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1

Studies of Perceptual Memory.  

National Technical Information Service (NTIS)

Perceptual memory refers to experience-induced changes in perceptual processing of particular objects or scenes. Part 1 of this report summarizes the results of 8 studies of the role of perceptual memory in recognition memory. The hypothesis was confirmed...

J. M. Farnham K. J. Hawley W. A. Johnston

1992-01-01

2

Between and Within-Individual Effects of Visual Contrast Sensitivity on Perceptual Matching, Processing Speed, and Associative Memory in Older Adults  

Microsoft Academic Search

Background: Although cross-sectional studies have demonstrated associations between visual contrast sensitivity and cognitive test performance, it remains unclear whether peripheral visual or perceptual factors explain the association. Objective: We aimed at determining whether reducing static contrast of the study stimuli would simulate the performance deficits on measures of processing speed and associative memory that are associated with aging. Methods: We

Kaarin J. Anstey; Peter Butterworth; Maria Borzycki; Sally Andrews

2006-01-01

3

On the relationship between autobiographical memory and perceptual learning  

Microsoft Academic Search

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

Larry L. Jacoby; Mark Dallas

1981-01-01

4

Generation and Perceptual Implicit Memory: Different Generation Tasks Produce Different Effects on Perceptual Priming  

ERIC Educational Resources Information Center

The generation manipulation has been critical in delineating differences between implicit and explicit memory. In contrast to past research, the present experiments indicate that generating from a rhyme cue produces as much perceptual priming as does reading. This is demonstrated for 3 visual priming tasks: perceptual identification, word-fragment…

Mulligan, Neil W.; Dew, Ilana T. Z.

2009-01-01

5

Great Expectations: Temporal Expectation Modulates Perceptual Processing Speed  

ERIC Educational Resources Information Center

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…

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

2012-01-01

6

Memory encoding of stimulus features in human perceptual learning  

Microsoft Academic Search

Two experiments analysed memory encoding in human perceptual learning. Both experiments started with preexposure without feedback to four checkerboards composed by a unique feature each and sharing a common feature (AX, BX, CX, and DX). Elements of one pair were presented intermixed and elements of the other pair were presented in separate blocks. Immediately after preexposure participants completed a memory

Paulo F. Carvalho; Pedro B. Albuquerque

2012-01-01

7

Perceptual Priming Versus Explicit Memory: Dissociable Neural Correlates at Encoding  

Microsoft Academic Search

We addressed the hypothesis that perceptual priming and explicit memory have distinct neural correlates at encoding. Event-related potentials (ERPs) were recorded while participants studied visually presented words at deep versus shallow levels of processing (LOPs). The ERPs were sorted by whether or not participants later used studied words as completions to three-letter word stems in an intentional memory test, and

Björn Schott; Alan Richardson-Klavehn; Hans-Jochen Heinze; Emrah Düzel

2002-01-01

8

Working memory does not dissociate between different perceptual categorization tasks.  

PubMed

Working memory is crucial for many higher level cognitive functions, ranging from mental arithmetic to reasoning and problem solving. Likewise, the ability to learn and categorize novel concepts forms an indispensable part of human cognition. However, very little is known about the relationship between working memory and categorization. This article reports 2 studies that related people's working memory capacity (WMC) to their learning performance on multiple rule-based and information-integration perceptual categorization tasks. In both studies, structural equation modeling revealed a strong relationship between WMC and category learning irrespective of the requirement to integrate information across multiple perceptual dimensions. WMC was also uniformly related to people's ability to focus on the most task-appropriate strategy, regardless of whether or not that strategy involved information integration. Contrary to the predictions of the multiple systems view of categorization, working memory thus appears to underpin performance in both major classes of perceptual category-learning tasks. PMID:22746954

Lewandowsky, Stephan; Yang, Lee-Xieng; Newell, Ben R; Kalish, Michael L

2012-07-01

9

Perceptual memory drives learning of retinotopic biases for bistable stimuli  

PubMed Central

The visual system exploits past experience at multiple timescales to resolve perceptual ambiguity in the retinal image. For example, perception of a bistable stimulus can be biased toward one interpretation over another when preceded by a brief presentation of a disambiguated version of the stimulus (positive priming) or through intermittent presentations of the ambiguous stimulus (stabilization). Similarly, prior presentations of unambiguous stimuli can be used to explicitly “train” a long-lasting association between a percept and a retinal location (perceptual association). These phenonema have typically been regarded as independent processes, with short-term biases attributed to perceptual memory and longer-term biases described as associative learning. Here we tested for interactions between these two forms of experience-dependent perceptual bias and demonstrate that short-term processes strongly influence long-term outcomes. We first demonstrate that the establishment of long-term perceptual contingencies does not require explicit training by unambiguous stimuli, but can arise spontaneously during the periodic presentation of brief, ambiguous stimuli. Using rotating Necker cube stimuli, we observed enduring, retinotopically specific perceptual biases that were expressed from the outset and remained stable for up to 40 min, consistent with the known phenomenon of perceptual stabilization. Further, bias was undiminished after a break period of 5 min, but was readily reset by interposed periods of continuous, as opposed to periodic, ambiguous presentation. Taken together, the results demonstrate that perceptual biases can arise naturally and may principally reflect the brain's tendency to favor recent perceptual interpretation at a given retinal location. Further, they suggest that an association between retinal location and perceptual state, rather than a physical stimulus, is sufficient to generate long-term biases in perceptual organization.

Murphy, Aidan P.; Leopold, David A.; Welchman, Andrew E.

2014-01-01

10

Perceptual Memory and Learning: Recognizing, Categorizing, and Relating  

Microsoft Academic Search

In this position paper we attempt to derive an architecture and mechanism for perceptual memory and learning for software agents and robots from what is known, or believed, about the same faculties in human and other animal cognition. Based on that of the IDA model of Global Workspace Theory, a conceptual and computational model of cognition, this architecture, together with

Stan Franklin

11

Retrieval-Induced Forgetting in Perceptually Driven Memory Tests  

ERIC Educational Resources Information Center

Recent data (T. J. Perfect, C. J. A. Moulin, M. A. Conway, & E. Perry, 2002) have suggested that retrieval-induced forgetting (RIF) depends on conceptual memory because the effect is not found in perceptually driven tasks. In 3 experiments, the authors aimed to show that the presence of RIF depends on whether the procedure induces appropriate…

Bajo, M. Teresa; Gomez-Ariza, Carlos J.; Fernandez, Angel; Marful, Alejandra

2006-01-01

12

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

ERIC Educational Resources Information Center

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…

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

2010-01-01

13

The development of explicit memory for basic perceptual features.  

PubMed

In three experiments with 164 individuals between 4 and 80 years old, we examined age-related changes in explicit memory for three perceptual features--item identity, color, and location. In Experiments 1-2, feature recognition was assessed in an incidental learning, gamelike task resembling the game Concentration. In Experiment 3, feature recognition was assessed using a pencil-and-paper task after intentional learning instructions. The form of the explicit memory function across the life span varied with the particular perceptual feature tested and the type of task. Item recognition was excellent at all ages but was significantly poorer for older adults than children, color recognition peaked in late childhood on the gamelike task, and location recognition peaked in early adulthood on the pencil-and-paper task. These findings indicate that performance on explicit memory tests is not a consistent inverted U-shaped function of age across various features. Explicit memory performance depends on what is measured and how. Because explicit memory typically reflects a composite of different features, age-related changes in explicit memory will not necessarily correspond to the function for any single one. PMID:11884091

Gulya, Michelle; Rossi-George, Alba; Hartshorn, Kristin; Vieira, Aurora; Rovee-Collier, Carolyn; Johnson, Marcia K; Chalfonte, Barbara L

2002-03-01

14

The Development of Explicit Memory for Basic Perceptual Features  

Microsoft Academic Search

In three experiments with 164 individuals between 4 and 80 years old, we examined age-related changes in explicit memory for three perceptual features—item identity, color, and location. In Experiments 1–2, feature recognition was assessed in an incidental learning, gamelike task resembling the game Concentration. In Experiment 3, feature recognition was assessed using a pencil-and-paper task after intentional learning instructions. The

Michelle Gulya; Alba Rossi-George; Kristin Hartshorn; Aurora Vieira; Carolyn Rovee-Collier; Marcia K. Johnson; Barbara L. Chalfonte

2002-01-01

15

Reducing traffic speed within roadwork sites using obtrusive perceptual countermeasures.  

PubMed

Excessive speed is currently one of the primary contributory factors in traffic accidents within roadwork sites around the world. The present study evaluated two novel interventions designed to control traffic speed within an open road, roadwork site in New Zealand where drivers were required to decrease their speed from 100 to 50km/h. Two different interventions were placed at the entrance to the work site and required drivers to pass between a 3.5m wide passage of either evenly or decreasingly spaced cones. A multi-element baseline design was utilised. Both interventions were highly effective at reducing vehicle speed, with the greatest initial decrease in speed to 9.47 km/h below baseline for the uneven arrangement. Additionally, both arrangements more than halved the proportion of 'dangerous' speeders travelling faster than 20 km/h over the speed limit. The findings indicate that both arrangements of cones are effective, convenient, cost-effective strategies. It is concluded that, although both arrangements are highly effective, the use of unevenly-spaced cones is likely to most markedly reduce the number of speed-related accidents within open road roadwork zones. The findings are discussed in relation to the perceptual mechanisms by which transverse and peripheral stimuli influence speed perception and driver behaviour. PMID:20159057

Allpress, Jesse A; Leland, Louis S

2010-03-01

16

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

PubMed Central

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.

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

2014-01-01

17

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

PubMed

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

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

2014-01-01

18

Evidence for working memory storage operations in perceptual cortex.  

PubMed

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 (1) whether these representations withstand intervening sensory input and (2) how communication between multimodal association cortex and the 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 a 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 the 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 is subsequently relayed forward. Together, these findings indicate that WM storage operations are carried out within perceptual cortex. PMID:24436009

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

2014-03-01

19

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

ERIC Educational Resources Information Center

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

Alderton, David L.

20

Neural correlates of relational memory: successful encoding and retrieval of semantic and perceptual associations  

Microsoft Academic Search

Using event-related functional magnetic resonance imaging, we identified brain regions involved in successful relational memory (RM) during encoding and retrieval for semantic and perceptual associations or in general, independent of phase and content. Participants were scanned while encoding and later retrieving associations between pairs of words (semantic RM) or associations between words and fonts (perceptual RM). Encoding success activity (ESA)

S. E. Prince; S. M. Daselaar; R. Cabeza

2005-01-01

21

Working memory effects in speeded RSVP tasks.  

PubMed

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

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

2014-01-01

22

Perceptual chunking and its effect on memory in speech processing: ERP and behavioral evidence.  

PubMed

We examined how perceptual chunks of varying size in utterances can influence immediate memory of heard items (monosyllabic words). Using behavioral measures and event-related potentials (N400) we evaluated the quality of the memory trace for targets taken from perceived temporal groups (TGs) of three and four items. Variations in the amplitude of the N400 showed a better memory trace for items presented in TGs of three compared to those in groups of four. Analyses of behavioral responses along with P300 components also revealed effects of chunk position in the utterance. This is the first study to measure the online effects of perceptual chunks on the memory trace of spoken items. Taken together, the N400 and P300 responses demonstrate that the perceptual chunking of speech facilitates information buffering and a processing on a chunk-by-chunk basis. PMID:24678304

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

2014-01-01

23

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

ERIC Educational Resources Information Center

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

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

2009-01-01

24

Beyond perceptual load and dilution: a review of the role of working memory in selective attention  

PubMed Central

The perceptual load and dilution models differ fundamentally in terms of the proposed mechanism underlying variation in distractibility during different perceptual conditions. However, both models predict that distracting information can be processed beyond perceptual processing under certain conditions, a prediction that is well-supported by the literature. Load theory proposes that in such cases, where perceptual task aspects do not allow for sufficient attentional selectivity, the maintenance of task-relevant processing depends on cognitive control mechanisms, including working memory. The key prediction is that working memory plays a role in keeping clear processing priorities in the face of potential distraction, and the evidence reviewed and evaluated in a meta-analysis here supports this claim, by showing that the processing of distracting information tends to be enhanced when load on a concurrent task of working memory is high. Low working memory capacity is similarly associated with greater distractor processing in selective attention, again suggesting that the unavailability of working memory during selective attention leads to an increase in distractibility. Together, these findings suggest that selective attention against distractors that are processed beyond perception depends on the availability of working memory. Possible mechanisms for the effects of working memory on selective attention are discussed.

de Fockert, Jan W.

2013-01-01

25

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

PubMed

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

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

2013-08-01

26

Regulation of Performance and Monitoring of Errors in a Test of Perceptual Speed.  

National Technical Information Service (NTIS)

A test of perceptual speed (cancellation of figures) in which usually the number of rights and wrongs (omissions) are uncorrelated, was applied to three groups with different instructions. Group 1 was told to work quickly and accurately; group 2 to take c...

K. Goeters

1987-01-01

27

Performance Regulation and Error Control in a Test of Perceptual Speed.  

National Technical Information Service (NTIS)

A test of perceptual speed (cancellation of figures) in which usually the number of rights and wrongs (omissions) are uncorrelated, was applied to three groups with different instructions. Group 1 was told to work quickly and accurately; group 2 to take c...

K. M. Goerters

1986-01-01

28

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

ERIC Educational Resources Information Center

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…

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

2013-01-01

29

Differentiation of perceptual and semantic subsequent memory effects using an orthographic paradigm.  

PubMed

This study aimed to differentiate perceptual and semantic encoding processes using subsequent memory effects (SMEs) elicited by the recognition of orthographs of single Chinese characters. Participants studied a series of Chinese characters perceptually (by inspecting orthographic components) or semantically (by determining the object making sounds), and then made studied or unstudied judgments during the recognition phase. Recognition performance in terms of d-prime measure in the semantic condition was higher, though not significant, than that of the perceptual condition. The between perceptual-semantic condition differences in SMEs at P550 and late positive component latencies (700-1000ms) were not significant in the frontal area. An additional analysis identified larger SME in the semantic condition during 600-1000ms in the frontal pole regions. These results indicate that coordination and incorporation of orthographic information into mental representation is essential to both task conditions. The differentiation was also revealed in earlier SMEs (perceptual>semantic) at N3 (240-360ms) latency, which is a novel finding. The left-distributed N3 was interpreted as more efficient processing of meaning with semantically learned characters. Frontal pole SMEs indicated strategic processing by executive functions, which would further enhance memory. PMID:23063888

Kuo, Michael C C; Liu, Karen P Y; Ting, Kin Hung; Chan, Chetwyn C H

2012-11-27

30

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

PubMed Central

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 possible that grouping reduces the effective number of “items” in the display. To test this hypothesis, we examined how mnemonic resolution declined as the number of items to be stored increased. Discrete resource models predict that precision will reach a stable plateau at relatively early set sizes, because no further items can be stored once putative item limits are exceeded. Thus, we examined whether the precision by set size function was bilinear when storage was enhanced via perceptual grouping. In line with the hypothesis that each perceptual group counted as a single “item,” precision still reached a clear plateau at a set size determined by the number of stored groups. Moreover, the maximum number of elements stored was doubled, and electrophysiological measures showed that selection and storage-related neural responses were the same for a single element and a multielement perceptual group. Thus, perceptual grouping allows more elements to be held in working memory while storage is still constrained by a discrete item limit.

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

2014-01-01

31

How do illusions constrain goal-directed movement: perceptual and visuomotor influences on speed/accuracy trade-off.  

PubMed

Recent research shows that visual processing influences the speed/accuracy trade-off people use when performing goal-directed movement. This raises the question of how this influence is produced in visual cognition. Visual influences on speed/accuracy trade-off could be produced in conscious visual perception, in non-conscious visuomotor transformation, or by some interaction of conscious perceptual and non-conscious visuomotor processes. There is independent evidence showing that both perceptual and visuomotor processes are involved in trading off speed and accuracy; however, the interaction between these processes has yet to be investigated. We present an experiment in which we show that a change in visual consciousness induced by a perceptual illusion affects the speed and accuracy of goal-directed movements, suggesting that perceptual and visuomotor processes do interact in speed/accuracy trade-off. We discuss the consequences of these results for theories of visual function more generally. PMID:21267551

Skewes, Joshua C; Roepstorff, Andreas; Frith, Christopher D

2011-03-01

32

Memory's aging echo: Age-related decline in neural reactivation of perceptual details during recollection.  

PubMed

Episodic memory decline is a hallmark of normal cognitive aging. Here, we report the first event-related fMRI study to directly investigate age differences in the neural reactivation of qualitatively rich perceptual details during recollection. Younger and older adults studied pictures of complex scenes at different presentation durations along with descriptive verbal labels, and these labels subsequently were used during fMRI scanning to cue picture recollections of varying perceptual detail. As expected from prior behavioral work, the two age groups subjectively rated their recollections as containing similar amounts of perceptual detail, despite objectively measured recollection impairment in older adults. In both age groups, comparisons of retrieval trials that varied in recollected detail revealed robust activity in brain regions previously linked to recollection, including hippocampus and both medial and lateral regions of the prefrontal and posterior parietal cortex. Critically, this analysis also revealed recollection-related activity in visual processing regions that were active in an independent picture-perception task, and these regions showed age-related reductions in activity during recollection that cannot be attributed to age differences in response criteria. These fMRI findings provide new evidence that aging reduces the absolute quantity of perceptual details that are reactivated from memory, and they help to explain why aging reduces the reliability of subjective memory judgments. PMID:24828546

McDonough, Ian M; Cervantes, Sasha N; Gray, Stephen J; Gallo, David A

2014-09-01

33

Working Memory Does Not Dissociate between Different Perceptual Categorization Tasks  

ERIC Educational Resources Information Center

Working memory is crucial for many higher level cognitive functions, ranging from mental arithmetic to reasoning and problem solving. Likewise, the ability to learn and categorize novel concepts forms an indispensable part of human cognition. However, very little is known about the relationship between working memory and categorization. This…

Lewandowsky, Stephan; Yang, Lee-Xieng; Newell, Ben R.; Kalish, Michael L.

2012-01-01

34

The Mere Exposure Effect Is Sensitive to Color Information: Evidence for Color Effects in a Perceptual Implicit Memory Test  

Microsoft Academic Search

Priming effects in perceptual tests of implicit memory are assumed to be perceptually specific. Surprisingly, changing object colors from study to test did not diminish priming in most previous studies. However, these studies used implicit tests that are based on object identification, which mainly depends on the analysis of the object shape and therefore operates color-independently. The present study shows

Almut Hupbach; André Melzer; Oliver Hardt

2006-01-01

35

The speed and accuracy of perceptual decisions in a random-tone pitch task.  

PubMed

Research in perceptual decision making is dominated by paradigms that tap the visual system, such as the random-dot motion (RDM) paradigm. In this study, we investigated whether the behavioral signature of perceptual decisions in the auditory domain is similar to those observed in the visual domain. We developed an auditory version of the RDM task, in which tones correspond to dots and pitch corresponds to motion (the random-tone pitch task, RTP). In this task, participants have to decide quickly whether the pitch of a "sound cloud" of tones is moving up or down. Stimulus strength and speed-accuracy trade-off were manipulated. To describe the relationship between stimulus strength and performance, we fitted the proportional-rate diffusion model to the data. The results showed a close coupling between stimulus strength and the speed and accuracy of perceptual decisions in both tasks. Additionally, we fitted the full drift diffusion model (DDM) to the data and showed that three of the four participants had similar speed-accuracy trade-offs in both tasks. However, for the RTP task, drift rates were larger and nondecision times slower, suggesting that some DDM parameters might be dependent on stimulus modality (drift rate and nondecision time), whereas others might not be (decision bound). The results illustrate that the RTP task is suitable for investigating the dynamics of auditory perceptual choices. Future studies using the task might help to investigate modality-specific effects on decision making at both the behavioral and neuronal levels. PMID:23572205

Mulder, Martijn J; Keuken, Max C; van Maanen, Leendert; Boekel, Wouter; Forstmann, Birte U; Wagenmakers, Eric-Jan

2013-07-01

36

The Comparison of Visual Working Memory Representations with Perceptual Inputs  

PubMed Central

The human visual system can notice differences between memories of previous visual inputs and perceptions of new visual inputs, but the comparison process that detects these differences has not been well characterized. This study tests the hypothesis that differences between the memory of a stimulus array and the perception of a new array are detected in a manner that is analogous to the detection of simple features in visual search tasks. That is, just as the presence of a task-relevant feature in visual search can be detected in parallel, triggering a rapid shift of attention to the object containing the feature, the presence of a memory-percept difference along a task-relevant dimension can be detected in parallel, triggering a rapid shift of attention to the changed object. Supporting evidence was obtained in a series of experiments that examined manual reaction times, saccadic reaction times, and event-related potential latencies. However, these experiments also demonstrated that a slow, limited-capacity process must occur before the observer can make a manual change-detection response.

Hyun, Joo-seok; Woodman, Geoffrey F.; Vogel, Edward K.; Hollingworth, Andrew

2008-01-01

37

Improving Reading Speed for People with Central Vision Loss through Perceptual Learning  

PubMed Central

Purpose. Perceptual learning has been shown to be effective in improving visual functions in the normal adult visual system, as well as in adults with amblyopia. In this study, the feasibility of applying perceptual learning to enhance reading speed in people with long-standing central vision loss was evaluated. Methods. Six observers (mean age, 73.8) with long-standing central vision loss practiced an oral sentence-reading task, with words presented sequentially using rapid serial visual presentation (RSVP). A pre-test consisted of measurements of visual acuities, RSVP reading speeds for six print sizes, the location of the preferred retinal locus for fixation (fPRL), and fixation stability. Training consisted of six weekly sessions of RSVP reading, with 300 sentences presented per session. A post-test, identical with the pre-test, followed the training. Results. All observers showed improved RSVP reading speed after training. The improvement averaged 53% (range, 34–70%). Comparisons of pre- and post-test measurements revealed little changes in visual acuity, critical print size, location of the fPRL, and fixation stability. Conclusions. The specificity of the learning effect, and the lack of changes to the fPRL location and fixation stability suggest that the improvements are not due to observers adopting a retinal location with better visual capability, or an improvement in fixation. Rather, the improvements are likely to represent genuine plasticity of the visual system despite the older ages of the observers, coupled with long-standing sensory deficits. Perceptual learning might be an effective way of enhancing visual performance for people with central vision loss.

2011-01-01

38

Human electrophysiological reflections of the recruitment of perceptual processing during actions that engage memory.  

PubMed

The N170 event-related potential (ERP) component reflects visual perceptual processes and is known to have a source in the lateral occipital cortex (LOC) and temporal lobe regions. Convergent evidence from neuropsychological and neuroimaging studies suggests that the LOC is recruited for action tasks in which visibility of a target is unavailable and a perceptual memory of the target's characteristics must be used instead. We tested the hypothesis that the N170 reflects the contribution of additional ventral stream processes required for performing actions in which vision of a target is occluded. We predicted that the amplitude of the ERP in the latency range of the N170 would be larger when perceptual mechanisms are engaged to a greater extent. Participants were auditorily cued to touch target dots appearing on a touchscreen. Two viewing conditions varied with respect to the contribution of the ventral visuomotor stream during response initiation. In condition 1, the target disappeared with movement initiation whereas in condition 2, it disappeared with the cue to respond. The N170 during the response-initiation phase of trials was larger in amplitude for condition 2. The effect was observed over temporal electrode sites bilaterally, likely reflecting an overlap between auditory cue-related processes and additional perceptual processes within regions in the inferior-temporal cortex. Thus, the N170 may be a marker of neural activity within the ventral stream, further supporting the notion that actions initiated in the absence of a visual target rely more on perceptual representations than those directed towards visually available targets. PMID:22728678

Cruikshank, Leanna C; Caplan, Jeremy B; Singhal, Anthony

2012-01-01

39

Executive working memory load does not compromise perceptual processing during visual search: evidence from additive factors analysis.  

PubMed

Executive working memory (WM) load reduces the efficiency of visual search, but the mechanisms by which this occurs are not fully known. In the present study, we assessed the effect of executive load on perceptual processing during search. Participants performed a serial oculomotor search task, looking for a circle target among gapped-circle distractors. The participants performed the task under high and low executive WM load, and the visual quality (Experiment 1) or discriminability of targets and distractors (Experiment 2) was manipulated across trials. By the logic of the additive factors method (Sternberg, 1969, 1998), if WM load compromises the quality of perceptual processing during visual search, manipulations of WM load and perceptual processing difficulty should produce nonadditive effects. Contrary to this prediction, the effects of WM load and perceptual difficulty were additive. The results imply that executive WM load does not degrade perceptual analysis during visual search. PMID:20139447

He, Jibo; McCarley, Jason S

2010-02-01

40

Out of Mind, Out of Sight: Language Affects Perceptual Vividness in Memory  

PubMed Central

We examined whether language affects the strength of a visual representation in memory. Participants studied a picture, read a story about the depicted object, and then selected out of two pictures the one whose transparency level most resembled that of the previously presented picture. The stories contained two linguistic manipulations that have been demonstrated to affect concept availability in memory, i.e., object presence and goal-relevance. The results show that described absence of an object caused people to select the most transparent picture more often than described presence of the object. This effect was not moderated by goal-relevance, suggesting that our paradigm tapped into the perceptual quality of representations rather than, for example, their linguistic availability. We discuss the implications of these findings within a framework of grounded cognition.

Vandeberg, Lisa; Eerland, Anita; Zwaan, Rolf A.

2012-01-01

41

Illusory speed is retained in memory during invisible motion  

PubMed Central

The brain can retain speed information in early visual short-term memory in an astonishingly precise manner. We investigated whether this (early) visual memory system is active during the extrapolation of occluded motion and whether it reflects speed misperception due to contrast and size. Experiments 1A and 2A showed that reducing target contrast or increasing its size led to an illusory speed underestimation. Experiments 1B, 2B, and 3 showed that this illusory phenomenon is reflected in the memory of speed during occluded motion, independent of the range of visible speeds, of the length of the visible trajectory or the invisible trajectory, and of the type of task. These results suggest that illusory speed is retained in memory during invisible motion.

Battaglini, Luca; Campana, Gianluca; Casco, Clara

2013-01-01

42

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

43

Perceptual organization masquerading as phonological storage: Further support for a perceptual-gestural view of short-term memory  

Microsoft Academic Search

Three experiments examined whether the survival of the phonological similarity effect (PSE) under articulatory suppression for auditory but not visual to-be-serially recalled lists is a perceptual effect rather than an effect arising from the action of a bespoke phonological store. Using a list of 5 auditory items, a list length at which the expression of phonological storage should, ostensibly, be

Dylan M. Jones; Robert W. Hughes; William J. Macken

2006-01-01

44

Perceptual Organization Masquerading as Phonological Storage: Further Support for a Perceptual-Gestural View of Short-Term Memory  

ERIC Educational Resources Information Center

Three experiments examined whether the survival of the phonological similarity effect (PSE) under articulatory suppression for auditory but not visual to-be-serially recalled lists is a perceptual effect rather than an effect arising from the action of a bespoke phonological store. Using a list of 5 auditory items, a list length at which the…

Jones, Dylan M.; Hughes, Robert W.; Macken, William J.

2006-01-01

45

High-Speed GaAs MESFET Memory Study.  

National Technical Information Service (NTIS)

A design and analysis study of potential high-speed GaAs-MESFET memory circuits was performed. The results show that a 1-kbit static RAM having a 1-nsec access time is feasible. The design of the flip-flop memory cell uses low-power enhancement-mode MESFE...

M. Waldner R. E. Lundgren

1981-01-01

46

Well-being affects changes in perceptual speed in advanced old age: longitudinal evidence for a dynamic link.  

PubMed

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 years at T1, M=85 years). Reports of well-being were found to influence subsequent decline in perceptual speed (time lags of 2 years). No evidence was found for a directed effect in the other direction. None of the potential covariates examined (initial health constraints, personality, and social participation) accounted for these differential lead-lag associations. Our results suggest that well-being is not only a consequence of but also a source for successful aging. The discussion focuses on conceptual implications and methodological considerations. PMID:17484582

Gerstorf, Denis; Lövdén, Martin; Röcke, Christina; Smith, Jacqui; Lindenberger, Ulman

2007-05-01

47

How do illusions constrain goal-directed movement: perceptual and visuomotor influences on speed\\/accuracy trade-off  

Microsoft Academic Search

Recent research shows that visual processing influences the speed\\/accuracy trade-off people use when performing goal-directed\\u000a movement. This raises the question of how this influence is produced in visual cognition. Visual influences on speed\\/accuracy\\u000a trade-off could be produced in conscious visual perception, in non-conscious visuomotor transformation, or by some interaction\\u000a of conscious perceptual and non-conscious visuomotor processes. There is independent evidence

Joshua C. Skewes; Andreas Roepstorff; Christopher D. Frith

2011-01-01

48

High-speed and low-leakage MTCMOS memory registers  

Microsoft Academic Search

Various high speed sequential multi-threshold voltage CMOS (MTCMOS) circuit techniques are presented and evaluated in this paper. Dedicated low leakage data preserving memory elements are integrated into the MTCMOS flip-flops. The leakage power consumption of an MTCMOS memory register is reduced by up to 67.72% as compared to the previously published conventional sequential MTCMOS circuits in a UMC 80nm CMOS

Hailong Jiao; Volkan Kursun

2010-01-01

49

High-speed spatially multimode atomic memory  

SciTech Connect

We study the coherent storage and retrieval of a very short multimode light pulse in an atomic ensemble. We consider a quantum memory process based on the conversion of a signal pulse into a long-lived spin coherence via light matter interaction in an on-resonant {Lambda} -type system. In order to study the writing and reading processes we analytically solve the partial differential equations describing the evolution of the field and of the atomic coherence in time as well as in space. We show how to optimize the process for writing as well as for reading. If the medium length is fixed, for each length, there is an optimal value of the pulse duration. We discuss the information capacity of this memory scheme and we estimate the number of transverse modes that can be stored as a quantum hologram.

Golubeva, T.; Golubev, Yu.; Mishina, O.; Bramati, A.; Laurat, J.; Giacobino, E. [St. Petersburg State University, 198504 St. Petersburg, Stary Petershof, ul. Ul'yanovskaya, 1 (Russian Federation); Laboratoire Kastler Brossel, Universite Pierre et Marie Curie, Ecole Normale Superieure, CNRS, Case 74, 4 place Jussieu, F-75252 Paris Cedex 05 (France)

2011-05-15

50

Breaking the Speed Limits of Phase-Change Memory  

NASA Astrophysics Data System (ADS)

Phase-change random-access memory (PCRAM) is one of the leading candidates for next-generation data-storage devices, but the trade-off between crystallization (writing) speed and amorphous-phase stability (data retention) presents a key challenge. We control the crystallization kinetics of a phase-change material by applying a constant low voltage via prestructural ordering (incubation) effects. A crystallization speed of 500 picoseconds was achieved, as well as high-speed reversible switching using 500-picosecond pulses. Ab initio molecular dynamics simulations reveal the phase-change kinetics in PCRAM devices and the structural origin of the incubation-assisted increase in crystallization speed. This paves the way for achieving a broadly applicable memory device, capable of nonvolatile operations beyond gigahertz data-transfer rates.

Loke, D.; Lee, T. H.; Wang, W. J.; Shi, L. P.; Zhao, R.; Yeo, Y. C.; Chong, T. C.; Elliott, S. R.

2012-06-01

51

Breaking the speed limits of phase-change memory.  

PubMed

Phase-change random-access memory (PCRAM) is one of the leading candidates for next-generation data-storage devices, but the trade-off between crystallization (writing) speed and amorphous-phase stability (data retention) presents a key challenge. We control the crystallization kinetics of a phase-change material by applying a constant low voltage via prestructural ordering (incubation) effects. A crystallization speed of 500 picoseconds was achieved, as well as high-speed reversible switching using 500-picosecond pulses. Ab initio molecular dynamics simulations reveal the phase-change kinetics in PCRAM devices and the structural origin of the incubation-assisted increase in crystallization speed. This paves the way for achieving a broadly applicable memory device, capable of nonvolatile operations beyond gigahertz data-transfer rates. PMID:22723419

Loke, D; Lee, T H; Wang, W J; Shi, L P; Zhao, R; Yeo, Y C; Chong, T C; Elliott, S R

2012-06-22

52

Speed of Processing, Working Memory, and Language Impairment in Children  

ERIC Educational Resources Information Center

Purpose: Children with language impairment (LI) often perform below the level of typically developing peers on measures of both processing speed and working memory. This study examined the relationship between these 2 types of measures and attempted to determine whether such measures can account for the LI itself. Method: Fourteen-year-old…

Leonard, Laurence B.; Weismer, Susan Ellis; Miller, Carol A.; Francis, David J.; Tomblin, J. Bruce; Kail, Robert V.

2007-01-01

53

High speed magneto-resistive random access memory  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

54

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

PubMed Central

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.

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

2014-01-01

55

A Latent Variable Analysis of Working Memory Capacity, Short-Term Memory Capacity, Processing Speed, and General Fluid Intelligence.  

ERIC Educational Resources Information Center

Studied the interrelationships among general fluid intelligence, short-term memory capacity, working memory capacity, and processing speed in 120 young adults and used structural equation modeling to determine the best predictor of general fluid intelligence. Results suggest that working memory capacity, but not short-term memory capacity or…

Conway, Andrew R. A.; Cowan, Nelsin; Bunting, Michael F.; Therriault, David J.; Minkoff, Scott R. B.

2002-01-01

56

Working memory and arithmetic calculation in children: The contributory roles of processing speed, short-term memory, and reading  

Microsoft Academic Search

The cognitive underpinnings of arithmetic calculation in children are noted to involve working memory; however, cognitive processes related to arithmetic calculation and working memory suggest that this relationship is more complex than stated previously. The purpose of this investigation was to examine the relative contributions of processing speed, short-term memory, working memory, and reading to arithmetic calculation in children. Results

Derek H. Berg

2008-01-01

57

Prediction, Postdiction, and Perceptual Length Contraction: A Bayesian Low-Speed Prior Captures the Cutaneous Rabbit and Related Illusions  

PubMed Central

Illusions provide a window into the brain’s perceptual strategies. In certain illusions, an ostensibly task-irrelevant variable influences perception. For example, in touch as in audition and vision, the perceived distance between successive punctate stimuli reflects not only the actual distance but curiously the inter-stimulus time. Stimuli presented at different positions in rapid succession are drawn perceptually toward one another. This effect manifests in several illusions, among them the startling cutaneous rabbit, in which taps delivered to as few as two skin positions appear to hop progressively from one position to the next, landing in the process on intervening areas that were never stimulated. Here we provide an accessible step-by-step exposition of a Bayesian perceptual model that replicates the rabbit and related illusions. The Bayesian observer optimally joins uncertain estimates of spatial location with the expectation that stimuli tend to move slowly. We speculate that this expectation – a Bayesian prior – represents the statistics of naturally occurring stimuli, learned by humans through sensory experience. In its simplest form, the model contains a single free parameter, tau: a time constant for space perception. We show that the Bayesian observer incorporates both pre- and post-dictive inference. Directed spatial attention affects the prediction-postdiction balance, shifting the model’s percept toward the attended location, as observed experimentally in humans. Applying the model to the perception of multi-tap sequences, we show that the low-speed prior fits perception better than an alternative, low-acceleration prior. We discuss the applicability of our model to related tactile, visual, and auditory illusions. To facilitate future model-driven experimental studies, we present a convenient freeware computer program that implements the Bayesian observer; we invite investigators to use this program to create their own testable predictions.

Goldreich, Daniel; Tong, Jonathan

2013-01-01

58

Prediction, postdiction, and perceptual length contraction: a bayesian low-speed prior captures the cutaneous rabbit and related illusions.  

PubMed

Illusions provide a window into the brain's perceptual strategies. In certain illusions, an ostensibly task-irrelevant variable influences perception. For example, in touch as in audition and vision, the perceived distance between successive punctate stimuli reflects not only the actual distance but curiously the inter-stimulus time. Stimuli presented at different positions in rapid succession are drawn perceptually toward one another. This effect manifests in several illusions, among them the startling cutaneous rabbit, in which taps delivered to as few as two skin positions appear to hop progressively from one position to the next, landing in the process on intervening areas that were never stimulated. Here we provide an accessible step-by-step exposition of a Bayesian perceptual model that replicates the rabbit and related illusions. The Bayesian observer optimally joins uncertain estimates of spatial location with the expectation that stimuli tend to move slowly. We speculate that this expectation - a Bayesian prior - represents the statistics of naturally occurring stimuli, learned by humans through sensory experience. In its simplest form, the model contains a single free parameter, tau: a time constant for space perception. We show that the Bayesian observer incorporates both pre- and post-dictive inference. Directed spatial attention affects the prediction-postdiction balance, shifting the model's percept toward the attended location, as observed experimentally in humans. Applying the model to the perception of multi-tap sequences, we show that the low-speed prior fits perception better than an alternative, low-acceleration prior. We discuss the applicability of our model to related tactile, visual, and auditory illusions. To facilitate future model-driven experimental studies, we present a convenient freeware computer program that implements the Bayesian observer; we invite investigators to use this program to create their own testable predictions. PMID:23675360

Goldreich, Daniel; Tong, Jonathan

2013-01-01

59

The global slowdown effect: why does perceptual grouping reduce perceived speed?  

PubMed

The percept of four rotating dot pairs is bistable. The "local percept" is of four pairs of dots rotating independently. The "global percept" is of two large squares translating over one another (Anstis & Kim 2011). We have previously demonstrated (Kohler, Caplovitz, & Tse 2009) that the global percept appears to move more slowly than the local percept. Here, we investigate and rule out several hypotheses for why this may be the case. First, we demonstrate that the global slowdown effect does not occur because the global percept is of larger objects than the local percept. Second, we show that the global slowdown effect is not related to rotation-specific detectors that may be more active in the local than in the global percept. Third, we find that the effect is also not due to a reduction of image elements during grouping and can occur with a stimulus very different from the one used previously. This suggests that the effect may reflect a general property of perceptual grouping. Having ruled out these possibilities, we suggest that the global slowdown effect may arise from emergent motion signals that are generated by the moving dots, which are interpreted as the ends of "barbell bars" in the local percept or the corners of the illusory squares in the global percept. Alternatively, the effect could be the result of noisy sources of motion information that arise from perceptual grouping that, in turn, increase the influence of Bayesian priors toward slow motion (Weiss, Simoncelli, & Adelson 2002). PMID:24448695

Kohler, Peter Jes; Caplovitz, Gideon Paul; Tse, Peter Ulric

2014-04-01

60

FoxP influences the speed and accuracy of a perceptual decision in Drosophila.  

PubMed

Decisions take time if information gradually accumulates to a response threshold, but the neural mechanisms of integration and thresholding are unknown. We characterized a decision process in Drosophila that bears the behavioral signature of evidence accumulation. As stimulus contrast in trained odor discriminations decreased, reaction times increased and perceptual accuracy declined, in quantitative agreement with a drift-diffusion model. FoxP mutants took longer than wild-type flies to form decisions of similar or reduced accuracy, especially in difficult, low-contrast tasks. RNA interference with FoxP expression in ?? core Kenyon cells, or the overexpression of a potassium conductance in these neurons, recapitulated the FoxP mutant phenotype. A mushroom body subdomain whose development or function require the transcription factor FoxP thus supports the progression of a decision toward commitment. PMID:24855268

DasGupta, Shamik; Ferreira, Clara Howcroft; Miesenböck, Gero

2014-05-23

61

Integration of Perceptual and Mnemonic Dysfunction: Sensory Auras Are Associated with Left Hemispheric Memory Impairment  

Microsoft Academic Search

Memory function during the intracarotid amobarbital test was studied to test the hypothesis that left hemisphere memory impairment is associated with sensory auras. In a series of 37 patients undergoing preoperative evaluation for epilepsy surgery, the quantitative memory scores during amobarbital inactivation of right and left hemisphere were analyzed for correlation with habitual epileptic auras classified as either (a) experiential,

Martin E. Weinand; David M. Labiner; Geoffrey L. Ahern

2001-01-01

62

Experts’ memory: an ERP study of perceptual expertise effects on encoding and recognition  

Microsoft Academic Search

This study examined how perceptual expertise facilitates encoding and recognition. The electroencephalogram of car experts\\u000a and car novices was recorded in the study as well as test phases of a remember\\/know task with car and bird stimuli. Car expertise\\u000a influenced performance and event-related potentials (ERPs) for cars but not birds. Experts recognized and “recollected” cars\\u000a more accurately, while novices had

Grit Herzmann; Tim Curran

2011-01-01

63

Memory and Processing Speed in Preterm Children at Eleven Years: A Comparison with Full-Terms.  

ERIC Educational Resources Information Center

Examined the effects of premature birth on ninety 11-year-olds' memory and processing speed, using the new Cognitive Abilities Test (CAT). Found that preterm subjects performed more poorly than their full-term counterparts on all CAT memory tasks, and that preterms were also slower on selected aspects of processing speed but not on motor speed.…

Rose, Susan A.; Feldman, Judith F.

1996-01-01

64

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

ERIC Educational Resources Information Center

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…

Nelson, Robert

2012-01-01

65

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

PubMed Central

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.

Dambacher, Michael; Hubner, Ronald; Schlosser, Jan

2011-01-01

66

Mental Fatigue Modulates Dynamic Adaptation to Perceptual Demand in Speeded Detection  

Microsoft Academic Search

When stimulus intensity in simple reaction-time tasks randomly varies across trials, detection speed usually improves after a low-intensity trial. With auditory stimuli, this improvement was often found to be asymmetric, being greater on current low-intensity trials. Our study investigated (1) whether asymmetric sequential intensity adaptation also occurs with visual stimuli; (2) whether these adjustments reflect decision-criterion shifts or, rather, a

Robert Langner; Simon B. Eickhoff; Michael B. Steinborn

2011-01-01

67

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

PubMed Central

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.

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

2014-01-01

68

Untangling perceptual memory: hysteresis and adaptation map into separate cortical networks.  

PubMed

Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain "decide" what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function). PMID:23236204

Schwiedrzik, Caspar M; Ruff, Christian C; Lazar, Andreea; Leitner, Frauke C; Singer, Wolf; Melloni, Lucia

2014-05-01

69

Perceptual Span of Poor Readersa  

Microsoft Academic Search

A model is described attributing narrow perceptual spans of poor readers to abnormally slow phonological coding speed. In a test of the model with elementary-age school boys, (1) poor readers were slower than average readers on a digit naming task; (2) perceptual span for random digits was impaired for poor readers; (3) a linear relation was found between perceptual span

Carl Spring; Robert Farmer

1975-01-01

70

Histamine H1 receptor antagonist cetirizine impairs working memory processing speed, but not episodic memory  

PubMed Central

BACKGROUND AND PURPOSE The histaminergic neurotransmitter system is currently under investigation as a target for drug treatment of cognitive deficits in clinical disorders. The therapeutic potential of new drugs may initially be screened using a model of histaminergic dysfunction, for example, as associated with the use of centrally active antihistamines. Of the selective second generation antihistamines, cetirizine has been found to have central nervous system effects. The aim of the present study was to determine whether cetirizine can be used as a tool to model cognitive deficits associated with histaminergic hypofunction. EXPERIMENTAL APPROACH The study was conducted according to a three-way, double-blind, cross-over design. Treatments were single oral doses of cetirizine 10 and 20 mg and placebo. Effects on cognition were assessed using tests of word learning, memory scanning, vigilance, divided attention, tracking and visual information processing speed. KEY RESULTS Cetirizine 10 mg impaired tracking performance and both doses impaired memory scanning speed. None of the other measures indicated impaired performance. CONCLUSION AND IMPLICATIONS Cetirizine affects information processing speed, but these effects were not sufficient to serve as a model for cognitive deficits in clinical disorders.

van Ruitenbeek, P; Vermeeren, A; Riedel, WJ

2010-01-01

71

Children's perceptual organization of seriated displays: evidence against a memory reorganization hypothesis.  

PubMed

The memory for a seriated display and its reorganization over an eight-month interval was examined in educationally subnormal children. By including groups of children who viewed a random display and an array of disordered sticks, it was found that the reorganization into a more seriated drawing after the passage of time was not directly based on the original stimulus. Various controls including copying of the original material, and matching and recognition conditions, give evidence that the child's cognitive level affects encoding of the material as well as its later output. The observed phenomenon of 'memory' improvement may have little to do with stored images, and may instead be linked to the developmental symbolic level of the child which influences original perception as well as 'memory'. It was also found that educationally subnormal children perform like normal children of the same mental age on the seriation task. PMID:326326

Cromer, R F

1977-05-01

72

A Latent Variables Examination of Processing Speed, Response Inhibition, and Working Memory during Typical Development  

ERIC Educational Resources Information Center

This study addressed three related aims: (a) to replicate and extend previous work regarding the nonunitary nature of processing speed, response inhibition, and working memory during development; (b) to quantify the rate at which processing speed, response inhibition, and working memory develop and the extent to which the development of these…

McAuley, Tara; White, Desiree A.

2011-01-01

73

The Ineluctable Modality of the Audible: Perceptual Determinants of Auditory Verbal Short-Term Memory  

ERIC Educational Resources Information Center

Classical cognitive accounts of verbal short-term memory (STM) invoke an abstract, phonological level of representation which, although it may be derived differently via different modalities, is itself amodal. Key evidence for this view is that serial recall of phonologically similar verbal items (e.g., the letter sounds "b", "c", "g", and "d") is…

Maidment, David W.; Macken, William J.

2012-01-01

74

A latent variable analysis of working memory capacity, short-term memory capacity, processing speed, and general fluid intelligence  

Microsoft Academic Search

Significant relationships exist between general fluid intelligence and each of the following constructs: short-term memory capacity, working memory capacity (WMC), and processing speed. However, the interrelationship among all four constructs has not been investigated. Multiple measures of each of these constructs were obtained from 120 healthy young adults. Structural equation modeling was then performed to determine which construct served as

Andrew R. a. Conway; Nelson Cowan; Michael F. Bunting; David J. Therriault; Scott R. b. Minkoff

2002-01-01

75

The role of speed versus working memory in predicting learning new information in multiple sclerosis.  

PubMed

The most common cognitive impairments in multiple sclerosis (MS) have been documented in specific domains, including new learning and memory, working memory, and information processing speed. However, little attempt has been made to increase our understanding of their relationship to one another. While recent studies have shown that processing speed impacts new learning and memory abilities in MS, the role of working memory in this relationship has received less attention. The present study examines the relative contribution of impaired working memory versus processing speed in new learning and memory functions in MS. Participants consisted of 51 individuals with clinically definite MS. Participants completed two measures of processing speed, two measures of working memory, and two measures of episodic memory. Data were analyzed via correlational and multiple regression analysis. Results indicate that the variance in new learning abilities in this sample was primarily associated with processing speed, with working memory exerting much less of an influence. Results are discussed in terms of the role of cognitive rehabilitation of new learning and memory abilities in persons with MS. PMID:23350959

Chiaravalloti, Nancy D; Stojanovic-Radic, Jelena; DeLuca, John

2013-01-01

76

Distinct Effects of Perceptual Quality on Auditory Word Recognition, Memory Formation and Recall in a Neural Model of Sequential Memory  

PubMed Central

Adults with sensory impairment, such as reduced hearing acuity, have impaired ability to recall identifiable words, even when their memory is otherwise normal. We hypothesize that poorer stimulus quality causes weaker activity in neurons responsive to the stimulus and more time to elapse between stimulus onset and identification. The weaker activity and increased delay to stimulus identification reduce the necessary strengthening of connections between neurons active before stimulus presentation and neurons active at the time of stimulus identification. We test our hypothesis through a biologically motivated computational model, which performs item recognition, memory formation and memory retrieval. In our simulations, spiking neurons are distributed into pools representing either items or context, in two separate, but connected winner-takes-all (WTA) networks. We include associative, Hebbian learning, by comparing multiple forms of spike-timing-dependent plasticity (STDP), which strengthen synapses between coactive neurons during stimulus identification. Synaptic strengthening by STDP can be sufficient to reactivate neurons during recall if their activity during a prior stimulus rose strongly and rapidly. We find that a single poor quality stimulus impairs recall of neighboring stimuli as well as the weak stimulus itself. We demonstrate that within the WTA paradigm of word recognition, reactivation of separate, connected sets of non-word, context cells permits reverse recall. Also, only with such coactive context cells, does slowing the rate of stimulus presentation increase recall probability. We conclude that significant temporal overlap of neural activity patterns, absent from individual WTA networks, is necessary to match behavioral data for word recall.

Miller, Paul; Wingfield, Arthur

2010-01-01

77

High-speed all-optical long-term memory using SOA MZIs: Simulation and experiment  

NASA Astrophysics Data System (ADS)

We propose and demonstrate a novel all-optical memory to store high-speed optical data for long term. The key elements of the memory are Mach-Zehnder Interferometers (MZIs) incorporating semiconductor optical amplifiers (SOAs), acting as AND gate and regenerator in a loop configuration. The simulations show that the memory can be operated up to 80 Gb/s. In addition, the memory was demonstrated at 21.3 Gb/s.

Yang, Xuelin; Weng, Qiwei; Hu, Weisheng

2012-09-01

78

Processing speed versus working memory: contributions to an information-processing task in multiple sclerosis.  

PubMed

Individuals with multiple sclerosis (MS) often experience cognitive impairments in information processing. However, the relative contributions of processing speed abilities and working memory abilities to information-processing tasks are not yet fully understood. The current study examined the extent to which processing speed and/or working memory abilities contributed to an information-processing task, the Keeping Track Task (KTT). Forty-nine individuals with MS were given tests to assess processing speed and working memory, as well as the KTT. Regression analyses indicated that in the MS group, processing speed abilities accounted for the majority of the explained variance in KTT performance. The findings suggest that processing speed plays a significant role on KTT performance in MS. Implications for cognitive rehabilitation treatments aimed at improving processing speed abilities in MS are discussed. PMID:23373581

Genova, Helen M; Lengenfelder, Jeannie; Chiaravalloti, Nancy D; Moore, Nancy B; DeLuca, John

2012-01-01

79

Memory effects in speed-changing collisions and their consequences for spectral line shape  

Microsoft Academic Search

The kinetic model accounting for speed-memory effects on the spectral line shape proposed in I [D. Robert, L. Bonamy, Eur. Phys. J. D 2, 245 (1998)] is extended for any density range, within the binary collision framework. The additional Doppler contribution requires to consider the 3D velocity-memory function instead of the 1D speed one, with distinct treatments for the velocity-orientation

L. Bonamy; H. Tran Thi Ngoc; P. Joubert; D. Robert

2004-01-01

80

Children's Arithmetical Difficulties: Contributions from Processing Speed, Item Identification, and Short-Term Memory  

Microsoft Academic Search

Children's arithmetical difficulties are often explained in terms of a short-term memory deficit. However, the underlying cause of this memory deficit is unclear, with some researchers suggesting a slow articulation rate and hence increased decay of information during recall, while others offer an explanation in terms of slow speed of item identification, indicating difficulty in retrieving information stored in long-term

Rebecca Bull; Rhona S. Johnston

1997-01-01

81

Predictors of memory and processing speed dysfunctions after traumatic brain injury.  

PubMed

Background. The aims of this study were to evaluate the predictive value of admission Glasgow Coma Scale (GCS) scores, duration of unconsciousness, neurosurgical intervention, and countercoup lesion on the impairment of memory and processing speed functions six months after a traumatic brain injury (TBI) based on a structural equation modeling. Methods. Thirty TBI patients recruited from Neurosurgical Department at the Kaohsiung Medical University Hospital were administered the Wechsler Memory Scale-III (WMS-III) and the Wechsler Adult Intelligence Scale-III processing speed index to evaluate the memory and processing speed functions. Results. The study showed that GCS scores accounted for 40% of the variance in memory/processing speed. No significant predictive effects were found for the other three variables. GCS classification at the time of TBI seems to correspond moderately to the severity of memory/processing speed dysfunctions. Conclusions. The present study demonstrated that admission GCS score is a robust predictor of memory/processing speed dysfunctions after TBI. The results should be replicated with a large sample of patients with TBI, or be extended by examining other potential clinical predictors. PMID:24877054

Winardi, William; Kwan, Aij-Lie; Wang, Tse-Lun; Su, Yu-Feng; Yen, Chun-Po; Tsai, Hung-Pei; Sheehan, Jason; Su, Chwen-Yng

2014-01-01

82

Predictors of Memory and Processing Speed Dysfunctions after Traumatic Brain Injury  

PubMed Central

Background. The aims of this study were to evaluate the predictive value of admission Glasgow Coma Scale (GCS) scores, duration of unconsciousness, neurosurgical intervention, and countercoup lesion on the impairment of memory and processing speed functions six months after a traumatic brain injury (TBI) based on a structural equation modeling. Methods. Thirty TBI patients recruited from Neurosurgical Department at the Kaohsiung Medical University Hospital were administered the Wechsler Memory Scale-III (WMS-III) and the Wechsler Adult Intelligence Scale-III processing speed index to evaluate the memory and processing speed functions. Results. The study showed that GCS scores accounted for 40% of the variance in memory/processing speed. No significant predictive effects were found for the other three variables. GCS classification at the time of TBI seems to correspond moderately to the severity of memory/processing speed dysfunctions. Conclusions. The present study demonstrated that admission GCS score is a robust predictor of memory/processing speed dysfunctions after TBI. The results should be replicated with a large sample of patients with TBI, or be extended by examining other potential clinical predictors.

Winardi, William; Kwan, Aij-Lie; Wang, Tse-Lun; Su, Yu-Feng; Yen, Chun-Po; Tsai, Hung-Pei; Sheehan, Jason; Su, Chwen-Yng

2014-01-01

83

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

PubMed Central

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.

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

84

The Effects of Alcohol on the Speed of Memory Retrieval.  

ERIC Educational Resources Information Center

Recent research has clearly indicated that intoxication with alcohol impairs memory. The present study investigated the effects of alcohol on retrieval from long-term memory by using a set of cognitive decision tasks. Subjects (N=24) were female college students in good health not taking oral contraceptives. Subjects were administered 0 or 1.0…

Stempel, Jennifer J.; And Others

85

Perceptual Constraints in Phonotactic Learning  

ERIC Educational Resources Information Center

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

Endress, Ansgar D.; Mehler, Jacques

2010-01-01

86

Neural correlates of the difference between working memory speed and simple sensorimotor speed: an fMRI study.  

PubMed

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

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

2012-01-01

87

Common Genetic Factors Influence Hand Strength, Processing Speed, and Working Memory  

PubMed Central

Background It is important to detect cognitive decline at an early stage, especially before onset of mild cognitive impairment and dementia. Processing speed and working memory are aspects of cognitive function that are associated with cognitive decline. Hand strength is an inexpensive, easily measurable indicator of cognitive decline. However, associations between hand strength, processing speed, and working memory have not been studied. In addition, the genetic and environmental structure of the association between hand strength and cognitive decline is unclear. We investigated phenotypic associations between hand strength, processing speed, and working memory and examined the genetic and environmental structure of the associations between phenotypes. Methods Hand strength, processing speed (digit symbol performance), and working memory (digit span performance) were examined in monozygotic and dizygotic twin pairs. Generalized estimating equations were used to identify phenotypic associations, and structural equation modeling was used to investigate the genetic and environmental structure of the association. Results Generalized estimating equations showed that hand strength was phenotypically associated with digit symbol performance but not with digit span performance. Structural equation modeling showed that common genetic factors influenced hand strength and digit symbol and digit span performance. Conclusions There was a phenotypic association between hand strength and processing speed. In addition, some genetic factors were common to hand strength, processing speed, and working memory.

Ogata, Soshiro; Kato, Kenji; Honda, Chika; Hayakawa, Kazuo

2014-01-01

88

Tightly coupled multiprocessor system speeds memory-access times  

Microsoft Academic Search

A tightly coupled architecture of multiple processors automates the functions of expansion, system tuning, load balancing and data-base distribution-a major part of designing and implementing online systems. To reduce memory-access times significantly, the n+1 multiprocessor system for fault-tolerant transaction processing also combines individual cache memories for each processor with a data-sharing scheme. Thus it overcomes the problems which have prevented

S. J Frank

1984-01-01

89

A Perceptual Repetition Blindness Effect  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

90

Intelligence and the Effects of Perceptual Processing Demands, Task Difficulty, and Processing Speed on P300, Reaction Time and Movement Time.  

ERIC Educational Resources Information Center

The latency and amplitude of the P300, an event-related potential, during the performance of a memory-scanning task were used as indices of the efficiency of information processing that may mediate individual differences in intelligence. Results with 61 female college students contradict a pure speed of processing explanation of the relationship…

Houlihan, Michael; Stelmack, Robert; Campbell, Kenneth

1998-01-01

91

Working memory and speed of information processing in chronic khat users: preliminary findings.  

PubMed

To date there are very few laboratory data available regarding the long-term effect of the psychostimulant khat on human neurocognitive functioning. The purpose of the present study was to assess whether chronic khat users would demonstrate impairments in working memory and speed of information processing compared to control subjects. Working memory was assessed using the forward and backward digit span test. Speed of information processing was assessed using the Digit Symbol Substitution Test. Results of the present study indicate that chronic khat use may have a long-term deleterious effect on working memory, particularly on digit backwards measures of short-term/working memory. The finding is consistent with results seen by several investigators in samples of methamphetamine users. PMID:22948202

Hoffman, Richard; al'Absi, Mustafa

2013-01-01

92

A simple and accurate method for measuring program/erase speed in a memory capacitor structure  

NASA Astrophysics Data System (ADS)

With the merits of a simple process and a short fabrication period, the capacitor structure provides a convenient way to evaluate memory characteristics of charge trap memory devices. However, the slow minority carrier generation in a capacitor often makes an underestimation of the program/erase speed. In this paper, illumination around a memory capacitor is proposed to enhance the generation of minority carriers so that an accurate measurement of the program/erase speed can be achieved. From the dependence of the inversion capacitance on frequency, a time constant is extracted to quantitatively characterize the formation of the inversion layer. Experimental results show that under a high enough illumination, this time constant is greatly reduced and the measured minority carrier-related program/erase speed is in agreement with the reported value in a transistor structure.

Jin, Lin; Zhang, Man-Hong; Huo, Zong-Liang; Wang, Yong; Yu, Zhao-An; Jiang, Dan-Dan; Chen, Jun-Ning; Liu, Ming

2013-01-01

93

Perceptual-Gestural (Mis)Mapping in Serial Short-Term Memory: The Impact of Talker Variability  

ERIC Educational Resources Information Center

The mechanisms underlying the poorer serial recall of talker-variable lists (e.g., alternating female-male voices) as compared with single-voice lists were examined. We tested the novel hypothesis that this "talker variability effect" arises from the tendency for perceptual organization to partition the list into streams based on voice such that…

Hughes, Robert W.; Marsh, John E.; Jones, Dylan M.

2009-01-01

94

Perceptual Repetition Blindness Effects  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

95

Effects of Age, Speed of Processing, and Working Memory on Comprehension of Sentences With Relative Clauses  

Microsoft Academic Search

Two hundred participants, 50 in each of four age ranges (19–29, 30–49, 50–69, 70–90) were tested for working memory, speed of processing, and the processing of sentences with relative clauses. In Experiment 1, participants read four sentence types (cleft subject, cleft object, subject-subject, subject-object) in a word-by-word, non-cumulative, self-paced reading task and made speeded plausibility judgments about them. In Experiment

David Caplan; Gayle DeDe; Gloria Waters; Jennifer Michaud; Yorghos Tripodis

2011-01-01

96

Perceptual Bandwidth  

Microsoft Academic Search

n the study of human-computer interaction, one of the two words surrounding the hyphen usually leads. Perceptual interfaces from the perspective of computers signal an interest in machines that can accomplish human-like sen- sory tasks. But it's the machines that do the perceiving. There may be clues in the science of human perception about how to automate perceptual tasks, but

Byron Reeves; Clifford Nass

2000-01-01

97

Relationships among processing speed, working memory, and fluid intelligence in children  

Microsoft Academic Search

The present review focuses on three issues, (a) the time course of developmental increases in cognitive abilities; (b) the impact of age on individual differences in these abilities, and (c) the mechanisms by which developmental increases in different aspects of cognition affect each other. We conclude from our review of the literature that the development of processing speed, working memory,

Astrid F. Fry; Sandra Hale

2000-01-01

98

The relative contributions of processing speed and cognitive load to working memory accuracy in multiple sclerosis.  

PubMed

Cognitive symptoms of multiple sclerosis (MS) include processing-speed deficits and working memory impairment. The precise manner in which these deficits interact in individuals with MS remains to be explicated. We hypothesized that providing more time on a complex working memory task would result in performance benefits for individuals with MS relative to healthy controls. Fifty-three individuals with clinically definite MS and 36 matched healthy controls performed a computerized task that systematically manipulated cognitive load. The interval between stimuli presentations was manipulated to provide increasing processing time. The results confirmed that individuals with MS who have processing-speed deficits significantly improve in performance accuracy when given additional time to process the information in working memory. Implications of these findings for developing appropriate cognitive rehabilitation interventions are discussed. PMID:21229437

Leavitt, Victoria M; Lengenfelder, Jean; Moore, Nancy B; Chiaravalloti, Nancy D; DeLuca, John

2011-06-01

99

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

PubMed

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

Zhang, Jiaxiang; Rowe, James B

2014-01-01

100

High-speed memory from carbon nanotube field-effect transistors with high-kappa gate dielectric.  

PubMed

We demonstrate 100 ns write/erase speed of single-walled carbon nanotube field-effect transistor (SWCNT-FET) memory elements. With this high operation speed, SWCNT-FET memory elements can compete with state of the art commercial Flash memories in this figure of merit. The endurance of the memory elements is shown to exceed 104 cycles. The SWCNT-FETs have atomic layer deposited hafnium oxide as a gate dielectric, and the devices are passivated by another hafnium oxide layer in order to reduce surface chemistry effects. We discuss a model where the hafnium oxide has defect states situated above, but close in energy to, the band gap of the SWCNT. The fast and efficient charging and discharging of these defects is a likely explanation for the observed operation speed of 100 ns which greatly exceeds the SWCNT-FET memory speeds of 10 ms observed earlier for devices with conventional gate oxides. PMID:19152310

Rinkiö, Marcus; Johansson, Andreas; Paraoanu, G S; Törmä, Päivi

2009-02-01

101

Working Memory, Short-Term Memory, and Naming Speed as Predictors of Children's Mathematical Performance  

ERIC Educational Resources Information Center

Working memory (WM) has been associated with the acquisition of arithmetic skills, however, the components of WM that underlie this acquisition have not been explored. This study explored the contribution of two WM systems (the phonological loop and the central executive) to mathematical performance in young children. The results showed that a…

Swanson, Lee; Kim, Kenny

2007-01-01

102

High-Speed Magnetoresistive Random-Access Memory Random Number Generator Using Error-Correcting Code  

NASA Astrophysics Data System (ADS)

A high-speed random number generator (RNG) circuit based on magnetoresistive random-access memory (MRAM) using an error-correcting code (ECC) post processing circuit is presented. ECC post processing increases the quality of randomness by increasing the entropy of random number. We experimentally show that a small error-correcting capability circuit is sufficient for this post processing. It is shown that the ECC post processing circuit powerfully improves the quality of randomness with minimum overhead, ending up with high-speed random number generation. We also show that coupling with a linear feedback shift resistor is effective for improving randomness.

Tanamoto, Tetsufumi; Shimomura, Naoharu; Ikegawa, Sumio; Matsumoto, Mari; Fujita, Shinobu; Yoda, Hiroaki

2011-04-01

103

Distributed Shared-Memory for a Workstation Cluster with a High Speed Serial Interface  

Microsoft Academic Search

In this paper, we introduce a distributed shared-memory system with a high speed serial communication interface called STAFF-Link. STAFF-Link is adopted in massively parallel computer JUMP-1 as I\\/O links between processing elements and an I\\/O subsystem consisting of many I\\/O units as well as an I\\/O network among I\\/O units. In this project, we have designed and manufacutured a STAFF-Link

Hironori Nakajo; Hidekazu Tanaka; Yoshinori Nakanishi; Masaki Kohata; Yukio Kaneda

1998-01-01

104

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

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…

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

2008-01-01

105

Cycles in Speed-Working Memory-G Relations: Towards a Developmental-Differential Theory of the Mind  

ERIC Educational Resources Information Center

This article presents three studies, two of them longitudinal, which investigated the relations between age, processing speed, working memory (WM), and fluid intelligence ("g[subscript f]") from 4 to 16 years of age. Structural equation modeling showed that speed was a powerful covariate of age ([approximately] - 0.6 to - 0.7) from 4 to 13 years,…

Demetriou, Andreas; Spanoudis, George; Shayer, Michael; Mouyi, Antigoni; Kazi, Smaragda; Platsidou, Maria

2013-01-01

106

A novel 2 T P-channel nano-crystal memory for low power/high speed embedded NVM applications  

NASA Astrophysics Data System (ADS)

We introduce a novel 2 T P-channel nano-crystal memory structure for low power and high speed embedded non-volatile memory (NVM) applications. By using the band-to-band tunneling-induced hot-electron (BTBTIHE) injection scheme, both high-speed and low power programming can be achieved at the same time. Due to the use of a select transistor, the “erased states" can be set to below 0 V, so that the periphery HV circuit (high-voltage generating and management) and read-out circuit can be simplified. Good memory cell performance has also been achieved, including a fast program/erase (P/E) speed (a 1.15 V memory window under 10 ?s program pulse), an excellent data retention (only 20% charge loss for 10 years). The data shows that the device has strong potential for future embedded NVM applications.

Junyu, Zhang; Yong, Wang; Jing, Liu; Manhong, Zhang; Zhongguang, Xu; Zongliang, Huo; Ming, Liu

2012-08-01

107

Lisdexamfetamine dimesylate improves processing speed and memory in cognitively impaired MS patients: a phase II study.  

PubMed

Multiple sclerosis (MS) causes cognitive impairment including slowed processing speed and problems with learning and memory. Stimulants are attractive candidates for improving mental speed but carry risk of addiction and other adverse behavioral effects. Lisdexamfetamine dimesylate (LDX) is a D-amphetamine prodrug currently approved for attention deficit (hyperactivity) disorder with the potential to be better tolerated due to its prolonged clinical effect. This phase II placebo-controlled, double-blind study aimed to assess the safety and efficacy of LDX in cognitively impaired MS patients. Subjects were patients with clinically definite MS, aged 18-56 years, and impaired on either of two primary outcomes: the Symbol Digit Modalities Test (SDMT) or the Paced Auditory Serial Addition Test (PASAT). Both SDMT and PASAT are measures of cognitive processing speed. Of 174 MS patients screened, 63 were randomized to 30 mg of LDX or placebo in a 2:1 fashion; the dose was increased as tolerated to 70 mg over 4 weeks and then maintained for another 4 weeks. Secondary outcomes were the Brief Visuospatial Memory Test Revised (BVMTR), the California Verbal Learning Test 2nd edition (CVLT2), both measures of episodic memory, and the Behavioral Rating Inventory of Executive Function for adults (BRIEF-A), a self-report measure of executive function. Fatigue and depression were also evaluated. There was significant improvement in the SDMT score (+4.6 vs. +1.3) and CVLT2 score (+4.7 vs. -0.9) in the LDX group compared with the placebo group among the 49 completers. There was no change on the other outcomes. A high proportion of both LDX-treated and placebo-treated subjects reported adverse events (73.5 % vs. 68.4 %). However, there were no serious adverse events noted in the study. These preliminary data indicate that LDX has the potential to be an efficacious treatment for MS patients with cognitive impairment. PMID:23001556

Morrow, Sarah A; Smerbeck, Audrey; Patrick, Kara; Cookfair, Diane; Weinstock-Guttman, Bianca; Benedict, Ralph H B

2013-02-01

108

Visual Perceptual Learning  

PubMed Central

Perceptual learning refers to the phenomenon that practice or training in perceptual tasks often substantially improves perceptual performance. Often exhibiting stimulus or task specificities, perceptual learning differs from learning in the cognitive or motor domains. Research on perceptual learning reveals important plasticity in adult perceptual systems, and as well as the limitations in the information processing of the human observer. In this article, we review the behavioral results, mechanisms, physiological basis, computational models, and applications of visual perceptual learning.

Lu, Zhong-Lin; Hua, Tianmiao; Huang, Chang-Bing; Zhou, Yifeng; Dosher, Barbara Anne

2010-01-01

109

Perceptual learning: Top to bottom.  

PubMed

Perceptual learning has traditionally been portrayed as a bottom-up phenomenon that improves encoding or decoding of the trained stimulus. Cognitive skills such as attention and memory are thought to drive, guide and modulate learning but are, with notable exceptions, not generally considered to undergo changes themselves as a result of training with simple perceptual tasks. Moreover, shifts in threshold are interpreted as shifts in perceptual sensitivity, with no consideration for non-sensory factors (such as response bias) that may contribute to these changes. Accumulating evidence from our own research and others shows that perceptual learning is a conglomeration of effects, with training-induced changes ranging from the lowest (noise reduction in the phase locking of auditory signals) to the highest (working memory capacity) level of processing, and includes contributions from non-sensory factors that affect decision making even on a "simple" auditory task such as frequency discrimination. We discuss our emerging view of learning as a process that increases the signal-to-noise ratio associated with perceptual tasks by tackling noise sources and inefficiencies that cause performance bottlenecks, and present some implications for training populations other than young, smart, attentive and highly-motivated college students. PMID:24296314

Amitay, Sygal; Zhang, Yu-Xuan; Jones, Pete R; Moore, David R

2014-06-01

110

Perceptual telerobotics  

NASA Technical Reports Server (NTRS)

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.

Ligomenides, Panos A.

1989-01-01

111

Perceptual transparency  

NASA Astrophysics Data System (ADS)

We suggest that color constancy and perceptual transparency might be explained by the same underlying mechanism. For color constancy, Foster and Nascimento (1994) found that cone-excitation ratios between surfaces seen under one illuminant and cone-excitation ratios between the same surfaces seen under a different illuminant were almost constant. In the case of perceptual transparency we also found that cone-excitation ratios between surfaces illuminated directly and cone-excitation ratios between the same surfaces seen through a transparent filter were almost invariant (Westland and Ripamonti, 2000). We compare the ability of the cone-excitation-ratio invariance model to predict perceptual transparency with an alternative model based on convergence in color space (D'Zmura et al., 1997). Psychophysical data are reported from experiments where by subjects were asked to select which of two stimuli represented a Mondrian image partially covered by a homogeneous transparent filter. One of the stimuli was generated from the convergence model and the other was a modified version of the first stimulus such that the cone- excitation ratios were perfectly invariant. Subjects consistently selected the invariant stimulus confirming our hypothesis that perception of transparency is predicted by the degree of deviation frm an invariant ratio for the cone excitations.

Ripamonti, Caterina; Westland, Stephen

2002-06-01

112

Intensive video gaming improves encoding speed to visual short-term memory in young male adults.  

PubMed

The purpose of this study was to measure the effect of action video gaming on central elements of visual attention using Bundesen's (1990) Theory of Visual Attention. To examine the cognitive impact of action video gaming, we tested basic functions of visual attention in 42 young male adults. Participants were divided into three groups depending on the amount of time spent playing action video games: non-players (<2h/month, N=12), casual players (4-8h/month, N=10), and experienced players (>15h/month, N=20). All participants were tested in three tasks which tap central functions of visual attention and short-term memory: a test based on the Theory of Visual Attention (TVA), an enumeration test and finally the Attentional Network Test (ANT). The results show that action video gaming does not seem to impact the capacity of visual short-term memory. However, playing action video games does seem to improve the encoding speed of visual information into visual short-term memory and the improvement does seem to depend on the time devoted to gaming. This suggests that intense action video gaming improves basic attentional functioning and that this improvement generalizes into other activities. The implications of these findings for cognitive rehabilitation training are discussed. PMID:23261420

Wilms, Inge L; Petersen, Anders; Vangkilde, Signe

2013-01-01

113

Design of gate stacks for improved program/erase speed, retention and process margin aiming next generation metal nanocrystal memories  

NASA Astrophysics Data System (ADS)

In this work, gate stacks in metal nanocrystal (NC) memories, as promising next generation storage devices and their systems, are extensively investigated. A comparative analysis and characterization of the program/erase (P/E) speed, retention and the process margin of cobalt NC memories including high-k and bandgap engineering technologies are performed by using the technology computer-aided design (TCAD) simulation. It is shown that NC memory with high-k dielectric (HfO2) has better performance in P/E speed and retention when the diameter of NC is below 5 nm. When the diameter is beyond 5 nm, on the other hand, the bandgap-engineered bottom oxide gate structure shows improved performance in P/E speed and retention. From the process margin perspective, as the permittivity of the dielectric gets larger, the limits of the diameter and the density of NCs allow the degree of freedom to become larger.

Jang, Jaeman; Choi, Changmin; Lee, Jang-Sik; Min, Kyeong-Sik; Lee, Jaegab; Kim, Dong Myong; Kim, Dae Hwan

2009-11-01

114

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

PubMed Central

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.

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

2012-01-01

115

Self-construal priming affects speed of retrieval from short-term memory.  

PubMed

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

Macdonald, Justin A; Sandry, Joshua; Rice, Stephen

2012-01-01

116

Visual prediction and perceptual expertise  

PubMed Central

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.

Cheung, Olivia S.; Bar, Moshe

2012-01-01

117

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

Microsoft Academic Search

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

Daniel Zimprich; Tanja Kurtz

2012-01-01

118

Depressive symptoms account for deficient information processing speed but not for impaired working memory in early phase multiple sclerosis (MS)  

Microsoft Academic Search

Depressive symptoms may influence neuropsychological functioning negatively. A substantial proportion of multiple sclerosis (MS) patients exhibit neuropsychological impairments and depressive symptomatology is more common in MS as compared to healthy controls and to other neurological diseases. The objectives of the present study were to assess information processing speed, working memory and executive functions in early phase MS and to investigate

Nils Inge Landrø; Elisabeth Gulowsen Celius; Helge Sletvold

2004-01-01

119

Processing Speed, Inhibitory Control, and Working Memory: Three Important Factors to Account for Age-Related Cognitive Decline  

ERIC Educational Resources Information Center

Processing speed, inhibitory control and working memory have been identified as the main possible culprits of age-related cognitive decline. This article describes a study of their interrelationships and dependence on age, including exploration of whether any of them mediates between age and the others. We carried out a LISREL analysis of the…

Pereiro Rozas, Arturo X.; Juncos-Rabadan, Onesimo; Gonzalez, Maria Soledad Rodriguez

2008-01-01

120

[Memory systems and memory disorders].  

PubMed

Recent cognitive models suggest that memory has a complex structure, composed of several independent systems (working memory, and four long-term memory systems: episodic memory, semantic memory, perceptual representation system, and procedural memory). Furthermore, neuropsychological studies show that a brain lesion can selectively impair some systems or some particular process in a system, while others are spared. In this theoretical context, the objective of assessment is to detect the impaired memory systems and processes as well as those, which remain intact. To do this, the clinician has to use various-tests specifically designed to assess the integrity of each memory system and process. PMID:12708274

Van der Linden, Martial; Juillerat, Anne-Claude

2003-02-15

121

Stochastic accumulation of feature information in perception and memory  

PubMed Central

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.

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

2014-01-01

122

Working Memory and Arithmetic Calculation in Children: The Contributory Roles of Processing Speed, Short-Term Memory, and Reading  

ERIC Educational Resources Information Center

The cognitive underpinnings of arithmetic calculation in children are noted to involve working memory; however, cognitive processes related to arithmetic calculation and working memory suggest that this relationship is more complex than stated previously. The purpose of this investigation was to examine the relative contributions of processing…

Berg, Derek H.

2008-01-01

123

Memory bias does not generalize across anxiety disorders.  

PubMed

Individuals with social phobia were compared with normal controls on their memory for socially-related threat words in contrast to positive and neutral words. A memory paradigm used in a previous study of panic disorder patients [Cloitre, M. & Liebowitz, M. R. (1991) Cognitive Therapy and Research, 15, 609-619] was applied to test the generalizability of findings of threat-biased memory in a semantic memory task (free recall) and a perceptual memory task (high-speed recognition) to social phobics. No evidence of threat-related memory bias among social phobics was obtained. Since both the social phobic and control groups showed better memory for affectively valenced (threat and positive) compared to neutral information, it is unlikely that the absence of threat-biased memory among social phobics was the result of insensitive measurement. PMID:7726806

Cloitre, M; Cancienne, J; Heimberg, R G; Holt, C S; Liebowitz, M

1995-03-01

124

Perceptual asynchrony for motion  

PubMed Central

Psychophysical experiments show that two different visual attributes, color and motion, processed in different areas of the visual brain, are perceived at different times relative to each other (Moutoussis and Zeki, 1997a). Here we demonstrate psychophysically that two variants of the same attribute, motion, which have the same temporal structure and are processed in the same visual areas, are also processed asynchronously. When subjects were asked to pair up–down motion of dots in one half of their hemifield with up-right motion in the other, they perceived the two directions of motion asynchronously, with the advantage in favor of up-right motion; when they were asked to pair the motion of white dots moving against a black background with that of red dots moving against an equiluminant green background, they perceived the luminant motion first, thus demonstrating a perceptual advantage of luminant over equiluminant motion. These results were not affected by motion speed or perceived motion “streaks.” We thus interpret these results to reflect the different processing times produced by luminant and equiluminant motion stimuli or by different degrees of motion direction change, thus adding to the evidence that processing time within the visual system is a major determinant of perceptual time.

Lo, Yu Tung; Zeki, Semir

2014-01-01

125

High-speed and localized resistive switching characteristics of double-layer SrZrO3 memory devices  

NASA Astrophysics Data System (ADS)

The fabrication of SrZrO3 (SZO) memory devices with oxygen-rich (OR) and oxygen-deficient (OD) double layers, their resistive switching (RS) characteristics and mechanisms are investigated in this study. Due to the difference in oxygen content between the OR and OD layers formed by an oxygen flow control (OFC) process during SZO deposition, the RS region is effectively reduced and localized within the OR layer, which leads to a low operation voltage and stable RS behaviours. Furthermore, the OFC SZO device exhibits high-speed switching (10 ns) over 400 times and long retention (>106 s), showing promising potential for next-generation nonvolatile memory applications.

Lin, Meng-Han; Wu, Ming-Chi; Huang, Chun-Yang; Lin, Chen-Hsi; Tseng, Tseung-Yuen

2010-07-01

126

Memory  

NSDL National Science Digital Library

Our memory must b exercised in order for it to function properly. Click on Memory Exhibition, then click on droodles and common cents. Memory Exhibition Now play the memory game Memory game Take this test Short Term Memory Test Play Simon Says Play Simon Says 2 ...

Hirschi, Mrs.

2005-10-25

127

Distinction between Perceptual and Attentional Processing in Working Memory Tasks: A Study of Phase-locked and Induced Oscillatory Brain Dynamics  

Microsoft Academic Search

Working memory involves the short-term storage and manipulation of information necessary for cognitive performance, including comprehension, learning, reasoning and planning. Although electroencephalogram (EEG) rhythms are modulated during working memory, the temporal relationship of EEG oscillations with the eliciting event has not been well studied. In particular, the dynamics of the neural network supporting memory processes may be best captured in

Marie-pierre Deiber; Pascal Missonnier; Olivier Bertrand; Gabriel Gold; Lara Fazio-costa; Vicente Ibañez; Panteleimon Giannakopoulos

2007-01-01

128

An ultrahigh-speed color video camera operating at 1,000,000 fps with 288 frame memories  

NASA Astrophysics Data System (ADS)

We developed an ultrahigh-speed color video camera that operates at 1,000,000 fps (frames per second) and had capacity to store 288 frame memories. In 2005, we developed an ultrahigh-speed, high-sensitivity portable color camera with a 300,000-pixel single CCD (ISIS-V4: In-situ Storage Image Sensor, Version 4). Its ultrahigh-speed shooting capability of 1,000,000 fps was made possible by directly connecting CCD storages, which record video images, to the photodiodes of individual pixels. The number of consecutive frames was 144. However, longer capture times were demanded when the camera was used during imaging experiments and for some television programs. To increase ultrahigh-speed capture times, we used a beam splitter and two ultrahigh-speed 300,000-pixel CCDs. The beam splitter was placed behind the pick up lens. One CCD was located at each of the two outputs of the beam splitter. The CCD driving unit was developed to separately drive two CCDs, and the recording period of the two CCDs was sequentially switched. This increased the recording capacity to 288 images, an increase of a factor of two over that of conventional ultrahigh-speed camera. A problem with the camera was that the incident light on each CCD was reduced by a factor of two by using the beam splitter. To improve the light sensitivity, we developed a microlens array for use with the ultrahigh-speed CCDs. We simulated the operation of the microlens array in order to optimize its shape and then fabricated it using stamping technology. Using this microlens increased the light sensitivity of the CCDs by an approximate factor of two. By using a beam splitter in conjunction with the microlens array, it was possible to make an ultrahigh-speed color video camera that has 288 frame memories but without decreasing the camera's light sensitivity.

Kitamura, K.; Arai, T.; Yonai, J.; Hayashida, T.; Kurita, T.; Maruyama, H.; Namiki, J.; Yanagi, T.; Yoshida, T.; van Kuijk, H.; Bosiers, Jan T.; Saita, A.; Kanayama, S.; Hatade, K.; Kitagawa, S.; Etoh, T. Goji

2008-11-01

129

Animacy, perceptual load, and inattentional blindness.  

PubMed

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

Calvillo, Dustin P; Jackson, Russell E

2014-06-01

130

Tradeoff Between Complexity and Memory Size in the 3GPP Enhanced aacPlus Decoder: Speed-Conscious and Memory-Conscious Decoders on a 16Bit Fixed-Point DSP  

Microsoft Academic Search

This paper investigates tradeoff between complexity and memory size (speed-memory tradeoff) in the 3GPP enhanced aacPlus decoder\\u000a based on a 16-bit fixed-point DSP implementation. In order to investigate this tradeoff, the speed- and the memory-conscious\\u000a decoders are implemented. The maximum number of operations for the implemented speed-conscious decoder is 29.3 million cycles\\u000a per second (MCPS) for a 32 kb\\/s bitstream. The

Osamu Shimada; Toshiyuki Nomura; Akihiko Sugiyama; Masahiro Serizawa

2009-01-01

131

Response-Time Approach to Contrasting Models of Perceptual Classification.  

National Technical Information Service (NTIS)

The long-term objective of this work is the development of general computational models of human perceptual classification and memory. An important goal is to develop and test models that explain the time course of classification and recognition decision ...

R. Nosofsky

2013-01-01

132

Electrical modeling and analysis of lead-bonded and wire-bonded ?BGA® packages for high-speed memory applications  

Microsoft Academic Search

Lead-bonded ?BGA (?BGA®) and wire-bonded ?BGA (?BGA®-W) packages with flex- and laminate-based substrates have been developed for high-speed memory devices. This work presents the inductance, capacitance, and resistance values for lead-bonded and wire-bonded ?BGA packages obtained from simulation study to demonstrate and compare their electrical performance. The effect of the bonding technology (lead or wire bond), die-shrink and the type

Byong-Su Seol; L. Elliott Pflughaupt

2002-01-01

133

Polymorphisms in the Brain-Derived Neurotrophic Factor Gene Influence Memory and Processing Speed One Month after Brain Injury  

PubMed Central

Abstract Brain-derived neurotrophic factor (BDNF) plays a role in cognition, as well as neural survival and plasticity. There are several common polymorphisms in the BDNF gene, one of which (rs6265) is an extensively studied non-synonymous coding polymorphism (Val66Met) which has been linked to cognitive performance in healthy controls and some clinical populations. We hypothesized that the Met allele of rs6265 would be associated with poorer cognitive performance in individuals with mild-to-moderate traumatic brain injury, and that other polymorphisms in the BDNF gene would also affect cognition. Genotype at 9 single-nucleotide polymorphisms (SNPs) in the BDNF gene, and measures of speed of information processing, learning, and memory were assessed in 75 patients with mTBI and 38 healthy subjects. Consistent with previous reports, the Met allele of rs6265 was associated with cognition (slower processing speed) in the entire group. Two other SNPs were associated with processing speed in the mTBI group, but both are in linkage disequilibrium with rs6265, and neither remained significant after adjustment for rs6265 status. Within the mTBI group, but not the controls, 4 SNPs, but not rs6265, were associated with memory measures. These associations were not affected by adjustment for rs6265 status. Polymorphisms in BDNF influence cognitive performance shortly after mTBI. The results raise the possibility that a functional polymorphism other than rs6265 may contribute to memory function after mTBI.

Tyler, Anna L.; Flashman, Laura A.; Rhodes, C. Harker; McDonald, Brenna C.; Saykin, Andrew J.; Tosteson, Tor D.; Tsongalis, Gregory J.; Moore, Jason H.

2012-01-01

134

Polymorphisms in the brain-derived neurotrophic factor gene influence memory and processing speed one month after brain injury.  

PubMed

Brain-derived neurotrophic factor (BDNF) plays a role in cognition, as well as neural survival and plasticity. There are several common polymorphisms in the BDNF gene, one of which (rs6265) is an extensively studied non-synonymous coding polymorphism (Val66Met) which has been linked to cognitive performance in healthy controls and some clinical populations. We hypothesized that the Met allele of rs6265 would be associated with poorer cognitive performance in individuals with mild-to-moderate traumatic brain injury, and that other polymorphisms in the BDNF gene would also affect cognition. Genotype at 9 single-nucleotide polymorphisms (SNPs) in the BDNF gene, and measures of speed of information processing, learning, and memory were assessed in 75 patients with mTBI and 38 healthy subjects. Consistent with previous reports, the Met allele of rs6265 was associated with cognition (slower processing speed) in the entire group. Two other SNPs were associated with processing speed in the mTBI group, but both are in linkage disequilibrium with rs6265, and neither remained significant after adjustment for rs6265 status. Within the mTBI group, but not the controls, 4 SNPs, but not rs6265, were associated with memory measures. These associations were not affected by adjustment for rs6265 status. Polymorphisms in BDNF influence cognitive performance shortly after mTBI. The results raise the possibility that a functional polymorphism other than rs6265 may contribute to memory function after mTBI. PMID:22188054

McAllister, Thomas W; Tyler, Anna L; Flashman, Laura A; Rhodes, C Harker; McDonald, Brenna C; Saykin, Andrew J; Tosteson, Tor D; Tsongalis, Gregory J; Moore, Jason H

2012-04-10

135

Perceptual symbol systems  

Microsoft Academic Search

Prior to the twentieth century, theories of knowledge were inherently perceptual. Since then, developments in logic, statis- tics, and programming languages have inspired amodal theories that rest on principles fundamentally different from those underlying perception. In addition, perceptual approaches have become widely viewed as untenable because they are assumed to implement record- ing systems, not conceptual systems. A perceptual theory

Lawrence W. Barsalou

1999-01-01

136

Brain Training Game Boosts Executive Functions, Working Memory and Processing Speed in the Young Adults: A Randomized Controlled Trial  

PubMed Central

Background Do brain training games work? The beneficial effects of brain training games are expected to transfer to other cognitive functions. Yet in all honesty, beneficial transfer effects of the commercial brain training games in young adults have little scientific basis. Here we investigated the impact of the brain training game (Brain Age) on a wide range of cognitive functions in young adults. Methods We conducted a double-blind (de facto masking) randomized controlled trial using a popular brain training game (Brain Age) and a popular puzzle game (Tetris). Thirty-two volunteers were recruited through an advertisement in the local newspaper and randomly assigned to either of two game groups (Brain Age, Tetris). Participants in both the Brain Age and the Tetris groups played their game for about 15 minutes per day, at least 5 days per week, for 4 weeks. Measures of the cognitive functions were conducted before and after training. Measures of the cognitive functions fell into eight categories (fluid intelligence, executive function, working memory, short-term memory, attention, processing speed, visual ability, and reading ability). Results and Discussion Our results showed that commercial brain training game improves executive functions, working memory, and processing speed in young adults. Moreover, the popular puzzle game can engender improvement attention and visuo-spatial ability compared to playing the brain training game. The present study showed the scientific evidence which the brain training game had the beneficial effects on cognitive functions (executive functions, working memory and processing speed) in the healthy young adults. Conclusions Our results do not indicate that everyone should play brain training games. However, the commercial brain training game might be a simple and convenient means to improve some cognitive functions. We believe that our findings are highly relevant to applications in educational and clinical fields. Trial Registration UMIN Clinical Trial Registry 000005618.

Nouchi, Rui; Taki, Yasuyuki; Takeuchi, Hikaru; Hashizume, Hiroshi; Nozawa, Takayuki; Kambara, Toshimune; Sekiguchi, Atsushi; Miyauchi, Carlos Makoto; Kotozaki, Yuka; Nouchi, Haruka; Kawashima, Ryuta

2013-01-01

137

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

ERIC Educational Resources Information Center

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…

Unsworth, Nash; Engle, Randall W.

2008-01-01

138

High Speed Memory Centric Protection on Software Execution Using One-Time-Pad Prediction  

Microsoft Academic Search

This paper presents a new security model for protecting soft- ware confldentiality. Difierent from the previous process- centric systems designed for the same purpose, the new model ties cryptographic properties and security attributes to memory instead of a user process. The advantages of such memory centric design over the previous process-centric de- sign are two folds. First, it provides a

Weidong Shi; Hsien-Hsin Sean Lee; Chenghuai Lu; Mrinmoy Ghosh

2004-01-01

139

Divergence of Explicit and Implicit Processing Speed during Associative Memory Retrieval  

PubMed Central

Consolidation theory assumes that as time passes, some memories are strengthened and become resistant to change while other memories are weakened and forgotten. Recent demonstrations that implicit, or procedural, memories are retrieved more efficiently after learning and retention are consistent with the idea that these particular memory traces have strengthened with time, and therefore may be accessed faster. However, it is not clear whether the process of explicit memory retrieval also becomes more efficient with time. In two experiments, we explored 1) how much time is required for retrieval of separate explicit and implicit components of hippocampal-dependent visuomotor associative memories after variable retention intervals, and 2) how the explicit and implicit processing times change when the associations are rehearsed after initial retrieval. We found that after learning and retention, explicit and implicit processing times diverged: 1) the time taken to retrieve successfully the explicit component increased relative to a pre-retention baseline but, after spaced rehearsal, decreased, although not to a level significantly below that obtained at the end of learning, and 2) the implicit, or procedural, component processing times continued to gradually decrease after retention, and with continued rehearsal, reached a level significantly below the pre-retention baseline. We conclude that the observed divergence in post-retention reaction times suggests that explicit and implicit memory systems may reorganize differently after learning, and that as a consequence, different amounts of processing time may be required for retrieval of these different memory components.

Ellmore, Timothy M.; Stouffer, Kari; Nadel, Lynn

2008-01-01

140

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

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…

Johnson, Wendy; Deary, Ian J.

2011-01-01

141

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

PubMed

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

Besken, Miri; Mulligan, Neil W

2014-03-01

142

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

DOEpatents

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.

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

1989-01-01

143

Cache Memories  

Microsoft Academic Search

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

Alan Jay Smith

1982-01-01

144

Speeded retrieval abolishes the false-memory suppression effect: Evidence for the distinctiveness heuristic  

Microsoft Academic Search

We examined two different accounts of why studying distinctive information reduces false memories within the DRM paradigm.\\u000a The impoverished relational encoding account predicts that less memorial information, such as overall familiarity, is elicited\\u000a by the critical lure after distinctive encoding than after nondistinctive encoding. By contrast, the distinctiveness heuristic\\u000a predicts that participants use a deliberate retrieval strategy to withhold responding

Chad S. Dodson; Amanda C. G. Hege

2005-01-01

145

Obesity and Perceptual Reactance  

Microsoft Academic Search

Similarities in anomalous perception of internal gastric states and sensitivity to distraction among the obese to variations in perceptual reactance suggest that the obese tend to augment the intensity of visceral cues associated with hunger. It was hypothesized that the obese would be overrepresented at the augmenter end of the perceptual reactance continuum. Thirteen obese (six male, seven female) and

Carol C. Hughes; John M. Mahoney

1978-01-01

146

Generation and Context Memory  

ERIC Educational Resources Information Center

Generation enhances memory for occurrence but may not enhance other aspects of memory. The present study further delineates the negative generation effect in context memory reported in N. W. Mulligan (2004). First, the negative generation effect occurred for perceptual attributes of the target item (its color and font) but not for extratarget…

Mulligan, Neil W.; Lozito, Jeffrey P.; Rosner, Zachary A.

2006-01-01

147

Memory  

NSDL National Science Digital Library

This is a description for a learning module from Maricopa Advanced Technology Education Center. This PDF describes the module; access may be purchased by visiting the MATEC website. PC memory is one of the most critical and rapidly advancing assemblies within modern microcomputers. The challenge of developing learners' knowledge of PC memory and keeping it current and directly applicable to today's microcomputer industry is addressed by this module. The three major topics included in this module are ROM/Flash, System Memory, and Cache Systems. Hands-on practice and final skill assessment verify learners' readiness for working with memory in an Intel-based PC system.

2012-12-07

148

Longitudinal mediation of processing speed on age-related change in memory and fluid intelligence.  

PubMed

Age-related decline in processing speed has long been considered a key driver of cognitive aging. While the majority of empirical evidence for the processing speed hypothesis has been obtained from analyses of between-person age differences, longitudinal studies provide a direct test of within-person change. Using recent developments in longitudinal mediation analysis, we examine the speed-mediation hypothesis at both the within-and between-person levels in two longitudinal studies, Longitudinal Aging Study Amsterdam (LASA) and Origins of Variance in the Oldest-Old (OCTO-Twin). We found significant within-person indirect effects of change in age, such that increasing age was related to lower speed, which in turn relates to lower performance across repeated measures on other cognitive outcomes. Although between-person indirect effects were also significant in LASA, they were not in OCTO-Twin which is not unexpected given the age homogeneous nature of the OCTO-Twin data. A more in-depth examination through measures of effect size suggests that, for the LASA study, the within-person indirect effects were small and between-person indirect effects were consistently larger. These differing magnitudes of direct and indirect effects across levels demonstrate the importance of separating between- and within-person effects in evaluating theoretical models of age-related change. PMID:23957224

Robitaille, Annie; Piccinin, Andrea M; Muniz-Terrera, Graciela; Hoffman, Lesa; Johansson, Boo; Deeg, Dorly J H; Aartsen, Marja J; Comijs, Hannie C; Hofer, Scott M

2013-12-01

149

Relationships among Linguistic Processing Speed, Phonological Working Memory, and Attention in Children Who Stutter  

ERIC Educational Resources Information Center

Relatively recently, experimental studies of linguistic processing speed in children who stutter (CWS) have emerged, some of which suggest differences in performance among CWS compared to children who do not stutter (CWNS). What is not yet well understood is the extent to which underlying cognitive skills may impact performance on timed tasks of…

Anderson, Julie D.; Wagovich, Stacy A.

2010-01-01

150

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

151

Verbal Knowledge, Working Memory, and Processing Speed as Predictors of Verbal Learning in Older Adults  

ERIC Educational Resources Information Center

The present study aimed at modeling individual differences in a verbal learning task by means of a latent structured growth curve approach based on an exponential function that yielded 3 parameters: initial recall, learning rate, and asymptotic performance. Three cognitive variables--speed of information processing, verbal knowledge, working…

Rast, Philippe

2011-01-01

152

Investigation of CuSb4Te2 alloy for high-speed phase change random access memory applications  

NASA Astrophysics Data System (ADS)

The thermal stability of amorphous Sb2Te film can be significantly improved by the addition of Cu. CuSb4Te2 alloy is considered to be a potential candidate for phase change random access memory (PCRAM), as evidenced by a higher crystallization temperature, a better data retention ability, and a faster switching speed in comparison with those of Ge2Sb2Te5. A reversible switching between set and reset states can be realized by an electric pulse as short as 7 ns for CuSb4Te2-based PCRAM cell. In addition, CuSb4Te2 shows endurance up to 1.5 × 105 cycles with a resistance ratio of about two orders of magnitude.

Lu, Yegang; Song, Sannian; Song, Zhitang; Rao, Feng; Wu, Liangcai; Zhu, Min; Liu, Bo; Yao, Dongning

2012-05-01

153

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

154

Psychophysical and neural evidence for emotion enhanced perceptual vividness  

PubMed Central

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. ERPs revealed a posterior P2 component at ~200 ms that was associated with both increased emotional salience and decreased objective noise levels, consistent with EEV. BOLD response in the lateral occipital complex (LOC), insula, and amygdala predicted online EEV. The LOC and insula represented complementary 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.

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

2012-01-01

155

Perceptually Near Pawlak Partitions  

NASA Astrophysics Data System (ADS)

The problem considered in this paper is how to compare perceptually indiscernible partitions of disjoint, non-empty sets such as pairs of digital images viewed as sets of points. Such partitions are called perceptual Pawlak partitions, named after Z. Pawlak, who introduced a attribute-based equivalence relation in 1981 (the well-known indiscernibility relation from rough set theory). The solution to the problem stems from an approach to pairwise comparison reminiscent of the G. Fechner's 1860 approach to comparing perceptions in psychophysics experiments. For Fechner, one perception of an object is indistinguishable from the perception of a different object, if there is no perceptible difference in the particular sensed feature value of the objects, e.g., perceptions resulting from lifting small objects where the object feature is weight. In comparing visual perceptions, partitions of images determined by a particular form of indiscernibility relation ˜{}_{B} are used. The L1 (Manhattan distance) norm form of what is known as a perceptual indiscernibility relation defined within the context of a perceptual system is used in this article to define what are known as perceptually indiscernible Pawlak partitions (PIPs). An application of PIPs and near sets is given in this article in terms of a new form of content-based image retrieval (CBIR). This article investigates the efficacy of perceptual CBIR using Hausdorff and Mahalanobis distance measures to determine the degree of correspondence between pairs of perceptual Pawlak partitions of digital images. The contribution of this article is the introduction of an approach to comparing perceptually indiscernible image partitions.

Ramanna, Sheela

156

Sb Rich Ge2Sb5Te5 Alloy for High-Speed Phase Change Random Access Memory Applications  

NASA Astrophysics Data System (ADS)

Sb rich Ge2Sb5Te5 materials are investigated for use as the storage medium for high-speed phase change memory (PCM). Compared with conventional Ge2Sb2Te5, Ge2Sb5Te5 films have a higher crystallisation temperature (~200°C), larger crystallisation activation energy (3.13 eV), and a better data retention ability (100.2°C for ten years). A reversible switching between set and reset states can be realised by an electric pulse as short as 5 ns for Ge2Sb5Te5-based PCM cells, over 10 times faster than the Ge2Sb2Te5-based one. In addition, Ge2Sb2Te5 shows a good endurance up to 3 × 106 cycles with a resistance ratio of about three orders of magnitude. This work clearly reveals the highly promising potential of Ge2Sb5Te5 films for applications in high-speed PCM.

Zhang, Qi; Song, San-Nian; Xu, Feng

2012-10-01

157

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

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…

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

2009-01-01

158

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

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…

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

2012-01-01

159

Memory  

Microsoft Academic Search

.  Progress towards amelioration and eventual cure of human cognitive disorders requires understanding the molecular signaling\\u000a mechanisms that normally govern learning and memory. The fly Drosophila melanogaster has been instrumental in the identification of molecules and signaling pathways essential for learning and memory, because\\u000a genetic screens have produced mutants in these processes and the system facilitates integrated genetic, molecular, histological\\u000a and

E. M. C. Skoulakis; S. Grammenoudi

2006-01-01

160

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

ERIC Educational Resources Information Center

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…

Koriat, Asher

2011-01-01

161

Toward an Explanation of the Genesis of Ketamine-Induced Perceptual Distortions and Hallucinatory States  

Microsoft Academic Search

The NMDA receptor (NMDAR) channel has been proposed to function as a coincidence-detection mechanism for afferent and reentrant signals, supporting conscious perception, learning, and memory formation. In this paper we discuss the genesis of distorted perceptual states induced by subanesthetic doses of ketamine, a well-known NMDA antagonist. NMDAR blockage has been suggested to perturb perceptual processing in sensory cortex, and

Alfredo Pereira Jr.; Gene Johnson

2003-01-01

162

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

ERIC Educational Resources Information Center

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…

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

2012-01-01

163

High-Speed Optical Library System Using Digital Versatile Disk Random Access Memory  

NASA Astrophysics Data System (ADS)

A high-data-transfer-rate optical storage system using a redundant array of inexpensive libraries (RAIL) has been developed and tested. It incorporates multiple libraries, where each library consists of dual digital versatile disk (DVD) random access memory (RAM) drives and a single robotic hand and holds 2.6 GB DVD disks. To increase the reliability of data storage and at the same time to eliminate the need for read-after-write verification, which doubles the recording time, a redundant array of inexpensive drives (RAID) 4 algorithm is implemented in the control unit of the storage system. Data sent by the host is transferred to a control unit, which stripes the data into five data groups plus one parity unit. The striped and parity data is sent to individual libraries and written to the DVD disks. This system writes and retrieves data with a transfer rate of approximately 6 MB/s, using write and read control methods that minimize the data striping overhead. This reliable library system can be used for networked multimedia applications.

Tanabe, Takaya; Ura, Tetsu; Yamamoto, Manabu

2000-02-01

164

Imagery and memory illusions  

Microsoft Academic Search

This article provides a summary of current knowledge about memory illusions. The memory illusions described here focus on\\u000a the recall of imagined events that have never actually occurred. The purpose is to review theoretical ideas and empirical\\u000a evidence about the reality-monitoring processes involved in memory illusions. Reality monitoring means deciding whether the\\u000a memory has been perceptually derived or been self-generated

Frédérique Robin

2010-01-01

165

Implicit Recognition Based on Lateralized Perceptual Fluency  

PubMed Central

In some circumstances, accurate recognition of repeated images in an explicit memory test is driven by implicit memory. We propose that this “implicit recognition” results from perceptual fluency that influences responding without awareness of memory retrieval. Here we examined whether recognition would vary if images appeared in the same or different visual hemifield during learning and testing. Kaleidoscope images were briefly presented left or right of fixation during divided-attention encoding. Presentation in the same visual hemifield at test produced higher recognition accuracy than presentation in the opposite visual hemifield, but only for guess responses. These correct guesses likely reflect a contribution from implicit recognition, given that when the stimulated visual hemifield was the same at study and test, recognition accuracy was higher for guess responses than for responses with any level of confidence. The dramatic difference in guessing accuracy as a function of lateralized perceptual overlap between study and test suggests that implicit recognition arises from memory storage in visual cortical networks that mediate repetition-induced fluency increments.

Vargas, Iliana M.; Voss, Joel L.; Paller, Ken A.

2012-01-01

166

Phase Evolution in Fe-Mn-Si Shape Memory Alloys due to Forging Speed  

NASA Astrophysics Data System (ADS)

The objective of this investigation is to compare the crystallographic characteristics of two different compositions of Fe-Mn-Si alloys forged with the newly designed and constructed High Energy Rate Forming (HERF) hammer with conventional hydraulic and mechanical presses. The degree of martensite formation may depend on metal forming conditions. For both of the alloys, one of the specimens was investigated in as "prepared form", the other specimen was investigated after air cooling with homogenization treatment and three specimens were deformed in different velocities after homogenization treatments. The changes which occurred in the transformation parameters of two FeMnSi alloys with different compositions due to the effects of thermal and mechanical procedures have been studied by using X-ray diffraction. In the alloy specimens cooled to different conditions from the high-temperature ? phase region, ??? and ?????? martensitic transformations were observed. The lattice parameters (LP) of fcc ? and hcp ? structures were determined, and changes in forging speed on the LPs were found.

Eskil, Murat; Kanca, Erdogan

2013-09-01

167

Low Voltage High Speed Programming\\/Erasing Charge Trapping Memory with Metal-Al2O3SiNSi3N4Si Structure  

Microsoft Academic Search

SONOS-type NAND flash memory cell with metal-Al2O3-SiN-Si3N4-Si was fabricated and key characteristics were investigated. Low voltage and high-speed programming\\/erasing characteristics were achieved, due to low barrier height of Si3N4 and high dielectric constant of Al2O3 compared with those of SiO2. It also showed good endurance up to 10 k cycles, and more than 1.5 V memory windows after 10 years.

Sun Il Shim; F. C. Yeh; X. W. Wang; T. P. Ma

2007-01-01

168

Hafnium aluminum oxide as charge storage and blocking-oxide layers in SONOS-type nonvolatile memory for high-speed operation  

Microsoft Academic Search

The charge storage and program\\/erase mechanisms in polysilicon-oxide-nitride-oxide-silicon (SONOS) memory structures with charge-storage layers of different materials are investigated in this paper. In particular, the use of a HfAlO charge-storage layer in a SONOS-type memory structure is proposed. Compared to other high-? charge-storage layers, HfAlO has the advantage of high-speed program\\/erase of HfO2 as well as the good charge-retention time

Yan Ny Tan; W. K. Chim; Wee Kiong Choi; Moon Sig Joo; Byung Jin Cho

2006-01-01

169

Acetylcholine and Olfactory Perceptual Learning  

ERIC Educational Resources Information Center

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…

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

2004-01-01

170

Why Chunking Should be Considered as an Explanation for Developmental Change before Short-Term Memory Capacity and Processing Speed  

PubMed Central

The chunking hypothesis suggests that during the repeated exposure of stimulus material, information is organized into increasingly larger chunks. Many researchers have not considered the full power of the chunking hypothesis as both a learning mechanism and as an explanation of human behavior. Indeed, in developmental psychology there is relatively little mention of chunking and yet it can be the underlying cause of some of the mechanisms of development that have been proposed. This paper illustrates the chunking hypothesis in the domain of non-word repetition, a task that is a strong predictor of a child’s language learning. A computer simulation of non-word repetition that instantiates the chunking mechanism shows that: (1) chunking causes task behavior to improve over time, consistent with children’s performance; and (2) chunking causes perceived changes in areas such as short-term memory capacity and processing speed that are often cited as mechanisms of child development. Researchers should be cautious when considering explanations of developmental data, since chunking may be able to explain differences in performance without the need for additional mechanisms of development.

Jones, Gary

2012-01-01

171

Perceptual Learning in Speech  

ERIC Educational Resources Information Center

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.,…

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

2003-01-01

172

Adaptation and perceptual norms  

NASA Astrophysics Data System (ADS)

We used adaptation to examine the relationship between perceptual norms--the stimuli observers describe as psychologically neutral, and response norms--the stimulus levels that leave visual sensitivity in a neutral or balanced state. Adapting to stimuli on opposite sides of a neutral point (e.g. redder or greener than white) biases appearance in opposite ways. Thus the adapting stimulus can be titrated to find the unique adapting level that does not bias appearance. We compared these response norms to subjectively defined neutral points both within the same observer (at different retinal eccentricities) and between observers. These comparisons were made for visual judgments of color, image focus, and human faces, stimuli that are very different and may depend on very different levels of processing, yet which share the property that for each there is a well defined and perceptually salient norm. In each case the adaptation aftereffects were consistent with an underlying sensitivity basis for the perceptual norm. Specifically, response norms were similar to and thus covaried with the perceptual norm, and under common adaptation differences between subjectively defined norms were reduced. These results are consistent with models of norm-based codes and suggest that these codes underlie an important link between visual coding and visual experience.

Webster, Michael A.; Yasuda, Maiko; Haber, Sara; Leonard, Deanne; Ballardini, Nicole

2007-03-01

173

Prediction Error Associated with the Perceptual Segmentation of Naturalistic Events  

ERIC Educational Resources Information Center

Predicting the near future is important for survival and plays a central role in theories of perception, language processing, and learning. Prediction failures may be particularly important for initiating the updating of perceptual and memory systems and, thus, for the subjective experience of events. Here, we asked observers to make predictions…

Zacks, Jeffrey M.; Kurby, Christopher A.; Eisenberg, Michelle L.; Haroutunian, Nayiri

2011-01-01

174

Attentional Modulation of Perceptual Comparison for Feature Binding  

ERIC Educational Resources Information Center

We investigated the neural correlates of attentional modulation in the perceptual comparison process for detecting feature-binding changes in an event-related functional magnetic resonance imaging (fMRI) experiment. Participants performed a variant of a cued change detection task. They viewed a memory array, a spatial retro-cue, and later a probe…

Kuo, Bo-Cheng; Rotshtein, Pia; Yeh, Yei-Yu

2011-01-01

175

Perceptual frames in frequency estimation.  

PubMed

This study is an introductory investigation of cognitive frames, focused on perceptual frames divided into information and formal perceptual frames, which were studied based on sub-additivity of frequency estimations. It was postulated that different presentations of a response scale would result in different percentage estimates of time spent watching TV or using the Internet. The results supported the existence of perceptual frames that influence the perception process and indicated that information perceptual frames had a stronger effect than formal frames. The measures made possible the exploration of the operation of perceptual frames and also outlined the relations between heuristics and cognitive frames. PMID:24765715

Zy?owska, Aleksandra; Kossek, Marcin; Wawrzyniak, Ma?gorzata

2014-02-01

176

Perceptual merging contributes to cueing effects.  

PubMed

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

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

2014-01-01

177

Acute, low-dose methamphetamine administration improves attention/information processing speed and working memory in methamphetamine-dependent individuals displaying poorer cognitive performance at baseline  

PubMed Central

Abstinent methamphetamine (Meth) dependent individuals demonstrate poorer performance on tests sensitive to attention/information processing speed, learning and memory, and working memory when compared to non-Meth dependent individuals. The poorer performance on these tests may contribute to the morbidity associated with Meth-dependence. In light of this, we sought to determine the effects of acute, low-dose Meth administration on attention, working memory, and verbal learning and memory in 19 non-treatment seeking, Meth-dependent individuals. Participants were predominantly male (89%), Caucasian (63%), and cigarette smokers (63%). Following a four day, drug-free washout period, participants were given a single-blind intravenous infusion of saline, followed the next day by 30 mg of Meth. A battery of neurocognitive tasks was administered before and after each infusion, and performance on measures of accuracy and reaction time were compared between conditions. While acute Meth exposure did not affect test performance for the entire sample, participants who demonstrated relatively poor performance on these tests at baseline, identified using a median split on each test, showed significant improvement on measures of attention/information processing speed and working memory when administered Meth. Improved performance was seen on the following measures of working memory: choice reaction time task (p?0.04), a 1-back task (p?0.01), and a 2-back task (p?0.04). In addition, those participants demonstrating high neurocognitive performance at baseline experienced similar or decreased performance following Meth exposure. These findings suggest that acute administration of Meth may temporarily improve Meth-associated neurocognitive performance in those individuals experiencing lower cognitive performance at baseline. As a result, stimulants may serve as a successful treatment for improving cognitive functioning in those Meth-dependent individuals experiencing neurocognitive impairment.

Mahoney, James J.; Jackson, Brian J.; Kalechstein, Ari D.; De La Garza, Richard; Newton, Thomas F.

2012-01-01

178

Neural mechanisms underlying the induction and relief of perceptual curiosity.  

PubMed

Curiosity is one of the most basic biological drives in both animals and humans, and has been identified as a key motive for learning and discovery. Despite the importance of curiosity and related behaviors, the topic has been largely neglected in human neuroscience; hence little is known about the neurobiological mechanisms underlying curiosity. We used functional magnetic resonance imaging (fMRI) to investigate what happens in our brain during the induction and subsequent relief of perceptual curiosity. Our core findings were that (1) the induction of perceptual curiosity, through the presentation of ambiguous visual input, activated the anterior insula and anterior cingulate cortex (ACC), brain regions sensitive to conflict and arousal; (2) the relief of perceptual curiosity, through visual disambiguation, activated regions of the striatum that have been related to reward processing; and (3) the relief of perceptual curiosity was associated with hippocampal activation and enhanced incidental memory. These findings provide the first demonstration of the neural basis of human perceptual curiosity. Our results provide neurobiological support for a classic psychological theory of curiosity, which holds that curiosity is an aversive condition of increased arousal whose termination is rewarding and facilitates memory. PMID:22347853

Jepma, Marieke; Verdonschot, Rinus G; van Steenbergen, Henk; Rombouts, Serge A R B; Nieuwenhuis, Sander

2012-01-01

179

Neural mechanisms underlying the induction and relief of perceptual curiosity  

PubMed Central

Curiosity is one of the most basic biological drives in both animals and humans, and has been identified as a key motive for learning and discovery. Despite the importance of curiosity and related behaviors, the topic has been largely neglected in human neuroscience; hence little is known about the neurobiological mechanisms underlying curiosity. We used functional magnetic resonance imaging (fMRI) to investigate what happens in our brain during the induction and subsequent relief of perceptual curiosity. Our core findings were that (1) the induction of perceptual curiosity, through the presentation of ambiguous visual input, activated the anterior insula and anterior cingulate cortex (ACC), brain regions sensitive to conflict and arousal; (2) the relief of perceptual curiosity, through visual disambiguation, activated regions of the striatum that have been related to reward processing; and (3) the relief of perceptual curiosity was associated with hippocampal activation and enhanced incidental memory. These findings provide the first demonstration of the neural basis of human perceptual curiosity. Our results provide neurobiological support for a classic psychological theory of curiosity, which holds that curiosity is an aversive condition of increased arousal whose termination is rewarding and facilitates memory.

Jepma, Marieke; Verdonschot, Rinus G.; van Steenbergen, Henk; Rombouts, Serge A. R. B.; Nieuwenhuis, Sander

2012-01-01

180

Perceptual and memory constraints on language acquisition  

Microsoft Academic Search

A wide variety of organisms employ specialized mech- anisms to cope with the demands of their environment. We suggest that the same is true for humans when acquiring artificial grammars, and at least some basic properties of natural grammars. We show that two basic mechanisms can explain many results in artificial gram- mar learning experiments, and different linguistic regularities rangingfrom

Ansgar D. Endress; Marina Nespor; Jacques Mehler

2009-01-01

181

Essential roles of exploiting internal parallelism of flash memory based solid state drives in high-speed data processing  

Microsoft Academic Search

Flash memory based solid state drives (SSDs) have shown a great potential to change storage infrastructure fundamentally through their high performance and low power. Most recent studies have mainly focused on addressing the technical limitations caused by special requirements for writes in flash memory. However, a unique merit of an SSD is its rich internal parallelism, which allows us to

Feng Chen; Rubao Lee; Xiaodong Zhang

2011-01-01

182

A low-cost high-speed twin-prefetching DSP-based shared- memory system for real-time image processing applications  

NASA Astrophysics Data System (ADS)

This dissertation introduces, investigates, and evaluates a low-cost high-speed twin-prefetching DSP-based bus- interconnected shared-memory system for real-time image processing applications. The proposed architecture can effectively support 32 DSPs in contrast to a maximum of 4 DSPs supported by existing DSP-based bus-interconnected systems. This significant enhancement is achieved by introducing two small programmable fast memories (Twins) between the processor and the shared bus interconnect. While one memory is transferring data from/to the shared memory, the other is supplying the core processor with data. The elimination of the traditional direct linkage of the shared bus and processor data bus makes feasible the utilization of a wider shared bus i.e., shared bus width becomes independent of the data bus width of the processors. The fast prefetching memories and the wider shared bus provide additional bus bandwidth into the system, which eliminates large memory latencies; such memory latencies constitute the major drawback for the performance of shared-memory multiprocessors. Furthermore, in contrast to existing DSP-based uniprocessor or multiprocessor systems the proposed architecture does not require all data to be placed on on-chip or off-chip expensive fast memory in order to reach or maintain peak performance. Further, it can maintain peak performance regardless of whether the processed image is small or large. The performance of the proposed architecture has been extensively investigated executing computationally intensive applications such as real-time high-resolution image processing. The effect of a wide variety of hardware design parameters on performance has been examined. More specifically tables and graphs comprehensively analyze the performance of 1, 2, 4, 8, 16, 32 and 64 DSP-based systems, for a wide variety of shared data interconnect widths such as 32, 64, 128, 256 and 512. In addition, the effect of the wide variance of temporal and spatial locality (present in different applications) on the multiprocessor's execution time is investigated and analyzed. Finally, the prefetching cache-size was varied from a few kilobytes to 4 Mbytes and the corresponding effect on the execution time was investigated. Our performance analysis has clearly showed that the execution time converges to a shallow minimum i.e., it is not sensitive to the size of the prefetching cache. The significance of this observation is that near optimum performance can be achieved with a small (16 to 300 Kbytes) amount of prefetching cache.

Christou, Charalambos Stephanou

1998-11-01

183

Reinforcement Learning with Perceptual Aliasing: The Perceptual Distinctions Approach  

Microsoft Academic Search

It is known that Perceptual Aliasing may significantlydiminish the effectiveness of reinforcementlearning algorithms [ Whitehead and Ballard,1991 ] . Perceptual aliasing occurs when multiplesituations that are indistinguishable from immediateperceptual input require different responsesfrom the system. For example, if a robot can onlysee forward, yet the presence of a battery chargerbehind it determines whether or not it shouldbackup, immediate perception alone

Lonnie Chrisman

1992-01-01

184

Differential frontal involvement in shifts of internal and perceptual attention  

PubMed Central

Background Perceptual attention enhances the processing of items in the environment, whereas internal attention enhances processing of items encoded in visual working memory. In perceptual and internal attention cueing paradigms, cues indicate the to-be-probed item before (pre-cueing) or after (retro-cueing) the memory display, respectively. Pre- and retro- cues confer similar behavioral accuracy benefits (pre-: 14–19%, retro-: 11–17%) and neuroimaging data show that they activate overlapping frontoparietal networks (1). Yet reports of behavioral and neuroimaging differences suggest that pre- and retro-cueing differentially recruit frontal and parietal cortices (1). Objective/Hypothesis This study examined whether perceptual and internal attention are equally disrupted by neurostimulation to frontal and parietal cortices. We hypothesized that neurostimulation applied to frontal cortex would disrupt internal attention to a greater extent than perceptual attention. Methods Cathodal transcranial direct current stimulation (tDCS) was applied to frontal or parietal cortices. After stimulation, participants completed a change detection task coupled with either pre- or retro- cues. Results Cathodal tDCS across site (frontal, parietal) hindered performance. However, frontal tDCS had a greater negative impact on the retro-cued trials demonstrating greater frontal involvement during shifts of internal attention. Conclusions These results complement the neuroimaging data and provide further evidence suggesting that perceptual and internal attention are not identical processes. We conclude that although internal and perceptual attention are mediated by similar frontoparietal networks, the weight of contribution of these structures differs, with internal attention relying more heavily on the frontal cortex.

Tanoue, Ryan T.; Jones, Kevin T.; Peterson, Dwight J.; Berryhill, Marian E.

2012-01-01

185

PERCEPTUAL LEARNING IN EDUCATIONAL SITUATIONS.  

ERIC Educational Resources Information Center

BOTH COGNITIVELY-ORIENTED AND RESPONSE-ORIENTED THEORIES OF PERCEPTUAL LEARNING ARE DISCUSSED AND CONTRASTED WITH A STIMULUS-ORIENTED THEORY. PERCEPTUAL LEARNING IS DEFINED AS AN INCREASE IN SPECIFICITY OF DISCRIMINATION OF THE STIMULUS INPUT. THE AUTHOR DESCRIBED WHAT IS LEARNED IN PERCEPUTAL LEARNING AS () THE DISTINCTIVE FEATURES OF THINGS, (2)…

GIBSON, ELEANOR J.

186

Conflict-Induced Perceptual Filtering  

ERIC Educational Resources Information Center

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…

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

2012-01-01

187

Design of a 270ps-access 7-transistor/2-magnetic-tunnel-junction cell circuit for a high-speed-search nonvolatile ternary content-addressable memory  

NASA Astrophysics Data System (ADS)

A novel 7-transistor/2-magnetic-tunnel-junction (7 T-2MTJ) cell circuit is proposed for a high-speed and compact nonvolatile ternary content-addressable memory (TCAM). Since critical path for switching in the TCAM cell circuit, which determines the performance of the TCAM, is only a single MOS transistor, switching delay of the TCAM word circuit is minimized. As a result, 270 ps of switching delay in 144-bit TCAM word circuit is achieved under a 90 nm CMOS/MTJ technology with magneto-resistance ratio of 100%, which is about two times faster than a conventional CMOS-based TCAM.

Matsunaga, Shoun; Katsumata, Akira; Natsui, Masanori; Endoh, Tetsuo; Ohno, Hideo; Hanyu, Takahiro

2012-04-01

188

Perceptual versus conceptual interference and pattern separation of verbal stimuli in young and older adults  

PubMed Central

Recently, several studies have strongly suggested that age-related decline in episodic memory is associated with deficits in hippocampal pattern separation (orthogonalizing overlapping experiences using distinct neural codes). The same studies also link these deficits to neurobiological features such as dentate/CA3 representational rigidity and perforant path loss. This decline in pattern separation is thought to underlie behavioral deficits in discriminating similar stimuli on pictorial tasks. Similar pictorial stimuli invoke interference both in the perceptual and conceptual domains, and do not allow one to be disentangled from another. For example, it is very difficult to design a set of pictorial stimuli that are perceptually similar yet conceptually unrelated. Verbal stimuli, on the other hand, allow experimenters to independently manipulate conceptual and perceptual interference. We tested discrimination on conceptually similar (semantically related) and perceptually similar (phonologically related) verbal stimuli in young (mean age 20) and older adults (mean age 69), and find that older adults are selectively impaired in perceptual pattern separation. This deficit was not secondary to failure in working memory, attention, or visual processing. Based on past studies, we suggest that perceptual discrimination relies on recollection while conceptual discrimination relies more on gist. Our results fit well within the notion that recollection but not familiarity (i.e. gist) is impaired in older adults, and suggests that the impairment observed in pictorial tasks may be driven mostly by failure in perceptual and not conceptual pattern separation.

Ly, Maria; Murray, Elizabeth; Yassa, Michael A.

2014-01-01

189

Developmental changes in source memory  

Microsoft Academic Search

Remembering how one learned a fact can be important in itself (e.g. for considering the value of information). However, source memory is also important, along with the temporal and perceptual information on which it is based, in giving memory an episodic or autobiographical quality. The present study investigated developmental changes in children's ability to monitor source, in a paradigm adapted

Anna B. Drummey; Nora S. Newcombe

2002-01-01

190

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

Microsoft Academic Search

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

Vitorino Ramos; Carlos Fernandes; Agostinho C. Rosa

2005-01-01

191

Writing to dictation and handwriting performance among Chinese children with dyslexia: relationships with orthographic knowledge and perceptual-motor skills.  

PubMed

The purpose of this study was to investigate the relationships between writing to dictation, handwriting, orthographic, and perceptual-motor skills among Chinese children with dyslexia. A cross-sectional design was used. A total of 45 third graders with dyslexia were assessed. Results of stepwise multiple regression models showed that Chinese character naming was the only predictor associated with word dictation (?=.32); handwriting speed was related to deficits in rapid automatic naming (?=-.36) and saccadic efficiency (?=-.29), and visual-motor integration predicted both of the number of characters exceeded grid (?=-.41) and variability of character size (?=-.38). The findings provided support to a multi-stage working memory model of writing for explaining the possible underlying mechanism of writing to dictation and handwriting difficulties. PMID:23911643

Cheng-Lai, Alice; Li-Tsang, Cecilia W P; Chan, Alan H L; Lo, Amy G W

2013-10-01

192

Balance in machine architecture: Bandwidth on board and offboard, integer/control speed and flops versus memory  

SciTech Connect

The issues to be addressed here are those of balance'' in machine architecture. By this, we mean how much emphasis must be placed on various aspects of the system to maximize its usefulness for physics. There are three components that contribute to the utility of a system: How the machine can be used, how big a problem can be attacked, and what the effective capabilities (power) of the hardware are like. The effective power issue is a matter of evaluating the impact of design decisions trading off architectural features such as memory bandwidth and interprocessor communication capabilities. What is studied is the effect these machine parameters have on how quickly the system can solve desired problems. There is a reasonable method for studying this: One selects a few representative algorithms and computes the impact of changing memory bandwidths, and so forth. The only room for controversy here is in the selection of representative problems. The issue of how big a problem can be attacked boils down to a balance of memory size versus power. Although this is a balance issue it is very different than the effective power situation, because no firm answer can be given at this time. The power to memory ratio is highly problem dependent, and optimizing it requires several pieces of physics input, including: how big a lattice is needed for interesting results; what sort of algorithms are best to use; and how many sweeps are needed to get valid results. We seem to be at the threshold of learning things about these issues, but for now, the memory size issue will necessarily be addressed in terms of best guesses, rules of thumb, and researchers' opinions.

Fischler, M.

1992-04-01

193

Balance in machine architecture: Bandwidth on board and offboard, integer/control speed and flops versus memory  

SciTech Connect

The issues to be addressed here are those of ``balance`` in machine architecture. By this, we mean how much emphasis must be placed on various aspects of the system to maximize its usefulness for physics. There are three components that contribute to the utility of a system: How the machine can be used, how big a problem can be attacked, and what the effective capabilities (power) of the hardware are like. The effective power issue is a matter of evaluating the impact of design decisions trading off architectural features such as memory bandwidth and interprocessor communication capabilities. What is studied is the effect these machine parameters have on how quickly the system can solve desired problems. There is a reasonable method for studying this: One selects a few representative algorithms and computes the impact of changing memory bandwidths, and so forth. The only room for controversy here is in the selection of representative problems. The issue of how big a problem can be attacked boils down to a balance of memory size versus power. Although this is a balance issue it is very different than the effective power situation, because no firm answer can be given at this time. The power to memory ratio is highly problem dependent, and optimizing it requires several pieces of physics input, including: how big a lattice is needed for interesting results; what sort of algorithms are best to use; and how many sweeps are needed to get valid results. We seem to be at the threshold of learning things about these issues, but for now, the memory size issue will necessarily be addressed in terms of best guesses, rules of thumb, and researchers` opinions.

Fischler, M.

1992-04-01

194

Psychophysical Analyses of Perceptual Representations.  

National Technical Information Service (NTIS)

Research during the year has been divided between studies at USC (Biederman and students) and Minnesota. Our research continues to focus on linking early sensory representations to higher-level perceptual representations. For this reason, we refer to our ...

I. Biederman

1993-01-01

195

Memory-Efficient and High-Speed VLSI Implementation of Two-Dimensional Discrete Wavelet Transform Using Decomposed Lifting Scheme  

Microsoft Academic Search

Novel decomposed lifting scheme (DLS) is presented to perform one-dimensional (1D) discrete wavelet transform (DWT) with consistent\\u000a data flow in both row and column dimension. Based on the proposed DLS, intermediate data can be transferred seamlessly between\\u000a the column processor and the row processor in the hardware implementation of two-dimensional (2D) DWT, resulting in the reduction\\u000a of on-chip memory, output

Peng Cao; Chao Wang; Long X. Shi

2010-01-01

196

Code Restructuring for Improving Real Time Response through Code Speed, Size Trade-offs on Limited Memory Embedded DSPs  

Microsoft Academic Search

Embedded systems are constrained by limited on-chip memory and by real time performance requirements. The traditional approach\\u000a to solve these problems has been to write the embedded code in assembly language, which can no longer be followed due to the\\u000a increasing complexity of the embedded systems. Programming in high-level language simplifies the software development cycle,\\u000a incurring a code size and

Vipin Jain; Siddharth Rele; Santosh Pande; J. Ramanujam

1999-01-01

197

Perceptually Lossless Wavelet Compression  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

198

Perceptual Anomalies in Schizophrenia: Integrating Phenomenology and Cognitive Neuroscience  

PubMed Central

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.

Uhlhaas, Peter J.; Mishara, Aaron L.

2007-01-01

199

Recent progress in perceptual learning research  

PubMed Central

Perceptual learning is defined as long-term improvement in perceptual or sensory systems resulting from repeated practice or experience. As the number of perceptual learning studies has increased, controversies and questions have arisen regarding divergent aspects of perceptual learning, including: (1) stages in which perceptual learning occurs, (2) effects of training type, (3) changes in neural processing during the time course of learning, (4) effects of feedback as to correctness of a subject’s responses and (5) double-training. Here we review each of these aspects and suggest fruitful directions for future perceptual learning research.

Sasaki, Yuka; Nanez, Jose E.

2013-01-01

200

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

PubMed

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

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

2014-02-01

201

Schizotypy and false memory.  

PubMed

Using the Deese-Roediger-McDermott (DRM) paradigm the present study examined the relationship between schizotypy and recognition memory. Participants scoring in the upper and lower quartile ranges for schizotypy (Schizotypal Personality Questionnaire brief version; SPQ-B) and on each of the SPQ-B subscales (cognitive-perceptual, interpersonal and disorganized) were compared on true and false memory performance. Participants scoring in the lower quartile range on the cognitive-perceptual subscale recognised a higher proportion of both true and false memories than those scoring in the higher quartile range. Participants scoring in the upper quartile on the interpersonal factor recognised fewer true items than those in the lower quartile range. No differences were found for overall schizotypy or on the disorganized subscale. PMID:18817907

Dagnall, Neil; Parker, Andrew

2009-03-01

202

Investigation of Ge-Sn-Te alloy for long data retention and high speed phase change memory application  

NASA Astrophysics Data System (ADS)

Ge44Sn14Te42 phase change material exhibits a higher crystallization temperature (~221 °C), a larger crystallization activation energy (~2.88 eV) and a better data retention ability (~126 °C for 10 years) in comparison with those of Ge2Sb2Te5. A reversible switching between set and reset can be realized by an electric pulse as short as 10 ns for Ge44Sn14Te42 based phase change memory (PCM) cell. In addition, PCM based on Ge44Sn14Te42 shows endurance up to 2.7 × 103 cycles with a resistance of about two orders of magnitude on/off ratio.

Zhang, Zhonghua; Song, Sannian; Song, Zhitang; Cheng, Yan; Rao, Feng; Wu, Liangcai; Liu, Bo; Chen, Bomy; Lu, Yegang

2013-09-01

203

Perceptual interference decays over short unfilled intervals.  

PubMed

The perceptual interference effect refers to the fact that object identification is directly related to the amount of information available at initial exposure. The present article investigated whether perceptual interference would dissipate when a short, unfilled interval was introduced between exposures to a degraded object. Across three experiments using both musical and pictorial stimuli, identification performance increased directly with the length of the unfilled interval. Consequently, significant perceptual interference was obtained only when the interval between exposures was relatively short (< 500 msec for melodies; < 300 msec for pictures). These results are consistent with explanations that attribute perceptual interference to increased perceptual noise created by exposures to highly degraded objects. The data also suggest that perceptual interference is mediated by systems that are not consciously controlled by the subject and that perceptual interference in the visual domain decays more rapidly than perceptual interference in the auditory domain. PMID:11105520

Schulkind, M D

2000-09-01

204

Memory-to-memory connection structures in FPGAs with embedded memory arrays  

Microsoft Academic Search

This paper shows that the speed of FPGAs with large embedded memory arrays can be improved by adding direct programmable connections between the memories. Nets that connect to multiple memory arrays are often difficult to route, and are often part of the critical path of circuit implementations. The memory-to-memory connection structure proposed in this paper allows for the efficient implementation

Steven J. E. Wilton; Jonathan Rose; Zvonko G. Vranesic

1997-01-01

205

Characterizing Perceptual Learning with External Noise  

ERIC Educational Resources Information Center

Performance in perceptual tasks often improves with practice. This effect is known as "perceptual learning," and it has been the source of a great deal of interest and debate over the course of the last century. Here, we consider the effects of perceptual learning within the context of signal detection theory. According to signal detection theory,…

Gold, Jason M.; Sekuler, Allison B.; Bennett, Partrick J.

2004-01-01

206

Neurally Constrained Modeling of Perceptual Decision Making  

ERIC Educational Resources Information Center

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…

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

2010-01-01

207

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

PubMed

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

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

2014-01-01

208

Ferroelectric memories  

Microsoft Academic Search

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

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

1989-01-01

209

Developmental Perceptual Exploration and Organization.  

ERIC Educational Resources Information Center

This study investigated the process of perceptual exploration and organization of children as a function of age and sex in two experiments. In Experiment I, 3- to 5-year-old children named the pictures of nine familiar objects arranged in 3 x 3 matrices (exploration tasks) and indicated preference for objects represented in pairs (pair-completion…

Randhawa, Bikkar S.; And Others

210

Cortical Synchronization and Perceptual Framing  

Microsoft Academic Search

How does the brain group together different parts of an object into a coherent visual object representation? Different parts of an object may be processed by the brain at different rates and may thus become desynchronized. Perceptual framing is a process that resynchronizes cortical activities corresponding to the same retinal object. A neural network model is presented that is able

Stephen Grossberg; Alexander Grunewald

1997-01-01

211

Perceptual Aspects of Cluttered Speech  

ERIC Educational Resources Information Center

The purpose of this descriptive investigation was to explore perceptual judgments of speech naturalness, compared to judgments of articulation, language, disfluency, and speaking rate, in the speech of two youths who differed in cluttering severity. Two groups of listeners, 48 from New York and 48 from West Virginia, judged 93 speaking samples on…

St. Louis, Kenneth O.; Myers, Florence L.; Faragasso, Kristine; Townsend, Paula S.; Gallaher, Amanda J.

2004-01-01

212

Perceptual Fading without Retinal Adaptation  

ERIC Educational Resources Information Center

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…

Hsieh, Po-Jang; Colas, Jaron T.

2012-01-01

213

The Perceptual Scalability of Visualization  

Microsoft Academic Search

Larger, higher resolution displays can be used to increase the scalability of information visualizations. But just how much can scalability increase using larger displays before hitting human perceptual or cognitive limits? Are the same visualization techniques that are good on a single monitor also the techniques that are best when they are scaled up using large, high-resolution displays? To answer

Beth Yost; Chris North

2006-01-01

214

Perceptually guided expressive facial animation  

Microsoft Academic Search

Most of current facial animation approaches largely focus on the accuracy or efficiency of their algorithms, or how to optimally utilize pre-collected facial motion data. However, human perception, the ultimate measuring stick of the visual fidelity of synthetic facial animations, was not effectively exploited in these approaches. In this paper, we present a novel perceptually guided computational framework for expressive

Zhigang Deng; Xiaohan Ma

2008-01-01

215

Is Perceptual Narrowing Too Narrow?  

ERIC Educational Resources Information Center

There is a growing list of examples illustrating that infants are transitioning from having earlier abilities that appear more "universal," "broadly tuned," or "unconstrained" to having later abilities that appear more "specialized," "narrowly tuned," or "constrained." Perceptual narrowing, a well-known phenomenon related to face, speech, and…

Cashon, Cara H.; Denicola, Christopher A.

2011-01-01

216

Perceptual basis for reactive teleoperation  

Microsoft Academic Search

To improve task performance in partially structured environments, enhancements to teleoperation have been proposed by introducing autonomous behaviors. Such autonomy is implemented based on a reactive robotic architecture, where reactive motor agents that directly couple sensory inputs and motor actions become the building blocks. To this end, a perceptual basis for the motor agents is presented in this paper. The

Young S. Park; Thomas F. Ewing; James M. Boyle; Thomas J. Yule

2001-01-01

217

THE EFFECTS OF FAMILIARITY ON THE PERCEPTUAL RECOGNITION AND CATEGORIZATION OF VERBAL INFORMATION.  

ERIC Educational Resources Information Center

THE EFFECTS OF FAMILIARITY ON THE PROCESSING OF STIMULUS AND MEMORIAL INFORMATION WERE INVESTIGATED IN TWO TASKS--ONE WHICH SUPPOSEDLY REQUIRED ONLY THE PERCEPTUAL RECOGNITION OF EACH STIMULUS WORD (E TASK) AND ONE WHICH REQUIRED A MEANINGFUL CATEGORIZATION OF EACH STIMULUS WORD (C TASK). FIFTY UNIVERSITY OF MICHIGAN UNDERGRADUATES WHO WERE PAID…

SMITH, EDWARD

218

Navigated transcranial magnetic stimulation of the primary somatosensory cortex impairs perceptual processing of tactile temporal discrimination  

Microsoft Academic Search

Previous studies indicate that transcranial magnetic stimulation (TMS) with biphasic pulses applied approximately over the primary somatosensory cortex (S1) suppresses performance in vibrotactile temporal discrimination tasks; these previous results, however, do not allow separating perceptual influence from memory or decision-making. Moreover, earlier studies using external landmarks for directing biphasic TMS pulses to the cortex do not reveal whether the changes

Henri Hannula; Tuomas Neuvonen; Petri Savolainen; Taru Tukiainen; Oili Salonen; Synnöve Carlson; Antti Pertovaara

2008-01-01

219

Perceptual learning modifies untrained pursuit eye movements.  

PubMed

PERCEPTUAL LEARNING IMPROVES DETECTION AND DISCRIMINATION OF RELEVANT VISUAL INFORMATION IN MATURE HUMANS, REVEALING SENSORY PLASTICITY WHETHER VISUAL PERCEPTUAL LEARNING AFFECTS MOTOR RESPONSES IS UNKNOWN HERE WE IMPLEMENTED A PROTOCOL THAT ENABLED US TO ADDRESS THIS QUESTION WE TESTED A PERCEPTUAL RESPONSE MOTION DIRECTION ESTIMATION, IN WHICH OBSERVERS OVERESTIMATE MOTION DIRECTION AWAY FROM A REFERENCE AND A MOTOR RESPONSE VOLUNTARY SMOOTH PURSUIT EYE MOVEMENTS PERCEPTUAL TRAINING LED TO GREATER OVERESTIMATION AND, REMARKABLY, IT MODIFIED UNTRAINED SMOOTH PURSUIT IN CONTRAST, PURSUIT TRAINING DID NOT AFFECT OVERESTIMATION IN EITHER PURSUIT OR PERCEPTION, EVEN THOUGH OBSERVERS IN BOTH TRAINING GROUPS WERE EXPOSED TO THE SAME STIMULI FOR THE SAME TIME PERIOD A SECOND EXPERIMENT REVEALED THAT ESTIMATION TRAINING ALSO IMPROVED DISCRIMINATION, INDICATING THAT OVERESTIMATION MAY OPTIMIZE PERCEPTUAL SENSITIVITY HENCE, ACTIVE PERCEPTUAL TRAINING IS NECESSARY TO ALTER PERCEPTUAL RESPONSES, AND AN ACQUIRED CHANGE IN PERCEPTION SUFFICES TO MODIFY PURSUIT, A MOTOR RESPONSE: PMID:25002412

Szpiro, Sarit F A; Spering, Miriam; Carrasco, Marisa

2014-01-01

220

Perceptual learning modifies untrained pursuit eye movements  

PubMed Central

Perceptual learning improves detection and discrimination of relevant visual information in mature humans, revealing sensory plasticity. Whether visual perceptual learning affects motor responses is unknown. Here we implemented a protocol that enabled us to address this question. We tested a perceptual response (motion direction estimation, in which observers overestimate motion direction away from a reference) and a motor response (voluntary smooth pursuit eye movements). Perceptual training led to greater overestimation and, remarkably, it modified untrained smooth pursuit. In contrast, pursuit training did not affect overestimation in either pursuit or perception, even though observers in both training groups were exposed to the same stimuli for the same time period. A second experiment revealed that estimation training also improved discrimination, indicating that overestimation may optimize perceptual sensitivity. Hence, active perceptual training is necessary to alter perceptual responses, and an acquired change in perception suffices to modify pursuit, a motor response.

Szpiro, Sarit F. A.; Spering, Miriam; Carrasco, Marisa

2014-01-01

221

Sex Differences in Phonological Coding: Alphabet Transformation Speed  

ERIC Educational Resources Information Center

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…

Majeres, Raymond L.

2007-01-01

222

Odor identification: perceptual and semantic dimensions.  

PubMed

Five studies explored identification of odors as an aspect of semantic memory. All dealt in one way or another with the accessibility of acquired olfactory information. The first study examined stability and showed that, consistent with personal reports, people can fail to identify an odor one day yet succeed another. Failure turned more commonly to success than vice versa, and once success occurred it tended to recur. Confidence ratings implied that subjects generally knew the quality of their answers. Even incorrect names, though, often carried considerable information which sometimes reflected a semantic and sometimes a perceptual source of errors. The second study showed that profiling odors via the American Society of Testing and Materials list of attributes, an exercise in depth of processing, effected no increment in the identifiability/accessibility beyond an unelaborated second attempt at retrieval. The third study showed that subjects had only a weak ability to predict the relative recognizability of odors they had failed to identify. Whereas the strength of the feeling that they would 'know' an answer if offered choices did not associate significantly with performance for odors, it did for trivia questions. The fourth study demonstrated an association between ability to discriminate among one set of odors and to identify another, but this emerged only after subjects had received feedback about identity, which essentially changed the task to one of recognition and effectively stabilized access. The fifth study illustrated that feedback improves performance dramatically only for odors involved with it, but that mere retrieval leads to some improvement. The studies suggest a research agenda that could include supplemental use of confidence judgments both retrospectively and prospectively in the same subjects to indicate the amount of accessible semantic information; use of second and third guesses to examine subjects' simultaneously held hypotheses about identity; use of category cuing or similar techniques to discover the minimum semantic information needed to precipitate identification; some use of subjects trained in quantitative descriptive analysis to explore whether such training enhances semantic memory; and judicious use of mixtures to explore perceptual versus semantic errors of identification. PMID:9669044

Cain, W S; de Wijk, R; Lulejian, C; Schiet, F; See, L C

1998-06-01

223

Improving pulse oximetry pitch perception with multisensory perceptual training.  

PubMed

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

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

2014-06-01

224

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

PubMed

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

Smith, Andrew P

2012-10-01

225

Procedural memory in Korsakoff's disease under different movement feedback conditions  

Microsoft Academic Search

Within the field of cognitive neuroscience, it has become widely accepted to distinguish between declarative and nondeclarative memory, with different neurobiological substrates subserving these memory structures. This distinction has been inferred from the study of amnesic patients, including those suffering from Korsakoff's syndrome. It is commonly agreed that Korsakoff patients demonstrate intact memory for motor and perceptual skills (nondeclarative) whereas

Stephan P. Swinnen; Veerle Puttemans; Sabine Lamote

2005-01-01

226

Ferroelectric Memories.  

National Technical Information Service (NTIS)

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 dens...

J. F. Scott C. A. Paz De Arujo

1989-01-01

227

Minimalist Approach to Perceptual Interactions  

PubMed Central

Work aimed at studying social cognition in an interactionist perspective often encounters substantial theoretical and methodological difficulties: identifying the significant behavioral variables; recording them without disturbing the interaction; and distinguishing between: (a) the necessary and sufficient contributions of each individual partner for a collective dynamics to emerge; (b) features which derive from this collective dynamics and escape from the control of the individual partners; and (c) the phenomena arising from this collective dynamics which are subsequently appropriated and used by the partners. We propose a minimalist experimental paradigm as a basis for this conceptual discussion: by reducing the sensory inputs to a strict minimum, we force a spatial and temporal deployment of the perceptual activities, which makes it possible to obtain a complete recording and control of the dynamics of interaction. After presenting the principles of this minimalist approach to perception, we describe a series of experiments on two major questions in social cognition: recognizing the presence of another intentional subject; and phenomena of imitation. In both cases, we propose explanatory schema which render an interactionist approach to social cognition clear and explicit. Starting from our earlier work on perceptual crossing we present a new experiment on the mechanisms of reciprocal recognition of the perceptual intentionality of the other subject: the emergent collective dynamics of the perceptual crossing can be appropriated by each subject. We then present an experimental study of opaque imitation (when the subjects cannot see what they themselves are doing). This study makes it possible to characterize what a properly interactionist approach to imitation might be. In conclusion, we draw on these results, to show how an interactionist approach can contribute to a fully social approach to social cognition.

Lenay, Charles; Stewart, John

2012-01-01

228

Schemata versus Dichotomous Constructs as Organizational System in Memory.  

National Technical Information Service (NTIS)

The nature of representational systems in memory was studied using a categorical form of the repertory grid and a perceptual identification task. Forty undergraduate psychology students completed a computer-administered repertory grid in which they provid...

D. L. Van Brunt

1993-01-01

229

Exploring perceptual skills in children with autism spectrum disorders: from target detection to dynamic perceptual discrimination.  

PubMed

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 throughout but systematically changing in difficulty. These tasks ranged through simple detection of stimulus onset to pairwise size discrimination across two approaching targets. Children with ASD were slower than controls even in simple detection tasks, but this did not explain further group differences found in the size discrimination of approaching targets. The results are discussed in terms of impairments in speed of responding in ASD under certain conditions of visuomotor coupling, stimulus presentation and increased information processing demands. PMID:24141747

Miller, Louisa; McGonigle-Chalmers, Maggie

2014-05-01

230

Optimizing Linked Perceptual Class Formation and Transfer of Function  

ERIC Educational Resources Information Center

A linked perceptual class consists of two distinct perceptual classes, A' and B', the members of which have become related to each other. For example, a linked perceptual class might be composed of many pictures of a woman (one perceptual class) and the sounds of that woman's voice (the other perceptual class). In this case, any sound of the…

Fields, Lanny; Garruto, Michelle

2009-01-01

231

Perceptual Organization for Generic Object Descriptions  

Microsoft Academic Search

\\u000a In this paper, we take the view that the key purpose of perceptual organization is to help detect, describe and recognize\\u000a generic objects in the environment. This viewpoint helps clarify the role of shape models and the interactions of the higher levels of vision with perceptual organization. The paper then describes a hierarchical hypothesize and verify paradigm for realizing perceptual

R. Nevatia

232

Olfactory perceptual learning requires adult neurogenesis  

PubMed Central

Perceptual learning is required for olfactory function to adapt appropriately to changing odor environments. We here show that newborn neurons in the olfactory bulb are not only involved in, but necessary for, olfactory perceptual learning. First, the discrimination of perceptually similar odorants improves in mice after repeated exposure to the odorants. Second, this improved discrimination is accompanied by an elevated survival rate of newborn inhibitory neurons, preferentially involved in processing of the learned odor, within the olfactory bulb. Finally, blocking neurogenesis before and during the odorant exposure period prevents this learned improvement in discrimination. Olfactory perceptual learning is thus mediated by the reinforcement of functional inhibition in the olfactory bulb by adult neurogenesis.

Moreno, Melissa M.; Linster, Christiane; Escanilla, Olga; Sacquet, Joelle; Didier, Anne; Mandairon, Nathalie

2009-01-01

233

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

234

Musically Cued Gait-Training Improves Both Perceptual and Motor Timing in Parkinson's Disease  

PubMed Central

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.

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

2014-01-01

235

No evidence of intelligence improvement after working memory training: a randomized, placebo-controlled study.  

PubMed

Numerous recent studies seem to provide evidence for the general intellectual benefits of working memory training. In reviews of the training literature, Shipstead, Redick, and Engle (2010, 2012) argued that the field should treat recent results with a critical eye. Many published working memory training studies suffer from design limitations (no-contact control groups, single measures of cognitive constructs), mixed results (transfer of training gains to some tasks but not others, inconsistent transfer to the same tasks across studies), and lack of theoretical grounding (identifying the mechanisms responsible for observed transfer). The current study compared young adults who received 20 sessions of practice on an adaptive dual n-back program (working memory training group) or an adaptive visual search program (active placebo-control group) with a no-contact control group that received no practice. In addition, all subjects completed pretest, midtest, and posttest sessions comprising multiple measures of fluid intelligence, multitasking, working memory capacity, crystallized intelligence, and perceptual speed. Despite improvements on both the dual n-back and visual search tasks with practice, and despite a high level of statistical power, there was no positive transfer to any of the cognitive ability tests. We discuss these results in the context of previous working memory training research and address issues for future working memory training studies. PMID:22708717

Redick, Thomas S; Shipstead, Zach; Harrison, Tyler L; Hicks, Kenny L; Fried, David E; Hambrick, David Z; Kane, Michael J; Engle, Randall W

2013-05-01

236

Shared Neural Substrates of Emotionally Enhanced Perceptual and Mnemonic Vividness  

PubMed Central

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.

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

2013-01-01

237

The time course of perceptual grouping in natural scenes.  

PubMed

Visual perception starts with localized filters that subdivide the image into fragments that undergo separate analyses. The visual system has to reconstruct objects by grouping image fragments that belong to the same object. A widely held view is that perceptual grouping occurs in parallel across the visual scene and without attention. To test this idea, we measured the speed of grouping in pictures of animals and vehicles. In a classification task, these pictures were categorized efficiently. In an image-parsing task, participants reported whether two cues fell on the same or different objects, and we measured reaction times. Despite the participants' fast object classification, perceptual grouping required more time if the distance between cues was larger, and we observed an additional delay when the cues fell on different parts of a single object. Parsing was also slower for inverted than for upright objects. These results imply that perception starts with rapid object classification and that rapid classification is followed by a serial perceptual grouping phase, which is more efficient for objects in a familiar orientation than for objects in an unfamiliar orientation. PMID:23137967

Korjoukov, Ilia; Jeurissen, Danique; Kloosterman, Niels A; Verhoeven, Josine E; Scholte, H Steven; Roelfsema, Pieter R

2012-12-01

238

Memory system reliability improvement through associative cache redundancy  

Microsoft Academic Search

A redundancy memory architecture that increases system memory reliability without incurring the memory access speed degradation or size impact that result from using error-correction coding or paper-swapping techniques have been developed. The architecture uses a small associative cache memory to provide redundant memory locations. Logic is provided to perform memory system testing and remapping of fault memory locations. A VLSI

M. A. Lucente; C. H. Harris; R. M. Muir

1990-01-01

239

Premotor cortex mediates perceptual performance.  

PubMed

Articulatory goals have long been proposed to mediate perception. Examples include direct realist and constructivist (analysis by synthesis) theories of speech perception. Although the activity in brain regions involved with action production has been shown to be present during action observation (Mirror Neuron System), the relationship of this activity to perceptual performance has not been clearly demonstrated at the event level. To this end we used functional magnetic resonance imaging fMRI and magnetoencephalography MEG to measure brain activity for correct and incorrect trials of an auditory phonetic identification in noise task. FMRI analysis revealed activity in the premotor cortex including the neighboring frontal opercular part of Broca's area (PMC/Broca's) for both perception and production tasks involving the same phonetic stimuli (potential mirror system site) that was significantly greater for correct over incorrect perceptual identification trials. Time-frequency analysis of single trials conducted over MEG current localized to PMC/Broca's using a hierarchical variational Bayesian source analysis technique revealed significantly greater event-related synchronization ERS and desynchronization ERD for correct over incorrect trials in the alpha, beta, and gamma frequency range prior to and after stimulus presentation. Together, these fMRI and MEG results are consistent with the hypothesis that articulatory processes serve to facilitate perceptual performance, while further dispelling concerns that activity found in ventral PMC/Broca's (mirror system) is merely a product of covert production of the perceived action. The finding of performance predictive activity prior to stimulus onset as well as activity related to task difficulty instead of information available in stimulation are consistent with constructivist and contrary to direct realist theories of perception. PMID:20184959

Callan, Daniel; Callan, Akiko; Gamez, Mario; Sato, Masa-aki; Kawato, Mitsuo

2010-06-01

240

Perceptual assessment of demosaicing algorithm performance  

Microsoft Academic Search

Demosaicing is an important part of the image-processing chain for many digital color cameras. The demosaicing operation converts a raw image acquired with a single sensor array, overlaid with a color filter array, into a full-color image. In this paper, we report the results of two perceptual experiments that compare the perceptual quality of the output of different demosaicing algorithms.

PHILIPPE LONGÈRE; Xuemei Zhang; PETER B. DELAHUNT; DAVID H. BRAINARD

2002-01-01

241

Enhanced Perceptual Processing of Speech in Autism  

ERIC Educational Resources Information Center

Theories of autism have proposed that a bias towards low-level perceptual information, or a featural/surface-biased information-processing style, may compromise higher-level language processing in such individuals. Two experiments, utilizing linguistic stimuli with competing low-level/perceptual and high-level/semantic information, tested…

Jarvinen-Pasley, Anna; Wallace, Gregory L.; Ramus, Franck; Happe, Francesca; Heaton, Pamela

2008-01-01

242

Children's perceptual organisation of hierarchical visual patterns  

Microsoft Academic Search

Children's perceptual organisation of hierarchical patterns was investigated in two experiments through similarity judgements. Previous studies with adults demonstrated that the perceptual relations between the global configuration and the local elements of such patterns depend critically on the number of elements embedded in the pattern: Patterns composed of a few, relatively large elements are perceived in terms of global form

Ruth Kimchi

1990-01-01

243

Perceptual Switching Evokes Frontal Delta Wave Activity  

Microsoft Academic Search

We studied spontaneous brain activity that relates to perceptual switching by using EEG. Five subjects participated in the study. The subjects sat in a quiet room and looked at the screen in front of them during the whole experiment. We measured whole-head EEG in three conditions of: 1) presentation of Necker cube and button press immediately after perceptual switching, 2)

Mayuko Okada; Yumie Ono; Yoshikazu Iijima; Atsushi Ishiyama; Naoko Kasai

244

Lateralized Anomalous Perceptual Experiences in Schizophrenia  

Microsoft Academic Search

Four cases of schizophrenia are described, in which subjects reported anomalous perceptual experiences confined to one visual field, in all cases the left visual field. The pattern, content and laterality of such anomalous perceptions point to the presence of right hemisphere dysfunction in schizophrenia. Further evidence to this effect comes from examining the type of anomalous perceptual experiences reported by

R. Persaud; J. Cutting

1991-01-01

245

Perceptual Grouping from Gabor Filter Responses  

Microsoft Academic Search

Perceptual organisation can be defined as the ability to impose structural organisation on sensory data, so as to group sensory primitives arising from a common underlying cause. Our organisational philosophy is hierarchical, with complex organisations being formed from simpler ones. In this paper, directional features extracted from Gabor responses are used as the primitives for perceptual grouping. In previous work,

María J. Carreira; James Orwell; Romón Turnes; James F. Boyce; Diego Cabello; John F. Haddon

1998-01-01

246

Self-perception, perceptual defense, and adjustment  

Microsoft Academic Search

The results in general support the hypotheses that the greater the agreement between the individual's self-description and an objective description of him, the less perceptual defense he will show, the more adequate will be his personal adjustment, and the more adequate his personal adjustment, the less perceptual defence he will show.

Bernard Chodorkoff

1954-01-01

247

Perceptual Differences between Hippies and College Students  

ERIC Educational Resources Information Center

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)

Brothers, Robert; Gaines, Rosslyn

1973-01-01

248

Not just speed control [variable speed AC drives  

Microsoft Academic Search

Today, the use of variable speed A.C. drives in the cement industry is well established. The development of power semiconductors, microprocessors and memory circuits, together with the latest motor speed and torque control methods like the DTC (Direct Torque Control), enables creating more functionality inside variable speed drives. Advances in technological development have resulted in sophisticated frequency converter supply units

P. Pulkki

2004-01-01

249

Perceptual scaling of room reverberation  

NASA Astrophysics Data System (ADS)

Recent evidence suggests that reverberant energy can provide listeners with important spatial information regarding the distance of a sound source. However, relatively little is known about the perceptual attributes of the reverberation itself, and how these attributes may be related to physical properties of the environment that also potentially impact perceived spatial location. Here, perceived similarity among 15 reverberant rooms simulated using virtual auditory space techniques was examined. Room size and surface absorption properties were varied, along with aspects of the virtual simulation including the use of individualized head-related transfer function (HRTF) measurements and properties of the room acoustic simulation. Seven listeners rated perceived similarity on a 100-point scale between all possible pairs of simulated rooms using a speech source signal. Multidimensional scaling techniques were used to estimate scales of perceived room reverberation. Although the resulting scales were complex and somewhat unique to individual listeners, it is clear that the perceptual effects of manipulating properties of the reverberant sound are much larger than the effects due to either nonindividualized HRTFs or nonoptimal room simulation methods. [Work supported by NIDCD.

Zahorik, Pavel

2001-05-01

250

State-dependent perceptual learning.  

PubMed

Learning constitutes a fundamental property of the human brain-yet an unresolved puzzle is the profound variability of the learning success between individuals. Here we highlight the relevance of individual ongoing brain states as sources of the learning variability in exposure-based somatosensory perceptual learning. Electroencephalogram recordings of ongoing rhythmic brain activity before and during learning revealed that prelearning parietal alpha oscillations as well as during-learning stimulus-induced contralateral central alpha changes are predictive for the learning outcome. These two distinct alpha rhythm sources predicted up to 64% of the observed learning variability, one source representing an idling state with posteroparietal focus and a potential link to the default mode network, the other representing the sensorimotor mu rhythm, whose desynchronization is indicative for the degree of engagement of sensorimotor neuronal populations during application of the learning stimuli. Unspecific effects due to global shifts of attention or vigilance do not explain our observations. Our study thus suggests a brain state-dependency of perceptual learning success in humans opening new avenues for supportive learning tools in the clinical and educational realms. PMID:23407948

Freyer, Frank; Becker, Robert; Dinse, Hubert R; Ritter, Petra

2013-02-13

251

Collapse models and perceptual processes  

NASA Astrophysics Data System (ADS)

Theories including a collapse mechanism have been presented various years ago. They are based on a modification of standard quantum mechanics in which nonlinear and stochastic terms are added to the evolution equation. Their principal merits derive from the fact that they are mathematically precise schemes accounting, on the basis of a unique universal dynamical principle, both for the quantum behavior of microscopic systems as well as for the reduction associated to measurement processes and for the classical behavior of macroscopic objects. Since such theories qualify themselves not as new interpretations but as modifications of the standard theory they can be, in principle, tested against quantum mechanics. Recently, various investigations identifying possible crucial test have been discussed. In spite of the extreme difficulty to perform such tests it seems that recent technological developments allow at least to put precise limits on the parameters characterizing the modifications of the evolution equation. Here we will simply mention some of the recent investigations in this direction, while we will mainly concentrate our attention to the way in which collapse theories account for definite perceptual process. The differences between the case of reductions induced by perceptions and those related to measurement procedures by means of standard macroscopic devices will be discussed. On this basis, we suggest a precise experimental test of collapse theories involving conscious observers. We make plausible, by discussing in detail a toy model, that the modified dynamics can give rise to quite small but systematic errors in the visual perceptual process.

Carlo Ghirardi, Gian; Romano, Raffaele

2014-04-01

252

Task-Irrelevant Perceptual Expertise  

PubMed Central

Perceptual learning (PL) and perceptual expertise (PE) are two fields of visual training studies that investigate how practice improves visual performance. However, previous research suggests that PL can be acquired in a task-irrelevant manner while PE cannot, and that PL is highly specific to the training objects and conditions while PE generalizes. These differences are difficult to interpret since PL and PE studies tend to differ on multiple dimensions. We designed a training study with novel objects to compare PL and PE while varying only the training task, such that the training objects, visual field, training duration and the type of learning assessment were kept constant. Manipulations of the training task sufficed to produce the standard effects obtained in PE and PL. In contrast to prior studies, we demonstrated that some degree of PE can be acquired in a task-irrelevant manner, similar to PL. Task-irrelevant PE resulted in similar shape matching ability compared to the directly trained PE. In addition, learning in both PE and PL generalizes to different untrained conditions, which does not support the idea that PE generalizes while PL is specific. Degrees of generalization can be explained by considering the psychological space of the stimuli used for training and the test of transfer.

Wong, Yetta K.; Folstein, Jonathan R.; Gauthier, Isabel

2012-01-01

253

Perceptual estimation obeys Occam's razor  

PubMed Central

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.

Gershman, Samuel J.; Niv, Yael

2013-01-01

254

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

255

Probing perceptual decisions in rodents  

PubMed Central

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.

Carandini, Matteo; Churchland, Anne K

2014-01-01

256

High Speed Random Access, Fourier Transform Holographic Associative And High Density Two-Photon Three-Dimensional Optical Memories Based On Bacteriorhodopsin.  

National Technical Information Service (NTIS)

The goals of this research and development program were to optimize bacteriorhodopsin based photochromic and photorefractive materials for use in optical memories. Two spatial light modulators (SLMs) based on bacteriorhodopsin were developed, one that cou...

R. R. Birge

1995-01-01

257

Perceptual Training Strongly Improves Visual Motion Perception in Schizophrenia  

ERIC Educational Resources Information Center

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…

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

2011-01-01

258

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

PubMed

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

Mettler, Everett; Kellman, Philip J

2014-06-01

259

The Role of Visual Processing Speed in Reading Speed Development  

PubMed Central

A steady increase in reading speed is the hallmark of normal reading acquisition. However, little is known of the influence of visual attention capacity on children's reading speed. The number of distinct visual elements that can be simultaneously processed at a glance (dubbed the visual attention span), predicts single-word reading speed in both normal reading and dyslexic children. However, the exact processes that account for the relationship between the visual attention span and reading speed remain to be specified. We used the Theory of Visual Attention to estimate visual processing speed and visual short-term memory capacity from a multiple letter report task in eight and nine year old children. The visual attention span and text reading speed were also assessed. Results showed that visual processing speed and visual short term memory capacity predicted the visual attention span. Furthermore, visual processing speed predicted reading speed, but visual short term memory capacity did not. Finally, the visual attention span mediated the effect of visual processing speed on reading speed. These results suggest that visual attention capacity could constrain reading speed in elementary school children.

Lobier, Muriel; Dubois, Matthieu; Valdois, Sylviane

2013-01-01

260

Development of Auditory-Vocal Perceptual Skills in Songbirds  

PubMed Central

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.

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

2012-01-01

261

Neurally Constrained Modeling of Perceptual Decision Making  

PubMed Central

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 test alternative models of how evidence is combined in the accumulation process. The models were evaluated on their ability to predict both response time distributions and movement neuron activity observed in monkeys performing a visual search task. Models that assume gating of perceptual evidence to the accumulating units provide the best account of both behavioral and neural data. These results identify discrete stages of processing with anatomically distinct neural populations and rule out several alternative architectures. The results also illustrate the use of neurophysiological data as a model selection tool and establish a novel framework to bridge computational and neural levels of explanation.

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

2010-01-01

262

Driver Perceptual Adaptation to Nonplanar Rearview Mirrors.  

National Technical Information Service (NTIS)

This study examined perceptual adaptation to nonplanar (spherical convex and aspheric) rearview mirrors. Subjects made magnitude estimates of the distance to a car seen in a rearview mirror. Three different mirrors were used: plane, aspheric (with a large...

M. J. Flannagan M. Sivak E. C. Traube

1996-01-01

263

Processes of Working Memory in Mind and Brain  

Microsoft Academic Search

Working memory is often conceptualized as storage buffers that retain information briefly, rehearsal processes that refresh the buffers, and executive processes that manipulate the contents of the buffers. We review evidence about the brain mechanisms that may underlie storage and rehearsal in working memory. We hypothesize that storage is mediated by the same brain structures that process perceptual information and

John Jonides; Steven C. Lacey; Derek Evan Nee

2005-01-01

264

Modeling Recognition Memory Using the Similarity Structure of Natural Input  

ERIC Educational Resources Information Center

The natural input memory (NAM) model is a new model for recognition memory that operates on natural visual input. A biologically informed perceptual preprocessing method takes local samples (eye fixations) from a natural image and translates these into a feature-vector representation. During recognition, the model compares incoming preprocessed…

Lacroix, Joyca P. W.; Murre, Jaap M. J.; Postma, Eric O.; van den Herik, H. Jaap

2006-01-01

265

Sex differences in sleep-dependent perceptual learning.  

PubMed

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 40minutes 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

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

2014-06-01

266

The Relationships of Working Memory, Secondary Memory, and General Fluid Intelligence: Working Memory is Special  

PubMed Central

Recent efforts have been made to elucidate the commonly observed link between working memory and reasoning ability. The results have been inconsistent, with some work suggesting the emphasis placed on retrieval from secondary memory by working memory tests is the driving force behind this association (Mogle, Lovett, Stawski, & Sliwinski, 2008), while other research suggests retrieval from secondary memory is only partly responsible for the observed link between working memory and reasoning (Unsworth & Engle, 2006, 2007b). The present study investigates the relationship between processing speed, working memory, secondary memory, primary memory, and fluid intelligence. Although our findings show all constructs are significantly correlated with fluid intelligence, working memory, but not secondary memory, accounts for significant unique variance in fluid intelligence. Our data support predictions made by Unsworth and Engle, and suggest that the combined need for maintenance and retrieval processes present in working memory tests makes them “special” in their prediction of higher-order cognition.

Shelton, Jill Talley; Elliott, Emily M.; Matthews, Russell A.; Hill, B. D.; Gouvier, Wm. Drew

2010-01-01

267

Does Perceptual Learning Suffer from Retrograde Interference?  

PubMed Central

In motor learning, training a task B can disrupt improvements of performance of a previously learned task A, indicating that learning needs consolidation. An influential study suggested that this is the case also for visual perceptual learning [1]. Using the same paradigm, we failed to reproduce these results. Further experiments with bisection stimuli also showed no retrograde disruption from task B on task A. Hence, for the tasks tested here, perceptual learning does not suffer from retrograde interference.

Aberg, Kristoffer C.; Herzog, Michael H.

2010-01-01

268

Individual Differences in Memory Span.  

National Technical Information Service (NTIS)

One series of experiments examined the correlation between memory span and the speed of symbol manipulation in short-term memory, and another experiment analyzed the effects of extended practice on memory span. In the first study, most of the estimates of...

W. G. Chase D. R. Lyon K. A. Ericsson

1979-01-01

269

Poor Anchoring Limits Dyslexics' Perceptual, Memory, and Reading Skills  

ERIC Educational Resources Information Center

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,…

Oganian, Yulia; Ahissar, Merav

2012-01-01

270

Abstract Code Network as a Model of Perceptual Memory.  

National Technical Information Service (NTIS)

According to Structural Information Theory human observers represent important aspects of the information of visual patterns in abstract sequential codes. The theory proposes a syntax for the structural form of these codes. In the paper a generative synta...

H. Mellink H. Buffart

1985-01-01

271

Perceptual categories for spatial layout.  

PubMed Central

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.

Kersten, D

1997-01-01

272

Using a multinomial tree model for detecting mixtures in perceptual detection  

PubMed Central

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.

Chechile, Richard A.

2014-01-01

273

Pupil dilation reflects perceptual selection and predicts subsequent stability in perceptual rivalry  

PubMed Central

During sustained viewing of an ambiguous stimulus, an individual's perceptual experience will generally switch between the different possible alternatives rather than stay fixed on one interpretation (perceptual rivalry). Here, we measured pupil diameter while subjects viewed different ambiguous visual and auditory stimuli. For all stimuli tested, pupil diameter increased just before the reported perceptual switch and the relative amount of dilation before this switch was a significant predictor of the subsequent duration of perceptual stability. These results could not be explained by blink or eye-movement effects, the motor response or stimulus driven changes in retinal input. Because pupil dilation reflects levels of norepinephrine (NE) released from the locus coeruleus (LC), we interpret these results as suggestive that the LC–NE complex may play the same role in perceptual selection as in behavioral decision making.

Einhauser, Wolfgang; Stout, James; Koch, Christof; Carter, Olivia

2008-01-01

274

Comparison of perceptual color spaces for natural image segmentation tasks  

NASA Astrophysics Data System (ADS)

Color image segmentation largely depends on the color space chosen. Furthermore, spaces that show perceptual uniformity seem to outperform others due to their emulation of the human perception of color. We evaluate three perceptual color spaces, CIELAB, CIELUV, and RLAB, in order to determine their contribution to natural image segmentation and to identify the space that obtains the best results over a test set of images. The nonperceptual color space RGB is also included for reference purposes. In order to quantify the quality of resulting segmentations, an empirical discrepancy evaluation methodology is discussed. The Berkeley Segmentation Dataset and Benchmark is used in test series, and two approaches are taken to perform the experiments: supervised pixelwise classification using reference colors, and unsupervised clustering using k-means. A majority filter is used as a postprocessing stage, in order to determine its contribution to the result. Furthermore, a comparison of elapsed times taken by the required transformations is included. The main finding of our study is that the CIELUV color space outperforms the other color spaces in both discriminatory performance and computational speed, for the average case.

Correa-Tome, Fernando E.; Sanchez-Yanez, Raul E.; Ayala-Ramirez, Victor

2011-11-01

275

Where do we store the memory representations that guide attention?  

PubMed Central

During the last decade one of the most contentious and heavily studied topics in the attention literature has been the role that working memory representations play in controlling perceptual selection. The hypothesis has been advanced that to have attention select a certain perceptual input from the environment, we only need to represent that item in working memory. Here we summarize the work indicating that the relationship between what representations are maintained in working memory and what perceptual inputs are selected is not so simple. First, it appears that attentional selection is also determined by high-level task goals that mediate the relationship between working memory storage and attentional selection. Second, much of the recent work from our laboratory has focused on the role of long-term memory in controlling attentional selection. We review recent evidence supporting the proposal that working memory representations are critical during the initial configuration of attentional control settings, but that after those settings are established long-term memory representations play an important role in controlling which perceptual inputs are selected by mechanisms of attention.

Woodman, Geoffrey F.; Carlisle, Nancy B.; Reinhart, Robert M. G.

2013-01-01

276

Stress Effects on Working Memory, Explicit Memory, and Implicit Memory for Neutral and Emotional Stimuli in Healthy Men  

PubMed Central

Stress is a strong modulator of memory function. However, memory is not a unitary process and stress seems to exert different effects depending on the memory type under study. Here, we explored the impact of social stress on different aspects of human memory, including tests for explicit memory and working memory (for neutral materials), as well as implicit memory (perceptual priming, contextual priming and classical conditioning for emotional stimuli). A total of 35 young adult male students were randomly assigned to either the stress or the control group, with stress being induced by the Trier Social Stress Test (TSST). Salivary cortisol levels were assessed repeatedly throughout the experiment to validate stress effects. The results support previous evidence indicating complex effects of stress on different types of memory: A pronounced working memory deficit was associated with exposure to stress. No performance differences between groups of stressed and unstressed subjects were observed in verbal explicit memory (but note that learning and recall took place within 1 h and immediately following stress) or in implicit memory for neutral stimuli. Stress enhanced classical conditioning for negative but not positive stimuli. In addition, stress improved spatial explicit memory. These results reinforce the view that acute stress can be highly disruptive for working memory processing. They provide new evidence for the facilitating effects of stress on implicit memory for negative emotional materials. Our findings are discussed with respect to their potential relevance for psychiatric disorders, such as post traumatic stress disorder.

Luethi, Mathias; Meier, Beat; Sandi, Carmen

2008-01-01

277

Perceptual Learning of Interrupted Speech  

PubMed Central

The intelligibility of periodically interrupted speech improves once the silent gaps are filled with noise bursts. This improvement has been attributed to phonemic restoration, a top-down repair mechanism that helps intelligibility of degraded speech in daily life. Two hypotheses were investigated using perceptual learning of interrupted speech. If different cognitive processes played a role in restoring interrupted speech with and without filler noise, the two forms of speech would be learned at different rates and with different perceived mental effort. If the restoration benefit were an artificial outcome of using the ecologically invalid stimulus of speech with silent gaps, this benefit would diminish with training. Two groups of normal-hearing listeners were trained, one with interrupted sentences with the filler noise, and the other without. Feedback was provided with the auditory playback of the unprocessed and processed sentences, as well as the visual display of the sentence text. Training increased the overall performance significantly, however restoration benefit did not diminish. The increase in intelligibility and the decrease in perceived mental effort were relatively similar between the groups, implying similar cognitive mechanisms for the restoration of the two types of interruptions. Training effects were generalizable, as both groups improved their performance also with the other form of speech than that they were trained with, and retainable. Due to null results and relatively small number of participants (10 per group), further research is needed to more confidently draw conclusions. Nevertheless, training with interrupted speech seems to be effective, stimulating participants to more actively and efficiently use the top-down restoration. This finding further implies the potential of this training approach as a rehabilitative tool for hearing-impaired/elderly populations.

Benard, Michel Ruben; Baskent, Deniz

2013-01-01

278

Perceptual Image Compression in Telemedicine  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

279

Multisensory perceptual learning and sensory substitution.  

PubMed

One of the most exciting recent findings in neuroscience has been the capacity for neural plasticity in adult humans and animals. Studies of perceptual learning have provided key insights into the mechanisms of neural plasticity and the changes in functional neuroanatomy that it affords. Key questions in this field of research concern how practice of a task leads to specific or general improvement. Although much of this work has been carried out with a focus on a single sensory modality, primarily visual, there is increasing interest in multisensory perceptual learning. Here we will examine how advances in perceptual learning research both inform and can be informed by the development and advancement of sensory substitution devices for blind persons. To allow 'sight' to occur in the absence of visual input through the eyes, visual information can be transformed by a sensory substitution device into a representation that can be processed as sound or touch, and thus give one the potential to 'see' through the ears or tongue. Investigations of auditory, visual and multisensory perceptual learning can have key benefits for the advancement of sensory substitution, and the study of sensory deprivation and sensory substitution likewise will further the understanding of perceptual learning in general and the reverse hierarchy theory in particular. It also has significant importance for the developing understanding of the brain in metamodal terms, where functional brain areas might be best defined by the computations they carry out rather than by their sensory-specific processing role. PMID:23220697

Proulx, Michael J; Brown, David J; Pasqualotto, Achille; Meijer, Peter

2014-04-01

280

Low-voltage high-speed programming/erasing floating-gate memory device with gate-all-around polycrystalline silicon nanowire  

NASA Astrophysics Data System (ADS)

A gate-all-around polycrystalline silicon nanowire (NW) floating-gate (FG) memory device was fabricated and characterized in this work. The cross-section of the NW channels was intentionally made to be triangular in shape in order to study the effects of the corners on the device operation. Our results indicate that the channel corners are effective in lowering the programming and erasing (P/E) operation voltages. As compared with the charge-trapping type devices, a larger memory window is obtained with the FG scheme under low-voltage P/E conditions. A model considering the nature of the charge storage medium is proposed to explain the above findings.

Lee, Ko-Hui; Tsai, Jung-Ruey; Chang, Ruey-Dar; Lin, Horng-Chih; Huang, Tiao-Yuan

2013-10-01

281

Orienting attention in time activates left intraparietal sulcus for both perceptual and motor task goals.  

PubMed

Attention can be directed not only toward a location in space but also to a moment in time ("temporal orienting"). Temporally informative cues allow subjects to predict when an imminent event will occur, thereby speeding responses to that event. In contrast to spatial orienting, temporal orienting preferentially activates left inferior parietal cortex. Yet, left parietal cortex is also implicated in selective motor attention, suggesting its activation during temporal orienting could merely reflect incidental engagement of preparatory motor processes. Using fMRI, we therefore examined whether temporal orienting would still activate left parietal cortex when the cued target required a difficult perceptual discrimination rather than a speeded motor response. Behaviorally, temporal orienting improved accuracy of target identification as well as speed of target detection, demonstrating the general utility of temporal cues. Crucially, temporal orienting selectively activated left inferior parietal cortex for both motor and perceptual versions of the task. Moreover, conjunction analysis formally revealed a region deep in left intraparietal sulcus (IPS) as common to both tasks, thereby identifying it as a core neural substrate for temporal orienting. Despite the context-independent nature of left IPS activation, complementary psychophysiological interaction analysis revealed how the functional connectivity of left IPS changed as a function of task context. Specifically, left IPS activity covaried with premotor activity during motor temporal orienting but with visual extrastriate activity during perceptual temporal orienting, thereby revealing a cooperative network that comprises both temporal orienting and task-specific processing nodes. PMID:21452942

Davranche, Karen; Nazarian, Bruno; Vidal, Franck; Coull, Jennifer

2011-11-01

282

Visible digital watermarking system using perceptual models  

NASA Astrophysics Data System (ADS)

This paper presents a visible watermarking system using perceptual models. %how and why A watermark image is overlaid translucently onto a primary image, for the purposes of immediate claim of copyright, instantaneous recognition of owner or creator, or deterrence to piracy of digital images or video. %perceptual The watermark is modulated by exploiting combined DCT-domain and DWT-domain perceptual models. % so that the watermark is visually uniform. The resulting watermarked image is visually pleasing and unobtrusive. The location, size and strength of the watermark vary randomly with the underlying image. The randomization makes the automatic removal of the watermark difficult even though the algorithm is known publicly but the key to the random sequence generator. The experiments demonstrate that the watermarked images have pleasant visual effect and strong robustness. The watermarking system can be used in copyright notification and protection.

Cheng, Qiang; Huang, Thomas S.

2001-03-01

283

How Adequate is the Concept of Perceptual Deficit for Education?  

ERIC Educational Resources Information Center

Performances on the Bender Visual Motor Gestalt Test and on a visual discrimination task using the same forms were found not to be related. Implication for identification of perceptual deficiencies and subsequent perceptual training are discussed. (KW)

Zach, Lillian; Kaufman, Judith

1972-01-01

284

Conjoint dissociations reveal involuntary "perceptual" priming from generating at study.  

PubMed

Incidental perceptual memory tests reveal priming when words are generated orally from a semantic cue at study, and this priming could reflect contamination by voluntary retrieval. We tested this hypothesis using a generate condition and two read conditions that differed in depth of processing (read-phonemic vs read-semantic). An intentional word-stem completion test showed an advantage for the read-semantic over the generate condition and an advantage for the generate over the read-phonemic condition, and completion times were longer than in a control test, prior to which there was no study phase. An incidental word-stem completion test showed equivalent priming for the read-semantic and read-phonemic study conditions, despite considerable power, and completion times were no longer than control, indicating that retrieval was involuntary, and insensitive to prior conceptual processing. The generate condition produced less priming than the read conditions, but significant priming nonetheless. The results show that priming from generating can be involuntary and suggest that lexical processes are responsible. They are also the first results conjointly showing a crossed double dissociation, a single dissociation, and a parallel effect across memory tests with identical physical retrieval cues. PMID:10487783

Richardson-Klavehn, A; Benjamin Clarke, A J; Gardiner, J M

1999-09-01

285

Image data compression having minimum perceptual error  

NASA Technical Reports Server (NTRS)

A method for performing image compression that eliminates redundant and invisible image components is described. The image compression uses a Discrete Cosine Transform (DCT) and each DCT coefficient yielded by the transform is quantized by an entry in a quantization matrix which determines the perceived image quality and the bit rate of the image being compressed. The present invention adapts or customizes the quantization matrix to the image being compressed. The quantization matrix comprises visual masking by luminance and contrast techniques and by an error pooling technique all resulting in a minimum perceptual error for any given bit rate, or minimum bit rate for a given perceptual error.

Watson, Andrew B. (inventor)

1995-01-01

286

Image Data Compression Having Minimum Perceptual Error  

NASA Technical Reports Server (NTRS)

A method is presented for performing color or grayscale image compression that eliminates redundant and invisible image components. The image compression uses a Discrete Cosine Transform (DCT) and each DCT coefficient yielded by the transform is quantized by an entry in a quantization matrix which determines the perceived image quality and the bit rate of the image being compressed. The quantization matrix comprises visual masking by luminance and contrast technique all resulting in a minimum perceptual error for any given bit rate, or minimum bit rate for a given perceptual error.

Watson, Andrew B. (Inventor)

1997-01-01

287

Perceptual and Cognitive Impairments and Driving  

PubMed Central

Perceptual and cognitive disorders that frequently accompany stroke and head injury influence an individual's ability to drive a motor vehicle. Canadian physicians are legally responsible for identifying patients who are potentially unsafe to drive and, if they fail to do so, may be held liable in a civil action suit. The authors review the guidelines for physicians evaluating a patient's fitness to drive after brain injury. They also examine the actions a physician should take when a patient with perceptual and cognitive problems wants to drive. Ultimately, by taking these actions, physicians will help to prevent driving accidents.

Korner-Bitensky, Nicol; Coopersmith, Henry; Mayo, Nancy; Leblanc, Ginette; Kaizer, Franceen

1990-01-01

288

A perceptual account of symbolic reasoning.  

PubMed

People can be taught to manipulate symbols according to formal mathematical and logical rules. Cognitive scientists have traditionally viewed this capacity-the capacity for symbolic reasoning-as grounded in the ability to internally represent numbers, logical relationships, and mathematical rules in an abstract, amodal fashion. We present an alternative view, portraying symbolic reasoning as a special kind of embodied reasoning in which arithmetic and logical formulae, externally represented as notations, serve as targets for powerful perceptual and sensorimotor systems. Although symbolic reasoning often conforms to abstract mathematical principles, it is typically implemented by perceptual and sensorimotor engagement with concrete environmental structures. PMID:24795662

Landy, David; Allen, Colin; Zednik, Carlos

2014-01-01

289

A perceptual account of symbolic reasoning  

PubMed Central

People can be taught to manipulate symbols according to formal mathematical and logical rules. Cognitive scientists have traditionally viewed this capacity—the capacity for symbolic reasoning—as grounded in the ability to internally represent numbers, logical relationships, and mathematical rules in an abstract, amodal fashion. We present an alternative view, portraying symbolic reasoning as a special kind of embodied reasoning in which arithmetic and logical formulae, externally represented as notations, serve as targets for powerful perceptual and sensorimotor systems. Although symbolic reasoning often conforms to abstract mathematical principles, it is typically implemented by perceptual and sensorimotor engagement with concrete environmental structures.

Landy, David; Allen, Colin; Zednik, Carlos

2014-01-01

290

Explicit pre-training instruction does not improve implicit perceptual-motor sequence learning  

PubMed Central

Memory systems theory argues for separate neural systems supporting implicit and explicit memory in the human brain. Neuropsychological studies support this dissociation, but empirical studies of cognitively healthy participants generally observe that both kinds of memory are acquired to at least some extent, even in implicit learning tasks. A key question is whether this observation reflects parallel intact memory systems or an integrated representation of memory in healthy participants. Learning of complex tasks in which both explicit instruction and practice is used depends on both kinds of memory, and how these systems interact will be an important component of the learning process. Theories that posit an integrated, or single, memory system for both types of memory predict that explicit instruction should contribute directly to strengthening task knowledge. In contrast, if the two types of memory are independent and acquired in parallel, explicit knowledge should have no direct impact and may serve in a “scaffolding” role in complex learning. Using an implicit perceptual-motor sequence learning task, the effect of explicit pre-training instruction on skill learning and performance was assessed. Explicit pre-training instruction led to robust explicit knowledge, but sequence learning did not benefit from the contribution of pre-training sequence memorization. The lack of an instruction benefit suggests that during skill learning, implicit and explicit memory operate independently. While healthy participants will generally accrue parallel implicit and explicit knowledge in complex tasks, these types of information appear to be separately represented in the human brain consistent with multiple memory systems theory.

Sanchez, Daniel J.; Reber, Paul J.

2012-01-01

291

Conceptual Distinctiveness Supports Detailed Visual Long-Term Memory for Real-World Objects  

PubMed Central

Humans have a massive capacity to store detailed information in visual long-term memory. The present studies explored the fidelity of these visual long-term memory representations and examined how conceptual and perceptual features of object categories support this capacity. Observers viewed 2,800 object images with a different number of exemplars presented from each category. At test, observers indicated which of 2 exemplars they had previously studied. Memory performance was high and remained quite high (82% accuracy) with 16 exemplars from a category in memory, demonstrating a large memory capacity for object exemplars. However, memory performance decreased as more exemplars were held in memory, implying systematic categorical interference. Object categories with conceptually distinctive exemplars showed less interference in memory as the number of exemplars increased. Interference in memory was not predicted by the perceptual distinctiveness of exemplars from an object category, though these perceptual measures predicted visual search rates for an object target among exemplars. These data provide evidence that observers’ capacity to remember visual information in long-term memory depends more on conceptual structure than perceptual distinctiveness.

Konkle, Talia; Brady, Timothy F.; Alvarez, George A.; Oliva, Aude

2012-01-01

292

Voice assessment: Updates on perceptual, acoustic, aerodynamic, and endoscopic imaging methods  

PubMed Central

Purpose of review This paper describes recent advances in perceptual, acoustic, aerodynamic, and endoscopic imaging methods for assessing voice production. Recent findings Perceptual assessment Speech-language pathologists are being encouraged to use the new CAPE-V inventory for auditory perceptual assessment of voice quality, and recent studies have provided new insights into listener reliability issues that have plagued subjective perceptual judgments of voice quality. Acoustic assessment Progress is being made on the development of algorithms that are more robust for analyzing disordered voices, including the capability to extract voice quality-related measures from running speech segments. Aerodynamic assessment New devices for measuring phonation threshold air pressures and air flows have the potential to serve as sensitive indices of glottal phonatory conditions, and recent developments in aeroacoustic theory may provide new insights into laryngeal sound production mechanisms. Endoscopic imaging The increased light sensitivity of new ultra high-speed color digital video processors is enabling high-quality endoscopic imaging of vocal fold tissue motion at unprecedented image capture rates, which promises to provide new insights into mechanisms of normal and disordered voice production. Summary Some of the recent research advances in voice quality assessment could be more readily adopted into clinical practice, while others will require further development.

Mehta, Daryush D.; Hillman, Robert E.

2013-01-01

293

An Additional Handicap: Visual Perceptual Learning Disabilities of Deaf Children.  

ERIC Educational Resources Information Center

The paper examines issues concerned with the incidence of visual perceptual learning disabilities among deaf and partially hearing children. Evidence indicating a high incidence (15.5 percent of 682 deaf students) of visual perceptual deficits is offered, as is a definition of visual perception. The impact of visual perceptual deficits on…

Ratner, Vivienne

294

Conceptualization of Perceptual Attributes: A Special Case for Color?  

ERIC Educational Resources Information Center

Compared the recognition, perceptual saliency, and naming of color to that of other perceptual object attributes in 2- to 5-year-olds as a function of language age. Found that although color was perceptually salient relative to other visual attributes, no selective impairment to color cognition was found relative to motion, form, and size.…

Pitchford, Nicola J.; Mullen, Kathy T.

2001-01-01

295

Reconciling simplicity and likelihood principles in perceptual organization  

Microsoft Academic Search

How does the perceptual system derive a complex and struc- tured description of the perceptual world from patterns of ac- tivity at the sensory receptors? Two apparently competing theo- ries of perceptual organization have been influential. The first, initiated by Helmholtz ( 1910\\/1962), advocates the likelihood principle: Sensory input will be organized into the most proba- ble distal object or

Nick Chater

1996-01-01

296

Two Forms of Spatial Memory: A Double Dissociation Between the Parietal Cortex and the Hippocampus in the Rat  

Microsoft Academic Search

Two variants of a continuous recognition training procedure were designed in order to query 2 forms of spatial memory. A continuous reinforcement condition (reflecting perceptual memory) and a differential reinforcement condition (reflecting episodic-like memory) were used to test rats on a 12-arm radial maze. After total hippocampal lesions, rats demonstrated intact performance on the continuous reinforcement condition, but impaired performance

Andrea A. Chiba; Raymond P. Kesner; Pamela A. Jackson

2002-01-01

297

Evaluating current deficit theories of poor reading: role of phonological processing, naming speed, balance automaticity, rapid verbal perception and working memory.  

PubMed

To clarify the nature of cognitive deficits experienced by poor readers, 9-10-yr.-old poor readers were matched against 9 chronological age and 9 younger reading age-matched controls screened and selected from regular classrooms. Poor readers performed significantly more poorly than chronological age-matched peers on digit naming speed, spoonerisms, and nonsense word reading. Poor readers were also significantly poorer than reading age-matched controls on nonword reading but were significantly better than reading age-matched controls on postural stability. Analyses of effect sizes were consistent with these findings, showing strong effects for digit naming speed, spoonerisms, and nonword reading. However, effect size analysis also suggested that poor readers experienced moderate difficulties with balance automatisation but did not show verbal speech perception deficits relative to either control PMID:16383062

Savage, Robert; Frederickson, Norah; Goodwin, Roz; Patni, Ulla; Smith, Nicola; Tuersley, Louise

2005-10-01

298

Sensory and Perceptual Functions in the Cerebral Palsied. III. Some Visual Perceptual Relationships  

ERIC Educational Resources Information Center

The relationships between specific aspects of peripheral ocular defects and perceptual deficits were investigated in a cerebral palsied population of 60 spastics, 60 athetoids, and 60 non-neurologically impaired Ss, 7 to 21 years of age. (Author/MC)

Breakey, Arnold Stewart; And Others

1974-01-01

299

Building perceptual textures to visualize multidimensional datasets  

Microsoft Academic Search

This paper presents a new method for using texture to visualize multidimensional data elements arranged on an underlying three- dimensional height field. We hope to use simple texture patterns in combination with other visual features like hue and intensity to in- crease the number of attribute values we can display simultaneously. Our technique builds perceptual texture elements (or pexels) to

Christopher G. Healey; James T. Enns

1998-01-01

300

Perceptual Load Influences Selective Attention across Development  

ERIC Educational Resources Information Center

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…

Couperus, Jane W.

2011-01-01

301

Annotated Bibliography on Perceptual-Motor Development.  

ERIC Educational Resources Information Center

This 115-page annotated bibliography contains material on perceptual motor development. The introductory portion of the bibliography presents general reading on perception, learning, and development. The first portion contains annotated works by six specific authors. The second portion presents works grouped under the following headings: a)…

American Association for Health, Physical Education, and Recreation, Washington, DC.

302

Perceptual Simulation in Developing Language Comprehension  

ERIC Educational Resources Information Center

We tested an embodied account of language proposing that comprehenders create perceptual simulations of the events they hear and read about. In Experiment 1, children (ages 7-13 years) performed a picture verification task. Each picture was preceded by a prerecorded spoken sentence describing an entity whose shape or orientation matched or…

Engelen, Jan A. A.; Bouwmeester, Samantha; de Bruin, Anique B. H.; Zwaan, Rolf A.

2011-01-01

303

Late Maturation of Auditory Perceptual Learning  

ERIC Educational Resources Information Center

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…

Huyck, Julia Jones; Wright, Beverly A.

2011-01-01

304

Perceptual Confusions Among Fricatives in Preschool Children.  

ERIC Educational Resources Information Center

This study examined perceptual and articulatory confusions among the fricatives /f, v, s, z/ and voiced and unvoiced "th" in preschool children. (These phonemes are among the most difficult for children to articulate.) Seventeen children from 3.3-5.1 years of age were tested on syllables formed by taking all combinations of the six fricatives in…

Skeel, Mary H.; And Others

305

DATA-DRIVEN PERCEPTUALLY BASED JOIN COSTS  

Microsoft Academic Search

Concatenative speech synthesis systems attempt to mini- mize audible discontinuities between two successive con- catenated units. In unit selection concatenative synthesis, a join cost is calculated that is intended to predict the extent of audible discontinuity introduced by the concatenation of two specific units. A study was conducted that used hu- man perceptual data on the detectability of mid-vowel con-

Ann K. Syrdal; Alistair D. Conkie

306

Physical Anhedonia, Perceptual Aberration, and Psychosis Proneness  

Microsoft Academic Search

Two groups of hypothetically psychosisprone subjects were chosen from among college students who scored deviantly high on scales of Physical Anhedonia (n = 50) or Perceptual Aberration (n = 65). Scores on these two scales had a small negative correlation, indicating that the scales identify different sets of deviant subjects. These experimental subjects and a control group (n = 66)

Loren J. Chapman; William S. Edell; Jean P. Chapman

1980-01-01

307

Improving Perceptual Skills with 3-Dimensional Animations.  

ERIC Educational Resources Information Center

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)

Johns, Janet Faye; Brander, Julianne Marie

1998-01-01

308

Eeg Changes in Perceptual and Sensory Deprivation.  

National Technical Information Service (NTIS)

Observations on changes in the EEG produced by 7-14 days sensory and perceptual deprivation in healthy young adults have been explored and attempts made to correlate the EEG changes with other factors. Continuous exposure to unpatterned light and noise pr...

M. G. Saunders J. P. Zubek

1967-01-01

309

Perceptual dimensions for a dynamic tactile display  

NASA Astrophysics Data System (ADS)

We propose a new approach for converting graphical and pictorial information into tactile patterns that can be displayed in a static or dynamic tactile device. The key components of the proposed approach are (1) an algorithm that segments a scene into perceptually uniform segments; (2) a procedure for generating perceptually distinct tactile patterns; and (3) a mapping of the visual textures of the segments into tactile textures that convey similar concepts. We used existing digital halftoning and other techniques to generate a wide variety of tactile textures. We then conducted formal and informal subjective tests with sighted (but visually blocked) and visually-impaired subjects to determine the ability of human tactile perception to perceive differences among them. In addition to generating perceptually distinguishable tactile patterns, our goal is to identify significant dimensions of tactile texture perception, which will make it possible to map different visual attributes into independent tactile attributes. Our experimental results indicate that it is poosible to generate a number of perceptually distinguishable tactile patterns, and that different dimensions of tactile texture perception can indeed be identified.

Pappas, Thrasyvoulos N.; Tartter, Vivien C.; Seward, Andrew G.; Genzer, Boris; Gourgey, Karen; Kretzschmar, Ilona

2009-02-01

310

Integration of perceptual information in word access.  

PubMed

According to experiential theories of language comprehension, perceptual information plays an essential role when word meanings are accessed. We conducted four experiments to investigate how different types of perceptual information such as colour and shape are combined during word access. One possibility is that the colour and shape of a word's referent are activated independently from one another and are combined in an additive manner. Alternatively, words might activate perceptual representations via a multiplicative integration of colour and shape. Experiment 1 established that participants follow a multiplicative similarity rule when they judge the similarity of schematic pictures to actual fruits and vegetables. In Experiments 2 to 4, participants performed a classification task, a lexical decision task, or a word-naming task on names of fruits and vegetables that were superimposed on a background picture. Responses were facilitated only when both colour and shape of the picture matched the word's referents. Response times were associated negatively with mean similarity ratings and the consistency of these ratings obtained in the first experiment. These results suggest a multiplicative integration of different types of perceptual information during word access. PMID:19424906

Richter, Tobias; Zwaan, Rolf A

2010-01-01

311

Properties and mechanisms of perceptual priming  

Microsoft Academic Search

Recent evidence suggests that the behavioral phenomenon of perceptual priming and the physiological finding of decreased neural responses with item repetition have similar properties. Both the behavioral and neurophysiological effects show graded changes with multiple repetitions, are resistant to manipulations of particular stimulus attributes (e.g. size and location), and occur independently of awareness. These and other recent findings (e.g. from

Cheri L Wiggs; Alex Martin

1998-01-01

312

Time and Tense in Perceptual Experience  

Microsoft Academic Search

We can not just see, hear or feel how things are at a time, but we also have perceptual experiences as of things moving or changing. I argue that such temporal experiences have a content that is tenseless, i.e. best characterized in terms of notions such as 'before' and 'after' (rather than, say, 'past', 'present' and 'future'), and that such

Christoph Hoerl

2009-01-01

313

Models of Perceptual Learning in Vernier Hyperacuity  

Microsoft Academic Search

Performance of human subjects in a wide variety of early visual processing tasks improveswith practice. HyperBF networks (Poggio and Girosi, 1990) constitute a mathematically wellfoundedframework for understanding such improvement in performance, or perceptual learning,in the class of tasks known as visual hyperacuity. The present article concentrates on two issuesraised by the recent psychophysical and computational findings reported in (Poggio et

Yair Weiss; Shimon Edelman; Manfred Fahle

1993-01-01

314

Using body size to predict perceptual range  

Microsoft Academic Search

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

Stephen G. Mech; Patrick A. Zollner

2002-01-01

315

Perceptual Completion in Newborn Human Infants  

ERIC Educational Resources Information Center

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…

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

2006-01-01

316

SEMANTIC AND PERCEPTUAL REPRESENTATIONS OF COLOR  

Microsoft Academic Search

Perceptual psychology widely operationalizes color appearance as a construct with very close, even isomorphic, ties to color naming structure. Indeed, a considerable body of psychological and psychophysics research uses naming-based tasks to derive structural properties of color ap- pearance space. New research investigating the relations linking color similarity and color naming structures suggest that assumptions involving strong structural correspondences between

Kimberly A. Jameson

317

Perceptual video coding: Challenges and approaches  

Microsoft Academic Search

Investigation on the human perception can play an important role in video signal processing. Recently, there has been great interest in incorporating the human perception in video coding systems to enhance the perceptual quality of the represented visual signal. However, the limited understanding of the human visual system and high complexity of computational models of human visual system make it

Zhenzhong Chen; Weisi Lin; King Ngi Ngan

2010-01-01

318

Achieving perceptually-accurate aural telepresence  

Microsoft Academic Search

Immersive multimedia requires not only realistic visual imagery but also a perceptually-accurate aural experience. A sound field may be presented simultaneously to a listener via a loudspeaker rendering system using the direct sound from acoustic sources as well as a simulation or \\

Paul D. Henderson

2006-01-01

319

Perceptual Adaptation to Non-Native Speech  

ERIC Educational Resources Information Center

This study investigated talker-dependent and talker-independent perceptual adaptation to foreign-accent English. Experiment 1 investigated talker-dependent adaptation by comparing native English listeners' recognition accuracy for Chinese-accented English across single and multiple talker presentation conditions. Results showed that the native…

Bradlow, Ann R.; Bent, Tessa

2008-01-01

320

Saccadic adaptation induced by a perceptual task.  

PubMed

The human motor system and muscles are subject to fluctuations in the short and long term. Motor adaptation is classically thought of as a low-level process that compensates for the error between predicted and executed movements in order to maintain movement accuracy. Contrary to a low-level account, accurate movements might be only a means to support high-level behavioral and perceptual goals. To isolate the influence of high-level goals in adaptation of saccadic eye movements, we manipulated perceptual task requirements in the absence of low-level errors. Observers had to discriminate one character within a peripheral array of characters. Between trials, the location of this character within the array was changed. This manipulation led to an immediate strategic change and a slower, gradual adaptation of saccade amplitude and direction. These changes had a similar magnitude to classical saccade adaptation and transferred at least partially to reactive saccades without a perceptual task. These results suggest that a perceptual task can modify oculomotor commands by generating a top-down error signal in saccade maps just like a bottom-up visual position error. Hence saccade adaptation not only maintains saccadic targeting accuracy, but also optimizes gaze behavior for the behavioral goal, showing that perception shapes even low-level oculomotor mechanisms. PMID:24799623

Schütz, Alexander C; Kerzel, Dirk; Souto, David

2014-01-01

321

The Mirage of the Perceptually Handicapped Syndrome  

ERIC Educational Resources Information Center

Emphasize the importance of a positive diagnosis of perceptual handicap, rather than a wastebasket" diagnosis. The tendency to separate the child's handicap from his feelings about it is reflected in the treatment process. There exists little concern with the totality of the child's development in his total environment. (Author)

West, Malcolm

1970-01-01

322

Electroglottographic and perceptual evaluation of tracheoesophageal speech.  

PubMed

To optimize tracheoesophageal (TO) speech after total laryngectomy, it is vital to have a robust tool of assessment to help investigate deficiencies, document changes, and facilitate therapy. We sought to evaluate and validate electroglottography (EGG) as an important tool in the multidimensional assessment of TO speech. This study is a cross-sectional study of the largest cohort of TO speakers treated by a single surgeon. A second group of normal laryngeal speakers served as a control group. EGG analysis of both groups using connected speech and sustained vowels was performed. Two trained expert raters undertook perceptual evaluation using two accepted scales. EGG measures were then analyzed for correlation with treatment variables. A separate correlation analysis was performed to identify EGG measures that may be associated with perceptual dimensions. Our data from EGG analysis are similar to data obtained from conventional acoustic signal analysis of TO speakers. Sustained vowel and connected speech parameters were poorer in TO speakers than in normal laryngeal speakers. In perceptual evaluation, only grade (G) of the GRBAS scale and Overall Voice Quality appeared reproducible and reliable. T stage, pharyngeal reconstruction and method of closure, cricopharyngeal myotomy, and postoperative complications appear to be correlated with the EGG measures. Five voice measures-jitter, shimmer, average frequency, normalized noise energy, and irregularity-correlated well with the key dimensions of perceptual assessment. EGG is an important assessment tool of TO speech, and can now be reliably used in a clinical setting. PMID:17490856

Kazi, Rehan; Kanagalingam, Jeeve; Venkitaraman, Ramachandran; Prasad, Vyas; Clarke, Peter; Nutting, Christopher M; Rhys-Evans, Peter; Harrington, Kevin J

2009-03-01

323

Infants Experience Perceptual Narrowing for Nonprimate Faces  

ERIC Educational Resources Information Center

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…

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

2011-01-01

324

Cholinesterase inhibitors and memory.  

PubMed

A consensus exists that cholinesterase inhibitors (ChEIs) are efficacious for mild to moderate Alzheimer's Disease (AD). Unfortunately, the number of non-responders is large and the therapeutic effect is usually short-lasting. In experimental animals, ChEIs exert three main actions: inhibit cholinesterase (ChE), increase extracellular levels of brain acetylcholine (ACh), improve cognitive processes, particularly when disrupted in models of AD. In this overview we shall deal with the cognitive processes that are improved by ChEI treatment because they depend on the integrity of brain cholinergic pathways and their activation. The role of cholinergic system in cognition can be investigated using different approaches. Microdialysis experiments demonstrate the involvement of the cholinergic system in attention, working, spatial and explicit memory, information encoding, sensory-motor gating, skill learning. No involvement in long-term memory has yet been demonstrated. Conversely, memory consolidation is facilitated by low cholinergic activity. Experiments on healthy human subjects, notwithstanding caveats concerning age, dose, and different memory tests, confirm the findings of animal experiments and demonstrate that stimulation of the cholinergic system facilitates attention, stimulus detection, perceptual processing and information encoding. It is not clear whether information retrieval may be improved but memory consolidation is reduced by cholinergic activation. ChEI effects in AD patients have been extensively investigated using rating scales that assess cognitive and behavioural responses. Few attempts have been made to identify which scale items respond better to ChEIs and therefore, presumably, depend on the activity of the cholinergic system. Improvement in attention and executive functions, communication, expressive language and mood stability have been reported. Memory consolidation and retrieval may be impaired by high ACh levels. Therefore, considering that in AD the degeneration of the cholinergic system is associated with alteration of other neurotransmitter systems and a diffuse synaptic loss, a limited efficacy of ChEIs on memory processes should be expected. PMID:19941841

Pepeu, Giancarlo; Giovannini, Maria Grazia

2010-09-01

325

Perceptual criteria in the human brain.  

PubMed

A critical component of decision making is the ability to adjust criteria for classifying stimuli. fMRI and drift diffusion models were used to explore the neural representations of perceptual criteria in decision making. The specific focus was on the relative engagement of perceptual- and decision-related neural systems in response to adjustments in perceptual criteria. Human participants classified visual stimuli as big or small based on criteria of different sizes, which effectively biased their choices toward one response over the other. A drift diffusion model was fit to the behavioral data to extract estimates of stimulus size, criterion size, and difficulty for each participant and condition. These parameter values were used as modulated regressors to create a highly constrained model for the fMRI analysis that accounted for several components of the decision process. The results show that perceptual criteria values were reflected by activity in left inferior temporal cortex, a region known to represent objects and their physical properties, whereas stimulus size was reflected by activation in occipital cortex. A frontoparietal network of regions, including dorsolateral prefrontal cortex and superior parietal lobule, corresponded to the decision variables resulting from the downstream stimulus-criterion comparison, independent of stimulus type. The results provide novel evidence that perceptual criteria are represented in stimulus space and serve as inputs to be compared with the presented stimulus, recruiting a common network of decision regions shown to be active in other simple decisions. This work advances our understanding of the neural correlates of decision flexibility and adjustments of behavioral bias. PMID:23175825

White, Corey N; Mumford, Jeanette A; Poldrack, Russell A

2012-11-21

326

Improved phase-change characteristics of Zn-doped amorphous Sb7Te3 films for high-speed and low-power phase change memory  

NASA Astrophysics Data System (ADS)

The superior performance of Zn-doped Sb7Te3 films might be favorable for the application in phase change memory. It was found that Zn dopants were able to suppress phase separation and form single stable Sb2Te crystal grain, diminish the grain size, and enhance the amorphous thermal stability of Sb7Te3 film. Especially, Zn30.19(Sb7Te3)69.81 film has higher crystallization temperature (~258 °C), larger crystallization activation energy (~4.15 eV), better data retention (~170.6 °C for 10 yr), wider band gap (~0.73 eV), and higher crystalline resistance. The minimum times for crystallization of Zn30.19(Sb7Te3)69.81 were revealed to be as short as ~10 ns at a given proper laser power of 70 mW.

Wang, Guoxiang; Shen, Xiang; Nie, Qiuhua; Wang, R. P.; Wu, Liangcai; Lu, Yegang; Dai, Shixun; Xu, Tiefeng; Chen, Yimin

2013-07-01

327

Phase-change material Ge0.61Sb2Te for application in high-speed phase change random access memory  

NASA Astrophysics Data System (ADS)

Compared with Ge2Sb2Te5, Ge0.61Sb2Te has higher crystallization temperature (~200.5 °C), larger crystallization activation energy (~3.28 eV), and better data retention (~120.8 °C for 10 yr). The switching between amorphous and crystalline state could be triggered by the electric pulse of as short as 10 ns. With the resistance ratio of two orders of magnitude, the endurance test was up to 106 cycles. Ge0.61Sb2Te material is a promising candidate for the trade-off between programming speed and data retention.

Gu, Yifeng; Song, Sannian; Song, Zhitang; Bai, Suyuan; Cheng, Yan; Zhang, Zhonghua; Liu, Bo; Feng, Songlin

2013-03-01

328

Mechanical memory  

DOEpatents

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.

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

329

Mechanical memory  

DOEpatents

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.

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

330

Visual short-term memory load strengthens selective attention.  

PubMed

Perceptual load theory accounts for many attentional phenomena; however, its mechanism remains elusive because it invokes underspecified attentional resources. Recent dual-task evidence has revealed that a concurrent visual short-term memory (VSTM) load slows visual search and reduces contrast sensitivity, but it is unknown whether a VSTM load also constricts attention in a canonical perceptual load task. If attentional selection draws upon VSTM resources, then distraction effects-which measure attentional "spill-over"-will be reduced as competition for resources increases. Observers performed a low perceptual load flanker task during the delay period of a VSTM change detection task. We observed a reduction of the flanker effect in the perceptual load task as a function of increasing concurrent VSTM load. These findings were not due to perceptual-level interactions between the physical displays of the two tasks. Our findings suggest that perceptual representations of distractor stimuli compete with the maintenance of visual representations held in memory. We conclude that access to VSTM determines the degree of attentional selectivity; when VSTM is not completely taxed, it is more likely for task-irrelevant items to be consolidated and, consequently, affect responses. The "resources" hypothesized by load theory are at least partly mnemonic in nature, due to the strong correspondence they share with VSTM capacity. PMID:24002967

Roper, Zachary J J; Vecera, Shaun P

2014-04-01

331

Perceptual versus mediational learning in a total change concept-shift paradigm.  

PubMed

The experiment investigated the effects of language acquisition by children in Grades 1 to 4 on performance in a concept-shift task in which the relevant stimulus attributes were either the colour of ink in which a word was written or the meaning of the word. Both English stream and French Immersion children served as subjects. The results indicated a developmental sequence from perceptual learning to verbal mediation. This process was demonstrated at an earlier stage in the French Immersion students who formed a more highly selected group, and intellectual or socio-economic explanations for these differences may be feasible. The relative speed of acquisition of intradimensional and extradimensional shifts interacts with the perceptual/mediational process. PMID:662558

Harpur, J G; Estabrooks, K A; Allen, N J; Asaph, C A

1978-04-01

332

Methods for memory assignment schemes and architecture for shareable parallel memory module based internet switches  

US Patent & Trademark Office Database

Systems and methods are described for high-speed memory assignment schemes for routing packets in a sharable parallel memory module based switch system. A method includes receiving a parameter, determining availability of memory location, determining if an available memory location is pre-assigned, and assigning a packet a parameter if the memory location is available. Systems of the present invention provides hardware and/or software based components for implementing the steps of receiving a parameter, determining available memory location, determining if available memory location is pre-assigned, and assigning a packet a parameter if the memory location is available.

2009-05-12

333

The Neurobiology of Semantic Memory  

PubMed Central

Semantic memory includes all acquired knowledge about the world and is the basis for nearly all human activity, yet its neurobiological foundation is only now becoming clear. Recent neuroimaging studies demonstrate two striking results: the participation of modality-specific sensory, motor, and emotion systems in language comprehension, and the existence of large brain regions that participate in comprehension tasks but are not modality-specific. These latter regions, which include the inferior parietal lobe and much of the temporal lobe, lie at convergences of multiple perceptual processing streams. These convergences enable increasingly abstract, supramodal representations of perceptual experience that support a variety of conceptual functions including object recognition, social cognition, language, and the remarkable human capacity to remember the past and imagine the future.

Binder, Jeffrey R.; Desai, Rutvik H.

2011-01-01

334

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

SciTech Connect

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.

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

1990-09-21

335

A coarse-grained analysis of the functional brain connectivity from EEG recordings of a visuo-perceptual discrimination task  

NASA Astrophysics Data System (ADS)

We report the emergent functional connectivity of cortical areas during a visuo-perceptual discrimination task with or without the retention in memory of the location of visual targets using EEG. The networks were computed using multivariate Granger causality on groups of electrodes reflecting coarse-grained brain areas. The analysis showed that at alpha band (8-12Hz) there are no significant differences. In contrast, in beta and gamma band, we identified a top-down information flow pattern which was evident for the task that required the activation of the working memory mechanism.

Protopapa, Foteini; Mylonas, Dimitris; Smyrnis, Nikolaos; Siettos, Constantinos

2013-10-01

336

Dual phase TiO(x)N(y)/TiN charge trapping layer for low-voltage and high-speed flash memory application.  

PubMed

Flash memory using a dual phase TiO(x)N(y)/TiN charge trapping layer has been fabricated and its electrical properties were investigated. The TiO(x)N(y)/TiN layer was formed by partial oxidation of a pre-deposited TiN layer, and the formation of TiO(x)N(y)/SiO(x)N(y) was confirmed by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The enlarged conduction (deltaphi(c) = 3.6 eV) and valence (deltaphi(v) = 2.5 eV) band offsets of the TiO(x)N(y)/TiN to SiO2 enabled low-voltage (+/- 6 V) and fast programming/erasing (P: 2.7 x 10(4) V/s and E: -5.1 x 10(4) V/s) operations, while the transition layer suppressed the trapped charge leakage, giving rise to good 10-year data retention with less than 35% V(th) decay. PMID:19908806

Zhang, Gang; Yoo, Won Jong

2009-12-01

337

Decoding oscillatory representations and mechanisms in memory.  

PubMed

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

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

2013-03-01

338

Current Status of Nonvolatile Semiconductor Memory Technology  

NASA Astrophysics Data System (ADS)

In this report, an overview of the current status of nonvolatile semiconductor memory technology is presented. We are reaching the integration limit of flash memories, and many new types of memories to replace conventional flash memories have been proposed. Unlike flash memories, new nonvolatile memories do not require electric charge storing. The possibility of phase-change random access memory (PRAM) or resistive-change RAM (ReRAM) replacing ultrahigh-density NAND flash memories has been discussed; however, there are many issues to overcome, making the replacement difficult. Nonetheless, ferroelectric RAMs (FeRAMs) and MRAMs are gradually penetrating into fields where the shortcomings of flash memories, such as high operating voltage, slow rewriting speed, and limited number of rewrites, make their use inconvenient. For the successful application of new nonvolatile semiconductor memories, they must be practically utilized in new fields in which flash memories are not applicable, and the technology for them must be developed.

Fujisaki, Yoshihisa

2010-10-01

339

A perceptual metric for photo retouching  

PubMed Central

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.

Kee, Eric; Farid, Hany

2011-01-01

340

Perceptual Spaces: Mathematical Structures to Neural Mechanisms  

PubMed Central

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.

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

2013-01-01

341

Perceptual spaces: mathematical structures to neural mechanisms.  

PubMed

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

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

2013-11-01

342

Conflict adjustment devoid of perceptual selection.  

PubMed

Task performance suffers when an aspect of a stimulus is associated with an incorrect response, thereby evoking cognitive conflict. Such impairment is reduced after recent or frequent conflict occurrence, suggesting attentional adjustment. We examined adjustment to conflict evoked by a temporarily irrelevant S-R rule when participants frequently switched between two semantic classification tasks by manipulating the proportion of conflict trials in one of them. Controlling stimulus-specific presentation frequencies, we found reduced conflict effects under conditions of a higher proportion of conflict trials in the task to which the manipulation was applied, whereas there was no such effect in the other task. Additional analyses demonstrated task-specificity regarding trial-to-trial conflict adjustment. Because conflict was evoked in the absence of perceptually distinct target and distractor stimulus features, these adjustment effects cannot be attributed to perceptual selection. PMID:23743343

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

2013-09-01

343

The role of source memory in older adults' recollective experience.  

PubMed

Younger adults' "remember" judgments are accompanied by better memory for the source of an item than "know" judgments. Furthermore, remember judgments are not merely associated with better memory for individual source features but also with bound memory for multiple source features. However, older adults, independent of their subjective memory experience, are generally less likely to "bind" source features to an item and to each other in memory (i.e., the associative deficit). In two experiments, we tested whether memory for perceptual source features, independently or bound, is also the basis for older adults' remember responses or if their associative deficit leads them to base their responses on other types of information. The results suggest that retrieval of perceptual source features, individually or bound, forms the basis for younger but not for older adults' remember judgments even when the overall level of memory for perceptual sources is closely equated (Experiment 1) and when attention is explicitly directed to the source information at encoding (Experiment 2). PMID:21843008

Boywitt, C Dennis; Kuhlmann, Beatrice G; Meiser, Thorsten

2012-06-01

344

Perceptual Phenomena in the Agenda Setting Process  

Microsoft Academic Search

The integration of formerly isolated theoretical concepts is probably one of the most challenging tasks in the development of media effects theory. While agenda setting has already been linked to priming and framing via the concept of second level agenda-setting, this article takes a closer look into perceptual phenomena within the agenda-setting process, thus linking micro-level psychological theories with macro-level

Inga Huck; Oliver Quiring; Hans-Bernd Brosius

2009-01-01

345

Sequential priming of 3-D perceptual organization  

Microsoft Academic Search

In four experiments, the effects of sequential priming on the perceptual organization of complex three-dimensional (3-D) displays\\u000a were examined. Observers were asked to view stereoscopic arrays and to search an embedded subset of items for an odd-colored\\u000a target while 3-D orientation of the stimuli was varied randomly between trials. Search times decreased reliably when 3-D stimulus\\u000a orientation was unchanged on

Jason S. McCarley; Zijiang J. He

2001-01-01

346

Perceptual uniformity of commonly used color spaces  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

347

Conceptual Distinctiveness Supports Detailed Visual Long-Term Memory for Real-World Objects  

ERIC Educational Resources Information Center

Humans have a massive capacity to store detailed information in visual long-term memory. The present studies explored the fidelity of these visual long-term memory representations and examined how conceptual and perceptual features of object categories support this capacity. Observers viewed 2,800 object images with a different number of exemplars…

Konkle, Talia; Brady, Timothy F.; Alvarez, George A.; Oliva, Aude

2010-01-01

348

Self-stimulatory behavior and perceptual reinforcement.  

PubMed Central

Self-stimulatory behavior is repetitive, stereotyped, functionally autonomous behavior seen in both normal and developmentally disabled populations, yet no satisfactory theory of its development and major characteristics has previously been offered. We present here a detailed hypothesis of the acquisition and maintenance of self-stimulatory behavior, proposing that the behaviors are operant responses whose reinforcers are automatically produced interoceptive and exteroceptive perceptual consequences. The concept of perceptual stimuli and reinforcers, the durability of self-stimulatory behaviors, the sensory extinction effect, the inverse relationship between self-stimulatory and other behaviors, the blocking effect of self-stimulatory behavior on new learning, and response substitution effects are discussed in terms of the hypothesis. Support for the hypothesis from the areas of sensory reinforcement and sensory deprivation is also reviewed. Limitations of major alternative theories are discussed, along with implications of the perceptual reinforcement hypothesis for the treatment of excessive self-stimulatory behavior and for theoretical conceptualizations of functionally related normal and pathological behaviors.

Lovaas, I; Newsom, C; Hickman, C

1987-01-01

349

Perceptual relevance of source spectral slope measures  

NASA Astrophysics Data System (ADS)

Researchers broadly agree that the spectral slope of the voice source is an important concomitant of voice quality. Many measures of source spectral slope have been proposed, including the relative amplitudes of the lowest few harmonics, the ratio of energy in low- versus high-frequency bands, and the average deviation from an ideal slope. It is unclear which (if any) of these measures best reflects the differences in vocal quality that result from the underlying acoustic variability. To examine this issue, a large corpus of voice samples was inverse filtered, and spectra were calculated for resulting source pulses. Different measures of spectral slope were calculated for each voice, and correlations among measures were examined. Finally, several series of synthetic stimuli were created in which only the source spectral slope varied in steps. Listeners judged the similarity of stimuli within each series. Similarity responses were evaluated with multidimensional scaling, and the resulting perceptual spaces were interpreted in terms of the different measures of source spectral slope. Measures that are highly correlated with the perceptual spaces reflect perceptually important aspects of the source signal. [Research supported by NIDCD.

Kreiman, Jody; Gerratt, Bruce R.

2001-05-01

350

Learning problems, delayed perceptual development, and puberty  

NASA Astrophysics Data System (ADS)

Language-based learning problems affect approximately one person in twelve with no other obvious signs of disorder. Many of these individuals have accompanying deficits in nonlinguistic perception. To determine whether age influences the magnitude of these deficits, thresholds on a set of auditory masking tasks were measured in individuals with learning problems and controls ranging in age from 6 years to adult. Performance improved with increasing age in both groups. However, the thresholds of the individuals with learning problems were most similar to those of controls approximately 2-4 years younger on every task, suggesting that the perceptual development of the affected individuals was delayed by a constant amount. Further, on the subset of conditions on which controls reached adult levels of performance after 10 years of age, the improvement of affected individuals halted at 10 years of age, suggesting that puberty may play a critical role in human perceptual development. Taken together, these data support the idea that some learning problems result from a neuromaturational delay, of unknown breadth, and indicate that neurological changes associated with puberty prevent the complete resolution of delayed perceptual development. [Work supported by NIH/NIDCD.

Wright, Beverly A.; Zecker, Steven G.; Reid, Miriam D.

2003-04-01

351

Perceptual asymmetries and handedness: a neglected link?  

PubMed Central

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.

Marzoli, Daniele; Prete, Giulia; Tommasi, Luca

2014-01-01

352

Generalized perceptual features for animal vocalization classification  

NASA Astrophysics Data System (ADS)

Two sets of generalized, perceptual-based features are investigated for use in classifying animal vocalizations. Since many species, especially mammals, share similar physical sound perception mechanisms which vary in size, two features sets commonly used in human speech processing, mel-frequency cepstral coefficients (MFCCs) and perceptual linear prediction (PLP) analysis, are modified for use in other species. One modification made to the feature extraction process is incorporating the frequency range of hearing and length of the basilar membrane of the animal in order to correctly determine the width and location of the critical band filters used for signal processing. Experimentally determined critical bands (equivalent rectangular bandwidth) and equal loudness curves (audiograms) can also be incorporated directly into the feature extraction process. Experiments are performed on African elephant (Loxodonta africana) vocalizations using a hidden Markov model (HMM) based classifier showing increased classification accuracy when using features sets based on the specific animals perceptual abilities compared to the original human perception-based feature sets.

Clemins, Patrick J.; Johnson, Michael T.

2001-05-01

353

Perceptual asymmetries and handedness: a neglected link?  

PubMed

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

Marzoli, Daniele; Prete, Giulia; Tommasi, Luca

2014-01-01

354

Solid State Memory Study Final Report  

NASA Technical Reports Server (NTRS)

Existing and future solid state nonvolatile memory technologies are described and evaluated in this report. Solid state memory technologies can offer size, speed, power, weight, and ruggedness advantages over conventional moving media storage technologoies such as disk or tape. This technology list is a broad sampling of past, present, emerging, and future solid state memory technologies.

Katti, R.

1994-01-01

355

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

PubMed

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

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

2014-06-01

356

Influence of early attentional modulation on working memory.  

PubMed

It is now established that attention influences working memory (WM) at multiple processing stages. This liaison between attention and WM poses several interesting empirical questions. Notably, does attention impact WM via its influences on early perceptual processing? If so, what are the critical factors at play in this attention-perception-WM interaction. I review recent data from our laboratory utilizing a variety of techniques (electroencephalography (EEG), functional MRI (fMRI) and transcranial magnetic stimulation (TMS)), stimuli (features and complex objects), novel experimental paradigms, and research populations (younger and older adults), which converge to support the conclusion that top-down modulation of visual cortical activity at early perceptual processing stages (100-200 ms after stimulus onset) impacts subsequent WM performance. Factors that affect attentional control at this stage include cognitive load, task practice, perceptual training, and aging. These developments highlight the complex and dynamic relationships among perception, attention, and memory. PMID:21184764

Gazzaley, Adam

2011-05-01

357

Perceived visual speed constrained by image segmentation  

NASA Technical Reports Server (NTRS)

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.

Verghese, P.; Stone, L. S.

1996-01-01

358

Perceptual mapping using the basic structure matrix decomposition  

Microsoft Academic Search

Perceptual mapping techniques are used to graphically represent perceptions of brands in a category, companies in an industry,\\u000a and so forth. The data required to construct perceptual maps using typical methods can be difficult for respondents to provide\\u000a and time-consuming to collect. An alternative, but relatively obscure perceptual mapping technique is rooted in correspondence\\u000a analysis, and involves a fundamental matrix

Richard J. Fox

1988-01-01

359

Impaired information-processing speed and working memory in leukoencephalopathy with brainstem and spinal cord involvement and elevated lactate (LBSL) and DARS2 mutations: a report of three adult patients.  

PubMed

Leukoencephalopathy with brainstem and spinal cord involvement and elevated lactate (LBSL) is clinically characterized by progressive pyramidal and cerebellar dysfunction, dorsal column dysfunction and sometimes with axonal neuropathy. Magnetic resonance imaging of brain and the spinal cord reveals characteristic findings. LBSL is caused by mutations in the DARS2 gene that encodes the mitochondrial aspartyl-tRNA synthetase. The presentation and clinical course of LBSL is not uniform, and there is lack of longitudinal data on these patients. In addition, the existing data on the prevalence and characteristics of cognitive abnormalities in patients with LBSL are scarce and somewhat conflicting. Here we report long-term data of neurological and cognitive functioning in three non-related adult patients with LBSL. Cognitive impairment seems to be common among patients with LBSL and DARS2 mutations. The cognitive profile in LBSL shares similarities with that reported in multiple sclerosis, as information-processing speed and working memory are especially affected. In addition, our results and the previously reported carrier frequencies of common pathogenic DARS2 mutations suggest that LBSL may be underdiagnosed in the population. PMID:23652419

Martikainen, Mika H; Ellfolk, Ulla; Majamaa, Kari

2013-08-01

360

False Memories for Suggestions: The Impact of Conceptual Elaboration  

ERIC Educational Resources Information Center

Relatively little attention has been paid to the potential role that reflecting on the meaning and implications of suggested events (i.e., conceptual elaboration) might play in promoting the creation of false memories. Two experiments assessed whether encouraging repeated conceptual elaboration, would, like perceptual elaboration, increase false…

Zaragoza, Maria S.; Mitchell, Karen J.; Payment, Kristie; Drivdahl, Sarah

2011-01-01

361

Event Boundaries in Perception Affect Memory Encoding and Updating  

PubMed Central

Memory for naturalistic events over short delays is important for visual scene processing, reading comprehension, and social interaction. The research presented here examined relations between how an ongoing activity is perceptually segmented into events and how those events are remembered a few seconds later. In several studies participants watched movie clips that presented objects in the context of goal-directed activities. Five seconds after an object was presented, the clip paused for a recognition test. Performance on the recognition test depended on the occurrence of perceptual event boundaries. Objects that were present when an event boundary occurred were better recognized than other objects, suggesting that event boundaries structure the contents of memory. This effect was strongest when an object’s type was tested, but was also observed for objects’ perceptual features. Memory also depended on whether an event boundary occurred between presentation and test; this variable produced complex interactive effects that suggested that the contents of memory are updated at event boundaries. These data indicate that perceptual event boundaries have immediate consequences for what, when, and how easily information can be remembered.

Swallow, Khena M.; Zacks, Jeffrey M.; Abrams, Richard A.

2010-01-01

362

Working Memory Enhances Visual Perception: Evidence from Signal Detection Analysis  

ERIC Educational Resources Information Center

We show that perceptual sensitivity to visual stimuli can be modulated by matches between the contents of working memory (WM) and stimuli in the visual field. Observers were presented with an object cue (to hold in WM or to merely attend) and subsequently had to identify a brief target presented within a colored shape. The cue could be…

Soto, David; Wriglesworth, Alice; Bahrami-Balani, Alex; Humphreys, Glyn W.

2010-01-01

363

Intersensory Redundancy Enhances Memory in Bobwhite Quail Embryos  

ERIC Educational Resources Information Center

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.…

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

2004-01-01

364

Cognitive approaches to the development of short-term memory  

Microsoft Academic Search

The capacity to retain information for brief periods of time increases dramatically during the childhood years. The increases in temporary storage of speech-based material that take place in the period spanning the pre-school years and adolescence reflect complex changes in many of the different component processes, including perceptual analysis, construction and maintenance of a memory trace, retention of order information,

Susan E. Gathercole

1999-01-01

365

Evaluation of Three Content-Addressable Memory Systems Using Glass Delay Lines.  

National Technical Information Service (NTIS)

Evaluation is made of three content-addressable (associative) digital memory system organizations using a circulating memory. Specific reference is made to glass delay-line memories since they offer the best solution to high-speed circulating storage. The...

P. T. Rux

1967-01-01

366

Variability-based Garner interference for perceptual estimations but not for grasping.  

PubMed

Garner's speeded classification task has been used as an effective tool to probe holistic processing of object shape. This is achieved by comparing classification performance of a given object dimension between two experimental conditions. Worse performance in a "filtering" condition in which a second, irrelevant dimension of the same object varies on a trial-to-trial basis, compared to a "baseline" condition in which the irrelevant dimension is held constant, is labeled Garner interference, and indicates that the two dimensions are processed in a holistic manner. About a decade ago, we used Garner's task to provide evidence for different frames of processing mediating action and perception. Unlike perceptual estimations, visually guided grasping showed no Garner interference when subjects were asked to reach out and grasp an object along a given dimension. In other words, slower reaction times were observed in the filtering compared to the baseline condition only for perceptual estimates but not for grasping. In two experiments, we extend these findings to kinematic measures beyond simple reaction times. The results showed that Garner interference is also expressed in the variability of the response, with more variable within-subject performance in the filtering compared to the baseline condition for perceptual estimates but not for grasping. These findings provide converging evidence for the idea that, unlike perception, which processes objects holistically, visually guided action is performed in an analytic manner. PMID:24534914

Ganel, Tzvi; Goodale, Melvyn A

2014-06-01

367

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

PubMed

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

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

2011-06-01

368

When more equals less: overtraining inhibits perceptual learning owing to lack of wakeful consolidation  

PubMed Central

Performance on perceptual tasks usually improves with training. However, too much consecutive training can be detrimental. Repeated within-day testing or overtraining demonstrates the detrimental effects this has on perceptual learning. Consolidation of learnt information during sleep has the power to prevent such deficits in learning. However, little is known regarding the role of wakeful consolidation in preventing the effects of overtraining. Here, we report that perceptual deterioration may result from the disruption of early wakeful consolidation processes. Three groups were tested on day 1 and again 24 h later, on a motion discrimination task. Participants who had a 1 h break between the two training sessions on the first day displayed improved accuracy on the second day (i.e. learning). Subjects who only completed the first training session on day 1 also exhibited learning. However, individuals who completed two blocks without a break (‘overtraining’) showed no improvement in accuracy on day 2. Interestingly, changes in reaction times were not susceptible to the effects of overtraining, but instead speeded up as a function of total performed trials. These data suggest that effects of overtraining might be due to disruption of wakeful consolidation processes.

Ashley, Soren; Pearson, Joel

2012-01-01

369

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

PubMed

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

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

2014-03-01

370

The Role of Textured Material in Supporting Perceptual-Motor Functions  

PubMed Central

Simple deformation of the skin surface with textured materials can improve human perceptual-motor performance. The implications of these findings are inexpensive, adaptable and easily integrated clothing, equipment and tools for improving perceptual-motor functionality. However, some clarification is needed because mixed results have been reported in the literature, highlighting positive, absent and/or negative effects of added texture on measures of perceptual-motor performance. Therefore the aim of this study was to evaluate the efficacy of textured materials for enhancing perceptual-motor functionality. The systematic review uncovered two variables suitable for sub-group analysis within and between studies: participant age (groupings were 18–51 years and 64.7–79.4 years) and experimental task (upright balance and walking). Evaluation of studies that observed texture effects during upright balance tasks, uncovered two additional candidate sub-groups for future work: vision (eyes open and eyes closed) and stability (stable and unstable). Meta-analysis (random effects) revealed that young participants improve performance by a small to moderate amount in upright balance tasks with added texture (SMD?=?0.28, 95%CI?=?0.46–0.09, Z?=?2.99, P?=?0.001; Tau2?=?0.02; Chi2?=?9.87, df?=?6, P?=?0.13; I2?=?39.22). Significant heterogeneity was found in, the overall effect of texture: Tau2?=?0.13; Chi2?=?130.71, df?=?26, P<0.0001; I2?=?85.98%, pooled samples in upright balance tasks: Tau2?=?0.09; Chi2?=?101.57, df?=?13, P<0.001; I2?=?72.67%, and in elderly in upright balance tasks: Tau2?=?0.16; Chi2?=?39.42, df?=?5, P<0.001; I2?=?83.05%. No effect was shown for walking tasks: Tau2?=?0.00; Chi2?=?3.45, df?=?4, P?=?0.27, I2?=?22.99%. Data provides unequivocal support for utilizing textured materials in young healthy populations for improving perceptual-motor performance. Future research is needed in young healthy populations under conditions where visual and proprioceptive information is challenged, as in high-speed movements, or where use of equipment mediates the performer-environment interaction or where dysfunctional information sources ‘compete’ for attention. In elderly and ailing populations data suggests further research is required to better understand contexts where texture can facilitate improved perceptual-motor performance.

Orth, Dominic; Davids, Keith; Wheat, Jon; Seifert, Ludovic; Liukkonen, Jarmo; Jaakkola, Timo; Ashford, Derek; Kerr, Graham

2013-01-01

371

Dazzle camouflage affects speed perception.  

PubMed

Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called "dazzle camouflage". Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle. PMID:21673797

Scott-Samuel, Nicholas E; Baddeley, Roland; Palmer, Chloe E; Cuthill, Innes C

2011-01-01

372

Dazzle Camouflage Affects Speed Perception  

PubMed Central

Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called “dazzle camouflage”. Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

Scott-Samuel, Nicholas E.; Baddeley, Roland; Palmer, Chloe E.; Cuthill, Innes C.

2011-01-01

373

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

ERIC Educational Resources Information Center

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…

Ratcliff, Roger; Smith, Philip L.

2010-01-01

374

Acoustic and perceptual evaluation of Mandarin tone productions before and after perceptual training  

Microsoft Academic Search

Training American listeners to perceive Mandarin tones has been shown to be effective, with trainees' identification improving by 21%. Improvement also generalized to new stimuli and new talkers, and was retained when tested six months after training [Y. Wang et al., J. Acoust. Soc. Am. 106, 3649-3658 (1999)]. The present study investigates whether the tone contrasts gained perceptually transferred to

Yue Wang; Allard Jongman; Joan A. Sereno

2003-01-01

375

Embedded test for a new memory-card architecture  

Microsoft Academic Search

Requirements for a new Cray Inc. computer system mean that the system's memory cards have high-speed SerDes interfaces and multiple memory controllers in a semicustom IC close to the memory chips. As a result, the functionality of a card is much greater than is current practice, and the cards can not be connected to existing memory testers. An embedded test

D. Resnick

2004-01-01

376

An integrated reweighting theory of perceptual learning  

PubMed Central

Improvements in performance on visual tasks due to practice are often specific to a retinal position or stimulus feature. Many researchers suggest that specific perceptual learning alters selective retinotopic representations in early visual analysis. However, transfer is almost always practically advantageous, and it does occur. If perceptual learning alters location-specific representations, how does it transfer to new locations? An integrated reweighting theory explains transfer over retinal locations by incorporating higher level location-independent representations into a multilevel learning system. Location transfer is mediated through location-independent representations, whereas stimulus feature transfer is determined by stimulus similarity at both location-specific and location-independent levels. Transfer to new locations/positions differs fundamentally from transfer to new stimuli. After substantial initial training on an orientation discrimination task, switches to a new location or position are compared with switches to new orientations in the same position, or switches of both. Position switches led to the highest degree of transfer, whereas orientation switches led to the highest levels of specificity. A computational model of integrated reweighting is developed and tested that incorporates the details of the stimuli and the experiment. Transfer to an identical orientation task in a new position is mediated via more broadly tuned location-invariant representations, whereas changing orientation in the same position invokes interference or independent learning of the new orientations at both levels, reflecting stimulus dissimilarity. Consistent with single-cell recording studies, perceptual learning alters the weighting of both early and midlevel representations of the visual system.

Dosher, Barbara Anne; Jeter, Pamela; Liu, Jiajuan; Lu, Zhong-Lin

2013-01-01

377

The Nature of the Influence of Speed on Adult Age Differences in Cognition.  

ERIC Educational Resources Information Center

Two studies of adults between the ages of 18 and 87 were conducted to determine the relations among age, motor speed, perceptual speed and 3 measures of cognitive performance: study time, decision time, and decision accuracy. Results indicated that increased age was associated with lower accuracy as well as with longer study and decision time.…

Salthouse, Timothy A.

1994-01-01

378

JPEG 2000 Encoding with Perceptual Distortion Control  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

379

Perceptual-components architecture for digital video  

NASA Technical Reports Server (NTRS)

A perceptual-components architecture for digital video partitions the image stream into signal components in a manner analogous to that used in the human visual system. These components consist of achromatic and opponent color channels, divided into static and motion channels, further divided into bands of particular spatial frequency and orientation. Bits are allocated to an individual band in accord with visual sensitivity to that band and in accord with the properties of visual masking. This architecture is argued to have desirable features such as efficiency, error tolerance, scalability, device independence, and extensibility.

Watson, Andrew B.

1990-01-01

380

Implicit Memory in Music and Language  

PubMed Central

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.

Ettlinger, Marc; Margulis, Elizabeth H.; Wong, Patrick C. M.

2011-01-01

381

Ongoing behavior predicts perceptual report of interval duration.  

PubMed

The ability to estimate the passage of time is essential for adaptive behavior in complex environments. Yet, it is not known how the brain encodes time over the durations necessary to explain animal behavior. Under temporally structured reinforcement schedules, animals tend to develop temporally structured behavior, and interval timing has been suggested to be accomplished by learning sequences of behavioral states. If this is true, trial to trial fluctuations in behavioral sequences should be predictive of fluctuations in time estimation. We trained rodents in an duration categorization task while continuously monitoring their behavior with a high speed camera. Animals developed highly reproducible behavioral sequences during the interval being timed. Moreover, those sequences were often predictive of perceptual report from early in the trial, providing support to the idea that animals may use learned behavioral patterns to estimate the duration of time intervals. To better resolve the issue, we propose that continuous and simultaneous behavioral and neural monitoring will enable identification of neural activity related to time perception that is not explained by ongoing behavior. PMID:24672473

Gouvêa, Thiago S; Monteiro, Tiago; Soares, Sofia; Atallah, Bassam V; Paton, Joseph J

2014-01-01

382

Perceptual separability of featural and configural information in congenital prosopagnosia.  

PubMed

The deficit in face recognition in individuals with prosopagnosia has often been attributed to an underlying impairment in holistic processing. Exactly what constitutes holistic processing has remained controversial, however. Here, we compare how configural information and featural information interact during face processing in a group of individuals with congenital prosopagnosia (CP) and matched controls. We adopted Amishav and Kimchi's version of Garner's speeded classification task, in which observers classify upright faces based on configural (intereyes and nose-mouth spacing) or featural (shape of eyes, nose, and mouth) information while the other dimension remains constant or varied randomly. We replicated the finding that normal observers evince symmetric Garner interference--failure to selectively attend to features without being influenced by irrelevant variation in configuration, and vice versa--indicating that featural and configural information are integral in normal face processing. In contrast, the CPs showed no Garner interference: They were able to attend to configural information without interference from irrelevant variation in featural information, and they were able to attend to featural information without interference from irrelevant variation in configural information. The absence of Garner interference in CP provides strong evidence that featural information and configural information are perceptually separable in CP's face processing. These findings indicate that CPs do not perceive faces holistically; rather, they process featural and configural information independently. PMID:23428081

Kimchi, Ruth; Behrmann, Marlene; Avidan, Galia; Amishav, Rama

2012-01-01

383

Auditory Perceptual Learning for Speech Perception Can be Enhanced by Audiovisual Training  

PubMed Central

Speech perception under audiovisual (AV) conditions is well known to confer benefits to perception such as increased speed and accuracy. Here, we investigated how AV training might benefit or impede auditory perceptual learning of speech degraded by vocoding. In Experiments 1 and 3, participants learned paired associations between vocoded spoken nonsense words and nonsense pictures. In Experiment 1, paired-associates (PA) AV training of one group of participants was compared with audio-only (AO) training of another group. When tested under AO conditions, the AV-trained group was significantly more accurate than the AO-trained group. In addition, pre- and post-training AO forced-choice consonant identification with untrained nonsense words showed that AV-trained participants had learned significantly more than AO participants. The pattern of results pointed to their having learned at the level of the auditory phonetic features of the vocoded stimuli. Experiment 2, a no-training control with testing and re-testing on the AO consonant identification, showed that the controls were as accurate as the AO-trained participants in Experiment 1 but less accurate than the AV-trained participants. In Experiment 3, PA training alternated AV and AO conditions on a list-by-list basis within participants, and training was to criterion (92% correct). PA training with AO stimuli was reliably more effective than training with AV stimuli. We explain these discrepant results in terms of the so-called “reverse hierarchy theory” of perceptual learning and in terms of the diverse multisensory and unisensory processing resources available to speech perception. We propose that early AV speech integration can potentially impede auditory perceptual learning; but visual top-down access to relevant auditory features can promote auditory perceptual learning.

Bernstein, Lynne E.; Auer, Edward T.; Eberhardt, Silvio P.; Jiang, Jintao

2013-01-01

384

Action control: Independent effects of memory and monocular viewing on reaching accuracy  

Microsoft Academic Search

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 action arise from a common mechanism as suggested by evidence

David A. Westwood; Christopher Robertson; Matthew Heath

2005-01-01

385

Developmental Skills of Advantaged and Disadvantaged Children of Perceptual Tasks  

ERIC Educational Resources Information Center

A group of perceptual and motor tests were administered to 155 advantaged and disadvantaged student. The results are discussed in terms of differential perceptual-motor and motor growth and need to structure educational experience that will contribute to growth. (Author)

Richmond, Bert O.; Aliotti, Nicholas C.

1977-01-01

386

A study on thresholds of perceptual size on geometric figures  

Microsoft Academic Search

geometric figures such as triangles, squares, pentagons, and circles are frequently used as the visual elements for the expression in graphic design and other basic design training courses. Many studies indicated that the perceptual accuracy of area sizes varied from geometric figures. This study aims to explore the perceptual accuracy of area size of four geometric figures, among them are:

Hsinfu Huang; Dengchuan Cai; Yingtzu Chen

387

Selective Attention to Perceptual Dimensions and Switching between Dimensions  

ERIC Educational Resources Information Center

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…

Meiran, Nachshon; Dimov, Eduard; Ganel, Tzvi

2013-01-01

388

Recent improvements on perceptual processing using DAF wavelets  

Microsoft Academic Search

New wavelet techniques are designed to improve the perceptual quality of images\\/signal, enhance and detect the detail features in the region of interest (ROI). Distributed approximating functionals (DAFs) are used to construct a new class of smooth wavelets, which enable better signal processing performance. This paper is focused on improvements in DAF wavelet signal processing. The combined perceptual techniques (such

Z. Shi; D. Zhang; H. Wang; D. Kouri; D. Hoffman

2000-01-01

389

Multisensory Cues Capture Spatial Attention Regardless of Perceptual Load  

ERIC Educational Resources Information Center

We compared the ability of auditory, visual, and audiovisual (bimodal) exogenous cues to capture visuo-spatial attention under conditions of no load versus high perceptual load. Participants had to discriminate the elevation (up vs. down) of visual targets preceded by either unimodal or bimodal cues under conditions of high perceptual load (in…

Santangelo, Valerio; Spence, Charles

2007-01-01

390

A multistage perceptual quality assessment for compressed digital angiogram images  

Microsoft Academic Search

This paper describes a multistage perceptual quality assessment (MPQA) model for compressed images. The motivation for the development of a perceptual quality assessment is to measure (in)visible differences between original and processed images. The MPQA produces visible distortion maps and quantitative error measures informed by considerations of the human visual system (HVS). Original and decompressed images are decomposed into different

Joonmi Oh; Sandra I. Woolley; Theodoros N. Arvanitis; John N. Townend

2001-01-01

391

Active and Passive Perceptual Learning in the Visually Impaired.  

ERIC Educational Resources Information Center

Active and passive perceptual training methods were tested with 30 macular degeneration patients to improve their residual vision. The main conclusion was that perceptual training may contribute to successful visual adjustment and that the effect of training is not limited to a particular level of visual impairment. (Author/CL)

Conrod, Beverley E.; And Others

1986-01-01

392

Teaching social perceptual skills to students with learning disabilities  

Microsoft Academic Search

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

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

1991-01-01

393

Perceptual Modality and Musical Aptitude among Kindergarten Students.  

ERIC Educational Resources Information Center

Examines the relationship between perceptual modality measured by the Swassing-Barbe Modality Index (SBMI) to musical aptitude measured by Primary Measures of Music Audiation (PMMA) in kindergarten students. Reports correlations between the measures that support findings at other grade levels. Supports the theory that perceptual modalities become…

Sanders, Paul D.

1996-01-01

394

Cortical plasticity in perceptual learning demonstrated by transcranial magnetic stimulation  

Microsoft Academic Search

Performance on a wide range of perceptual tasks improves with practice. Most accounts of perceptual learning are concerned with changes in neuronal sensitivity or changes in the way a stimulus is represented. Another possibility is that different areas of the brain are involved in performing a task during and after learning it. Here, we demonstrate that the right parietal cortex

Vincent Walsh; Elisabeth Ashbridge; Alan Cowey

1998-01-01

395

On the Design of Perceptual MPEG-Video Encryption Algorithms  

Microsoft Academic Search

In this paper, some existing perceptual encryption algorithms of MPEG videos are reviewed and some problems, especially security defects of two recently proposed MPEG- video perceptual encryption schemes, are pointed out. Then, a simpler and more effective design is suggested, which selec- tively encrypts fixed-length codewords (FLC) in MPEG-video bitstreams under the control of three perceptibility factors. The proposed design

Shujun Li; Guanrong Chen; Albert Cheung; Bharat Bhargava; Kwok-tung Lo

2007-01-01

396

Harnessing the Wandering Mind: The Role of Perceptual Load  

ERIC Educational Resources Information Center

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…

Forster, Sophie; Lavie, Nilli

2009-01-01

397

Perceptual Mapping: A Methodology in the Assessment of Environmental Perceptions.  

ERIC Educational Resources Information Center

Describes perceptual mapping, a newly developed method for assessing perceptions of campus environments. Describes evaluation of a student union by students using this method. Discusses the advantages and disadvantages of this perceptual mapping method for assessing college environments. (Author/ABL)

Sergent, Marie T.; Sedlacek, William E.

1989-01-01

398

Hebbian Reweighting on Stable Representations in Perceptual Learning  

PubMed Central

Perceptual learning is the improvement in perceptual task performance with practice or training. The observation of specificity in perceptual learning has been widely associated with plasticity in early visual cortex representations. Here, we review the evidence supporting the plastic reweighting of readout from stable sensory representations, originally proposed by Dosher & Lu (1998), as an alternative explanation of perceptual learning. A task-analysis that identifies circumstances in which specificity supports representation enhancement and those in which it implies reweighting provides a framework for evaluating the literature; reweighting is broadly consistent with the behavioral results and almost all of the physiological reports. We also consider the evidence that the primary mode of perceptual learning is through augmented Hebbian learning of the reweighted associations, which has implications for the role and importance of feedback. Feedback is not necessary for perceptual learning, but can improve it in some circumstances, and in some cases block feedback is also helpful – all effects that are generally compatible with an augmented Hebbian model (Petrov, Dosher, & Lu, 2005). The two principles of perceptual learning through reweighting evidence from stable sensory representations and of augmented Hebbian learning provide a theoretical structure for the consideration of issues such as task difficulty, task roving, and cuing in perceptual learning.

Lu, Zhong-Lin

2009-01-01

399

Estimating the Growth of Internal Evidence Guiding Perceptual Decisions  

ERIC Educational Resources Information Center

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…

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

2011-01-01

400

Subjective perceptual methods for comparing backpacks in the field  

Microsoft Academic Search

Subjective perceptual methods have provided useful information in the laboratory about small differences in backpack design when physiological and biomechanical comparisons are ineffective, but have never been used in the field. This study therefore evaluated, in a controlled field trial with 10 male participants, the suitability of quantitative and qualitative subjective perceptual approaches to distinguish between subtle design differences in

SJ Legg; A Barr; DI Hedderley

2003-01-01

401

Correlates of Perceptual Learning in an Oculomotor Decision Variable  

PubMed Central

In subjects trained extensively to indicate a perceptual decision with an action, neural commands that generate the action can represent the process of forming the decision. However, it is unknown whether this representation requires overtraining or reflects a more general link between perceptual and motor processing. We examined how perceptual processing is represented in motor commands in naïve monkeys being trained on a demanding perceptual task, as they first establish the sensory-motor association and then learn to form more accurate perceptual judgments. The task required the monkeys to decide the direction of random-dot motion and respond with an eye movement to one of two visual targets. Using electrically evoked saccades, we examined oculomotor commands that developed during motion viewing. Throughout training, these commands tended to reflect both the subsequent binary choice of saccade target and the weighing of graded motion evidence used to arrive at that choice. Moreover, these decision-related oculomotor signals, along with the time needed to initiate the voluntary saccadic response, changed steadily as training progressed, roughly matching concomitant improvements in behavioral sensitivity to the motion stimulus. Thus, motor circuits may have general access to perceptual processing used to select between actions, even without extensive training. The results also suggest a novel candidate mechanism for some forms of perceptual learning, in which the brain learns rapidly to treat a perceptual decision as a problem of action selection and then over time to use sensory input more effectively to guide the selection process.

Connolly, Patrick M.; Bennur, Sharath; Gold, Joshua I.

2009-01-01

402

Bayesian Face Recognition and Perceptual Narrowing in Face-Space  

ERIC Educational Resources Information Center

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…

Balas, Benjamin

2012-01-01

403

Recovery Planning for Ambiguous Cases in Perceptual Anchoring  

Microsoft Academic Search

An autonomous robot using symbolic reasoning, sensing and acting in a real environment needs the ability to create and maintain the connection between symbols representing ob- jects in the world and the corresponding perceptual repre- sentations given by its sensors. This connection has been named perceptual anchoring. In complex environments, an- choring is not always easy to establish: the situation

Mathias Broxvall; Silvia Coradeschi; Lars Karlsson; Alessandro Saffiotti

2005-01-01

404

Perceptual information from OVD diffraction security devices  

NASA Astrophysics Data System (ADS)

The criteria by which optically variable devices are judged are aesthetic, semantic, security, ergonomic, and physical/chemical. This paper addresses ergonomic aspects which relate to the human vision and perceptual-cognitive system. Applying some pertinent rules may help greatly to improve the image visual information for easier, more straight-forward reception of a persistent security message. We consider two important aspects of the human visual system that help to determine the ergonomic response to visual displays created using optical diffraction. The human visual system aspect treats the retinal source of information, which is the retinal signal produced when an image of the external world is projected on the retina. The other aspect is the underlying information-processing mechanism of our brains and its constructive operations, which yields the final perceptual information. In this paper we consider information processing methods hidden in the biology of our cognition system. Findings on the relationship between physiology and psychology, sensory results and the activities of the optic pathway and subjective brightness sensations can be applied directly in designing images. Some effects are demonstrated by video tape.

Moser, Jean-Frederic; Staub, Rene; Tompkin, Wayne R.

1996-03-01

405

Facial expression recognition in perceptual color space.  

PubMed

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

Lajevardi, Seyed Mehdi; Wu, Hong Ren

2012-08-01

406

Learning object models for adaptive perceptual systems  

NASA Astrophysics Data System (ADS)

Real world perceptual environments are characterized by objects that often co-occur, occlude one another, and display time-variant behavior. In addition there may be variations in the signal-to-noise ratio. Successful object recognition depends on the extraction of adequate disambiguating features, which are neither easily identifiable nor stationary in such environments. In an effort to improve recognition accuracy and do so efficiently, Adaptive Perceptual Systems have emerged that re-configure their signal processing in response to variations in the signal to ensure extraction of adequate features. Key to adaptive signal processing is determining when and in what manner to modify signal processing. Symbolic object models play a pivotal role in this process by serving to interpret data, predict signal behavior and account for interference from objects simultaneously present. Unfortunately, symbolic object models are typically hand-crafted, a tedious error-prone task that constitutes a knowledge acquisition bottleneck, which limits object database size and impedes deployment for new and changing environments. This thesis explores the integration of feature extraction with model construction, viewing the two processes as driving one another until the goal of producing unambiguous symbolic object models is satisfied. The paradigm has been fielded to acquire acoustic-event models for a sound understanding system.

Bhandaru, Malini Krishnan

1998-08-01

407

Attentional control of early perceptual learning.  

PubMed Central

The performance of adult humans in simple visual tasks improves dramatically with practice. This improvement is highly specific to basic attributes of the trained stimulus, suggesting that the underlying changes occur at low-level processing stages in the brain, where different orientations and spatial frequencies are handled by separate channels. We asked whether these practice effects are determined solely by activity in stimulus-driven mechanisms or whether high-level attentional mechanisms, which are linked to the perceptual task, might control the learning process. We found that practicing one task did not improve performance in an alternative task, even though both tasks used exactly the same visual stimuli but depended on different stimulus attributes (either orientation of local elements or global shape). Moreover, even when the experiment was designed so that the same responses were associated with the same stimuli (although subjects were instructed to attend to the attribute underlying one task), learning did not transfer from one task to the other. These results suggest that specific high-level attentional mechanisms, controlling changes at early visual processing levels, are essential in perceptual learning. Images Fig. 3

Ahissar, M; Hochstein, S

1993-01-01

408

Perceptual study of the impact of varying frame rate on motion imagery interpretability  

NASA Astrophysics Data System (ADS)

The development of a motion imagery (MI) quality scale, akin to the National Image Interpretibility Rating Scale (NIIRS) for still imagery, would have great value to designers and users of surveillance and other MI systems. A multiphase study has adopted a perceptual approach to identifying the main MI attributes that affect interpretibility. The current perceptual study measured frame rate effects for simple motion imagery interpretation tasks of detecting and identifying a known target. By using synthetic imagery, there was full control of the contrast and speed of moving objects, motion complexity, the number of confusers, and the noise structure. To explore the detectibility threshold, the contrast between the darker moving objects and the background was set at 5%, 2%, and 1%. Nine viewers were to detect or identify a moving synthetic "bug" in each of 288 10-second clip. We found that frame rate, contrast, and confusers had a statistically significant effect on image interpretibility (at the 95% level), while the speed and background showed no significant effect. Generally, there was a significant loss in correct detection and identification for frame rates below 10 F/s. Increasing the contrast improved detection and at high contrast, confusers did not affect detection. Confusers reduced detection of higher speed objects. Higher speed improved detection, but complicated identification, although this effect was small. Higher speed made detection harder at 1 Frame/s, but improved detection at 30 F/s. The low loss of quality at moderately lower frame rates may have implications for bandwidth limited systems. A study is underway to confirm, with live action imagery, the results reported here with synthetic.

Fenimore, Charles; Irvine, John; Cannon, David; Roberts, John; Aviles, Ivelisse; Isreal, Steven; Brennan, Michelle; Simon, Larry; Miller, James; Haverkamp, Donna; Tighe, Paul F.; Gross, Michael

2006-02-01

409

Can language-action links explain language laterality?: an ERP study of perceptual and articulatory learning of novel pseudowords.  

PubMed

We here investigate whether the well-known laterality of spoken language to the dominant left hemisphere could be explained by the learning of sensorimotor links between a word's articulatory program and its corresponding sound structure. Human-specific asymmetry of acoustic-articulatory connectivity is evident structurally, at the neuroanatomical level, in the arcuate fascicle, which connects superior-temporal and frontal cortices and is more developed in the left hemisphere. Because these left-lateralised fronto-temporal fibres provide a substrate for auditory-motor associations, we hypothesised that learning of acoustic-articulatory coincidences produces laterality, whereas perceptual learning does not. Twenty subjects studied a large (n=48) set of novel meaningless syllable combinations, pseudowords, in a perceptual learning condition, where they carefully listened to repeatedly presented novel items, and, crucially, in an articulatory learning condition, where each item had to be repeated immediately, so that articulatory and auditory speech-evoked cortical activations coincided. In the 14 subjects who successfully passed the learning routine and could recognize the learnt items reliably, both perceptual and articulatory learning were found to lead to an increase of pseudoword-elicited event-related potentials (ERPs), thus reflecting the formation of new memory circuits. Importantly, after articulatory learning, pseudoword-elicited ERPs were more strongly left-lateralised than after perceptual learning. Source localisation confirmed that perceptual learning led to increased activation in superior-temporal cortex bilaterally, whereas items learnt in the articulatory condition activated bilateral superior-temporal auditory in combination with left-pre-central motor areas. These results support a new explanation of the laterality of spoken language based on the neuroanatomy of sensorimotor links and Hebbian learning principles. PMID:21440252

Pulvermüller, Friedemann; Kiff, James; Shtyrov, Yury

2012-07-01

410

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

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.

Bender, Andrew R.; Raz, Naftali

2012-01-01

411

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

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

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

412

Optimizing linked perceptual class formation and transfer of function.  

PubMed

A linked perceptual class consists of two distinct perceptual classes, A' and B', the members of which have become related to each other. For example, a linked perceptual class might be composed of many pictures of a woman (one perceptual class) and the sounds of that woman's voice (the other perceptual class). In this case, any sound of the woman's voice would occasion the selection of any picture of the woman and vice versa. In addition, after learning to name the woman in the presence of one picture, that name would be uttered when presented with all of the images of the woman's face and all of the sounds of her voice. This study involved 15 participants and sought to (a) maximize the percentage of participants who formed linked perceptual classes, and (b) determine whether those classes acted as transfer networks, that is, whether the discriminative function of one class member would generalize to other members of the class and not to members of a different class. The rate of emergence of each linked perceptual class was maximized by establishing a single class-linking conditional relation between the clearest member of one class used as a sample stimulus and the most ambiguous member of the other class used as a comparison stimulus. Class formation was demonstrated using the serial and programmed presentation of A'-B' probes that consisted of untrained pairs of stimuli drawn from the A' and B' classes. Most participants showed immediate emergence of the two linked perceptual classes. The remaining participants showed delayed emergence following a second exposure to each originally error-producing probes. Once the linked perceptual classes had emerged, a differential response to a specific member of one perceptual class generalized mostly or completely to the other members of that linked class and rarely, if ever, to members of the other linked class. Thus, generalization did not depend on the specific class members that had been used for discrimination training. PMID:19794836

Fields, Lanny; Garruto, Michelle

2009-03-01

413

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

PubMed

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

Hanslmayr, Simon; Staudigl, Tobias

2014-01-15

414

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

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.

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

2013-01-01

415

Tangential Speed  

NSDL National Science Digital Library

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

Horton, Michael

2009-05-30

416

Places and faces: Geographic environment influences the ingroup memory advantage.  

PubMed

The preferential allocation of attention and memory to the ingroup (the ingroup memory advantage) is one of the most replicated effects in the psychological literature. But little is known about what factors may influence such effects. Here the authors investigated a potential influence: category salience as determined by the perceiver's geographic environment. They did so by studying the ingroup memory advantage in perceptually ambiguous groups for whom perceptual cues do not make group membership immediately salient. Individuals in an environment in which a particular group membership was salient (Mormon and non-Mormon men and women living in Salt Lake City, Utah) showed better memory for faces belonging to their ingroup in an incidental encoding paradigm. Majority group participants in an environment where this group membership was not salient (non-Mormon men and women in the northeastern United States), however, showed no ingroup memory advantage whereas minority group participants (Mormons) in the same environment did. But in the same environment, when differences in group membership were made accessible via an unobtrusive priming task, non-Mormons did show an ingroup memory advantage and Mormons' memory for ingroup members increased. Environmental context cues therefore influence the ingroup memory advantage for categories that are not intrinsically salient. PMID:20175617

Rule, Nicholas O; Garrett, James V; Ambady, Nalini

2010-03-01

417

Drawing from Memory: Hand-Eye Coordination at Multiple Scales  

PubMed Central

Eyes move to gather visual information for the purpose of guiding behavior. This guidance takes the form of perceptual-motor interactions on short timescales for behaviors like locomotion and hand-eye coordination. More complex behaviors require perceptual-motor interactions on longer timescales mediated by memory, such as navigation, or designing and building artifacts. In the present study, the task of sketching images of natural scenes from memory was used to examine and compare perceptual-motor interactions on shorter and longer timescales. Eye and pen trajectories were found to be coordinated in time on shorter timescales during drawing, and also on longer timescales spanning study and drawing periods. The latter type of coordination was found by developing a purely spatial analysis that yielded measures of similarity between images, eye trajectories, and pen trajectories. These results challenge the notion that coordination only unfolds on short timescales. Rather, the task of drawing from memory evokes perceptual-motor encodings of visual images that preserve coarse-grained spatial information over relatively long timescales as well.

Spivey, Michael J.

2013-01-01

418

Implicit and explicit memory: a functional dissociation in persons with Down syndrome.  

PubMed

This study aimed at investigating implicit and explicit long-term memory functioning in subjects with Down syndrome (DS) compared to Mental-Age (MA) matched normal children. For this purpose, tests of verbal and visuo-perceptual explicit memory, verbal and visual repetition priming and procedural learning tasks were administered to 14 DS and 20 MA subjects. Our results document comparable implicit memory abilities in the two groups. In contrast, regarding explicit memory, normal children performed better than DS individuals. These results reveal a functional dissociation between implicit and explicit memory in subjects with DS. Theoretical and rehabilitative implications are discussed. PMID:10678691

Vicari, S; Bellucci, S; Carlesimo, G A

2000-01-01

419

Interactions between speed and contrast tuning in the middle temporal area: implications for the neural code for speed.  

PubMed

A car driving through the fog appears to move more slowly than one driving on a clear and sunny day. In the laboratory, this observation has been confirmed as a pronounced reduction of perceived speed caused by a reduction in contrast. We measured the influence of contrast on cells in the middle temporal area (MT) of the macaque, which has been hypothesized to underlie the perception of speed. The influence of contrast on the responsiveness and speed tuning of these cells was pervasive and highly regular. As expected, most cells responded less at low contrast. More importantly, the preferred speed of most cells shifted to lower speeds at lower contrasts. Moreover, approximately one-third of cells surprisingly responded more strongly to slow low-contrast stimuli than to slow high-contrast stimuli. Current models of speed perception suggest that each MT cell votes for its preferred speed, with a vote determined by its firing rate. We tested a number of these labeled-line models by entering the neural responses we recorded from MT and comparing the predictions of the models with the perceptual reports of human subjects and monkeys. Contrary to the perceptual reports, the labeled-line models predicted that perceived speed should increase when contrast is decreased. We therefore conclude that perceived speed is not based on a labeled-line interpretation of MT cells. PMID:16943555

Krekelberg, Bart; van Wezel, Richard J A; Albright, Thomas D

2006-08-30

420

Galvanic vestibular stimulation speeds visual memory recall  

Microsoft Academic Search

The experiments of Alessandro Volta were amongst the first to indicate that visuo-spatial function can be altered by stimulating\\u000a the vestibular nerves with galvanic current. Until recently, the beneficial effects of the procedure were masked by the high\\u000a levels of electrical current applied, which induced nystagmus-related gaze deviation and spatial disorientation. However,\\u000a several neuropsychological studies have shown that much weaker,

David Wilkinson; Sophie Nicholls; Charlotte Pattenden; Patrick Kilduff; William Milberg

2008-01-01

421

High-Speed Scanning in Human Memory  

Microsoft Academic Search

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.

Saul Sternberg

1966-01-01

422

Aging, Perceptual learning, and Changes in Efficiency of Motion Processing  

PubMed Central

In the present study we examined the use of perceptual learning to improve motion processing in older and younger individuals. Using the Perceptual Template Model (Lu & Dosher, 1998; 1999), age-related differences in baseline perceptual inefficiencies and changes due to training were assessed for additive internal noise, tolerance to external noise, and internal multiplicative noise. In Experiments 1 and 2 we trained participants by manipulating contrast in noise embedded sine-wave gratings and Random Dot Cinematograms (RDCs). The results indicate that older observers have higher additive internal noise and lower tolerance to external noise compared to younger observers. The rate of perceptual learning in older observers was found to be similar to that of younger observers suggesting that plasticity of motion processing mechanisms is well preserved in advancing age. Transfer of learning between sine-wave gratings and RDCs for both older and younger observers was examined in an analysis of pre/post-test measurements. The results indicate that transfer of learning occurred for both age groups. This suggests that older individuals maintain a sufficient degree of plasticity to allow generalization between sine-wave gratings and RDCs. In addition, training with RDCs was found to produce greater perceptual learning than training with sine-wave gratings. These experiments provide important findings regarding changes in perceptual efficiency for motion perception in older adults and suggest that perceptual learning is an effective approach for recovering from age-related declines in visual processing.

Bower, Jeffrey D.; Andersen, George J.

2011-01-01

423

The Neural Basis of Implicit Perceptual Sequence Learning  

PubMed Central

The present fMRI study investigated the neural areas involved in implicit perceptual sequence learning. To obtain more insight in the functional contributions of the brain areas, we tracked both the behavioral and neural time course of the learning process, using a perceptual serial color matching task. Next, to investigate whether the neural time course was specific for perceptual information, imaging results were compared to the results of implicit motor sequence learning, previously investigated using an identical serial color matching task (Gheysen et al., 2010). Results indicated that implicit sequences can be acquired by at least two neural systems: the caudate nucleus and the hippocampus, having different operating principles. The caudate nucleus contributed to the implicit sequence learning process for perceptual as well as motor information in a similar and gradual way. The hippocampus, on the other hand, was engaged in a much faster learning process which was more pronounced for the motor compared to the perceptual task. Interestingly, the perceptual and motor learning process occurred on a comparable implicit level, suggesting that consciousness is not the main determinant factor dissociating the hippocampal from the caudate learning system. This study is not only the first to successfully and unambiguously compare brain activation between perceptual and motor levels of implicit sequence learning, it also provides new insights into the specific hippocampal and caudate learning function.

Gheysen, Freja; Van Opstal, Filip; Roggeman, Chantal; Van Waelvelde, Hilde; Fias, Wim

2011-01-01

424

Accurate expectancies diminish perceptual distraction during visual search  

PubMed Central

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.

Sy, Jocelyn L.; Guerin, Scott A.; Stegman, Anna; Giesbrecht, Barry

2014-01-01

425

Dynamics of Active Sensing and perceptual selection.  

PubMed

Sensory processing is often regarded as a passive process in which biological receptors like photoreceptors and mechanoreceptors transduce physical energy into a neural code. Recent findings, however, suggest that: first, most sensory processing is active, and largely determined by motor/attentional sampling routines; second, owing to rhythmicity in the motor routine, as well as to its entrainment of ambient rhythms in sensory regions, sensory inflow tends to be rhythmic; third, attentional manipulation of rhythms in sensory pathways is instrumental to perceptual selection. These observations outline the essentials of an Active Sensing paradigm, and argue for increased emphasis on the study of sensory processes as specific to the dynamic motor/attentional context in which inputs are acquired. PMID:20307966

Schroeder, Charles E; Wilson, Donald A; Radman, Thomas; Scharfman, Helen; Lakatos, Peter

2010-04-01

426

Motor and tactile-perceptual skill differences between individuals with high-functioning autism and typically developing individuals ages 5-21.  

PubMed

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 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

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

2013-10-01

427

Asymmetric Transfer of Auditory Perceptual Learning  

PubMed Central

Perceptual skills can improve dramatically even with minimal practice. A major and practical benefit of learning, however, is in transferring the improvement on the trained task to untrained tasks or stimuli, yet the mechanisms underlying this process are still poorly understood. Reduction of internal noise has been proposed as a mechanism of perceptual learning, and while we have evidence that frequency discrimination (FD) learning is due to a reduction of internal noise, the source of that noise was not determined. In this study, we examined whether reducing the noise associated with neural phase locking to tones can explain the observed improvement in behavioral thresholds. We compared FD training between two tone durations (15 and 100?ms) that straddled the temporal integration window of auditory nerve fibers upon which computational modeling of phase locking noise was based. Training on short tones resulted in improved FD on probe tests of both the long and short tones. Training on long tones resulted in improvement only on the long tones. Simulations of FD learning, based on the computational model and on signal detection theory, were compared with the behavioral FD data. We found that improved fidelity of phase locking accurately predicted transfer of learning from short to long tones, but also predicted transfer from long to short tones. The observed lack of transfer from long to short tones suggests the involvement of a second mechanism. Training may have increased the temporal integration window which could not transfer because integration time for the short tone is limited by its duration. Current learning models assume complex relationships between neural populations that represent the trained stimuli. In contrast, we propose that training-induced enhancement of the signal-to-noise ratio offers a parsimonious explanation of learning and transfer that easily accounts for asymmetric transfer of learning.

Amitay, Sygal; Zhang, Yu-Xuan; Moore, David R.

2012-01-01

428

A neural network reflecting individual differences in cognitive processing of emotions during perceptual decision making  

Microsoft Academic Search

Even simple perceptual decisions are influenced by the emotional content of a stimulus. Recent neuroimaging studies provide evidence about the neural mechanisms of perceptual decision making on emotional stimuli. However, the effect of individual differences in cognitive processing of emotions on perceptual decision making remains poorly understood. Here, we investigated how changes in the fMRI signal during perceptual decision making

Katja Mériau; Isabell Wartenburger; Philipp Kazzer; Kristin Prehn; Claas-Hinrich Lammers; Elke van der Meer; Arno Villringer; Hauke R. Heekeren

2006-01-01

429

Perceiving flirtatious communication: An exploration of the perceptual dimensions underlying judgments of flirtatiousness  

Microsoft Academic Search

Perceptual dimensions underlying flirtatiousness judgments were examined in a three?phased study. This study was conducted to answer the following research questions: (a) What perceptual dimensions underlie flirtatiousness judgments? (b) Do men and women use similar perceptual dimensions in assessing flirtatiousness? and (c) Do men and women vary in the degree to which they employ these perceptual dimensions in making their

Matthew F. Abrahams

1994-01-01

430

The Effects of Differential Training Procedures on Linked Perceptual Class Formation  

ERIC Educational Resources Information Center

When the stimuli in one perceptual class (A') become related to the stimuli in another perceptual class (B'), the two are functioning as a single "linked perceptual class". A common linked perceptual class would be the sounds of a person's voice (class A') and the pictures of that person (class B'). Such classes are ubiquitous in real world…

Fields, Lanny; Tittelbach, Danielle; Shamoun, Kimberly; Watanabe, Mari; Fitzer, Adrienne; Matneja, Priya

2007-01-01

431

Perceptual organization in computer vision: a review and a proposal for a classificatory structure  

Microsoft Academic Search

The role of perceptual organization in computer vision systems is explored. This is done from four vantage points. A brief history of perceptual organization research in both humans and computer vision is offered. A classificatory structure in which to cast perceptual organization research to clarify both the nomenclature and the relationships among the many contributions is proposed. The perceptual organization

Sudeep Sarkar; Kim L. Boyer

1993-01-01

432

Perceptual training of height and brightness seriation in kindergarten children.  

PubMed

A study of seriation was conducted from the perspective of Gibson's theory of perceptual development. Kindergarten children who evidenced little seriation of height or brightness were assigned to either 1 of 3 perceptual training conditions or to a fourth, control condition. Training consisted of nonreinforced same-different judgments to wooden dowels varying in height, or in brightness, or simultaneously in height and brightness. The theoretical rationale for this training was that it would facilitate perception of the stimulus dimension(s) on which the dowels differed. It was found that perceptual training did facilitate seriation, particularly if both the height and brightness dimensions varied simultaneously in training. PMID:1201663

Timmons, S A; Smothergill, D W

1975-12-01

433

Causal evidence for subliminal percept-to-memory interference in early visual cortex.  

PubMed

There has been recent interest in the neural correlates of visual short-term memory (VSTM) interference by irrelevant perceptual input. These studies, however, presented distracters that were subjected to conscious scrutiny by participants thus strongly involving attentional control mechanisms. In order to minimize the role of attentional control and to investigate interference occurring at the level of sensory representations, we developed a paradigm in which a subliminal visual distracter is presented during the delay period of a visual short-term memory task requiring the maintenance of stimulus orientation. This subliminal distracter could be either congruent or incongruent with the orientation of the memory item. Behavioral results showed that the intervening distracter affected the fidelity of VSTM when it was incongruent with the memory cue. We then assessed the causal role of the early visual cortex in this interaction by using transcranial magnetic stimulation (TMS). We found that occipital TMS impaired the fidelity VSTM content in the absence of the memory mask. Interestingly, TMS facilitated VSTM performance in the presence of a subliminal memory mask that was incongruent with the memory content. Signal detection analyses indicated that TMS did not modulate perceptual sensitivity of the masked distracter. That the impact of TMS on the precision of VSTM was dissociated by the presence vs. absence of a subliminal perceptual distracter and its congruency with the VSTM content provides causal evidence for the view that competitive interactions between memory and perception can occur at the earliest cortical stages of visual processing. PMID:21839180

Silvanto, Juha; Soto, David

2012-01-01

434

Increasing Speed of Processing With Action Video Games  

PubMed Central

In many everyday situations, speed is of the essence. However, fast decisions typically mean more mistakes. To this day, it remains unknown whether reaction times can be reduced with appropriate training, within one individual, across a range of tasks, and without compromising accuracy. Here we review evidence that the very act of playing action video games significantly reduces reaction times without sacrificing accuracy. Critically, this increase in speed is observed across various tasks beyond game situations. Video gaming may therefore provide an efficient training regimen to induce a general speeding of perceptual reaction times without decreases in accuracy of performance.

Dye, Matthew W.G.; Green, C. Shawn; Bavelier, Daphne

2010-01-01

435

Perceptual Organization Impairment in Schizophrenia and Associated Brain Mechanisms: Review of Research from 2005 to 2010  

PubMed Central

Perceptual organization (PO) refers to the processes by which visual information is structured into coherent patterns such as groups, contours, perceptual wholes, and object representations. Impairments in PO have been demonstrated in schizophrenia since the 1960s and have been linked to several illness-related factors including poor premorbid functioning, poor prognosis, and disorganized symptoms. This literature was last reviewed in 2005. Since then, electrophysiological (electroencephalographic, event-related potential, and magnetoencephalographic) and fMRI studies in both patient and nonpatient samples have clarified brain mechanisms involved in the impairment, and additional behavioral studies in patients and nonpatients have clarified the computational mechanisms. In addition, data now exist on the functional consequences of PO impairments, in terms of secondary difficulties in face processing, selective attention, working memory, and social cognition. Preliminary data on drug effects on PO and on changes in response to treatment suggest that anomalies in PO may furnish a biomarker for the integrity of its associated biological mechanisms. All of this recent evidence allows for a clearer picture of the nature of the impairment and how it relates to broader aspects of brain and behavioral functioning in schizophrenia.

Silverstein, Steven M.; Keane, Brian P.

2011-01-01

436

The benefits of cholinergic enhancement during perceptual learning are long-lasting  

PubMed Central

The neurotransmitter acetylcholine (ACh) regulates many aspects of cognition, including attention and memory. Previous research in animal models has shown that plasticity in sensory systems often depends on the behavioral relevance of a stimulus and/or task. However, experimentally increasing ACh release in the cortex can result in experience-dependent plasticity, even in the absence of behavioral relevance. In humans, the pharmacological enhancement of ACh transmission by administration of the cholinesterase inhibitor donepezil during performance of a perceptual task increases the magnitude of perceptual learning (PL) and its specificity to physical parameters of the stimuli used for training. Behavioral effects of PL have previously been shown to persist for many months. In the present study, we tested whether enhancement of PL by donepezil is also long-lasting. Healthy human subjects were trained on a motion direction discrimination task during cholinergic enhancement, and follow-up testing was performed 5–15 months after the end of training and without additional drug administration. Increases in performance associated with training under donepezil were evident in follow-up retesting, indicating that cholinergic enhancement has beneficial long-term effects on PL. These findings suggest that cholinergic enhancement of training procedures used to treat clinical disorders should improve long-term outcomes of these procedures.

Rokem, Ariel; Silver, Michael A.

2013-01-01

437

Visual and auditory influence on perceptual stability in visual competition.  

PubMed

In visual competition, the perception of ambiguous visual patterns changes spontaneously. Although the process causing this perceptual alternation remains unclear, recent evidence suggests various types of non-visual influences in resolving visual ambiguity. In the present study, we investigated cross-modal modulation of a transient stimulus on visual perceptual stability (i.e., alternation frequency). Participants observed an ambiguous visual figure and reported their perceptual alternations. Concurrently, we presented visual and auditory transient events. The results revealed that the auditory as well as visual transient events destabilize the current perception (i.e., they increase alternation frequency) around 0.5-1.5 s after the event. In addition, the magnitudes of auditory and visual effects were comparable and positively correlated within participants. These results suggest that the visual perceptual stability can be under the influence of processes that are shared by different senses. PMID:21902880

Takahashi, Kohske; Watanabe, Katsumi

2011-01-01

438

Transfer of perceptual learning between different visual tasks  

PubMed Central

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.

McGovern, David P.; Webb, Ben S.; Peirce, Jonathan W.

2012-01-01

439

Variance misperception explains illusions of confidence in simple perceptual decisions.  

PubMed

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

Zylberberg, Ariel; Roelfsema, Pieter R; Sigman, Mariano

2014-07-01

440

Working Memory  

Microsoft Academic Search

The term working memory refers to a brain system that provides temporary storage and manipulation of the information necessary for such complex cognitive tasks as language comprehension, learning, and reasoning. This definition has evolved from the concept of a unitary short-term memory system. Working memory has been found to require the simultaneous storage and processing of information. It can be

Alan Baddeley

1992-01-01

441

Virtual Memory  

Microsoft Academic Search

\\\\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

Peter J. Denning

1970-01-01

442

Distinct Neural Markers of TVA-Based Visual Processing Speed and Short-Term Storage Capacity Parameters.  

PubMed

An individual's visual attentional capacity is characterized by 2 central processing resources, visual perceptual processing speed and visual short-term memory (vSTM) storage capacity. Based on Bundesen's theory of visual attention (TVA), independent estimates of these parameters can be obtained from mathematical modeling of performance in a whole report task. The framework's neural interpretation (NTVA) further suggests distinct brain mechanisms underlying these 2 functions. Using an interindividual difference approach, the present study was designed to establish the respective ERP correlates of both parameters. Participants with higher compared to participants with lower processing speed were found to show significantly reduced visual N1 responses, indicative of higher efficiency in early visual processing. By contrast, for participants with higher relative to lower vSTM storage capacity, contralateral delay activity over visual areas was enhanced while overall nonlateralized delay activity was reduced, indicating that holding (the maximum number of) items in vSTM relies on topographically specific sustained activation within the visual system. Taken together, our findings show that the 2 main aspects of visual attentional capacity are reflected in separable neurophysiological markers, validating a central assumption of NTVA. PMID:23535180

Wiegand, Iris; Töllner, Thomas; Habekost, Thomas; Dyrholm, Mads; Müller, Hermann J; Finke, Kathrin

2014-08-01

443

Task contingencies and perceptual strategies shape behavioral effects on neuronal response profiles  

PubMed Central

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.

Sato, Nobuya; Page, William K.

2013-01-01

444

Imaging tactile imagery: Changes in brain connectivity support perceptual grounding of mental images in primary sensory cortices.  

PubMed

Constructing mental representations in the absence of sensory stimulation is a fundamental ability of the human mind and has been investigated in numerous brain imaging studies. However, it is still unclear how brain areas facilitating mental construction processes interact with brain regions related to specific sensory representations. In this fMRI study subjects formed mental representations of tactile stimuli either from memory (imagery) or from presentation of actual corresponding vibrotactile patterned stimuli. First our analysis addressed the question of whether tactile imagery recruits primary somatosensory cortex (SI), because the activation of early perceptual areas is classically interpreted as perceptual grounding of the mental image. We also tested whether a network, referred to as 'core construction system', is involved in the generation of mental representations in the somatosensory domain. In fact, we observed imagery-induced activation of SI. We further found support for the notion of a modality independent construction network with the retrosplenial cortices and the precuneus as core components, which were supplemented with the left inferior frontal gyrus (IFG). Finally, psychophysiological interaction (PPI) analyses revealed robust imagery-modulated changes in the connectivity of these construction related areas, which suggests that they orchestrate the assembly of an abstract mental representation. Interestingly, we found increased coupling between prefrontal cortex (left IFG) and SI during mental imagery, indicating the augmentation of an abstract mental representation by reactivating perceptually grounded sensory details. PMID:24836010