent multiunit tuning to combinations of binocular depth and direction of motion, while the monkey made perceptual decisions about the rotation of SFM stimuli. For both ambiguous and unambiguous SFM figures, rotation judgments shifted as if we had added a specific conjunction of disparity and motion signals to the stimulus elements. This is the first causal demonstration that the activity of neurons in V5/MT contributes directly to the perception of SFM stimuli and by implication to decoding the specific conjunction of disparity and motion, the two different visual cues whose combination drives the perceptual judgment. PMID:23871244

  9. Perceptual constancy in auditory perception of distance to railway tracks.

    PubMed

    De Coensel, Bert; Nilsson, Mats E; Berglund, Birgitta; Brown, A L

    2013-07-01

    Distance to a sound source can be accurately estimated solely from auditory information. With a sound source such as a train that is passing by at a relatively large distance, the most important auditory information for the listener for estimating its distance consists of the intensity of the sound, spectral changes in the sound caused by air absorption, and the motion-induced rate of change of intensity. However, these cues are relative because prior information/experience of the sound source-its source power, its spectrum and the typical speed at which it moves-is required for such distance estimates. This paper describes two listening experiments that allow investigation of further prior contextual information taken into account by listeners-viz., whether they are indoors or outdoors. Asked to estimate the distance to the track of a railway, it is shown that listeners assessing sounds heard inside the dwelling based their distance estimates on the expected train passby sound level outdoors rather than on the passby sound level actually experienced indoors. This form of perceptual constancy may have consequences for the assessment of annoyance caused by railway noise. PMID:23862822

  10. Motor impairments screened by the movement assessment battery for children-2 are related to the visual-perceptual deficits in children with developmental coordination disorder.

    PubMed

    Cheng, Chih-Hsiu; Ju, Yan-Ying; Chang, Hsin-Wen; Chen, Chia-Ling; Pei, Yu-Cheng; Tseng, Kevin C; Cheng, Hsin-Yi Kathy

    2014-09-01

    This study was to examine to what extent the motor deficits of children with Developmental Coordination Disorder (DCD) verified by the Movement Assessment Battery for Children-2 (MABC-2) are linked to their visual-perceptual abilities. Seventeen children with DCD and seventeen typically developing children (TD) aged 5-10 years screened from a total of 250 children were recruited. The assessments included MABC-2, traditional test of visual perceptual skills (TVPS-R), and computerized test for sequential coupling of eye and hand as well as motion coherence. The results indicated that children with DCD scored lower than TD in MABC-2, and their total scores were highly correlated with manual dexterity component scores. DCD group also showed poor visual-perceptual abilities in various aspects. The visual discrimination and visual sequential memory from the TVPS-R, the sequential coupling of eye and hand, and the motion coherence demonstrated a moderate or strong correlation with the MABC-2 in the DCD rather than the TD group. It was concluded that the motor problems screened by MABC-2 were significantly related to the visual-perceptual deficits of children with DCD. MABC-2 is suggested to be a prescreening tool to identify the visual-perceptual related motor deficits. PMID:24915646

  11. Evidence accumulation in obsessive-compulsive disorder: the role of uncertainty and monetary reward on perceptual decision-making thresholds.

    PubMed

    Banca, Paula; Vestergaard, Martin D; Rankov, Vladan; Baek, Kwangyeol; Mitchell, Simon; Lapa, Tatyana; Castelo-Branco, Miguel; Voon, Valerie

    2015-01-01

    The compulsive behaviour underlying obsessive-compulsive disorder (OCD) may be related to abnormalities in decision-making. The inability to commit to ultimate decisions, for example, patients unable to decide whether their hands are sufficiently clean, may reflect failures in accumulating sufficient evidence before a decision. Here we investigate the process of evidence accumulation in OCD in perceptual discrimination, hypothesizing enhanced evidence accumulation relative to healthy volunteers. Twenty-eight OCD patients and thirty-five controls were tested with a low-level visual perceptual task (random-dot-motion task, RDMT) and two response conflict control tasks. Regression analysis across different motion coherence levels and Hierarchical Drift Diffusion Modelling (HDDM) were used to characterize response strategies between groups in the RDMT. Patients required more evidence under high uncertainty perceptual contexts, as indexed by longer response time and higher decision boundaries. HDDM, which defines a decision when accumulated noisy evidence reaches a decision boundary, further showed slower drift rate towards the decision boundary reflecting poorer quality of evidence entering the decision process in patients under low uncertainty. With monetary incentives emphasizing speed and penalty for slower responses, patients decreased the decision thresholds relative to controls, accumulating less evidence in low uncertainty. These findings were unrelated to visual perceptual deficits and response conflict. This study provides evidence for impaired decision-formation processes in OCD, with a differential influence of high and low uncertainty contexts on evidence accumulation (decision threshold) and on the quality of evidence gathered (drift rates). It further emphasizes that OCD patients are sensitive to monetary incentives heightening speed in the speed-accuracy tradeoff, improving evidence accumulation. PMID:25425323

  12. Tone Language Speakers and Musicians Share Enhanced Perceptual and Cognitive Abilities for Musical Pitch: Evidence for Bidirectionality between the Domains of Language and Music

    PubMed Central

    Bidelman, Gavin M.; Hutka, Stefanie; Moreno, Sylvain

    2013-01-01

    Psychophysiological evidence suggests that music and language are intimately coupled such that experience/training in one domain can influence processing required in the other domain. While the influence of music on language processing is now well-documented, evidence of language-to-music effects have yet to be firmly established. Here, using a cross-sectional design, we compared the performance of musicians to that of tone-language (Cantonese) speakers on tasks of auditory pitch acuity, music perception, and general cognitive ability (e.g., fluid intelligence, working memory). While musicians demonstrated superior performance on all auditory measures, comparable perceptual enhancements were observed for Cantonese participants, relative to English-speaking nonmusicians. These results provide evidence that tone-language background is associated with higher auditory perceptual performance for music listening. Musicians and Cantonese speakers also showed superior working memory capacity relative to nonmusician controls, suggesting that in addition to basic perceptual enhancements, tone-language background and music training might also be associated with enhanced general cognitive abilities. Our findings support the notion that tone language speakers and musically trained individuals have higher performance than English-speaking listeners for the perceptual-cognitive processing necessary for basic auditory as well as complex music perception. These results illustrate bidirectional influences between the domains of music and language. PMID:23565267

  13. Perceptual Discrimination in Static and Dynamic Noise: The Temporal Relation between Perceptual Encoding and Decision Making

    ERIC Educational Resources Information Center

    Ratcliff, Roger; Smith, Philip L.

    2010-01-01

    The authors report 9 new experiments and reanalyze 3 published experiments that investigate factors affecting the time course of perceptual processing and its effects on subsequent decision making. Stimuli in letter-discrimination and brightness-discrimination tasks were degraded with static and dynamic noise. The onset and the time course of…

  14. Exploring Perceptual Skills in Children with Autism Spectrum Disorders: From Target Detection to Dynamic Perceptual Discrimination

    ERIC Educational Resources Information Center

    Miller, Louisa; McGonigle-Chalmers, Maggie

    2014-01-01

    Perceptual processing in autism is associated with both "strengths" and "weaknesses" but within a literature that varies widely in terms of the assessments used. We report data from 12 children with autism spectrum disorders (ASD) and 12 age and IQ matched neurotypical controls tested on a set of tasks using the same stimuli…

  15. Computing Speed

    NSDL National Science Digital Library

    2011-01-01

    This lesson should take one day of class time. The purpose of this lesson is to develop an understanding of quadratic functions. We use the linear relation between distance, constant speed and time and the quadratic relation between the vertical distance of a falling object and time. From these, students will develop two new quadratic functions. The graph of one of these provides a picture of the physical phenomenon they have viewed.

  16. Perceptual learning without signal Nicolas Dupuis-Roy *, Frederic Gosselin

    E-print Network

    Gosselin, Frédéric

    by an improvement in a perceptual task following practice. Several studies have demonstrated that top-down processes report an experiment that isolated top-down processes in perceptual learning, using a variant of the Gosselin and Schyns (1992) no-signal procedure. Results indicate that top-down processes can be sufficient

  17. Selective Attention to Perceptual Dimensions and Switching between Dimensions

    ERIC Educational Resources Information Center

    Meiran, Nachshon; Dimov, Eduard; Ganel, Tzvi

    2013-01-01

    In the present experiments, the question being addressed was whether switching attention between perceptual dimensions and selective attention to dimensions are processes that compete over a common resource? Attention to perceptual dimensions is usually studied by requiring participants to ignore a never-relevant dimension. Selection failure…

  18. Neural Correlates of Perceptual Rivalry in the Human Brain

    Microsoft Academic Search

    Erik D. Lumer; Karl J. Friston; Geraint Rees

    1998-01-01

    When dissimilar images are presented to the two eyes, perception alternates spontane- ously between each monocular view, a phenomenon called binocular rivalry. Functional brain imaging in humans was used to study the neural basis of these subjective perceptual changes. Cortical regions whose activity reflected perceptual transitions included extra- striate areas of the ventral visual pathway, and parietal and frontal regions

  19. Perceptual Specificity Effects in Rereading: Evidence from Eye Movements

    ERIC Educational Resources Information Center

    Sheridan, Heather; Reingold, Eyal M.

    2012-01-01

    The present experiments examined perceptual specificity effects using a rereading paradigm. Eye movements were monitored while participants read the same target word twice, in two different low-constraint sentence frames. The congruency of perceptual processing was manipulated by either presenting the target word in the same distortion typography…

  20. Bayesian Face Recognition and Perceptual Narrowing in Face-Space

    ERIC Educational Resources Information Center

    Balas, Benjamin

    2012-01-01

    During the first year of life, infants' face recognition abilities are subject to "perceptual narrowing", the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in…

  1. Psychophysical indices of perceptual functioning in dyslexia: A psychometric analysis

    E-print Network

    Nottingham, University of

    Psychophysical indices of perceptual functioning in dyslexia: A psychometric analysis Steve M dyslexia to visual and/or auditory perceptual deficits. This theory derives from group differences between individuals with dyslexia and controls on a range of psychophysical tasks, but there is substantial variation

  2. Perceptual and communicative indices of employee performance with new technology

    Microsoft Academic Search

    Michael J. Papa; Wendy H. Papa

    1990-01-01

    The relationship between employee performance with new technology and perceptual and communicative factors was investigated in a field study of 157 employees from a large corporation. Multiple regression analysis revealed that three perceptual factors (relative advantage, complexity, and trialability) and two communication factors (receiving task?related messages and receiving negative evaluations of the new technology) explained a significant amount of the

  3. Teacher Manual in Visual-Motor-Perceptual Training.

    ERIC Educational Resources Information Center

    Ramapo Central School District 1, Suffern, NY.

    The experimental program in visual-motor-perceptual training in Ramapo Central School District No. 1, Suffern, New York, was used as a guideline to prepare a detailed description of specific activities and exercises to be used by administrators and teachers. In the program, 80 visual-motor-perceptual handicapped children in first, second, and…

  4. Perceptual Organization as a Foundation for Intelfigent Sketch Editing

    Microsoft Academic Search

    Eric Saund; James Mahoney; David Fleet; Dan Lamer; Edward Lank

    2002-01-01

    This paper discusses the design of intelligent sketch editing tools exploiting intermediate levels of visual interpretation known as Perceptual Organization. Sketches are much more than an accumulation of strokes: they convey information largely through spatial configurations and patterns among markings. We propose that the detection of this visual structure, based on the principles of Perceptual Organization, will make sketch editing

  5. Neurological Evidence Linguistic Processes Precede Perceptual Simulation in Conceptual Processing

    PubMed Central

    Louwerse, Max; Hutchinson, Sterling

    2012-01-01

    There is increasing evidence from response time experiments that language statistics and perceptual simulations both play a role in conceptual processing. In an EEG experiment we compared neural activity in cortical regions commonly associated with linguistic processing and visual perceptual processing to determine to what extent symbolic and embodied accounts of cognition applied. Participants were asked to determine the semantic relationship of word pairs (e.g., sky – ground) or to determine their iconic relationship (i.e., if the presentation of the pair matched their expected physical relationship). A linguistic bias was found toward the semantic judgment task and a perceptual bias was found toward the iconicity judgment task. More importantly, conceptual processing involved activation in brain regions associated with both linguistic and perceptual processes. When comparing the relative activation of linguistic cortical regions with perceptual cortical regions, the effect sizes for linguistic cortical regions were larger than those for the perceptual cortical regions early in a trial with the reverse being true later in a trial. These results map upon findings from other experimental literature and provide further evidence that processing of concept words relies both on language statistics and on perceptual simulations, whereby linguistic processes precede perceptual simulation processes. PMID:23133427

  6. Better discrimination for illusory than for occluded perceptual completions

    E-print Network

    Zhou, Yi-Feng

    Better discrimination for illusory than for occluded perceptual completions School of Life Sciences Liu We applied the thin­fat Kanizsa shape discrimination task invented by D. L. Ringach and R. Shapley (1996) to study perceptual completion by measuring whether the discrimination was more accurate

  7. SECOND-ORDER PROBLEMS IN STUDIES OF PERCEPTUAL DEVELOPMENT.

    ERIC Educational Resources Information Center

    WHITE, BURTON L.

    RECENT RESEARCH FINDINGS ON THE PERCEPTUAL DEVELOPMENT OF YOUNG INFANTS WERE SURVEYED, AND THE NEED FOR SYNTHESIZING THESE NEW FINDINGS INTO WORKABLE CONCEPTS WAS SUGGESTED FOR THE FRUITFUL STUDY OF HIGHER ORDER CONSIDERATIONS IN THE FUTURE. A DISCUSSION WAS MADE ON THE DEVELOPMENTAL ISSUES OF--(1) SUPERORDINATE CATEGORIES OF PERCEPTUAL FUNCTION,…

  8. Teaching social perceptual skills to students with learning disabilities

    Microsoft Academic Search

    Andrew B. Sandier; Jane Y. Murdock; Elizabeth Dofny; Paul J. Gerber

    1991-01-01

    We investigated the effects of descriptive feedback and reinforcement on the acquisition and exhibition of social perceptual skills in three students with identified learning disabilities and social perceptual deficits. The students rated their teacher's affect based on six emotions, and received feedback regarding the accuracy of their ratings plus reinforcement for accurate ratings. Descriptive feedback and reinforcement resulted in a

  9. Effect of Scenario on Perceptual Sensitivity to Errors in Animation

    E-print Network

    Treuille, Adrien

    -Dimensional Graphics and Realism-- Animation General Terms: Experimentation, Human Factors, Measurement Additional KeyEffect of Scenario on Perceptual Sensitivity to Errors in Animation PAUL S. A. REITSMA and CAROL O'SULLIVAN Trinity College Dublin A deeper understanding of what makes animation perceptually plausible would benefit

  10. A Scanner Darkly: Protecting User Privacy From Perceptual Applications

    E-print Network

    Shmatikov, Vitaly

    , third-party perceptual ap- plication is running on a trusted device. DARKLY is integrated with OpenCV unmodified or with very few modifications and minimal performance overheads vs. native OpenCV. In most cases's perceptual sensors via special-purpose software libraries. DARKLY is integrated with OpenCV, a popular

  11. Estimating the Growth of Internal Evidence Guiding Perceptual Decisions

    ERIC Educational Resources Information Center

    Ludwig, Casimir J. H.; Davies, J. Rhys

    2011-01-01

    Perceptual decision-making is thought to involve a gradual accrual of noisy evidence. Temporal integration of the evidence reduces the relative contribution of dynamic internal noise to the decision variable, thereby boosting its signal-to-noise ratio. We aimed to estimate the internal evidence guiding perceptual decisions over time, using a novel…

  12. Harnessing the Wandering Mind: The Role of Perceptual Load

    ERIC Educational Resources Information Center

    Forster, Sophie; Lavie, Nilli

    2009-01-01

    Perceptual load is a key determinant of distraction by task-irrelevant stimuli (e.g., Lavie, N. (2005). "Distracted and confused?: Selective attention under load." "Trends in Cognitive Sciences," 9, 75-82). Here we establish the role of perceptual load in determining an internal form of distraction by task-unrelated thoughts (TUTs or…

  13. Perceptual Learning: 12-Month-Olds' Discrimination of Monkey Faces

    ERIC Educational Resources Information Center

    Fair, Joseph; Flom, Ross; Jones, Jacob; Martin, Justin

    2012-01-01

    Six-month-olds reliably discriminate different monkey and human faces whereas 9-month-olds only discriminate different human faces. It is often falsely assumed that perceptual narrowing reflects a permanent change in perceptual abilities. In 3 experiments, ninety-six 12-month-olds' discrimination of unfamiliar monkey faces was examined. Following…

  14. The Role of Perceptual Load in Inattentional Blindness

    ERIC Educational Resources Information Center

    Cartwright-Finch, Ula; Lavie, Nilli

    2007-01-01

    Perceptual load theory offers a resolution to the long-standing early vs. late selection debate over whether task-irrelevant stimuli are perceived, suggesting that irrelevant perception depends upon the perceptual load of task-relevant processing. However, previous evidence for this theory has relied on RTs and neuroimaging. Here we tested the…

  15. Extraneous Perceptual Information Interferes with Children's Acquisition of Mathematical Knowledge

    ERIC Educational Resources Information Center

    Kaminski, Jennifer A.; Sloutsky, Vladimir M.

    2013-01-01

    Educational material often includes engaging perceptual information. However, this perceptual information is often extraneous and may compete with the deeper to-be-learned structure, consequently hindering either the learning of relevant structure or its transfer to new situations. This hypothesis was tested in 4 experiments in which 6- to…

  16. JPEG 2000 Encoding with Perceptual Distortion Control

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Liu, Zhen; Karam, Lina J.

    2008-01-01

    An alternative approach has been devised for encoding image data in compliance with JPEG 2000, the most recent still-image data-compression standard of the Joint Photographic Experts Group. Heretofore, JPEG 2000 encoding has been implemented by several related schemes classified as rate-based distortion-minimization encoding. In each of these schemes, the end user specifies a desired bit rate and the encoding algorithm strives to attain that rate while minimizing a mean squared error (MSE). While rate-based distortion minimization is appropriate for transmitting data over a limited-bandwidth channel, it is not the best approach for applications in which the perceptual quality of reconstructed images is a major consideration. A better approach for such applications is the present alternative one, denoted perceptual distortion control, in which the encoding algorithm strives to compress data to the lowest bit rate that yields at least a specified level of perceptual image quality. Some additional background information on JPEG 2000 is prerequisite to a meaningful summary of JPEG encoding with perceptual distortion control. The JPEG 2000 encoding process includes two subprocesses known as tier-1 and tier-2 coding. In order to minimize the MSE for the desired bit rate, a rate-distortion- optimization subprocess is introduced between the tier-1 and tier-2 subprocesses. In tier-1 coding, each coding block is independently bit-plane coded from the most-significant-bit (MSB) plane to the least-significant-bit (LSB) plane, using three coding passes (except for the MSB plane, which is coded using only one "clean up" coding pass). For M bit planes, this subprocess involves a total number of (3M - 2) coding passes. An embedded bit stream is then generated for each coding block. Information on the reduction in distortion and the increase in the bit rate associated with each coding pass is collected. This information is then used in a rate-control procedure to determine the contribution of each coding block to the output compressed bit stream.

  17. Memory Matters

    MedlinePLUS

    ... blood vessel (which carries the blood) bursts. Continue Brain Injuries Affect Memory At any age, an injury to ... with somebody's memory. Some people who recover from brain injuries need to learn old things all over again, ...

  18. Motor and Tactile-Perceptual Skill Differences Between Individuals with High-Functioning Autism and Typically Developing Individuals Ages 5 – 21

    PubMed Central

    Abu-Dahab, Sana M. N.; Holm, Margo B.; Rogers, Joan C.; Skidmore, Elizabeth; Minshew, Nancy J.

    2012-01-01

    We examined motor and tactile-perceptual skills in individuals with high-functioning autism (IHFA) and matched typically developing individuals (TDI) ages 5 – 21 years. Grip strength, motor speed and coordination were impaired in IHFA compared to matched TDI, and the differences between groups varied with age. Although tactile-perceptual skills of IHFA were impaired compared to TDI on several measures, impairments were statistically and clinically significant only for stereognosis. Motor and tactile-perceptual skills should be assessed in children with IHFA and intervention should begin early because these skills are essential to school performance. Impairments in coordination and stereognosis suggest a broad though selective under-development of the circuitry for higher order abilities regardless of domain that is important in the search for the underlying disturbances in neurological development. PMID:22318760

  19. Neural Mechanisms of Speed-Accuracy Tradeoff

    PubMed Central

    Heitz, Richard P.; Schall, Jeffrey D.

    2012-01-01

    SUMMARY Intelligent agents balance speed of responding with accuracy of deciding. Stochastic accumulator models commonly explain this speed-accuracy tradeoff by strategic adjustment of response threshold. Several laboratories identify specific neurons in prefrontal and parietal cortex with this accumulation process, yet no neurophysiological correlates of speed-accuracy tradeoff have been described. We trained macaque monkeys to trade speed for accuracy on cue during visual search and recorded the activity of neurons in the frontal eye field. Unpredicted by any model, we discovered that speed-accuracy tradeoff is accomplished through several distinct adjustments. Visually responsive neurons modulated baseline firing rate, sensory gain, and the duration of perceptual processing. Movement neurons triggered responses with activity modulated in a direction opposite of model predictions. Thus, current stochastic accumulator models provide an incomplete description of the neural processes accomplishing speed-accuracy tradeoffs. The diversity of neural mechanisms was reconciled with the accumulator framework through an integrated accumulator model constrained by requirements of the motor system. PMID:23141072

  20. Dynamic Memory Hierarchy Performance Optimization

    Microsoft Academic Search

    Rajeev Balasubramonian; David Albonesi; Alper Buyuktosunoglu; Sandhya Dwarkadas

    2000-01-01

    Although microprocessor performance continues to in- crease at a rapid pace, the growing processor-memory speed gap threatens to limit future performance gains. In this paper, we propose a novel configurable cache and TLB as an alternative to conventional two-level hierar- chies. This organization leverages repeater insertion to provide low-cost configurability of size and speed. A novel configuration management algorithm dynamically

  1. Virtual Memory

    Microsoft Academic Search

    Peter J. Denning

    1970-01-01

    \\\\The need for automatic storage allocation arises from desires for program modularity, machine independence, and resource sharing. Virtual memory is an elegant way of achieving these objectives. In a virtual memory, the addresses a program may use to identify information are distinguished from the addresses the memory system uses to identify physical storage sites, and program-generated addresses are translated automatically

  2. Is Statistical Learning Constrained by Lower Level Perceptual Organization?

    PubMed Central

    Emberson, Lauren L.; Liu, Ran; Zevin, Jason D.

    2013-01-01

    In order for statistical information to aid in complex developmental processes such as language acquisition, learning from higher-order statistics (e.g. across successive syllables in a speech stream to support segmentation) must be possible while perceptual abilities (e.g. speech categorization) are still developing. The current study examines how perceptual organization interacts with statistical learning. Adult participants were presented with multiple exemplars from novel, complex sound categories designed to reflect some of the spectral complexity and variability of speech. These categories were organized into sequential pairs and presented such that higher-order statistics, defined based on sound categories, could support stream segmentation. Perceptual similarity judgments and multi-dimensional scaling revealed that participants only perceived three perceptual clusters of sounds and thus did not distinguish the four experimenter-defined categories, creating a tension between lower level perceptual organization and higher-order statistical information. We examined whether the resulting pattern of learning is more consistent with statistical learning being “bottom-up,” constrained by the lower levels of organization, or “top-down,” such that higher-order statistical information of the stimulus stream takes priority over the perceptual organization, and perhaps influences perceptual organization. We consistently find evidence that learning is constrained by perceptual organization. Moreover, participants generalize their learning to novel sounds that occupy a similar perceptual space, suggesting that statistical learning occurs based on regions of or clusters in perceptual space. Overall, these results reveal a constraint on learning of sound sequences, such that statistical information is determined based on lower level organization. These findings have important implications for the role of statistical learning in language acquisition. PMID:23618755

  3. Memory Impairment in Children with Language Impairment

    ERIC Educational Resources Information Center

    Baird, Gillian; Dworzynski, Katharina; Slonims, Vicky; Simonoff, Emily

    2010-01-01

    Aim: The aim of this study was to assess whether any memory impairment co-occurring with language impairment is global, affecting both verbal and visual domains, or domain specific. Method: Visual and verbal memory, learning, and processing speed were assessed in children aged 6 years to 16 years 11 months (mean 9y 9m, SD 2y 6mo) with current,…

  4. System-Level Integration of Mass Memory

    NASA Technical Reports Server (NTRS)

    Cox, Brian; Mellstrom, Jeffrey; Wysocky, Terry

    2008-01-01

    A report discusses integrating multiple memory modules on the high-speed serial interconnect (IEEE 1393) that is used by a spacecraft?s inter-module communications in order to ease data congestion and provide for a scalable, strong, flexible system that can meet new system-level mass memory requirements.

  5. The Effect of a Perceptual-Motor Training Program Upon the Readiness and Perceptual Development of Culturally Disadvantaged Kindergarten Children.

    ERIC Educational Resources Information Center

    Turner, Robert V.; Fisher, Maurice D.

    As a part of a Title III project, a program was initiated to provide disadvantaged kindergarten children with planned perceptual-motor training exercises. This study investigates the effects of that program on the perceptual development and academic readiness of a group of 76 such children. The exercises, derived from the Kephart developmental…

  6. A model of memory for incidental learning

    NASA Astrophysics Data System (ADS)

    Browse, Roger A.; Drewell, Lisa Y.

    2009-02-01

    This paper describes a radial basis memory system that is used to model the performance of human participants in a task of learning to traverse mazes in a virtual environment. The memory model is a multiple-trace system, in which each event is stored as a separate memory trace. In the modeling of the maze traversal task, the events that are stored as memories are the perceptions and decisions taken at the intersections of the maze. As the virtual agent traverses the maze, it makes decisions based upon all of its memories, but those that match best to the current perceptual situation, and which were successful in the past, have the greatest influence. As the agent carries out repeated attempts to traverse the same maze, memories of successful decisions accumulate, and performance gradually improves. The system uses only three free parameters, which most importantly includes adjustments to the standard deviation of the underlying Gaussian used as the radial basis function. It is demonstrated that adjustments of these parameters can easily result in exact modeling of the average human performance in the same task, and that variation of the parameters matches the variation in human performance. We conclude that human memory interaction that does not involve conscious memorization, as in learning navigation routes, may be much more primitive and simply explained than has been previously thought.

  7. Age effects on explicit and implicit memory

    PubMed Central

    Ward, Emma V.; Berry, Christopher J.; Shanks, David R.

    2013-01-01

    It is well-documented that explicit memory (e.g., recognition) declines with age. In contrast, many argue that implicit memory (e.g., priming) is preserved in healthy aging. For example, priming on tasks such as perceptual identification is often not statistically different in groups of young and older adults. Such observations are commonly taken as evidence for distinct explicit and implicit learning/memory systems. In this article we discuss several lines of evidence that challenge this view. We describe how patterns of differential age-related decline may arise from differences in the ways in which the two forms of memory are commonly measured, and review recent research suggesting that under improved measurement methods, implicit memory is not age-invariant. Formal computational models are of considerable utility in revealing the nature of underlying systems. We report the results of applying single and multiple-systems models to data on age effects in implicit and explicit memory. Model comparison clearly favors the single-system view. Implications for the memory systems debate are discussed. PMID:24065942

  8. Capacity-Speed Relationships in Prefrontal Cortex

    PubMed Central

    Prabhakaran, Vivek; Rypma, Bart; Narayanan, Nandakumar S.; Meier, Timothy B.; Austin, Benjamin P.; Nair, Veena A.; Naing, Lin; Thomas, Lisa E.; Gabrieli, John D. E.

    2011-01-01

    Working memory (WM) capacity and WM processing speed are simple cognitive measures that underlie human performance in complex processes such as reasoning and language comprehension. These cognitive measures have shown to be interrelated in behavioral studies, yet the neural mechanism behind this interdependence has not been elucidated. We have carried out two functional MRI studies to separately identify brain regions involved in capacity and speed. Experiment 1, using a block-design WM verbal task, identified increased WM capacity with increased activity in right prefrontal regions, and Experiment 2, using a single-trial WM verbal task, identified increased WM processing speed with increased activity in similar regions. Our results suggest that right prefrontal areas may be a common region interlinking these two cognitive measures. Moreover, an overlap analysis with regions associated with binding or chunking suggest that this strategic memory consolidation process may be the mechanism interlinking WM capacity and WM speed. PMID:22132105

  9. Perceptual learning: Toward a comprehensive theory

    PubMed Central

    Watanabe, Takeo; Sasaki, Yuka

    2014-01-01

    Visual perceptual learning (VPL) is long-term performance increase resulting from visual perceptual experience. Task-relevant VPL of a feature results from training of a task on the feature relevant to the task. Task-irrelevant VPL arises as a result of exposure to the feature irrelevant to the trained task. There are at least two serious problems. First, which stage of information processing is changed in association with task-relevant VPL is controversial. Second, no model has ever explained both task-relevant and task-irrelevant VPL. Here we propose a dual plasticity model, in which there are feature-based plasticity that is a change in a representation of the learned feature and task-based plasticity that is a change in processing of the trained task. While the two types of plasticity underlie task-relevant VPL, only feature-based plasticity lies under task-irrelevant VPL. This model provides a new comprehensive framework in which apparently contradictory results could be explained. PMID:25251494

  10. Facial expression recognition in perceptual color space.

    PubMed

    Lajevardi, Seyed Mehdi; Wu, Hong Ren

    2012-08-01

    This paper introduces a tensor perceptual color framework (TPCF) for facial expression recognition (FER), which is based on information contained in color facial images. The TPCF enables multi-linear image analysis in different color spaces and demonstrates that color components provide additional information for robust FER. Using this framework, the components (in either RGB, YCbCr, CIELab or CIELuv space) of color images are unfolded to two-dimensional (2- D) tensors based on multi-linear algebra and tensor concepts, from which the features are extracted by Log-Gabor filters. The mutual information quotient (MIQ) method is employed for feature selection. These features are classified using a multi-class linear discriminant analysis (LDA) classifier. The effectiveness of color information on FER using low-resolution and facial expression images with illumination variations is assessed for performance evaluation. Experimental results demonstrate that color information has significant potential to improve emotion recognition performance due to the complementary characteristics of image textures. Furthermore, the perceptual color spaces (CIELab and CIELuv) are better overall for facial expression recognition than other color spaces by providing more efficient and robust performance for facial expression recognition using facial images with illumination variation. PMID:22575677

  11. Nanoporous silicon oxide memory.

    PubMed

    Wang, Gunuk; Yang, Yang; Lee, Jae-Hwang; Abramova, Vera; Fei, Huilong; Ruan, Gedeng; Thomas, Edwin L; Tour, James M

    2014-08-13

    Oxide-based two-terminal resistive random access memory (RRAM) is considered one of the most promising candidates for next-generation nonvolatile memory. We introduce here a new RRAM memory structure employing a nanoporous (NP) silicon oxide (SiOx) material which enables unipolar switching through its internal vertical nanogap. Through the control of the stochastic filament formation at low voltage, the NP SiOx memory exhibited an extremely low electroforming voltage (? 1.6 V) and outstanding performance metrics. These include multibit storage ability (up to 9-bits), a high ON-OFF ratio (up to 10(7) A), a long high-temperature lifetime (? 10(4) s at 100 °C), excellent cycling endurance (? 10(5)), sub-50 ns switching speeds, and low power consumption (? 6 × 10(-5) W/bit). Also provided is the room temperature processability for versatile fabrication without any compliance current being needed during electroforming or switching operations. Taken together, these metrics in NP SiOx RRAM provide a route toward easily accessed nonvolatile memory applications. PMID:24992278

  12. Memory protection

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1988-01-01

    Accidental overwriting of files or of memory regions belonging to other programs, browsing of personal files by superusers, Trojan horses, and viruses are examples of breakdowns in workstations and personal computers that would be significantly reduced by memory protection. Memory protection is the capability of an operating system and supporting hardware to delimit segments of memory, to control whether segments can be read from or written into, and to confine accesses of a program to its segments alone. The absence of memory protection in many operating systems today is the result of a bias toward a narrow definition of performance as maximum instruction-execution rate. A broader definition, including the time to get the job done, makes clear that cost of recovery from memory interference errors reduces expected performance. The mechanisms of memory protection are well understood, powerful, efficient, and elegant. They add to performance in the broad sense without reducing instruction execution rate.

  13. Voluntary Explicit versus Involuntary Conceptual Memory Are Associated with Dissociable fMRI Responses in Hippocampus, Amygdala, and Parietal Cortex for Emotional and Neutral Word Pairs

    ERIC Educational Resources Information Center

    Ramponi, Cristina; Barnard, Philip J.; Kherif, Ferath; Henson, Richard N.

    2011-01-01

    Although functional neuroimaging studies have supported the distinction between explicit and implicit forms of memory, few have matched explicit and implicit tests closely, and most of these tested perceptual rather than conceptual implicit memory. We compared event-related fMRI responses during an intentional test, in which a group of…

  14. Perceptual Factors Influence Visual Search for Meaningful Symbols In Individuals with Intellectual Disabilities and Down Syndrome or Autism Spectrum Disorders

    PubMed Central

    Wilkinson, Krista M.; McIlvane, William J.

    2013-01-01

    Augmentative and alternative communication (AAC) systems often supplement oral communication of individuals with intellectual and communication disabilities. Research with nondisabled preschoolers has demonstrated that two visual perceptual factors influence speed and/or accuracy of finding a target - the internal color and spatial organization of symbols. Twelve participants with Down syndrome and 12 with ASD underwent two search tasks. In one, the symbols were clustered by internal color; in the other the identical symbols had no arrangement cue. Visual search was superior in participants with ASD compared to those with Down syndrome. In both groups, responses were significantly faster when the symbols were clustered by internal color. Construction of aided AAC displays may benefit from attention to their physical/perceptual features. PMID:24245729

  15. Experimental High Speed CMOS Image Sensor System and Applications

    E-print Network

    Wandell, Brian A.

    Liu Department of Electrical Engineering Psychology Department Department of Electrical Engineering Brian Wandell Department of Electrical Engineering Department of Electrical Engineering Psychology high speed non - destructive readout [1, 2, 3]. This capability and the potential of integrating memory

  16. Probing short-term face memory in developmental prosopagnosia.

    PubMed

    Shah, Punit; Gaule, Anne; Gaigg, Sebastian B; Bird, Geoffrey; Cook, Richard

    2015-03-01

    It has recently been proposed that the face recognition deficits seen in neurodevelopmental disorders may reflect impaired short-term face memory (STFM). For example, introducing a brief delay between the presentation of target and test faces seems to disproportionately impair matching or recognition performance in individuals with Autism Spectrum Disorders. The present study sought to determine whether deficits of STFM contribute to impaired face recognition seen in Developmental Prosopagnosia. To determine whether developmental prosopagnosics exhibit impaired STFM, the present study used a six-alternative-forced-choice match-to-sample procedure. Memory demand was manipulated by employing a short or long delay between the presentation of the target face, and the six test faces. Crucially, the perceptual demands were identical in both conditions, thereby allowing the independent contribution of STFM to be assessed. Prosopagnosics showed clear evidence of a category-specific impairment for face-matching in both conditions; they were both slower and less accurate than matched controls. Crucially, however, the prosopagnosics showed no evidence of disproportionate face recognition impairment in the long-interval condition. While individuals with DP may have problems with the perceptual encoding of faces, it appears that their representations are stable over short durations. These results suggest that the face recognition difficulties seen in DP and autism may be qualitatively different, attributable to deficits of perceptual encoding and perceptual maintenance, respectively. PMID:25461712

  17. Cognit activation: a mechanism enabling temporal integration in working memory

    PubMed Central

    Fuster, Joaquín M.; Bressler, Steven L.

    2012-01-01

    Working memory is critical to the integration of information across time in goal-directed behavior, reasoning and language, yet its neural substrate is unknown. Based on recent research, we propose a mechanism by which the brain can retain working memory for prospective use, thereby bridging time in the perception/action cycle. The essence of the mechanism is the activation of cognits, which consist of distributed, overlapping and interactive cortical networks that in the aggregate encode the long-term memory of the subject. Working memory depends on the excitatory reentry between perceptual and executive cognits of posterior and frontal cortices, respectively. Given the pervasive role of working memory in the structuring of purposeful cognitive sequences, its mechanism looms essential to the foundation of behavior, reasoning and language. PMID:22440831

  18. Quantum memory Quantum memory

    NASA Astrophysics Data System (ADS)

    Le Gouët, Jean-Louis; Moiseev, Sergey

    2012-06-01

    Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The quest for higher efficiency, better fidelity, broader bandwidth, multimode capacity and longer storage lifetime is pursued in all those approaches, as shown in this special issue. The improvement of quantum memory operation specifically requires in-depth study and control of numerous physical processes leading to atomic decoherence. The present issue reflects the development of rare earth ion doped matrices offering long lifetime superposition states, either as bulk crystals or as optical waveguides. The need for quantum sources and high efficiency detectors at the single photon level is also illustrated. Several papers address the networking of quantum memories either in long-haul cryptography or in the prospect of quantum processing. In this context, much attention has been paid recently to interfacing quantum light with superconducting qubits and with nitrogen-vacancy centers in diamond. Finally, the quantum interfacing of light with matter raises questions on entanglement. The last two papers are devoted to the generation of entanglement by dissipative processes. It is shown that long lifetime entanglement may be built in this way. We hope this special issue will help readers to become familiar with the exciting field of ensemble-based quantum memories and will stimulate them to bring deeper insights and new ideas to this area.

  19. Accurate expectancies diminish perceptual distraction during visual search.

    PubMed

    Sy, Jocelyn L; Guerin, Scott A; Stegman, Anna; Giesbrecht, Barry

    2014-01-01

    The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively "spills-over" to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information. PMID:24904374

  20. Auditory-perceptual learning improves speech motor adaptation in children.

    PubMed

    Shiller, Douglas M; Rochon, Marie-Lyne

    2014-08-01

    Auditory feedback plays an important role in children's speech development by providing the child with information about speech outcomes that is used to learn and fine-tune speech motor plans. The use of auditory feedback in speech motor learning has been extensively studied in adults by examining oral motor responses to manipulations of auditory feedback during speech production. Children are also capable of adapting speech motor patterns to perceived changes in auditory feedback; however, it is not known whether their capacity for motor learning is limited by immature auditory-perceptual abilities. Here, the link between speech perceptual ability and the capacity for motor learning was explored in two groups of 5- to 7-year-old children who underwent a period of auditory perceptual training followed by tests of speech motor adaptation to altered auditory feedback. One group received perceptual training on a speech acoustic property relevant to the motor task while a control group received perceptual training on an irrelevant speech contrast. Learned perceptual improvements led to an enhancement in speech motor adaptation (proportional to the perceptual change) only for the experimental group. The results indicate that children's ability to perceive relevant speech acoustic properties has a direct influence on their capacity for sensory-based speech motor adaptation. PMID:24842067

  1. Accurate expectancies diminish perceptual distraction during visual search

    PubMed Central

    Sy, Jocelyn L.; Guerin, Scott A.; Stegman, Anna; Giesbrecht, Barry

    2014-01-01

    The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively “spills-over” to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information. PMID:24904374

  2. Expertise for upright faces improves the precision but not the capacity of visual working memory.

    PubMed

    Lorenc, Elizabeth S; Pratte, Michael S; Angeloni, Christopher F; Tong, Frank

    2014-10-01

    Considerable research has focused on how basic visual features are maintained in working memory, but little is currently known about the precision or capacity of visual working memory for complex objects. How precisely can an object be remembered, and to what extent might familiarity or perceptual expertise contribute to working memory performance? To address these questions, we developed a set of computer-generated face stimuli that varied continuously along the dimensions of age and gender, and we probed participants' memories using a method-of-adjustment reporting procedure. This paradigm allowed us to separately estimate the precision and capacity of working memory for individual faces, on the basis of the assumptions of a discrete capacity model, and to assess the impact of face inversion on memory performance. We found that observers could maintain up to four to five items on average, with equally good memory capacity for upright and upside-down faces. In contrast, memory precision was significantly impaired by face inversion at every set size tested. Our results demonstrate that the precision of visual working memory for a complex stimulus is not strictly fixed but, instead, can be modified by learning and experience. We find that perceptual expertise for upright faces leads to significant improvements in visual precision, without modifying the capacity of working memory. PMID:24627213

  3. Overview of emerging nonvolatile memory technologies.

    PubMed

    Meena, Jagan Singh; Sze, Simon Min; Chand, Umesh; Tseng, Tseung-Yuen

    2014-01-01

    Nonvolatile memory technologies in Si-based electronics date back to the 1990s. Ferroelectric field-effect transistor (FeFET) was one of the most promising devices replacing the conventional Flash memory facing physical scaling limitations at those times. A variant of charge storage memory referred to as Flash memory is widely used in consumer electronic products such as cell phones and music players while NAND Flash-based solid-state disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. The integration limit of Flash memories is approaching, and many new types of memory to replace conventional Flash memories have been proposed. Emerging memory technologies promise new memories to store more data at less cost than the expensive-to-build silicon chips used by popular consumer gadgets including digital cameras, cell phones and portable music players. They are being investigated and lead to the future as potential alternatives to existing memories in future computing systems. Emerging nonvolatile memory technologies such as magnetic random-access memory (MRAM), spin-transfer torque random-access memory (STT-RAM), ferroelectric random-access memory (FeRAM), phase-change memory (PCM), and resistive random-access memory (RRAM) combine the speed of static random-access memory (SRAM), the density of dynamic random-access memory (DRAM), and the nonvolatility of Flash memory and so become very attractive as another possibility for future memory hierarchies. Many other new classes of emerging memory technologies such as transparent and plastic, three-dimensional (3-D), and quantum dot memory technologies have also gained tremendous popularity in recent years. Subsequently, not an exaggeration to say that computer memory could soon earn the ultimate commercial validation for commercial scale-up and production the cheap plastic knockoff. Therefore, this review is devoted to the rapidly developing new class of memory technologies and scaling of scientific procedures based on an investigation of recent progress in advanced Flash memory devices. PMID:25278820

  4. Overview of emerging nonvolatile memory technologies

    PubMed Central

    2014-01-01

    Nonvolatile memory technologies in Si-based electronics date back to the 1990s. Ferroelectric field-effect transistor (FeFET) was one of the most promising devices replacing the conventional Flash memory facing physical scaling limitations at those times. A variant of charge storage memory referred to as Flash memory is widely used in consumer electronic products such as cell phones and music players while NAND Flash-based solid-state disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. The integration limit of Flash memories is approaching, and many new types of memory to replace conventional Flash memories have been proposed. Emerging memory technologies promise new memories to store more data at less cost than the expensive-to-build silicon chips used by popular consumer gadgets including digital cameras, cell phones and portable music players. They are being investigated and lead to the future as potential alternatives to existing memories in future computing systems. Emerging nonvolatile memory technologies such as magnetic random-access memory (MRAM), spin-transfer torque random-access memory (STT-RAM), ferroelectric random-access memory (FeRAM), phase-change memory (PCM), and resistive random-access memory (RRAM) combine the speed of static random-access memory (SRAM), the density of dynamic random-access memory (DRAM), and the nonvolatility of Flash memory and so become very attractive as another possibility for future memory hierarchies. Many other new classes of emerging memory technologies such as transparent and plastic, three-dimensional (3-D), and quantum dot memory technologies have also gained tremendous popularity in recent years. Subsequently, not an exaggeration to say that computer memory could soon earn the ultimate commercial validation for commercial scale-up and production the cheap plastic knockoff. Therefore, this review is devoted to the rapidly developing new class of memory technologies and scaling of scientific procedures based on an investigation of recent progress in advanced Flash memory devices. PMID:25278820

  5. The perceptual effects of learning object categories that predict perceptual goals.

    PubMed

    Van Gulick, Ana E; Gauthier, Isabel

    2014-09-01

    In classic category learning studies, subjects typically learn to assign items to 1 of 2 categories, with no further distinction between how items on each side of the category boundary should be treated. In real life, however, we often learn categories that dictate further processing goals, for instance, with objects in only 1 category requiring further individuation. Using methods from category learning and perceptual expertise, we studied the perceptual consequences of experience with objects in tasks that rely on attention to different dimensions in different parts of the space. In 2 experiments, subjects first learned to categorize complex objects from a single morphspace into 2 categories based on 1 morph dimension, and then learned to perform a different task, either naming or a local feature judgment, for each of the 2 categories. A same-different discrimination test before and after each training measured sensitivity to feature dimensions of the space. After initial categorization, sensitivity increased along the category-diagnostic dimension. After task association, sensitivity increased more for the category that was named, especially along the nondiagnostic dimension. The results demonstrate that local attentional weights, associated with individual exemplars as a function of task requirements, can have lasting effects on perceptual representations. PMID:24820671

  6. Perceptual and contextual awareness: methodological considerations in the search for the neural correlates of consciousness

    PubMed Central

    Navajas, Joaquin; Rey, Hernan G.; Quian Quiroga, Rodrigo

    2014-01-01

    In the last decades, the neural correlates of consciousness (NCCs) have been explored using both invasive and non-invasive recordings by comparing the brain activity elicited by seen versus unseen visual stimuli (i.e., the contrastive analysis). Here, we review a selection of these studies and discuss a set of considerations to improve the search for the NCCs using the contrastive analysis. In particular, we first argue in favor of implementing paradigms where different perceptual outputs are obtained using identical visual inputs. Second, we propose that the large disagreement in the field -in terms of the dissimilar neural patterns proposed as NCCs- is partially explained by the fact that different studies report the neural correlates of different conscious processes in the brain. More specifically, we distinguish between the perceptual awareness of a visual stimulus, associated to a boost in object-selective neural assemblies, and a more elaborate process (contextual awareness) that we argue is reflected in the firing of concept neurons in the medial temporal lobe, triggering a rich representation of the context, associations, and memories linked to the specific stimulus. PMID:25221537

  7. Perceptual prominence of Hering's chromatic primaries.

    PubMed

    Kuehni, Rolf G; Shamey, Renzo; Mathews, Mara; Keene, Brandi

    2010-02-01

    Reported are results of an experiment involving perceptual assessment of very large color differences using samples representing approximate mean Hering opponent generic unique hues (guHs) based on subject selections, intermediate hues (iHs) using Munsell samples intermediate between guHs, and pairings of both guHs and iHs with a neutral gray. Sample pairs were assessed by 28 color normal subjects twice, with a gap of at least 24 hours between assessments. Results were calculated for individual subjects and the entire group. The hypothesis was that perceived chromatic differences of Hering's guHs are larger than those of iHs, and this was found to be statistically valid at the 99% confidence level based on a t-test. In addition, gray as a percept was found to have prominence comparable to that of generic unique hues. PMID:20126225

  8. Continuous assessment of perceptual image quality

    NASA Astrophysics Data System (ADS)

    Hamberg, Roelof; de Ridder, Huib

    1995-12-01

    The study addresses whether subjects are able to assess the perceived quality of an image sequence continuously. To this end, a new method for assessing time-varying perceptual image quality is presented by which subjects continuously indicate the perceived strength of image quality by moving a slider along a graphical scale. The slider's position on this scale is sampled every second. In this way, temporal variations in quality can be monitored quantitatively, and a means is provided by which differences between, for example, alternative transmission systems can be analyzed in an informative way. The usability of this method is illustrated by an experiment in which, for a period of 815 s, subjects assessed the quality of still pictures comprising time-varying degrees of sharpness. Copyright (c) 1995 Optical Society of America

  9. Cognitive Differences for Ages 16 to 89 Years (Canadian WAIS-III): Curvilinear with Flynn and Processing Speed Corrections

    ERIC Educational Resources Information Center

    Lee, Hoyee Flora; Gorsuch, Richard L.; Saklofske, Donald H.; Patterson, Colleen A.

    2008-01-01

    Adult cognitive age differences in the Wechsler Adult Intelligence Scale-III Canadian normative data were curvilinear for most scales and for the Verbal Comprehension (VC), Perceptual Organization (PO), and Working Memory (WM) factors. These showed stable or increasing scores in early adulthood followed by decreasing scores, necessitating a…

  10. Attention, short-term memory, and action selection: A unifying theory

    Microsoft Academic Search

    Gustavo Deco; Edmund T. Rolls

    2005-01-01

    Cognitive behaviour requires complex context-dependent processing of information that emerges from the links between attentional perceptual processes, working memory and reward-based evaluation of the performed actions. We describe a computational neuroscience theoretical framework which shows how an attentional state held in a short term memory in the prefrontal cortex can by top-down processing influence ventral and dorsal stream cortical areas

  11. Stepping into a Map: Initial Heading Direction Influences Spatial Memory Flexibility

    ERIC Educational Resources Information Center

    Gagnon, Stephanie A.; Brunyé, Tad T.; Gardony, Aaron; Noordzij, Matthijs L.; Mahoney, Caroline R.; Taylor, Holly A.

    2014-01-01

    Learning a novel environment involves integrating first-person perceptual and motoric experiences with developing knowledge about the overall structure of the surroundings. The present experiments provide insights into the parallel development of these egocentric and allocentric memories by intentionally conflicting body- and world-centered frames…

  12. Tell me more: Can a memory test reduce analogue traumatic intrusions?

    Microsoft Academic Search

    Julie Krans; Gérard Näring; Emily A. Holmes; Eni S. Becker

    2009-01-01

    Information processing theories of post-traumatic stress disorder (PTSD) state that intrusive images emerge due to a lack of integration of perceptual trauma representations in autobiographical memory. To test this hypothesis experimentally, participants were shown an aversive film to elicit intrusive images. After viewing, they received a recognition test for just one part of the film. The test contained neutrally formulated

  13. Spike-Based Population Coding and Working Memory Martin Boerlin1,2

    E-print Network

    Gutkin, Boris

    suggests that humans can make optimal decisions despite the uncertainty inherent in perceptual or motor distributions and not only single stimulus values. These memories are reflected by sustained, asynchronous,6,7,8,9,10]. In cortical areas, sensory and motor variables are encoded by the joint activity of populations of spiking

  14. Temporal Characteristics of TopDown Modulations during Working Memory Maintenance

    E-print Network

    Jha, Amishi P.

    investigated the top­down influence of working mem- ory (WM) maintenance on feedforward perceptual process- ing'' sensoriperceptual processing struc- tures. The temporal characteristics of top­down modu- lations have been wellTemporal Characteristics of Top­Down Modulations during Working Memory Maintenance: An Event

  15. Heterarchy of cognition: The depths and the highs of a framework for memory research

    Microsoft Academic Search

    Boris M. Velichkovsky

    2002-01-01

    To celebrate the levels-of-processing approach, I describe a multilevel evolutionary architecture for human behaviour and cognition. New experimental data on human eye movements are presented that demonstrate a possibility of splitting visual perceptual activity at least on two hierarchical but closely interrelated levels of processing. Furthermore, data from behavioural studies of human memory and neuroimaging testify that within the domain

  16. Selective Interference on the Holistic Processing of Faces in Working Memory

    ERIC Educational Resources Information Center

    Cheung, Olivia S.; Gauthier, Isabel

    2010-01-01

    Faces and objects of expertise compete for early perceptual processes and holistic processing resources (Gauthier, Curran, Curby, & Collins, 2003). Here, we examined the nature of interference on holistic face processing in working memory by comparing how various types of loads affect selective attention to parts of face composites. In dual tasks,…

  17. Virtual memory

    NASA Technical Reports Server (NTRS)

    Denning, P. J.

    1986-01-01

    Virtual memory was conceived as a way to automate overlaying of program segments. Modern computers have very large main memories, but need automatic solutions to the relocation and protection problems. Virtual memory serves this need as well and is thus useful in computers of all sizes. The history of the idea is traced, showing how it has become a widespread, little noticed feature of computers today.

  18. Perceptual and motor learning underlies human stick-balancing skill.

    PubMed

    Lee, Kwee-Yum; O'Dwyer, Nicholas; Halaki, Mark; Smith, Richard

    2015-01-01

    We investigated the acquisition of skill in balancing a stick (52 cm, 34 g) on the fingertip in nine participants using three-dimensional motion analysis. After 3.5 h of practice over 6 wk, the participants could more consistently balance the stick for longer durations with greatly reduced magnitude and speed of stick and finger movements. Irrespective of level of skill, the balanced stick behaved like a normal noninverted pendulum oscillating under greater-than-gravity torque with simple harmonic motion about a virtual pivot located at the radius of gyration above the center of mass. The control input parameter was the magnitude ratio between the torque applied on the stick by the participant and the torque due to gravity. The participants utilized only a narrow range of this parameter, which did not change with practice, to rotate the stick like a linear mass-spring system. With increased skill, the stick therefore maintained the same period of oscillation but showed marked reductions in magnitude of both oscillation and horizontal translation. Better balancing was associated with 1) more accurate visual localization of the stick and proprioceptive localization of the finger and 2) reduced cross-coupling errors between finger and stick movements in orthogonal directions; i.e., finger movements in the anteroposterior plane became less coupled with stick tip movements in the mediolateral plane, and vice versa. Development of this fine motor skill therefore depended on perceptual and motor learning to provide improved estimation of sensorimotor state and precision of motor commands to an unchanging internal model of the rotational dynamics. PMID:25298388

  19. Task contingencies and perceptual strategies shape behavioral effects on neuronal response profiles

    PubMed Central

    Sato, Nobuya; Page, William K.

    2013-01-01

    We presented optic flow simulating eight directions of self-movement in the ground plane, while monkeys performed delayed match-to-sample tasks, and we recorded dorsal medial superior temporal (MSTd) neuronal activity. Randomly selected sample headings yield smaller test responses to the neuron's preferred heading when it is near the sample's heading direction and larger test responses to the preferred heading when it is far from the sample's heading. Limiting test stimuli to matching or opposite headings suppresses responses to preferred stimuli in both test conditions, whereas focusing on each neuron's preferred vs. antipreferred stimuli enhances responses to the antipreferred stimulus. Match vs. opposite paradigms create bimodal heading profiles shaped by interactions with late delay-period activity. We conclude that task contingencies, determining the prior probabilities of specific stimuli, interact with the monkeys' perceptual strategy for optic flow analysis. These influences shape attentional and working memory effects on the heading direction selectivities and preferences of MSTd neurons. PMID:23100141

  20. IEEE TRANSACTIONS ON COMPUTERS, VOL. 52, NO. 10, OCTOBER 2003 1 A Dynamically Tunable Memory Hierarchy

    E-print Network

    Dwarkadas, Sandhya

    on our design. Keywords-- High performance microprocessors, Memory hierarchy, Reconfigurable- processors. The sheer number of transistors dedicated to the on-chip memory hierarchy in future processors in order to trade size for speed in the memory hierarchy. The most common conventional memory system today

  1. Coding for a Model of RandomAccess Memories of a Computer and

    E-print Network

    Bielefeld, University of

    Coding for a Model of Random­Access Memories of a Computer and Write­Unidirectional Memories length is viewed as an operation between the new and old content of a random­access memory used to increase the speed of the access to the memory. Coding procedures that allow us to recover x based on x

  2. Extending the Hong-Kung Model to Memory Hierarchies

    Microsoft Academic Search

    John E. Savage

    1995-01-01

    The speed of CPUs is accelerating rapidly, outstripping that of peripheral storage devices and making it increasingly difficult to keep CPUs busy. Consequently multi-level memory hierarchies, scaled to simulate single-level memories, are increasing in importance. In this paper we introduce the Memory Hierarchy Game, a multi-level pebble game that simulates data movement in memory hierarchies in terms of which we

  3. Perceptual Discrimination of Computer Generated and Photographic Faces

    E-print Network

    Bravo, Mary J.

    Perceptual Discrimination of Computer Generated and Photographic Faces Hany Farid and Mary J. Bravo Department of Computer Science, Dartmouth College Department of Psychology, Rutgers University Abstract child pornogra- phy is protected speech, while pornographic photographs depicting an actual child

  4. Variance misperception explains illusions of confidence in simple perceptual decisions.

    PubMed

    Zylberberg, Ariel; Roelfsema, Pieter R; Sigman, Mariano

    2014-07-01

    Confidence in a perceptual decision is a judgment about the quality of the sensory evidence. The quality of the evidence depends not only on its strength ('signal') but critically on its reliability ('noise'), but the separate contribution of these quantities to the formation of confidence judgments has not been investigated before in the context of perceptual decisions. We studied subjective confidence reports in a multi-element perceptual task where evidence strength and reliability could be manipulated independently. Our results reveal a confidence paradox: confidence is higher for stimuli of lower reliability that are associated with a lower accuracy. We show that the subjects' overconfidence in trials with unreliable evidence is caused by a reduced sensitivity to stimulus variability. Our results bridge between the investigation of miss-attributions of confidence in behavioral economics and the domain of simple perceptual decisions amenable to neuroscience research. PMID:24951943

  5. Perceptual data mining : bootstrapping visual intelligence from tracking behavior

    E-print Network

    Stauffer, Christopher P. (Christopher Paul), 1971-

    2002-01-01

    One common characteristic of all intelligent life is continuous perceptual input. A decade ago, simply recording and storing a a few minutes of full frame-rate NTSC video required special hardware. Today, an inexpensive ...

  6. Cultural Differences in Perceptual Reorganization in US and Pirahã Adults

    PubMed Central

    Yoon, Jennifer M. D.; Witthoft, Nathan; Winawer, Jonathan; Frank, Michael C.; Everett, Daniel L.; Gibson, Edward

    2014-01-01

    Visual illusions and other perceptual phenomena can be used as tools to uncover the otherwise hidden constructive processes that give rise to perception. Although many perceptual processes are assumed to be universal, variable susceptibility to certain illusions and perceptual effects across populations suggests a role for factors that vary culturally. One striking phenomenon is seen with two-tone images—photos reduced to two tones: black and white. Deficient recognition is observed in young children under conditions that trigger automatic recognition in adults. Here we show a similar lack of cue-triggered perceptual reorganization in the Pirahã, a hunter-gatherer tribe with limited exposure to modern visual media, suggesting such recognition is experience- and culture-specific. PMID:25411970

  7. Acquisition of intellectual and perceptual-motor skills.

    PubMed

    Rosenbaum, D A; Carlson, R A; Gilmore, R O

    2001-01-01

    Recent evidence indicates that intellectual and perceptual-motor skills are acquired in fundamentally similar ways. Transfer specificity, generativity, and the use of abstract rules and reflexlike productions are similar in the two skill domains; brain sites subserving thought processes and perceptual-motor processes are not as distinct as once thought; explicit and implicit knowledge characterize both kinds of skill; learning rates, training effects, and learning stages are remarkably similar for the two skill classes; and imagery, long thought to play a distinctive role in high-level thought, also plays a role in perceptual-motor learning and control. The conclusion that intellectual skills and perceptual-motor skills are psychologically more alike than different accords with the view that all knowledge is performatory. PMID:11148313

  8. Transfer of perceptual learning between different visual tasks

    PubMed Central

    McGovern, David P.; Webb, Ben S.; Peirce, Jonathan W.

    2012-01-01

    Practice in most sensory tasks substantially improves perceptual performance. A hallmark of this ‘perceptual learning' is its specificity for the basic attributes of the trained stimulus and task. Recent studies have challenged the specificity of learned improvements, although transfer between substantially different tasks has yet to be demonstrated. Here, we measure the degree of transfer between three distinct perceptual tasks. Participants trained on an orientation discrimination, a curvature discrimination, or a ‘global form' task, all using stimuli comprised of multiple oriented elements. Before and after training they were tested on all three and a contrast discrimination control task. A clear transfer of learning was observed, in a pattern predicted by the relative complexity of the stimuli in the training and test tasks. Our results suggest that sensory improvements derived from perceptual learning can transfer between very different visual tasks. PMID:23048211

  9. Perceptual tools for quality-aware video networks

    NASA Astrophysics Data System (ADS)

    Bovik, A. C.

    2014-01-01

    Monitoring and controlling the quality of the viewing experience of videos transmitted over increasingly congested networks (especially wireless networks) is a pressing problem owing to rapid advances in video-centric mobile communication and display devices that are straining the capacity of the network infrastructure. New developments in automatic perceptual video quality models offer tools that have the potential to be used to perceptually optimize wireless video, leading to more efficient video data delivery and better received quality. In this talk I will review key perceptual principles that are, or could be used to create effective video quality prediction models, and leading quality prediction models that utilize these principles. The goal is to be able to monitor and perceptually optimize video networks by making them "quality-aware."

  10. An ecological perceptual aid for precision vertical landings

    E-print Network

    Smith, Cristin Anne

    2006-01-01

    Pilots of vertical landing vehicles face numerous control challenges which often involve the loss of outside visual perceptual cues or the control of flight parameters within tight constraints. These challenges are often ...

  11. Phonetic knowledge, phonotactics and perceptual validation for automatic language identification

    E-print Network

    Boula de Mareüil, Philippe

    Phonetic knowledge, phonotactics and perceptual validation for automatic language identification- tribute to human language identification: among the most important are acoustics, phonetics, phonotactics for automatic LId. Acoustic-phonetic and phonotactic modelling benefit from many decades of research first

  12. Perceptual Disanalogy: On the Alstonian Analogy Argument from Religious Experience

    E-print Network

    Williams, William Coleman

    2010-10-12

    and how such statements can be further qualified as sensory perceptual in nature. Mavrodes' analysis of ordinary experiential statements is useful for a thorough treatment of sentences which refer to experiences of some kind, and I will restrict them... one. In sum, I have offered a brief description of the intuitive notion of experience, and have analyzed forms of experiential statements and how those statements can be qualified as sensory perceptual experiences. In preparation for my...

  13. Attentional set interacts with perceptual load in visual search

    Microsoft Academic Search

    Jan Theeuwes; Arthur F. Kramer; Artem V. Belopolsky

    2004-01-01

    In the present study, we examined the hypothesis that perceptual load is the primary factor that determines the efficiency\\u000a of attentional selection. Participants performed a visual search task under conditions of high- and low-load. In line with\\u000a the perceptual load hypothesis, presenting conditions of highand low-load in separate blocks of trials resulted in processing\\u000a of to-be-ignored stimuli only in the

  14. Divided attention can enhance memory encoding: the attentional boost effect in implicit memory.

    PubMed

    Spataro, Pietro; Mulligan, Neil W; Rossi-Arnaud, Clelia

    2013-07-01

    Distraction during encoding has long been known to disrupt later memory performance. Contrary to this long-standing result, we show that detecting an infrequent target in a dual-task paradigm actually improves memory encoding for a concurrently presented word, above and beyond the performance reached in the full-attention condition. This absolute facilitation was obtained in 2 perceptual implicit tasks (lexical decision and word fragment completion) but not in a conceptual implicit task (semantic classification). In the case of recognition memory, the facilitation was relative, bringing accuracy in the divided attention condition up to the level of accuracy in the full attention condition. The findings follow from the hypothesis that the attentional boost effect reflects enhanced visual encoding of the study stimulus consequent to the transient orienting response to the dual-task target. PMID:23356238

  15. Categorization training increases the perceptual separability of novel dimensions.

    PubMed

    Soto, Fabian A; Ashby, F Gregory

    2015-06-01

    Perceptual separability is a foundational concept in cognitive psychology. A variety of research questions in perception - particularly those dealing with notions such as "independence," "invariance," "holism," and "configurality" - can be characterized as special cases of the problem of perceptual separability. Furthermore, many cognitive mechanisms are applied differently to perceptually separable dimensions than to non-separable dimensions. Despite the importance of dimensional separability, surprisingly little is known about its origins. Previous research suggests that categorization training can lead to learning of novel dimensions, but it is not known whether the separability of such dimensions also increases with training. Here, we report evidence that training in a categorization task increases perceptual separability of the category-relevant dimension according to a variety of tests from general recognition theory (GRT). In Experiment 1, participants who received pre-training in a categorization task showed reduced Garner interference effects and reduced violations of marginal invariance, compared to participants who did not receive such pre-training. Both of these tests are theoretically related to violations of perceptual separability. In Experiment 2, participants who received pre-training in a categorization task showed reduced violations of perceptual separability according to a model-based analysis of data using GRT. These results are at odds with the common assumption that separability and independence are fixed, hardwired characteristics of features and dimensions. PMID:25817370

  16. The influence of dopamine-related genes on perceptual stability.

    PubMed

    Schmack, Katharina; Sekutowicz, Maria; Rössler, Hannes; Brandl, Eva J; Müller, Daniel J; Sterzer, Philipp

    2013-11-01

    Bistable perception is the spontaneous and automatic alternation between two different perceptual states that occurs when sensory information is ambiguous. Perceptual alternation rates are robust within individuals but vary substantially between individuals. Slowed perceptual switching has been consistently reported in patients with bipolar disorder (BPD) and has been suggested as a trait marker for this disease. Although genetic factors have been implicated in both BPD and bistable perception, the underlying biological mechanisms that mediate the observed perceptual stability in BPD remain elusive. Here, we tested the effect of two variable number tandem repeat (VNTR) polymorphisms in DRD4 and DAT1 (SLC6A3), both candidate genes for BPD with functional impact on dopaminergic neurotransmission, on bistable perception in a cohort of 108 healthy human subjects. The BPD risk allele DRD4-2R was significantly associated with slow perceptual switching. There was no effect of DAT1 genotype on bistable perception. Our findings indicate that genetic differences in dopaminergic neurotransmission linked to BPD also account for interindividual variability in bistable perception, thus providing a genetic basis for perceptual stability as a trait marker of BPD. PMID:23968246

  17. Consensus paper: the role of the cerebellum in perceptual processes.

    PubMed

    Baumann, Oliver; Borra, Ronald J; Bower, James M; Cullen, Kathleen E; Habas, Christophe; Ivry, Richard B; Leggio, Maria; Mattingley, Jason B; Molinari, Marco; Moulton, Eric A; Paulin, Michael G; Pavlova, Marina A; Schmahmann, Jeremy D; Sokolov, Arseny A

    2015-04-01

    Various lines of evidence accumulated over the past 30 years indicate that the cerebellum, long recognized as essential for motor control, also has considerable influence on perceptual processes. In this paper, we bring together experts from psychology and neuroscience, with the aim of providing a succinct but comprehensive overview of key findings related to the involvement of the cerebellum in sensory perception. The contributions cover such topics as anatomical and functional connectivity, evolutionary and comparative perspectives, visual and auditory processing, biological motion perception, nociception, self-motion, timing, predictive processing, and perceptual sequencing. While no single explanation has yet emerged concerning the role of the cerebellum in perceptual processes, this consensus paper summarizes the impressive empirical evidence on this problem and highlights diversities as well as commonalities between existing hypotheses. In addition to work with healthy individuals and patients with cerebellar disorders, it is also apparent that several neurological conditions in which perceptual disturbances occur, including autism and schizophrenia, are associated with cerebellar pathology. A better understanding of the involvement of the cerebellum in perceptual processes will thus likely be important for identifying and treating perceptual deficits that may at present go unnoticed and untreated. This paper provides a useful framework for further debate and empirical investigations into the influence of the cerebellum on sensory perception. PMID:25479821

  18. Perceptual, cognitive, and personality rigidity in Parkinson's disease.

    PubMed

    Díaz-Santos, Mirella; Cao, Bo; Yazdanbakhsh, Arash; Norton, Daniel J; Neargarder, Sandy; Cronin-Golomb, Alice

    2015-03-01

    Parkinson's disease (PD) is associated with motor and non-motor rigidity symptoms (e.g., cognitive and personality). The question is raised as to whether rigidity in PD also extends to perception, and if so, whether perceptual, cognitive, and personality rigidities are correlated. Bistable stimuli were presented to 28 non-demented individuals with PD and 26 normal control adults (NC). Necker cube perception and binocular rivalry were examined during passive viewing, and the Necker cube was additionally used for two volitional-control conditions: Hold one percept in front, and Switch between the two percepts. Relative to passive viewing, PD were significantly less able than NC to reduce dominance durations in the Switch condition, indicating perceptual rigidity. Tests of cognitive flexibility and a personality questionnaire were administered to explore the association with perceptual rigidity. Cognitive flexibility was not correlated with perceptual rigidity for either group. Personality (novelty seeking) correlated with dominance durations on Necker passive viewing for PD but not NC. The results indicate the presence in mild-moderate PD of perceptual rigidity and suggest shared neural substrates with novelty seeking, but functional divergence from those supporting cognitive flexibility. The possibility is raised that perceptual rigidity may be a harbinger of cognitive inflexibility later in the disease course. PMID:25640973

  19. Prediction of kindergarteners' behavior on Metropolitan Readiness Tests from preschool perceptual and perceptual-motor performances: a validation study.

    PubMed

    Belka, D E

    1981-06-01

    Multiple regression equations were generated to predict cognitive achievement for 40 children (ages 57 to 68 mo.) 1 yr. after administration of a battery of 6 perceptual and perceptual-motor tests to determine if previous results from Toledo could be replicated. Regression equations generated from maximum R2 improvement techniques indicated that performance at prekindergarten is useful for prediction of cognitive performance (total score and total score without the copying subtest on the Metropolitan Readiness Tests) 1 yr. later at the end of kindergarten. The optimal battery included scores on auditory perception, fine perceptual-motor, and gross perceptual-motor tasks. The moderate predictive power of the equations obtained was compared with high predictive power generated in the Toledo study. PMID:7267262

  20. Episodic Memories

    ERIC Educational Resources Information Center

    Conway, Martin A.

    2009-01-01

    An account of episodic memories is developed that focuses on the types of knowledge they represent, their properties, and the functions they might serve. It is proposed that episodic memories consist of "episodic elements," summary records of experience often in the form of visual images, associated to a "conceptual frame" that provides a…

  1. Pittsburgh Memories.

    ERIC Educational Resources Information Center

    Judson, Bay

    1986-01-01

    By studying the painting "Pittsburgh Memories" by the Black artist Romare Bearden, student in grades K-3 learn that artists use their visual memories of real places and people when they make art. The students also learn how various types of space are depicted in a semi-abstract style. (RM)

  2. Collaging Memories

    ERIC Educational Resources Information Center

    Wallach, Michele

    2011-01-01

    Even middle school students can have memories of their childhoods, of an earlier time. The art of Romare Bearden and the writings of Paul Auster can be used to introduce ideas about time and memory to students and inspire works of their own. Bearden is an exceptional role model for young artists, not only because of his astounding art, but also…

  3. Retrieval Speed as a Determinant of Adult Reading Comprehension.

    ERIC Educational Resources Information Center

    Haupt, Edward J.; Jacobowitz, Tina

    More than 100 college students enrolled in a reading and study skills course participated in a study designed to show the effects of retrieval speed on adult reading comprehension. A microcomputer version of the Posner task was used to measure memory retrieval speed, and reading and listening comprehension were measured from McCall-Crabbs…

  4. High speed quantitative digital microscopy

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; Price, K. H.; Eskenazi, R.; Ovadya, M. M.; Navon, M. A.

    1984-01-01

    Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.

  5. Practical memory checking with Dr. Memory

    Microsoft Academic Search

    Derek Bruening; Qin Zhao

    2011-01-01

    Memory corruption, reading uninitialized memory, using freed memory, and other memory-related errors are among the most difficult programming bugs to identify and fix due to the delay and non-determinism linking the error to an observable symptom. Dedicated memory checking tools are invaluable for finding these errors. However, such tools are difficult to build, and because they must monitor all memory

  6. It does belong together: cross-modal correspondences influence cross-modal integration during perceptual learning

    PubMed Central

    Brunel, Lionel; Carvalho, Paulo F.; Goldstone, Robert L.

    2015-01-01

    Experiencing a stimulus in one sensory modality is often associated with an experience in another sensory modality. For instance, seeing a lemon might produce a sensation of sourness. This might indicate some kind of cross-modal correspondence between vision and gustation. The aim of the current study was to explore whether such cross-modal correspondences influence cross-modal integration during perceptual learning. To that end, we conducted two experiments. Using a speeded classification task, Experiment 1 established a cross-modal correspondence between visual lightness and the frequency of an auditory tone. Using a short-term priming procedure, Experiment 2 showed that manipulation of such cross-modal correspondences led to the creation of a crossmodal unit regardless of the nature of the correspondence (i.e., congruent, Experiment 2a or incongruent, Experiment 2b). However, a comparison of priming effects sizes suggested that cross-modal correspondences modulate cross-modal integration during learning, leading to new learned units that have different stability over time. We discuss the implications of our results for the relation between cross-modal correspondence and perceptual learning in the context of a Bayesian explanation of cross-modal correspondences.

  7. Role of the indirect pathway of the Basal Ganglia in perceptual decision making.

    PubMed

    Wei, Wei; Rubin, Jonathan E; Wang, Xiao-Jing

    2015-03-01

    The basal ganglia (BG) play an important role in motor control, reinforcement learning, and perceptual decision making. Modeling and experimental evidence suggest that, in a speed-accuracy tradeoff, the corticostriatal pathway can adaptively adjust a decision threshold (the amount of information needed to make a choice). In this study, we go beyond the focus of previous works on the direct and hyperdirect pathways to examine the contribution of the indirect pathway of the BG system to decision making in a biophysically based spiking network model. We find that the mechanism of adjusting the decision threshold by plasticity of the corticostriatal connections is effective, provided that the indirect pathway counterbalances the direct pathway in their projections to the output nucleus. Furthermore, in our model, changes within basal ganglia connections similar to those that arise in parkinsonism give rise to strong beta oscillations. Specifically, beta oscillations are produced by an abnormal enhancement of the interactions between the subthalamic nucleus (STN) and the external segment of globus pallidus (GPe) in the indirect pathway, with an oscillation frequency that depends on the excitatory cortical input to the STN and the inhibitory input to the GPe from the striatum. In a parkinsonian state characterized by pronounced beta oscillations, the mean reaction time and range of threshold variation (a measure of behavioral flexibility) are significantly reduced compared with the normal state. Our work thus reveals a specific circuit mechanism for impairments of perceptual decision making associated with Parkinson's disease. PMID:25740532

  8. Perceptual organization, phonological awareness, and reading comprehension in adults with and without learning disabilities.

    PubMed

    Stothers, Margot; Klein, Perry D

    2010-12-01

    It is not clear from research whether, or to what extent, reading comprehension is impaired in adults who have learning disabilities (LD). The influence of perceptual organization (PO) and phonological awareness (PA) on reading comprehension was investigated. PO and PA are cognitive functions that have been examined in previous research for their roles in nonverbal LD and phonological dyslexia, respectively. Nonverbal tests of PO and non-reading tests of PA were administered to a sample of adults with postsecondary education. Approximately two thirds of the sample had previously been diagnosed as having LD. In a multiple regression analysis, tests of PO and PA were used to predict scores for tests of reading comprehension and mechanics. Despite the nonverbal nature of the perceptual organizational test stimuli, PO strongly predicted reading comprehension. Tests of PA predicted decoding and reading speed. Results were interpreted as supporting the hypothesis that integrative processes usually characterized as nonverbal were nonetheless used by readers with and without disabilities to understand text. The study's findings have implications for understanding the reading of adults with learning disabilities, and the nature of reading comprehension in general. PMID:20838941

  9. Source memory in normal aging and Parkinson's disease.

    PubMed

    Davidson, Patrick S R; Cook, Shaun P; McGhan, Leslie; Bouchard, Thomas; Camicioli, Richard

    2013-09-01

    Several theorists have described memory in Parkinson's disease (PD) as involving an amplification of the deficits seen in normal aging, and drawn parallels between PD and frontal lesion patients. Both normal aging and frontal lobe damage impair memory for the context in which one has encountered information (i.e., source memory). We thus sought to determine whether PD patients would show especially poor source memory. We assessed memory for perceptual (voice), spatial (location of loudspeaker), and temporal (list) source memory in 18 PD patients, 23 healthy older adults, and 35 young people. Although both the healthy aged and PD groups performed more poorly than the young on most of the memory tests, the PD patients failed to show significantly greater impairments than the healthy older adults. The PD patients did perform more poorly, however, on a measure of executive function (the Wisconsin Card Sorting Test [WCST]). We discuss potential reasons why PD had a surprisingly minimal effect on source memory in our study, and relate our data to broader theories of memory impairment in Parkinson's disease. PMID:23560529

  10. The perceptual basis of common photographic practice

    PubMed Central

    Cooper, Emily A.; Piazza, Elise A.; Banks, Martin S.

    2012-01-01

    Photographers, cinematographers, and computer-graphics engineers use certain techniques to create striking pictorial effects. By using lenses of different focal lengths, they can make a scene look compressed or expanded in depth, make a familiar object look natural or distorted, or make a person look smarter, more attractive, or more neurotic. We asked why pictures taken with a certain focal length look natural, while those taken with other focal lengths look distorted. We found that people’s preferred viewing distance when looking at pictures leads them to view long-focal-length pictures from too near and short-focal-length pictures from too far. Perceptual distortions occur because people do not take their incorrect viewing distances into account. By following the rule of thumb of using a 50-mm lens, photographers greatly increase the odds of a viewer looking at a photograph from the correct distance, where the percept will be undistorted. Our theory leads to new guidelines for creating pictorial effects that are more effective than conventional guidelines. PMID:22637709

  11. Perceptual guidelines for creating rectangular treemaps.

    PubMed

    Kong, Nicholas; Heer, Jeffrey; Agrawala, Maneesh

    2010-01-01

    Treemaps are space-filling visualizations that make efficient use of limited display space to depict large amounts of hierarchical data. Creating perceptually effective treemaps requires carefully managing a number of design parameters including the aspect ratio and luminance of rectangles. Moreover, treemaps encode values using area, which has been found to be less accurate than judgments of other visual encodings, such as length. We conduct a series of controlled experiments aimed at producing a set of design guidelines for creating effective rectangular treemaps. We find no evidence that luminance affects area judgments, but observe that aspect ratio does have an effect. Specifically, we find that the accuracy of area comparisons suffers when the compared rectangles have extreme aspect ratios or when both are squares. Contrary to common assumptions, the optimal distribution of rectangle aspect ratios within a treemap should include non-squares, but should avoid extremes. We then compare treemaps with hierarchical bar chart displays to identify the data densities at which length-encoded bar charts become less effective than area-encoded treemaps. We report the transition points at which treemaps exhibit judgment accuracy on par with bar charts for both leaf and non-leaf tree nodes. We also find that even at relatively low data densities treemaps result in faster comparisons than bar charts. Based on these results, we present a set of guidelines for the effective use of treemaps and suggest alternate approaches for treemap layout. PMID:20975136

  12. Perceptually controlled doping for audio source separation

    NASA Astrophysics Data System (ADS)

    Mahé, Gaël; Nadalin, Everton Z.; Suyama, Ricardo; Romano, João MT

    2014-12-01

    The separation of an underdetermined audio mixture can be performed through sparse component analysis (SCA) that relies however on the strong hypothesis that source signals are sparse in some domain. To overcome this difficulty in the case where the original sources are available before the mixing process, the informed source separation (ISS) embeds in the mixture a watermark, which information can help a further separation. Though powerful, this technique is generally specific to a particular mixing setup and may be compromised by an additional bitrate compression stage. Thus, instead of watermarking, we propose a `doping' method that makes the time-frequency representation of each source more sparse, while preserving its audio quality. This method is based on an iterative decrease of the distance between the distribution of the signal and a target sparse distribution, under a perceptual constraint. We aim to show that the proposed approach is robust to audio coding and that the use of the sparsified signals improves the source separation, in comparison with the original sources. In this work, the analysis is made only in instantaneous mixtures and focused on voice sources.

  13. Perceptual compensation for differences in speaking style

    PubMed Central

    Vitela, A. Davi; Warner, Natasha; Lotto, Andrew J.

    2013-01-01

    It is well-established that listeners will shift their categorization of a target vowel as a function of acoustic characteristics of a preceding carrier phrase (CP). These results have been interpreted as an example of perceptual normalization for variability resulting from differences in talker anatomy. The present study examined whether listeners would normalize for acoustic variability resulting from differences in speaking style within a single talker. Two vowel series were synthesized that varied between central and peripheral vowels (the vowels in “beat”–“bit” and “bod”–“bud”). Each member of the series was appended to one of four CPs that were spoken in either a “clear” or “reduced” speech style. Participants categorized vowels in these eight contexts. A reliable shift in categorization as a function of speaking style was obtained for three of four phrase sets. This demonstrates that phrase context effects can be obtained with a single talker. However, the directions of the obtained shifts are not reliably predicted on the basis of the speaking style of the talker. Instead, it appears that the effect is determined by an interaction of the average spectrum of the phrase with the target vowel. PMID:23847573

  14. Neuroticism as Distancing: Perceptual Sources of Evidence

    PubMed Central

    Liu, Tianwei; Ode, Scott; Moeller, Sara K.; Robinson, Michael D.

    2013-01-01

    Several theories and self-reported sources of data link individual differences in negative affectivity to avoidance motivation. Chronic avoidance motivation, through repeated practice, may result in a relatively cognitive distance-enhancing dynamic whereby events and stimuli are perceived as further away from the self, even when they are not threatening. Such predictions are novel, but follow from cybernetic theories of self-regulation. In five studies (total N = 463), relations of this type were investigated. Study 1 presented participants with phrases that were ambiguous and found that trait negative affect predicted phrase interpretation in a distance-enhancing temporal direction. Study 2 replicated this effect across a systematic manipulation of event valence. Study 3 asked individuals to estimate the size of words and found that individuals higher in neuroticism generally perceived words to be smaller than did individuals lower in neuroticism. In Study 4, people high (but not low) in neuroticism perceived words to be shrinking faster than they were growing. In Study 5, greater perceptual distancing, in a font size estimation task, predicted more adverse reactions to negative events in daily life. Although normative effects varied across studies, consistent support for a chronic distancing perspective of individual differences in negative affectivity was found. PMID:23527850

  15. Visual perceptual load induces inattentional deafness.

    PubMed

    Macdonald, James S P; Lavie, Nilli

    2011-08-01

    In this article, we establish a new phenomenon of "inattentional deafness" and highlight the level of load on visual attention as a critical determinant of this phenomenon. In three experiments, we modified an inattentional blindness paradigm to assess inattentional deafness. Participants made either a low- or high-load visual discrimination concerning a cross shape (respectively, a discrimination of line color or of line length with a subtle length difference). A brief pure tone was presented simultaneously with the visual task display on a final trial. Failures to notice the presence of this tone (i.e., inattentional deafness) reached a rate of 79% in the high-visual-load condition, significantly more than in the low-load condition. These findings establish the phenomenon of inattentional deafness under visual load, thereby extending the load theory of attention (e.g., Lavie, Journal of Experimental Psychology. Human Perception and Performance, 25, 596-616, 1995) to address the cross-modal effects of visual perceptual load. PMID:21611856

  16. Enhancing perceptual and attentional skills requires common demands between the action video games and transfer tasks

    PubMed Central

    Oei, Adam C.; Patterson, Michael D.

    2015-01-01

    Despite increasing evidence that shows action video game play improves perceptual and cognitive skills, the mechanisms of transfer are not well-understood. In line with previous work, we suggest that transfer is dependent upon common demands between the game and transfer task. In the current study, participants played one of four action games with varying speed, visual, and attentional demands for 20 h. We examined whether training enhanced performance for attentional blink, selective attention, attending to multiple items, visual search and auditory detection. Non-gamers who played the game (Modern Combat) with the highest demands showed transfer to tasks of attentional blink and attending to multiple items. The game (MGS Touch) with fewer attentional demands also decreased attentional blink, but to a lesser degree. Other games failed to show transfer, despite having many action game characteristics but at a reduced intensity. The results support the common demands hypothesis. PMID:25713551

  17. Enhancing perceptual and attentional skills requires common demands between the action video games and transfer tasks.

    PubMed

    Oei, Adam C; Patterson, Michael D

    2015-01-01

    Despite increasing evidence that shows action video game play improves perceptual and cognitive skills, the mechanisms of transfer are not well-understood. In line with previous work, we suggest that transfer is dependent upon common demands between the game and transfer task. In the current study, participants played one of four action games with varying speed, visual, and attentional demands for 20 h. We examined whether training enhanced performance for attentional blink, selective attention, attending to multiple items, visual search and auditory detection. Non-gamers who played the game (Modern Combat) with the highest demands showed transfer to tasks of attentional blink and attending to multiple items. The game (MGS Touch) with fewer attentional demands also decreased attentional blink, but to a lesser degree. Other games failed to show transfer, despite having many action game characteristics but at a reduced intensity. The results support the common demands hypothesis. PMID:25713551

  18. Implicit memory in music and language.

    PubMed

    Ettlinger, Marc; Margulis, Elizabeth H; Wong, Patrick C M

    2011-01-01

    Research on music and language in recent decades has focused on their overlapping neurophysiological, perceptual, and cognitive underpinnings, ranging from the mechanism for encoding basic auditory cues to the mechanism for detecting violations in phrase structure. These overlaps have most often been identified in musicians with musical knowledge that was acquired explicitly, through formal training. In this paper, we review independent bodies of work in music and language that suggest an important role for implicitly acquired knowledge, implicit memory, and their associated neural structures in the acquisition of linguistic or musical grammar. These findings motivate potential new work that examines music and language comparatively in the context of the implicit memory system. PMID:21927608

  19. Implicit Memory in Music and Language

    PubMed Central

    Ettlinger, Marc; Margulis, Elizabeth H.; Wong, Patrick C. M.

    2011-01-01

    Research on music and language in recent decades has focused on their overlapping neurophysiological, perceptual, and cognitive underpinnings, ranging from the mechanism for encoding basic auditory cues to the mechanism for detecting violations in phrase structure. These overlaps have most often been identified in musicians with musical knowledge that was acquired explicitly, through formal training. In this paper, we review independent bodies of work in music and language that suggest an important role for implicitly acquired knowledge, implicit memory, and their associated neural structures in the acquisition of linguistic or musical grammar. These findings motivate potential new work that examines music and language comparatively in the context of the implicit memory system. PMID:21927608

  20. Dynamic interactions between visual working memory and saccade target selection

    PubMed Central

    Schneegans, Sebastian; Spencer, John P.; Schöner, Gregor; Hwang, Seongmin; Hollingworth, Andrew

    2014-01-01

    Recent psychophysical experiments have shown that working memory for visual surface features interacts with saccadic motor planning, even in tasks where the saccade target is unambiguously specified by spatial cues. Specifically, a match between a memorized color and the color of either the designated target or a distractor stimulus influences saccade target selection, saccade amplitudes, and latencies in a systematic fashion. To elucidate these effects, we present a dynamic neural field model in combination with new experimental data. The model captures the neural processes underlying visual perception, working memory, and saccade planning relevant to the psychophysical experiment. It consists of a low-level visual sensory representation that interacts with two separate pathways: a spatial pathway implementing spatial attention and saccade generation, and a surface feature pathway implementing color working memory and feature attention. Due to bidirectional coupling between visual working memory and feature attention in the model, the working memory content can indirectly exert an effect on perceptual processing in the low-level sensory representation. This in turn biases saccadic movement planning in the spatial pathway, allowing the model to quantitatively reproduce the observed interaction effects. The continuous coupling between representations in the model also implies that modulation should be bidirectional, and model simulations provide specific predictions for complementary effects of saccade target selection on visual working memory. These predictions were empirically confirmed in a new experiment: Memory for a sample color was biased toward the color of a task-irrelevant saccade target object, demonstrating the bidirectional coupling between visual working memory and perceptual processing. PMID:25228628

  1. The cost of misremembering: Inferring the loss function in visual working memory.

    PubMed

    Sims, Chris R

    2015-01-01

    Visual working memory (VWM) is a highly limited storage system. A basic consequence of this fact is that visual memories cannot perfectly encode or represent the veridical structure of the world. However, in natural tasks, some memory errors might be more costly than others. This raises the intriguing possibility that the nature of memory error reflects the costs of committing different kinds of errors. Many existing theories assume that visual memories are noise-corrupted versions of afferent perceptual signals. However, this additive noise assumption oversimplifies the problem. Implicit in the behavioral phenomena of visual working memory is the concept of a loss function: a mathematical entity that describes the relative cost to the organism of making different types of memory errors. An optimally efficient memory system is one that minimizes the expected loss according to a particular loss function, while subject to a constraint on memory capacity. This paper describes a novel theoretical framework for characterizing visual working memory in terms of its implicit loss function. Using inverse decision theory, the empirical loss function is estimated from the results of a standard delayed recall visual memory experiment. These results are compared to the predicted behavior of a visual working memory system that is optimally efficient for a previously identified natural task, gaze correction following saccadic error. Finally, the approach is compared to alternative models of visual working memory, and shown to offer a superior account of the empirical data across a range of experimental datasets. PMID:25740875

  2. Effectiveness of a specific cueing method for improving autobiographical memory recall in patients with schizophrenia.

    PubMed

    Potheegadoo, Jevita; Cordier, Adrian; Berna, Fabrice; Danion, Jean-Marie

    2014-01-01

    Autobiographical memory deficits in schizophrenia have a significant impact on patients' daily life. Our study was aimed at testing the effectiveness of a specific cueing (SC) method for improving autobiographical memory recall in patients with schizophrenia, particularly the phenomenological details of their memories. Twenty-five patients with schizophrenia and 25 comparison participants took part in the study. They recalled 6 specific autobiographical events which occurred during 3 different life periods. After each memory recall, participants were given a general cue which allowed them to add further information to their narration. The SC was then applied by means of a series of specific questions to elicit more precise memory detail. The overall memory specificity as well as the number and richness of 5 categories of memory detail (perceptual/sensory, temporal, contextual, emotional, and cognitive) were assessed before and after the SC phase. Before SC, patients' memories were less specific and less detailed. SC had a beneficial effect on patients' memory recall. The overall memory specificity of patients improved. The gain in the number and richness of memory details was comparable between patients and comparison participants. The difference between groups in terms of the number of memory details was not significant. Richness of details was still lower in patients, except for emotional and cognitive details, which were similarly rich in both groups. The cueing method reduces the autobiographical memory impairment of patients with schizophrenia and paves the way for developing specific cognitive remediation therapies to help patients in their daily life. PMID:24268933

  3. Episodic and Semantic Autobiographical Memory and Everyday Memory during Late Childhood and Early Adolescence

    PubMed Central

    Willoughby, Karen A.; Desrocher, Mary; Levine, Brian; Rovet, Joanne F.

    2012-01-01

    Few studies have examined both episodic and semantic autobiographical memory (AM) performance during late childhood and early adolescence. Using the newly developed Children’s Autobiographical Interview (CAI), the present study examined the effects of age and sex on episodic and semantic AM and everyday memory in 182 children and adolescents. Results indicated that episodic and semantic AM both improved between 8 and 16?years of age; however, age-related changes were larger for episodic AM than for semantic AM. In addition, females were found to recall more episodic AM details, but not more semantic AM details, than males. Importantly, this sex difference in episodic AM recall was attenuated under conditions of high retrieval support (i.e., the use of probing questions). The ability to clearly visualize past events at the time of recollection was related to children’s episodic AM recall performance, particularly the retrieval of perceptual details. Finally, similar age and sex effects were found between episodic AM and everyday memory ability (e.g., memory for everyday activities). More specifically, older participants and females exhibited better episodic AM and everyday memory performance than younger participants and males. Overall, the present study provides important new insight into both episodic and semantic AM performance, as well as the relation between episodic AM and everyday memory, during late childhood and adolescence. PMID:22403560

  4. Memory Technologies Vivek Asthana

    E-print Network

    Kumar, M. Jagadesh

    Disk Memory 32KB -4MB 4 ns 2GB 60 ns 200 GB 8 ms SoC Board Computer memory Hierarchy USB Flash DriveMemory Technologies Vivek Asthana 13th Mar 2013 #12;13-Mar-13 2 Memory Usage (2025) #12;13-Mar-13 3 Outline What is a Memory Current Memory technologies · SRAM · DRAM · Flash Upcoming Memory technologies

  5. Specification state space memory

    E-print Network

    Hehner, Eric C.R.

    Specification state space memory 1/116 #12;Specification state space memory state memory contents 2/116 #12;Specification state space memory int; (0,..20); char; rat state memory contents 3/116 #12;Specification state space memory int; (0,..20); char; rat state memory contents ­2; 15; "A"; 3.14 4/116 #12

  6. Up-down Asymmetries in Speed Perception

    NASA Technical Reports Server (NTRS)

    Thompson, Peter; Stone, Leland S.

    1997-01-01

    We compared speed matches for pairs of stimuli that moved in opposite directions (upward and downward). Stimuli were elliptical patches (2 deg horizontally by 1 deg vertically) of horizontal sinusoidal gratings of spatial. frequency 2 cycles/deg. Two sequential 380 msec reveal presentations were compared. One of each pair of gratings (the standard) moved at 4 Hz (2 deg/sec), the other (the test) moved at a rate determined by a simple up-down staircase. The point of subjectively equal speed was calculated from the average of the last eight reversals. The task was to fixate a central point and to determine which one of the pair appeared to move faster. Eight of 10 observers perceived the upward drifting grating as moving faster than a grating moving downward but otherwise identical. on average (N = 10), when the standard moved downward, it was matched by a test moving upward at 94.7+/-1.7(SE)% of the standard speed, and when the standard moved upward it was matched by a test moving downward at 105.1+/-2.3(SE)% of the standard speed. Extending this paradigm over a range of spatial (1.5 to 13.5 c/d) and temporal (1.5 to 13.5 Hz) frequencies, preliminary results (N = 4) suggest that, under the conditions of our experiment, upward matter is seen as faster than downward for speeds greater than approx.1 deg/sec, but the effect appears to reverse at speeds below approx.1 deg/sec with downward motion perceived as faster. Given that an up-down asymmetry has been observed for the optokinetic response, both perceptual and oculomotor contributions to this phenomenon deserve exploration.

  7. POW Memory

    NSDL National Science Digital Library

    Science Update

    2004-07-12

    Most people think eyewitness testimony is the best possible evidence against an alleged criminal -- especially when that testimony comes from the victim. But people who survive terrifying situations may actually have surprisingly unreliable memories of who or what caused them.

  8. Memory Solitaire

    NSDL National Science Digital Library

    Exploratorium

    2000-01-01

    In this online game, learners practice memory recall. They are shown a collage of pictures for two minutes, then have to write down everything they remember and check how they did. After, they learn a memory-improving method of "tell yourself a story" to help train their brain, and try again. Although this activity is designed to be done online and individually, it can easily be adapted to be done using a printout and in a group setting.

  9. Template changes with perceptual learning are driven by feature informativeness

    PubMed Central

    Kurki, Ilmari; Eckstein, Miguel P.

    2014-01-01

    Perceptual learning changes the way the human visual system processes stimulus information. Previous studies have shown that the human brain's weightings of visual information (the perceptual template) become better matched to the optimal weightings. However, the dynamics of the template changes are not well understood. We used the classification image method to investigate whether visual field or stimulus properties govern the dynamics of the changes in the perceptual template. A line orientation discrimination task where highly informative parts were placed in the peripheral visual field was used to test three hypotheses: (1) The template changes are determined by the visual field structure, initially covering stimulus parts closer to the fovea and expanding toward the periphery with learning; (2) the template changes are object centered, starting from the center and expanding toward edges; and (3) the template changes are determined by stimulus information, starting from the most informative parts and expanding to less informative parts. Results show that, initially, the perceptual template contained only the more peripheral, highly informative parts. Learning expanded the template to include less informative parts, resulting in an increase in sampling efficiency. A second experiment interleaved parts with high and low signal-to-noise ratios and showed that template reweighting through learning was restricted to stimulus elements that are spatially contiguous to parts with initial high template weights. The results suggest that the informativeness of features determines how the perceptual template changes with learning. Further, the template expansion is constrained by spatial proximity. PMID:25194018

  10. Perceptual learning reconfigures the effects of visual adaptation

    PubMed Central

    McGovern, David P.; Roach, Neil W.; Webb, Ben S.

    2012-01-01

    Our sensory experiences over a range of different timescales shape our perception of the environment. Two particularly striking short-term forms of plasticity with manifestly different time courses and perceptual consequences are those caused by visual adaptation and perceptual learning. Although conventionally treated as distinct forms of experience-dependent plasticity, their neural mechanisms and perceptual consequences have become increasingly blurred, raising the possibility that they might interact. To optimise our chances of finding a functionally meaningful interaction between learning and adaptation, we examined in humans the perceptual consequences of learning a fine discrimination task whilst adapting the neurons that carry most information for performing this task. Learning improved discriminative accuracy to a level that ultimately surpassed that in an unadapted state. This remarkable improvement came at a price: adapting directions that prior to learning had little effect elevated discrimination thresholds afterwards. The improvements in discriminative accuracy grew quickly and surpassed unadapted levels within the first few training sessions, whereas the deterioration in discriminative accuracy had a different time course. This learned reconfiguration of adapted discriminative accuracy occurred without a concomitant change to the characteristic perceptual biases induced by adaptation, suggesting that the system was still in an adapted state. Our results point to a functionally meaningful push-pull interaction between learning and adaptation where a gain in sensitivity in one adapted state is balanced by a loss of sensitivity in other adapted states. PMID:23015451

  11. Persistent Hemispheric Differences in the Perceptual Selection of Spatial Frequencies

    PubMed Central

    Piazza, Elise A.; Silver, Michael A.

    2015-01-01

    Previous research has shown that the right hemisphere processes low spatial frequencies more efficiently than the left hemisphere, which preferentially processes high spatial frequencies. These studies have typically measured RTs to single, briefly flashed gratings and/or have directed observers to attend to a particular spatial frequency immediately before making a judgment about a subsequently presented stimulus. Thus, it is unclear whether the hemispheres differ in perceptual selection from multiple spatial frequencies that are simultaneously present in the environment, without bias from selective attention. Moreover, the time course of hemispheric asymmetry in spatial frequency processing is unknown. We addressed both of these questions with binocular rivalry, a measure of perceptual selection from competing alternatives over time. Participants viewed a pair of rivalrous orthogonal gratings with different spatial frequencies, presented either to the left or right of central fixation, and continuously reported which grating they perceived. At the beginning of a trial, the low spatial frequency grating was perceptually selected more often when presented in the left hemifield (right hemisphere) than in the right hemifield (left hemisphere), whereas the high spatial frequency grating showed the opposite pattern of results. This hemispheric asymmetry in perceptual selection persisted for the entire 30-sec stimulus presentation, continuing long after stimulus onset. These results indicate stable differences in the resolution of ambiguity across spatial locations and demonstrate the importance of considering sustained differences in perceptual selection across space when characterizing conscious representations of complex scenes. PMID:24666124

  12. Persistent hemispheric differences in the perceptual selection of spatial frequencies.

    PubMed

    Piazza, Elise A; Silver, Michael A

    2014-09-01

    Previous research has shown that the right hemisphere processes low spatial frequencies more efficiently than the left hemisphere, which preferentially processes high spatial frequencies. These studies have typically measured RTs to single, briefly flashed gratings and/or have directed observers to attend to a particular spatial frequency immediately before making a judgment about a subsequently presented stimulus. Thus, it is unclear whether the hemispheres differ in perceptual selection from multiple spatial frequencies that are simultaneously present in the environment, without bias from selective attention. Moreover, the time course of hemispheric asymmetry in spatial frequency processing is unknown. We addressed both of these questions with binocular rivalry, a measure of perceptual selection from competing alternatives over time. Participants viewed a pair of rivalrous orthogonal gratings with different spatial frequencies, presented either to the left or right of central fixation, and continuously reported which grating they perceived. At the beginning of a trial, the low spatial frequency grating was perceptually selected more often when presented in the left hemifield (right hemisphere) than in the right hemifield (left hemisphere), whereas the high spatial frequency grating showed the opposite pattern of results. This hemispheric asymmetry in perceptual selection persisted for the entire 30-sec stimulus presentation, continuing long after stimulus onset. These results indicate stable differences in the resolution of ambiguity across spatial locations and demonstrate the importance of considering sustained differences in perceptual selection across space when characterizing conscious representations of complex scenes. PMID:24666124

  13. Bayesian natural selection and the evolution of perceptual systems.

    PubMed Central

    Geisler, Wilson S; Diehl, Randy L

    2002-01-01

    In recent years, there has been much interest in characterizing statistical properties of natural stimuli in order to better understand the design of perceptual systems. A fruitful approach has been to compare the processing of natural stimuli in real perceptual systems with that of ideal observers derived within the framework of Bayesian statistical decision theory. While this form of optimization theory has provided a deeper understanding of the information contained in natural stimuli as well as of the computational principles employed in perceptual systems, it does not directly consider the process of natural selection, which is ultimately responsible for design. Here we propose a formal framework for analysing how the statistics of natural stimuli and the process of natural selection interact to determine the design of perceptual systems. The framework consists of two complementary components. The first is a maximum fitness ideal observer, a standard Bayesian ideal observer with a utility function appropriate for natural selection. The second component is a formal version of natural selection based upon Bayesian statistical decision theory. Maximum fitness ideal observers and Bayesian natural selection are demonstrated in several examples. We suggest that the Bayesian approach is appropriate not only for the study of perceptual systems but also for the study of many other systems in biology. PMID:12028784

  14. Suitable Stimuli to Obtain (No) Gender Differences in the Speed of Cognitive Processes Involved in Mental Rotation

    ERIC Educational Resources Information Center

    Jansen-Osmann, Petra; Heil, Martin

    2007-01-01

    Gender differences in speed of perceptual comparison, of picture-plane mental rotation, and in switching costs between trials that do and do not require mental rotation, were investigated as a function of stimulus material with a total sample size of N=360. Alphanumeric characters, PMA symbols, animal drawings, polygons and 3D cube figures were…

  15. Transcranial Direct Current Stimulation Augments Perceptual Sensitivity and 24-Hour Retention in a

    E-print Network

    Parasuraman, Raja

    Transcranial Direct Current Stimulation Augments Perceptual Sensitivity and 24-Hour Retention Abstract We have previously shown that transcranial direct current stimulation (tDCS) improved performance) Transcranial Direct Current Stimulation Augments Perceptual Sensitivity and 24-Hour Retention in a Complex

  16. Music Lessons Improve Auditory Perceptual and Cognitive Performance in Deaf Children

    PubMed Central

    Rochette, Françoise; Moussard, Aline; Bigand, Emmanuel

    2014-01-01

    Despite advanced technologies in auditory rehabilitation of profound deafness, deaf children often exhibit delayed cognitive and linguistic development and auditory training remains a crucial element of their education. In the present cross-sectional study, we assess whether music would be a relevant tool for deaf children rehabilitation. In normal-hearing children, music lessons have been shown to improve cognitive and linguistic-related abilities, such as phonetic discrimination and reading. We compared auditory perception, auditory cognition, and phonetic discrimination between 14 profoundly deaf children who completed weekly music lessons for a period of 1.5–4?years and 14 deaf children who did not receive musical instruction. Children were assessed on perceptual and cognitive auditory tasks using environmental sounds: discrimination, identification, auditory scene analysis, auditory working memory. Transfer to the linguistic domain was tested with a phonetic discrimination task. Musically trained children showed better performance in auditory scene analysis, auditory working memory and phonetic discrimination tasks, and multiple regressions showed that success on these tasks was at least partly driven by music lessons. We propose that musical education contributes to development of general processes such as auditory attention and perception, which, in turn, facilitate auditory-related cognitive and linguistic processes. PMID:25071518

  17. Inferior frontal gyrus activation predicts individual differences in perceptual learning of cochlear-implant simulations

    PubMed Central

    Eisner, Frank; McGettigan, Carolyn; Faulkner, Andrew; Rosen, Stuart; Scott, Sophie K.

    2010-01-01

    Summary This study investigated the neural plasticity associated with perceptual learning of a cochlear implant (CI) simulation. Normal-hearing listeners were trained with vocoded and spectrally-shifted speech simulating a CI while cortical responses were measured with fMRI. A condition in which the vocoded speech was spectrally inverted provided a control for learnability and adaptation. Behavioral measures showed considerable individual variability both in the ability to learn to understand the degraded speech, and in phonological working memory capacity. Neurally, left-lateralized regions in superior temporal sulcus and inferior frontal gyrus (IFG) were sensitive to the learnability of the simulations, but only the activity in prefrontal cortex correlated with inter-individual variation in intelligibility scores and phonological working memory. A region in left angular gyrus (AG) showed an activation pattern that reflected learning over the course of the experiment, and co-variation of activity in AG and IFG was modulated by the learnability of the stimuli. These results suggest that variation in listeners' ability to adjust to vocoded and spectrally-shifted speech is partly reflected in differences in the recruitment of higher-level language processes in prefrontal cortex, and that this variability may further depend on functional links between the left inferior frontal gyrus and angular gyrus. Differences in the engagement of left inferior prefrontal cortex, and its co-variation with posterior parietal areas, may thus underlie some of the variation in speech perception skills that have been observed in clinical populations of CI users. PMID:20505085

  18. Perceptual similarity of regional dialects of American English

    PubMed Central

    Clopper, Cynthia G.; Levi, Susannah V.; Pisoni, David B.

    2012-01-01

    Previous research on the perception of dialect variation has measured the perceptual similarity of talkers based on regional dialect using only indirect methods. In the present study, a paired comparison similarity ratings task was used to obtain direct measures of perceptual similarity. Naive listeners were asked to make explicit judgments about the similarity of a set of talkers based on regional dialect. The talkers represented four regional varieties of American English and both genders. Results revealed an additive effect of gender and dialect on mean similarity ratings and two primary dimensions of perceptual dialect similarity: geography (northern versus southern varieties) and dialect markedness (many versus few characteristic properties). The present findings are consistent with earlier research on the perception of dialect variation, as well as recent speech perception studies which demonstrate the integral role of talker gender in speech perception. PMID:16454310

  19. Automatic Perceptual Color Map Generation for Realistic Volume Visualization

    PubMed Central

    Silverstein, Jonathan C.; Parsad, Nigel M.; Tsirline, Victor

    2008-01-01

    Advances in computed tomography imaging technology and inexpensive high performance computer graphics hardware are making high-resolution, full color (24-bit) volume visualizations commonplace. However, many of the color maps used in volume rendering provide questionable value in knowledge representation and are non-perceptual thus biasing data analysis or even obscuring information. These drawbacks, coupled with our need for realistic anatomical volume rendering for teaching and surgical planning, has motivated us to explore the auto-generation of color maps that combine natural colorization with the perceptual discriminating capacity of grayscale. As evidenced by the examples shown that have been created by the algorithm described, the merging of perceptually accurate and realistically colorized virtual anatomy appears to insightfully interpret and impartially enhance volume rendered patient data. PMID:18430609

  20. DCTune Perceptual Optimization of Compressed Dental X-Rays

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Null, Cynthia H. (Technical Monitor)

    1997-01-01

    In current dental practice, x-rays of completed dental work are often sent to the insurer for verification. It is faster and cheaper to transmit instead digital scans of the x-rays. Further economies result if the images are sent in compressed form. DCtune is a technology for optimizing DCT quantization matrices to yield maximum perceptual quality for a given bit-rate, or minimum bit-rate for a given perceptual quality. In addition, the technology provides a means of setting the perceptual quality of compressed imagery in a systematic way. The purpose of this research was, with respect to dental x-rays: (1) to verify the advantage of DCTune over standard JPEG; (2) to verify the quality control feature of DCTune; and (3) to discover regularities in the optimized matrices of a set of images. Additional information is contained in the original extended abstract.

  1. Perceptual compression of magnitude-detected synthetic aperture radar imagery

    NASA Technical Reports Server (NTRS)

    Gorman, John D.; Werness, Susan A.

    1994-01-01

    A perceptually-based approach for compressing synthetic aperture radar (SAR) imagery is presented. Key components of the approach are a multiresolution wavelet transform, a bit allocation mask based on an empirical human visual system (HVS) model, and hybrid scalar/vector quantization. Specifically, wavelet shrinkage techniques are used to segregate wavelet transform coefficients into three components: local means, edges, and texture. Each of these three components is then quantized separately according to a perceptually-based bit allocation scheme. Wavelet coefficients associated with local means and edges are quantized using high-rate scalar quantization while texture information is quantized using low-rate vector quantization. The impact of the perceptually-based multiresolution compression algorithm on visual image quality, impulse response, and texture properties is assessed for fine-resolution magnitude-detected SAR imagery; excellent image quality is found at bit rates at or above 1 bpp along with graceful performance degradation at rates below 1 bpp.

  2. The effects of perceptual load on semantic processing under inattention.

    PubMed

    Koivisto, Mika; Revonsuo, Antti

    2009-10-01

    Inattentional blindness refers to a failure to consciously detect an irrelevant object that appears without any expectation when attention is engaged with another task. The perceptual load theory predicts that task-irrelevant stimuli will reach awareness only when the primary task is of low load, which allows processing resources to spill over to processing task-irrelevant stimuli as well. We studied whether perceptual load has an effect on inattentional blindness for a task-irrelevant stimulus whose meaning is or is not relevant to the attentional goals of the observer. In the critical trial, a word appeared without any expectation in the center of a display of attended pictures. The results showed that, under both high and low load, unexpected words belonging to the attended semantic category were detected more often than semantically unrelated words. These results imply that task-irrelevant stimuli, whose meanings are relevant to the observer's task, enter awareness irrespective of perceptual load. PMID:19815790

  3. Trinary Associative Memory Would Recognize Machine Parts

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Awwal, Abdul Ahad S.; Karim, Mohammad A.

    1991-01-01

    Trinary associative memory combines merits and overcomes major deficiencies of unipolar and bipolar logics by combining them in three-valued logic that reverts to unipolar or bipolar binary selectively, as needed to perform specific tasks. Advantage of associative memory: one obtains access to all parts of it simultaneously on basis of content, rather than address, of data. Consequently, used to exploit fully parallelism and speed of optical computing.

  4. Perceptually-driven signal analysis for acoustic event classification

    NASA Astrophysics Data System (ADS)

    Philips, Scott M.

    In many acoustic signal processing applications human listeners are able to outperform automated processing techniques, particularly in the identification and classification of acoustic events. The research discussed in this paper develops a framework for employing perceptual information from human listening experiments to improve automatic event classification. We focus on the identification of new signal attributes, or features, that are able to predict the human performance observed in formal listening experiments. Using this framework, our newly identified features have the ability to elevate automatic classification performance closer to the level of human listeners. We develop several new methods for learning a perceptual feature transform from human similarity measures. In addition to providing a more fundamental basis for uncovering perceptual features than previous approaches, these methods also lead to a greater insight into how humans perceive sounds in a dataset. We also develop a new approach for learning a perceptual distance metric. This metric is shown to be applicable to modern kernel-based techniques used in machine learning and provides a connection between the fields of psychoacoustics and machine learning. Our research demonstrates these new methods in the area of active sonar signal processing. There is anecdotal evidence within the sonar community that human operators are adept in the task of discriminating between active sonar target and clutter echoes. We confirm this ability in a series of formal listening experiments. With the results of these experiments, we then identify perceptual features and distance metrics using our novel methods. The results show better agreement with human performance than previous approaches. While this work demonstrates these methods using perceptual similarity measures from active sonar data, they are applicable to any similarity measure between signals.

  5. Comparing the landscape level perceptual abilities of forest sciurids in fragmented agricultural landscapes

    Microsoft Academic Search

    Patrick A. Zollner

    2000-01-01

    Perceptual range is the maximum distance from which an animal can perceive the presence of remote landscape elements such as patches of habitat. Such perceptual abilities are of interest because they influence the probability that an animal will successfully disperse to a new patch in a landscape. Furthermore, understanding how perceptual range differs between species may help to explain differential

  6. Comparing thelandscape level perceptual abilities of forest sciurids in fragmented agricultural landscapes* I

    Microsoft Academic Search

    Patrick A. Zollner

    • Abstract • Perceptual range is the maximum distance from which an animal can perceive the presence of remote landscape ' . elements such as patches of habitat. Such perceptual abilities are of interest because they influence the probability that an animal will successfully disperse to a new patch in a landscape. Furthermore, understanding how perceptual range differs between species

  7. Strength of Perceptual Experience Predicts Word Processing Performance Better than Concreteness or Imageability

    ERIC Educational Resources Information Center

    Connell, Louise; Lynott, Dermot

    2012-01-01

    Abstract concepts are traditionally thought to differ from concrete concepts by their lack of perceptual information, which causes them to be processed more slowly and less accurately than perceptually-based concrete concepts. In two studies, we examined this assumption by comparing concreteness and imageability ratings to a set of perceptual

  8. Perceptual Strategies in the Estimation of Physical Quantities by Orangutans (Pongo pygmaeus )

    Microsoft Academic Search

    Josep Call; Philippe Rochat

    1997-01-01

    The perceptual strategies used by 4 orangutans (2 subadults, 2 adults) when choosing the larger of 2 volumes in a Piagetian conservation task were investigated. Three possible perceptual strategies were investigated: (a) direct perceptual estimation of the container's content independent of its shape, (b) use of the spatial and temporal cues provided by the pouring of liquid from one container

  9. Naval Research Laboratory Memorandum Report, 2003 Perceptual and Ergonomic Issues in

    E-print Network

    Swan II, J. Edward

    Naval Research Laboratory Memorandum Report, 2003 1 Perceptual and Ergonomic Issues in Mobile paradigm, the field needs a much better understanding of the fundamental perceptual and ergonomic issues aimed at both understanding the fundamental perceptual and ergonomic issues in AR display

  10. A perceptually tuned subband image coder based on the measure of just-noticeable-distortion profile

    Microsoft Academic Search

    Chun-Hsien Chou; Yun-Chin Li

    1995-01-01

    To represent an image of high perceptual quality with the lowest possible bit rate, an effective image compression algorithm should not only remove the redundancy due to statistical correlation but also the perceptually insignificant components from image signals. In this paper, a perceptually tuned subband image coding scheme is presented, where a just-noticeable distortion (JND) or minimally noticeable distortion (MND)

  11. Perceptual and Cognitive Load Interact to Control the Spatial Focus of Attention

    ERIC Educational Resources Information Center

    Linnell, Karina J.; Caparos, Serge

    2011-01-01

    Caparos and Linnell (2009, 2010) used a variable-separation flanker paradigm to show that (a) when cognitive load is low, increasing perceptual load causes spatial attention to focus and (b) when perceptual load is high, decreasing cognitive load causes spatial attention to focus. Here, we tested whether the effects of perceptual and cognitive…

  12. Capturing Human Body Motion from Video for Perceptual Interfaces by Sequential Variational MAP

    E-print Network

    Wu, Ying

    Capturing Human Body Motion from Video for Perceptual Interfaces by Sequential Variational MAP Gang human body motion from video for perceptual interfaces. Most probabilistic methods for visual tracking for articulated human body tracking, and its applicability to vision based perceptual interfaces. 1 Introduction

  13. Identity modulates short-term memory for facial emotion

    PubMed Central

    Galster, Murray; Kahana, Michael J.; Wilson, Hugh R.; Sekuler, Robert

    2010-01-01

    For some time, the relationship between processing of facial expression and facial identity has been in dispute. Using realistic synthetic faces, we reexamined this relationship for both perception and short-term memory. In Experiment 1, subjects tried to identify whether the emotional expression on a probe stimulus face matched the emotional expression on either of two remembered faces that they had just seen. The results showed that identity strongly influenced recognition short-term memory for emotional expression. In Experiment 2, subjects’ similarity/dissimilarity judgments were transformed by multidimensional scaling (MDS) into a 2-D description of the faces’ perceptual representations. Distances among stimuli in the MDS representation, which showed a strong linkage of emotional expression and facial identity, were good predictors of correct and false recognitions obtained previously in Experiment 1. The convergence of the results from Experiments 1 and 2 suggests that the overall structure and configuration of faces’ perceptual representations may parallel their representation in short-term memory and that facial identity modulates the representation of facial emotion, both in perception and in memory. The stimuli from this study may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental. PMID:19897794

  14. Non-volatile memory based on the ferroelectric photovoltaic effect

    PubMed Central

    Guo, Rui; You, Lu; Zhou, Yang; Shiuh Lim, Zhi; Zou, Xi; Chen, Lang; Ramesh, R.; Wang, Junling

    2013-01-01

    The quest for a solid state universal memory with high-storage density, high read/write speed, random access and non-volatility has triggered intense research into new materials and novel device architectures. Though the non-volatile memory market is dominated by flash memory now, it has very low operation speed with ~10??s programming and ~10?ms erasing time. Furthermore, it can only withstand ~105 rewriting cycles, which prevents it from becoming the universal memory. Here we demonstrate that the significant photovoltaic effect of a ferroelectric material, such as BiFeO3 with a band gap in the visible range, can be used to sense the polarization direction non-destructively in a ferroelectric memory. A prototype 16-cell memory based on the cross-bar architecture has been prepared and tested, demonstrating the feasibility of this technique. PMID:23756366

  15. Worthington Memory

    NSDL National Science Digital Library

    This Online Scrapbook of Worthington History is a collaborative project between the Worthington (Ohio) Libraries and the Worthington Historical Society to present local history materials. Visitors can search or browse the digitized collection, currently over 117 photographs and documents. Those unfamiliar with Worthington can use the browse feature to retrieve collection items organized into broad categories such as Arts, Architecture, Agriculture, Business and Commerce, or by decade from 1800 to 2002. Documentation, such as selection criteria, and a 36-page manual "Worthington Memory Digital Imaging Workflow" is provided, making Worthington Memory a handy resource for other public libraries wishing to begin a local history digitization project.

  16. Memory clinics

    PubMed Central

    Jolley, D; Benbow, S M; Grizzell, M

    2006-01-01

    Memory clinics were first described in the 1980s. They have become accepted worldwide as useful vehicles for improving practice in the identification, investigation, and treatment of memory disorders, including dementia. They are provided in various settings, the setting determining clientele and practice. All aim to facilitate referral from GPs, other specialists, or by self referral, in the early stages of impairment, and to avoid the stigma associated with psychiatric services. They bring together professionals with a range of skills for the benefit of patients, carers, and colleagues, and contribute to health promotion, health education, audit, and research, as well as service to patients. PMID:16517802

  17. A compact PE memory for vision chips

    NASA Astrophysics Data System (ADS)

    Cong, Shi; Zhe, Chen; Jie, Yang; Nanjian, Wu; Zhihua, Wang

    2014-09-01

    This paper presents a novel compact memory in the processing element (PE) for single-instruction multiple-data (SIMD) vision chips. The PE memory is constructed with 8 × 8 register cells, where one latch in the slave stage is shared by eight latches in the master stage. The memory supports simultaneous read and write on the same address in one clock cycle. Its compact area of 14.33 ?m2/bit promises a higher integration level of the processor. A prototype chip with a 64 × 64 PE array is fabricated in a UMC 0.18 ?m CMOS technology. Five types of the PE memory cell structure are designed and compared. The testing results demonstrate that the proposed PE memory architecture well satisfies the requirement of the vision chip in high-speed real-time vision applications, such as 1000 fps edge extraction.

  18. Effectiveness of speed trailers on low-speed urban roadways

    E-print Network

    Perrillo, Kerry Victoria

    1997-01-01

    the roadway to observe speed changes. Speed data were collected before, during, and after the speed trailer was used. The results indicated that speed trailers are effective in reducing vehicle speeds and the proportion of speeders. Each study site had...

  19. Time perception, attention, and memory: a selective review.

    PubMed

    Block, Richard A; Gruber, Ronald P

    2014-06-01

    This article provides a selective review of time perception research, mainly focusing on the authors' research. Aspects of psychological time include simultaneity, successiveness, temporal order, and duration judgments. In contrast to findings at interstimulus intervals or durations less than 3.0-5.0 s, there is little evidence for an "across-senses" effect of perceptual modality (visual vs. auditory) at longer intervals or durations. In addition, the flow of time (events) is a pervasive perceptual illusion, and we review evidence on that. Some temporal information is encoded All rights reserved. relatively automatically into memory: People can judge time-related attributes such as recency, frequency, temporal order, and duration of events. Duration judgments in prospective and retrospective paradigms reveal differences between them, as well as variables that moderate the processes involved. An attentional-gate model is needed to account for prospective judgments, and a contextual-change model is needed to account for retrospective judgments. PMID:24365036

  20. Data Reuse Analysis Technique for Software-Controlled Memory Hierarchies

    Microsoft Academic Search

    Ilya Issenin; Erik Brockmeyer; Miguel Miranda; Nikil Dutt

    2004-01-01

    In multimedia and other streaming applications a significant portion of energy is spent on data transfers. Exploiting data reuse opportunities in the application, we can reduce this energy by making copies of frequently used data in a small local memory and replacing speed and power inefficient transfers from main off-chip memory by more efficient local data transfers. In this paper