Showing papers on "Perceptual learning published in 2003"

Action video game modifies visual selective attention

Abstract: As video-game playing has become a ubiquitous activity in today's society, it is worth considering its potential consequences on perceptual and motor skills. It is well known that exposing an organism to an altered visual environment often results in modification of the visual system of the organism. The field of perceptual learning provides many examples of training-induced increases in performance. But perceptual learning, when it occurs, tends to be specific to the trained task; that is, generalization to new tasks is rarely found. Here we show, by contrast, that action-video-game playing is capable of altering a range of visual skills. Four experiments establish changes in different aspects of visual attention in habitual video-game players as compared with non-video-game players. In a fifth experiment, non-players trained on an action video game show marked improvement from their pre-training abilities, thereby establishing the role of playing in this effect.

Sleep-dependent learning: a nap is as good as a night.

Abstract: The learning of perceptual skills has been shown in some cases to depend on the plasticity of the visual cortex and to require post-training nocturnal sleep. We now report that sleep-dependent learning of a texture discrimination task can be accomplished in humans by brief (60- 90 min) naps containing both slow-wave sleep (SWS) and rapid eye movement (REM) sleep. This nap-dependent learning closely resembled that previously reported for an 8-h night of sleep in terms of magnitude, sleep-stage dependency and retinotopic specificity, and it was additive to subsequent sleep-dependent improvement, such that performance over 24 h showed as much learning as is normally seen after twice that length of time. Thus, from the perspective of behavioral improvement, a nap is as good as a night of sleep for learning on this perceptual task.

Consolidation during sleep of perceptual learning of spoken language

Abstract: Memory consolidation resulting from sleep has been seen broadly: in verbal list learning, spatial learning, and skill acquisition in visual and motor tasks. These tasks do not generalize across spatial locations or motor sequences, or to different stimuli in the same location. Although episodic rote learning constitutes a large part of any organism's learning, generalization is a hallmark of adaptive behaviour. In speech, the same phoneme often has different acoustic patterns depending on context. Training on a small set of words improves performance on novel words using the same phonemes but with different acoustic patterns, demonstrating perceptual generalization. Here we show a role of sleep in the consolidation of a naturalistic spoken-language learning task that produces generalization of phonological categories across different acoustic patterns. Recognition performance immediately after training showed a significant improvement that subsequently degraded over the span of a day's retention interval, but completely recovered following sleep. Thus, sleep facilitates the recovery and subsequent retention of material learned opportunistically at any time throughout the day. Performance recovery indicates that representations and mappings associated with generalization are refined and stabilized during sleep.

Pharmacological modulation of perceptual learning and associated cortical reorganization.

Abstract: The pharmacological basis of perceptual learning and associated cortical reorganizations remains elusive. We induced perceptual learning by Hebbian coactivation of the skin of the tip of the right index finger in humans. Under placebo, tactile two-point discrimination was improved on the coactivated but not on the left index finger. This augmentation was blocked by an N -methyl-D-aspartate–receptor blocker, but doubled by amphetamine. No drug effects were found on the left index finger. The individual amount of cortical reorganization as assessed by mapping of somatosensory evoked potentials was linearly correlated with the pharmacological modulation of discrimination thresholds, implying that perceptual learning and associated cortical changes are controlled by basic mechanisms known to mediate and modulate synaptic plasticity.

Is subliminal learning really passive

Abstract: Perceptual learning can occur as a result of exposure to a subliminal stimulus, without the subject having to pay attention and without relevance to the particular task in hand1 — but is this type of learning purely passive? Here we show that perceptual learning is not passive, but instead results from reinforcement by an independent task2,3. As this learning occurred on a subliminal feature, our results are inconsistent with attentional learning theories4,5 in which learning occurs only on stimuli to which attention is directed. Instead, our findings suggest that the successful recognition of a relevant stimulus can trigger an internal reward6 and give rise to the learning of irrelevant and even subliminal features that are correlated with the occurrence of the reward5,6.

Sensory Perceptual Issues in Autism and Asperger Syndrome: Different Sensory Experiences, Different Perceptual Worlds

Abstract: Foreword, Wendy Lawson. Foreword, Theo Peeters. Introduction to the Problem. 1. Sensory Dysfunction or Different Sensory Experiences. 2. Perception. 3. Possible Sensory Experiences in Autism. 4. Perceptual Styles 5. Cognitive Styles. 6. Other Sensory Conditions. 7. Treatments. 8. Sensory Perceptual Profile. 9. Recommendations: rainbows and Umbrellas. Conclusion. References. Appendix 1: Sensory Profile Checklist. Appendix 2: Key for Decoding Questionnaire. Photocopiable Rainbow and Table.

Environmentally mediated synergy between perception and behaviour in mobile robots

Abstract: The notion that behaviour influences perception seems self-evident, but the mechanism of their interaction is not known. Perception and behaviour are usually considered to be separate processes. In this view, perceptual learning constructs compact representations of sensory events, reflecting their statistical properties1,2, independently of behavioural relevance3,4. Behavioural learning5,6, however, forms associations between perception and action, organized by reinforcement7,8, without regard for the construction of perception. It is generally assumed that the interaction between these two processes is internal to the agent, and can be explained solely in terms of the neuronal substrate9. Here we show, instead, that perception and behaviour can interact synergistically via the environment. Using simulated and real mobile robots, we demonstrate that perceptual learning directly supports behavioural learning and so promotes a progressive structuring of behaviour. This structuring leads to a systematic bias in input sampling, which directly affects the organization of the perceptual system. This external, environmentally mediated feedback matches the perceptual system to the emerging behavioural structure, so that the behaviour is stabilized.

First-hand accounts of sensory perceptual experiences in autism: a qualitative analysis

Abstract: Five first-hand web page accounts of unusual sensory perceptual experiences written by persons who claimed to have high-functioning autism were selected for qualitative analysis. Four core categori...

Perceptual organization in vision : behavioral and neural perspectives

Abstract: Contents: Preface. Part I: Cognitive Approaches to Perceptual Organization. S.E. Palmer, Perceptual Organization and Grouping. M. Kubovy, S. Gepshtein, Perceptual Grouping in Space and in Space-Time: An Exercise in Phenomenological Psychophysics. M.A. Peterson, On Figures, Grounds, and Varieties of Surface Completion. R. Kimchi, Visual Perceptual Organization: A Microgenetic Analysis. P.J. Kellman, Visual Perception of Objects and Boundaries: A Four-Dimensional Approach. Part II: Development and Learning in Perceptual Organization. A. Needham, S.M. Ormsbee, The Development of Object Segregation During the First Year of Life. R.L. Goldstone, Learning to Perceive While Perceiving to Learn. Part III: Neural Approaches to Perceptual Organization. R. von der Heydt, H. Zhou, H.S. Friedman, Neural Coding of Border Ownership: Implications for the Theory of Figure-Ground Perception. T.D. Albright, L.J. Croner, R.O. Duncan, G.R. Stoner, Neuronal Correlates of Perceptual Organization in the Primate Visual System. M. Behrmann, R. Kimchi, Visual Perceptual Organization: Lessons From Lesions. G.W. Humphreys, Binding in Vision as a Multistage Process. Part IV: Computational Approaches to Perceptual Organization. D.W. Jacobs, Perceptual Completion and Memory. T.S. Lee, Neural Basis of Attentive Perceptual Organization.

How does the cerebral cortex work? Development, learning, attention, and 3-D vision by laminar circuits of visual cortex.

Abstract: A key goal of behavioral and cognitive neuroscience is to link brain mechanisms to behavioral functions. The present article describes recent progress toward explaining how the visual cortex sees. Visual cortex, like many parts of perceptual and cognitive neocortex, is organized into six main layers of cells, as well as characteristic sublamina. Here it is proposed how these layered circuits help to realize processes of development, learning, perceptual grouping, attention, and 3-D vision through a combination of bottom-up, horizontal, and top-down interactions. A main theme is that the mechanisms which enable development and learning to occur in a stable way imply properties of adult behavior. These results thus begin to unify three fields: infant cortical development, adult cortical neurophysiology and anatomy, and adult visual perception. The identified cortical mechanisms promise to generalize to explain how other perceptual and cognitive processes work.

Temporal specificity of perceptual learning in an auditory discrimination task.

Abstract: Although temporal processing is used in a wide range of sensory and motor tasks, there is little evidence as to whether a single centralized clock or a distributed system underlies timing in the range of tens to hundreds of milliseconds We investigated this question by studying whether learning on an auditory interval discrimination task generalizes across stimulus types, intervals, and frequencies The degree to which improvements in timing carry over to different stimulus features constrains the neural mechanisms underlying timing Human subjects trained on a 100- or 200-msec interval discrimination task showed an improvement in temporal resolution This learning generalized to a perceptually distinct duration stimulus, as well as to the trained interval presented with tones at untrained spectral frequencies The improvement in performance did not generalize to untrained intervals To determine if spectral generalization was dependent on the importance of frequency information in the task, subjects were simultaneously trained on two different intervals identified by frequency As a whole, our results indicate that the brain uses circuits that are dedicated to specific time spans, and that each circuit processes stimuli across nontemporal stimulus features The patterns of generalization additionally indicate that temporal learning does not rely on changes in early, subcortical processing, because the nontemporal features are encoded by different channels at early stages

Cross-modal recognition of shape from hand to eyes in human newborns.

Abstract: The hypothesis that the ability to coordinate information between tactual and visual modalities is present at birth and dependent on perceptual inherent structures was tested in human newborns. Using an intersensory paired-preference procedure, we showed that newborns can visually recognize the shape of an object that they have previously manipulated with their right hand, out of sight. This is an experimental evidence that newborns can extract shape information in a tactual format and transform it in a visual format before they have had the opportunity to learn from the pairings of visual and tactual experience. This is contrary to a host of theories and models of perceptual learning, both traditional (empiricist philosophers) and modern (connectionist).

Acquisition of knowledge about spatial location: assessing the generality of the mechanism of learning.

Abstract: A selection of studies in the last 20 years is reviewed. These studies show basic Pavlovian phenomena in the spatial domain (like blocking, overshadowing, latent inhibition, and perceptual learning) with nonhuman subjects, specifically with rats, both in the radial maze and in the circular pool. The generality of these phenomena with respect to other species and to other spatial preparations is also discussed. The conclusion is that the mechanism responsible for the acquisition of knowledge about spatial location seems to be associative in nature.

Effects of perceptual learning exercises on standing balance using a hardness discrimination task in hemiplegic patients following stroke: a randomized controlled pilot trial

Abstract: Objective: To investigate the effect of perceptual learning exercises for hardness discrimination by the soles on standing balance in stroke patients with hemiplegia.Subjects: Twenty-eight subjects were randomly assigned to an experimental or a control group and participated in a rehabilitation programme.Intervention: The experimental group received perceptual learning exercises on hardness discrimination using three different levels of hardness of a rubber sponge for 10 days.Main measures: Length, enveloped area and rectangular area of the parameter of postural sway were measured by a stabilometer on entry into the study and after 10 days.Results: Twenty-six subjects completed the study. Data indicate that more parameters indicating postural sway were significantly decreased in the experimental group than in the control group. Also, there was a significant difference between the groups in change scores (pre-exercise minus postexercise) of length and enveloped area.Conclusion: The plantar perception exerc...

The World Is So Full of a Number of Things: On Specification and Perceptual Learning

Abstract: Two basic concepts of James Gibson's ecological theory of perception are information and affordance. Discovering the information that specifies an affordance is a task confronting all of us and is an essential process in development. Information in the world is manifold and must be narrowed down to perceive what specifies an affordance. Perceptual learning is the process that we study to understand how this comes about.

Nonlinear ideal observation and recurrent preprocessing in perceptual learning.

Abstract: Residual micro-saccades, tremor and fixation errors imply that, on different trials in visual tasks, stimulus arrays are inevitably presented at different positions on the retina. Positional variation is likely to be specially important for tasks involving visual hyperacuity, because of the severe demands that these tasks impose on spatial resolution. In this paper, we show that small positional variations lead to a structural change in the nature of the ideal observer's solution to a hyperacuity-like visual discrimination task such that the optimal discriminator depends quadratically rather than linearly on noisy neural activities. Motivated by recurrent models of early visual processing, we show how a recurrent preprocessor of the noisy activities can produce outputs which, when passed through a linear discriminator, lead to better discrimination even when the positional variations are much larger than the threshold acuity of the task. Since, psychophysically, hyperacuity typically improves greatly over the course of perceptual learning, we discuss our model in the light of results on the speed and nature of learning.

Specificity and generalization of visual perceptual learning in humans: an event-related potential study.

Abstract: To investigate the neural correlates of specificity and generalization of visual perceptual learning, we recorded event-related potentials from human adults when they were trained with a simple visual discrimination task. While reaction times decreased significantly across training sessions, event-related potentials showed larger P2 amplitudes ( approximately 210 ms) over the left occipital/parietal areas and smaller N1 amplitudes ( approximately 140 ms) at the left parietal site with more practice. Similar to reaction times, the training effect on the P2 amplitudes was specific to stimulus orientation. However, the N1 effect was generalized over differently oriented stimuli. These results indicated the complexity of the neural substance underlying perceptual learning, relative to behavioral level.

Time Course of Perceptual Grouping by Color

Abstract: Does perceptual grouping operate early or late in visual processing? One position is that the elements in perceptual layouts are grouped early in vision, by properties of the retinal image, before perceptual constancies have been determined. A second position is that perceptual grouping operates on a postconstancy representation, one that is available only after stereoscopic depth perception, light- ness constancy, and amodal completion have occurred. The present experiments indicate that grouping can operate on both a precon- stancy representation and a postconstancy representation. Perceptual grouping was based on retinal color similarity at short exposure dura- tions and based on surface color similarity at long durations. These results permit an integration of the preconstancy and postconstancy positions with regard to grouping by color.

GABAergic mechanisms gate tactile discrimination learning.

Abstract: In contrast to mechanisms mediating synaptic plasticity, the pharmacological basis of perceptual learning remains to be clari¢ed. Here we report that a speci¢c form of perceptual learning is in£uenced by GABAergic mechanisms.We induced perceptual learning by Hebbian co-activation of the skin of the tip of the right index ¢ngers in human subjects. Under placebo conditions, tactile 2point discrimination was improved on the co-activated, but not on the left, index ¢nger. This augmentation was completely eliminated by lorazepam, a GABAA receptor agonist. No drug eiects were found on the left index ¢nger indicating that the drugs had no eiect per se on performance. The results demonstrate that perceptual learning is subject to pharmacological gating by basic mechanisms known to mediate and modulate synaptic plasticity. NeuroReport14:1747^1751 � c 2003 Lippincott Williams & Wilkins.

Auditory perceptual learning.

Abstract: An interesting phenomenon in science is how the discovery of new techniques, findings, or theoretical understanding can produce cyclical waves of interest in a research area. Such is the case for perceptual learning, which is currently enjoying a renaissance following previous periods of excitement, some 50 and 100 years ago (Meyer 1899; Seashore et al. 1908; Gibson 1953). In this issue, Karmarkar and Buonomano (2003) energize this resurgence with exciting work on auditory perceptual learning. There seem to be two converging reasons for the revival of interest in this field. The first derives from discoveries in neuroscience of plasticity in the mature brain (for review, see Calford 2002). Initially prompted by findings that lesions in the peripheral somatosensory system led to remapping of the lesioned limb or digit in the cortex, this field evolved in several directions, including studies of how intensive, specific training could also lead to remapping in the cortex. The second reason for the current interest in perceptual learning derives from an increased understanding of the nature of learning difficulties, particularly in children. In the mid-1990s, neuroscientists latched on to a stream of research in developmental psychology showing that some children with language-based learning impairments (LLIs), such as dyslexia, had poor visual and auditory temporal processing abilities. Since then, there has been a huge surge of activity (for review, see Ramus 2001) showing that children with LLI have a wider range of difficulties processing sensory stimuli. These difficulties typically involve multiple sensory, cognitive, and motor systems. But most controversial, and potentially most significant from an applied perspective, has been the finding that training based on the principles of perceptual learning can effectively treat these processing problems and the LLI that they are associated with (Merzenich et al. 1996; Tallal et al. 1996; Kujala et al. 2001). Against this background, Karmarkar and Buonomano (2003) present data on the learning of an auditory interval discrimination task. During training, adult listeners had to decide whether a test pair of tones were separated by a shorter or longer interval than a target pair presented at the onset of a trial block. The frequency of the tones and the target interval were varied between listeners. All listeners were tested on a battery of similar stimuli at both trained and untrained frequencies and target durations before and after 10 d of training. For listeners who learned, the results showed generalization of training across tone frequency but not across target interval. Generalization of training to a tone-duration discrimination task was also observed. This suggested that training for auditory temporal information occurs in centralized brain circuits that are accessed across frequency channels. One of the goals of Karmarkar and Buonomano’s work was to ensure that enhanced performance resulted from improved timing per se, rather than from an enhanced ability to store and/or compare a standard and a comparison stimulus. To achieve this, they allowed the participant to hear the standard several times only at the beginning of a block, and on each trial, participants were presented only with the comparison stimulus. As it seems unlikely that the relatively few presentations of the standard were sufficient to develop a concept of the standard, the authors interpreted the improved performance as indicating that the participants formed a dynamic representation of the time frame, and adjusted this timing based on the feedback from their decisions. However, their results can be interpreted as showing an enhanced ability to store and/or compare stimuli from trial to trial. A strategy of comparing the current interval with the previous one (for which the correct response was known) would have worked well, as trials that were long relative to the standard were also longer than an immediately preceding short trial, and vice versa. Using this strategy, the participant’s ability to discriminate successive intervals would be improved by training, but the learning would be confined to intervals around the trained interval, since generalization to other intervals was not observed. This hypothesis could be tested by examining generalization to a standard closer to the trained standard (e.g., one threshold away). Alternatively, trial by trial comparisons could be controlled as an independent variable by use of different presentation methods such as a conventional, two-interval task, or the method of constant stimuli. This fascinating study addresses several other research themes that are central to an understanding of perceptual learning and its application. A major one is generalization. The authors focused on the implications of the pattern of learning generalization that they observed for the locus of the learning. Thus, learning across frequency suggested that the learning occurred outside of the core auditory pathway, Corresponding author. E-MAIL David.Moore@ihr.mrc.ac.uk; FAX 44 115 9518503. Article and publication are at http://www.learnmem.org/cgi/doi/ 10.1101/lm.59703.

Evaluating the evidence for implicit perceptual learning: a re-analysis of Farrow and Abernethy (2002).

Abstract: I present a re-analysis of the data from Farrow and Abernethy's (2002) study of implicit perceptual training in tennis. I argue that there are several weaknesses and mistakes in the original analysis, which, when rectified, lead to a fundamentally different set of conclusions to those given in the original paper. Specifically, there are significant group differences in anticipatory performance before the intervention that make subsequent between-group comparisons at specific occlusion points problematic. Second, in contrast to what is reported in the original paper, the explicit learning intervention resulted in a significant improvement in performance. In addition, a comparison of the effects of the different interventions indicates that the placebo group demonstrated the largest mean improvement in anticipation for the four occlusion points up to racquet-ball impact. Third, the non-significant change in performance over a 32-day retention period indicates that any improvements in performance were retained, not lost, over this period of time. Following a re-analysis of the original data, I conclude that Farrow and Abernethy's study provides no evidence that an implicit perceptual training paradigm improves anticipatory performance more than either an explicit learning paradigm or, indeed, an intervention involving mere observation of tennis matches.

Visual Perception of Objects

Abstract: Visual perception of objects is discussed in terms of two major topics: the perceptual organization of images into hierarchical structures of scenes (containing groups, objects, and parts) and the identification of individual objects as instances of known meaningful categories (such as chairs, houses, and dogs) The major phenomena of perceptual organization are demonstrated and discussed, including grouping, region segmentation, figure-ground perception, parsing, completion, part-whole structure, and reference frames Several important phenomena of object identification are also demonstrated and discussed, including categorical prototypes, basic level categories, perspective effects, orientational effects, and contextual effects Two major types of theories of object identification are outlined—part-based and view-specific theories—both of which are examined for their effectiveness in understanding how visual categorization of objects might occur Keywords: object identification; perceptual grouping; perceptual organization; visual categorization; visual perception

Evaluating the "Critical Period" Hypothesis: Perceptual Learning of Mandarin Tones in American Adults and American Children at 6, 10 and 14 Years of Age

Abstract: In this study, we examined the perceptual learning of lexical tones in Mandarin Chinese by American young adults, and children from 6 to 14 years old, covering the age range surrounding the “critical period”. The participants received a two-week computerized Mandarin tone training program designed to be child-friendly. The results showed that, for the trainees in each of the four age groups but not the controls, percent correct identification increased significantly from the pre-training test to the post-training test, indicating significant improvement after training across age groups. However, comparing the pre-puberty and the post-puberty groups, we did not find an abrupt decrease in the degree of improvement, as would have been predicted by the Critical Period Hypothesis. These results support the view that language learning is not a strictly timed developmental process with rigid cut-off periods.

Visual Perceptual Organization: A Microgenetic Analysis

Abstract: The visual world consciously perceived is very different from the retinal mosaic of intensities and colors that arises from external objects We perceive an organized visual world consisting of discrete objects, such as people, houses, and trees, that are coherently arranged in space Some internal processes of organization must be responsible for this achievement