Showing papers on "Perceptual learning published in 1995"

Human perceptual learning in identifying the oblique orientation: retinotopy, orientation specificity and monocularity.

Abstract: 1. Human perceptual learning in discrimination of the oblique orientation was studied using psychophysical methods. Subjects were trained daily to improve their ability to identify the orientation of a circular 2.5 deg diameter unidimensional noise field. Dramatic improvements in sensitivity to contour orientation occurred over a period of 15-20 days. The improved performance persisted for several months. Improvement was more evident between daily sessions than within sessions. This was partly due to fatigue interfering with the learning effect. Moreover, a consolidation period seemed to be required. 2. Improvement was restricted to the position of the stimulus being trained. This position dependency of the learning effect proved very precise. After training at a specific stimulus position, merely displacing the stimulus to an adjacent position caused a marked increase in thresholds. 3. No transfer of the training effect was observed between orientations. Following a shift of 90 deg away from the trained orientation, performance fell, even below the initial level. 4. We observed complete to almost complete transfer between the two eyes. 5. Our results suggest plastic changes at a level of the visual processing stream where input from both eyes has come together, but where generalization for spatial localization and orientation has not yet occurred.

Learning surgical technical skills

Abstract: Training issues raised by the recent introduction of laparoscopic surgical techniques led to this analysis of motor-skill learning principles as they apply specifically to the learning of technical surgical skills. The most accepted theories of motor-skill learning are presented, not as opposing views, but as complementary constructs. The behaviourist school of thought's main contribution is the executive routine or knowledge of the steps of a procedure. Schmidt's schema theory and MacKay's node theory suggest that perceptual information may play an important role in the quality of the performance. The conclusions reached from neuropsychologic testing experiments on surgeons are that visuospatial perceptual skills (the ability to represent mentally the physical environment and the movement to be performed) are the major determinants of surgical technical performance. Learners should make use of learning strategies that improve mental representation of a skill and the corresponding anatomy. Specific strategies discussed include imagery, mental practice and a systematic review of performance that focuses on the perceptual feedback received by the learner.

The Discrimination-Transfer Procedure for Studying Auditory Perception and Perceptual Invariance in Animals

Abstract: This chapter describes methods for studying auditory perception of complex acoustic stimuli in animals. First, we describe techniques for establishing an initial baseline discrimination between two or more auditory patterns. Then, we discuss transfer procedures used to assay for the acoustic features that control the baseline discrimination. To illustrate the procedures, we use data from an experiment on the perception of auditory spectra by European starlings (Sturnus vulgaris). The procedures are adaptable, in principle, for use with a wide variety of species to study a broad array of problems in the comparative psychology of auditory perception.

Perceptual Latency and Complex Random-Dot Stereograms

Abstract: Naive observers of random-dot stereograms depicting complex surfaces often find that they require several tens of seconds before the impression of depth emerges. With practice, however, perception times often decrease markedly: perceptual learning occurs. Current explanations of these effects were assessed in two experiments. In the first experiment the perception times of naive observers for random-dot stereograms which depicted the same complex shape but contained different ranges of disparity were measured. In the second experiment the minimum times required by experienced observers to perceive a given complex shape in stereograms that contained different ranges of disparity were determined. Perception times for the naive observers were all very fast (<3 s) and showed no evidence of perceptual learning. There was no effect of disparity range on perception times in either experiment. It was found that very large-disparity (80 min arc) complex stereograms could be perceived quickly, even by naive observers. It is concluded that the long initial latencies previously reported are not due to surface complexity nor to the range of disparities present. Other factors. such as dot size, dot density, and the correlation of the stereo images, appear to be important determinants of efficient stereoscopic performance when viewing complex random-dot stereograms.

Relational learning in pigeons: The role of perceptual processes in between-key recognition of complex stimuli

Abstract: In Experiment 1, we used six procedures in a series of unsuccessful attempts to obtain relational learning using trial-unique pictorial stimuli in pigeons. The Experiment began by testing conventional (three-key) matching-to-sample (MTS) and nonmatching-to-sample (NMTS); in subsequent stages of the experiment we progressively incorporated features of techniques that do obtain relational learning in a single-key apparatus. In Experiment 2, we found that acquisition of NMTS using pictorial stimuli proceeded no more rapidly than acquisition of a conditional discrimination. Experiment 3 showed that acquisition of NMTS was more rapid than acquisition of MTS when plain colored stimuli were used, but not when pictorial stimuli were used. These three experiments suggest that pigeons do not recognize pictorial stimuli shown on different keys. In Experiment 4, between-key recognition was obtained with familiar but not with novel pictorial stimuli. It is argued that perceptual learning facilitates the detection of the between-key identity of complex stimuli, and that perceptual processes may underlie the difficulty in demonstrating relational learning in pigeons.

On Perceptual Learning

Abstract: A fundamental concern in Psychology is the extent to which we learn to perceive our world and, further, the degree to which perception remains modif"Iable even in adulthood. Yet despite the significance of these concerns, perceptual learning has been somewhat sporadically studied, and often only at a phenomenal level. This thesis proposes a new theoretical framework for perceptual learning, and argues that a multiplicity of processes have been examined under this single term. The empirical work reported in this thesis examines a range of these different learning processes, and illustrates methods by which the process/processes underlying a particular phenomenon can be revealed. Extended replications of seminal studies on 'perceptual learning' demonstrate the non-perceptual learning nature of the processes reported in those studies. Further empirical work presents new evidence for the plasticity of human vision on fundamental dimensions of visual processing. These fmdings suggest that even adults I perceptual experience is modifiable as a result of changes at an early stage of visual processing. Final empirical work considers the types of learning that may occur in the more complex and naturalistic task of detecting features in X-rays, and this leads on to an examination of visual search learning. It is concluded that, given the varied nature of the learning processes identified, a unified theory of perceptual learning may be an unrealistic goal. Instead, a detailed understanding of the different mechanisms underlying each of the identified learning processes is likely to prove more useful. Finally, it is argued that all of the identified processes, previously regarded as perceptual learning, could underlie improvements on complex 'real-world' discrimination tasks. This is illustrated through the application of the theoretical framework, developed in this thesis, to mammographic ftlm reading. It is argued that by isolating and systematically targeting each of the learning processes involved in a task, more effective training programmes could be designed.

How Perception Guides Production in Birdsong Learning

Abstract: A computational model of song learning in the song sparrow (Melospiza melodia) learns to categorize the different syllables of a song sparrow song and uses this categorization to train itself to reproduce song. The model fills a crucial gap in the computational explanation of birdsong learning by exploring the organization of perception in songbirds. It shows how competitive learning may lead to the organization of a specific nucleus in the bird brain, replicates the song production results of a previous model (Doya and Sejnowski, 1995), and demonstrates how perceptual learning can guide production through reinforcement learning.

Two-dimensional symmetric form discrimination: Fast learning, but notthat fast

Abstract: Several authors have characterized a striking phenomenon of perceptual learning in visual discrimination tasks. This learning process is selective for the stimulus characteristics and location in the visual field. Since the human visual system exploits symmetry for object recognition we were interested in exploring how it learns to use preattentive symmetry cues for discriminating simple, meaningless, forms. In this study, similar to previous studies of perceptual learning, we asked whether the effects of practice acquired in the discrimination of pairs of shape with a specific orientation of the symmetry axis would transfer to the discrimination of shapes with different orientation of symmetry axis, or to shapes presented in different areas of the visual field. We found that there was no learning transfer between forms with very different axes of symmetry (90° apart). Interestingly, however, we found a transfer of learning effect to horizontally oriented symmetry axis from a condition with an axis of symmetry differing by 45°. Also it appears that some subjects took a longer time to learn than the typical “fast learning” paradigm would predict. Data showed that when observers practice discrimination of meaningless symmetric forms, consistent improvement in the performance occurs. This improvement is lasting over days, and it tends to be specific for the area of the visual field trained. We will discuss results from some of the observers whose learning was not “fast”, but who actually improved with more practice and with large time intervals (1 day) between training sessions.

Effects of perceptual learning on the production of a non‐native contrast

Abstract: Previous research has shown a significant correlation between the perception and production of English /r/ and /l/ by Japanese speakers [Yamada et al., Proc. ICSLP94, 2023–2026 (1994)]. The present study further investigated this perception‐production link by examining the transfer of training in perception to production of a non‐native contrast. Twelve monolingual Japanese speakers were trained to perceive the English /r/–/l/ contrast using a high‐variability training program [Lively et al., 2076–2087]. Recordings were also made of the trainees’ productions of English /r/‐/l/ minimal pairs before and after the perceptual training. These pretest and post‐test recordings were then evaluated perceptually by American listeners who were presented with pairs of tokens in an A‐B test format. As expected, subjects’ accuracy on the perceptual task improved by about 16% after 45 training sessions. More importantly, subjects’ productions at pretest and at post‐test were distinguishable by American listeners. More p...

Perceptual Learning in the Acquisition of Flight Skills.

Abstract: : Many skills transfer effects observed in flight training research may be explained by an appeal to invariant perceptual properties of the task environment. If training in a simulator serves to enhance sensitivity to perceptual properties that are critical to flight performance, a high level of transfer will result. The theory forwarded here assumes that a relatively low-dimensional set of properties supports flight control. It is those properties that need not be represented accurately, or even at all. One implication of the approach outlined here is that the unquestioning pursuit of high fidelity is, in large part, wasted effort. (AN)

Nature of perceptual skills in screening mammography: implications for training

Abstract: The perceptual skills of the radiological expert are acquired through cumulative exposure to large numbers of radiographs. This extensive practice probably engenders two kinds of perceptual learning: 'low- level' feature learning, and 'search-learning'. We report here two experiments aimed at establishing the relative importance of these two mechanisms. The first experiment investigated detection of high spatial frequency - low contrast 'targets' in radiographs, and sought to locate the level at which learning occurred by using transfer of training across eyes and across stimuli as indicators of the locus of learning. Detection times improved after extensive practice (200 trials a day for 8 days) with no loss in accuracy. This improvement transferred across eyes, but transferred just partially to targets at new levels of contrast. This pattern of results suggests that both low-level feature learning and some more general, higher level learning, had occurred. Experiment two investigated this possibility in more detail using a visual search paradigm. The possibility that perceptual learning included a change from serial to parallel processing was explored, and measures of transfer of learning to new distractor sets and to novel stimulus dimensions were used to explore the likely locus of learning. Reaction times to the presence of absence of targets among distractors on a random noise background improved as the result of practice (1440 training trials). This learning transferred across eyes, to a new stimulus dimensions set and to different distractor sets. Further, true positive detection rates showed an increase for stimuli with a homogenous distractor set whilst there was no change in false positive rates. The implications of the results for training programs are discussed.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.