Showing papers on "Visual perception published in 1972"

Visual properties of neurons in inferotemporal cortex of the Macaque.

Abstract: IN THE LAST DEC,ADE, considerable progress has been made in understanding the physiology of one of the most fundamental aspects of human experience: perception of the visual world. It is now clear that the retina and visual pathways do not simply transmit a mosaic of Iight and dark to some central sensorium. Rather, even at the retinal level, specific features of visual stimuli are detected and their presence communicated to the next level. In cats and monkeys, the geniculostriate visual system consists of a series of converging and diverging connections such that at each successive tier of processing mechanism, single neurons respond to increasingly more specific visual stimuli falling on an increasingly wider area of the retina (19-Z). How far does this analytical-synthetic process continue whereby individual cells have more and more specific trigger features? Are there regions of the brain beyond striate and prestriatel cortex where this processing of visual information is carrie,d further? If so, how far and in what way? Are there cells that are concerned with the storage of visual information as well as its analysis? There are several lines of evidence suggesting that a possible site for further processing of visual information and perhaps even for storage of such information might, in the monkey, be inferotemporal cortexthe cortex on the inferior convexity of the temporal lobe. First, this area receives afferents from prestriate cortex which itself processes visual information received from

Temporal and spatial characteristics of selective encoding from visual displays.

Abstract: The time required for Ss to voice a target letter in a visual display was studied as a function of the spatial proximity of two kinds of noise elements (letters or disks) to the target and as a function of when the noise elements were presented following the onset of the target letter. The results were not consistent with a focusing model of attention or selective encoding. Instead, there appears to be a small area in the visual field (about 1 deg of angle) in which all stimuli are processed in detail.

Eye Movements and Perceived Visual Direction

Abstract: The implicit assumption that visual perception is not susceptible to influences from extraretinal sources1 has held extremely well in the areas of color vision, contour perception, and intensity discrimination. It has permitted the development of theoretical models of considerable generality for treatment of psychophysical phenomena in these areas that are based essentially on reasonable inferences from present knowledge regarding the neurophysiology, photochemistry, and neuroanatomy of the primary visual projection system. As will be indicated below, where this assumption can be reasonably made in the area of space perception some progress has taken place in a search for physiologically-based theoretical mechanisms for treatment of psychophysical data.

Similarity grouping and peripheral discriminability under uncertainty.

Abstract: The effectiveness of rotated figures in producing similarity grouping corresponded to their peripheral discriminability under uncertainty in a patterned visual field--but not to their discriminability in an empty visual field. The results support the hypothesis that similarity grouping is a segregative process based on the response of the visual system to stimulus differences before attention narrows or focuses.

Auditory, Visual, and Auditory-Visual Recognition of Consonants by Children with Normal and Impaired Hearing.

Abstract: The consonants /b, d, g, k, m, n, p, t/ were presented to normal-hearing, severely hearing-impaired, and profoundly deaf children through auditory, visual, and combined auditory-visual modalities. ...

Visual spatial illusions: a general explanation.

Abstract: Representation at the visual receptors of such properties of the object as its size, shape, orientation, and movement undergo considerable variation as the distance, bearing, posture, and motion of the observer, relative to the object, changes. However, despite these gross and frequent deformations of the image, perceived properties remain extraordinarily stable. Such constancy has obvious biological utility; the observer perceives his world according to its fixed physicalfeatures rather than in terms of its variable sensory representation. Constancy of apparent size, shape, orientation, and movement is dependent on information for the distance, bearing, lateral tilt, and movement of the observer, respectively. Thus, as the retinal image shrinks with distance, constancy of apparent size is maintained by five classes of distance, stimuli that operate singly or in various combinations. Likewise, visual orientation and visual stimuli for the orientation of the observer, and movement constancy on visual and nonvisual stimuli for the movement of the observer. Illusion occur when stimuli that normally preserve constancy are operative but with the image of the object not varied. Thus if retinal disparity, convergence-accommodation, projected stimuli, or other distance stimuli are varied with the image not varied, illusions of size occur. Those rsluting from variation of projected stimuli are the. well-known geometrical size illusions and include the Mu llerLyer group. In essentially the same manner, independent manipulation of stimuli for the orientation and the motion of the observer, with the orientation and the motion of the image at the retina not varied, gives rise to illusory orientations and movements of the object. Limited attempts to explain size illusions in terms of the projected stimuli that preserve perceptual constancy are by no means new; Thiery (51) proposed such a view in the later part of the last century, and in recent times there has been a spate of such proposals including the " misapplied constancy hypothesis" advanced by Gregory (2). However, Gregory's theory is confined largely to geometrical size illusions and invoks only distance scaling given by a limited number of projected stimuli. Furthermore, the Muller-Lyer illusion is seen by him to be a consequence of distance scaling resulting from the converging arrows. There is no recognition of the range of such effects with various attached elements, as shown in Fig3, and no attention is accorded the recently established difference between the illusions with inward and outward-directed elements. The theory of spatial illusions outlined here distinguishes between classes of illusory effect and, in linking each to its particular class of spatial constancy, offers a general and testable explanation. Failure to recognize classes of illusion(and perceptual constancy), such as those of size, orientation, and movement, can be regarded as among the major deficiencies of recent attempts (2, 44) to explain illusory effects. I do not claim that this explanation, which I call the general constancy theory, satisfactorily encompasses all known illusions, but merely that it is more comprehensive than alternative explantions I conclude that any stimulus which serves to maintain perceptual constancy of a property of an object as the visual representation of that property varies will, when independently manipulated with the retinal image not varied, produce an illusion. This general principle predictS the conditions under which illusory effects will occur and has wide explanatory application.

Neuropsychological evidence of visual storage in short-term memory tasks.

Abstract: Auditory and visual presentation of verbal material were compared in a single patient having an auditory verbal S.T.M. deficit. A Peterson short-term forgetting experiment and an immediate memory s...

Training Visual Perceptual Processes

Abstract: In this article, recent research and writing has been organized for the purpose of (1) operationally defining “visual perception,” (2) investigating the relationship between visual perception and reading comprehension, and (3) determining the effects of visual perceptual training on reading and visual perception. Visual perception was defined as those brain operations which involve interpreting the physical elements of the stimulus rather than the symbolic aspects of the stimulus and are usually referred to as visual discriminations and/or spatial relationships. It was concluded that little correlation existed between measures of visual perception and tests of reading comprehension and that training visual perceptual skills, using currently available programs, has no positive effect on reading and possibly none on visual perception.

Object perception in infants.

Abstract: Natural responses, reaching and grasping, are used in an attempt to show that young infants perceive the distal properties of objects rather than their proximal correlates. The attempt seems to be successful for the properties, solidity, size, and distance. The developmental bases of these capacities are discussed.

The latency operating characteristic. I. Effects of stimulus probability on choice reaction time.

Abstract: The latency operating characteristic (LOG), denned as the trade-off relation between reaction time (RT) and discrimination accuracy, is proposed as a measure of the perceptual process that is invariant over changes in decision strategies in RT tasks. The LOC was computed from confusion matrices constructed from sets of trials on which the RT fell within a given range. The convergent validity of the LOC was supported by findings of a strong and consistent relation between speed and accuracy that was invariant under changes in stimulus and response probability. Several models of the underlying perceptual processes are discussed which lead to a good description of LOC by a set of straight lines.

Visual and Auditory Modalities Related to Methods for Beginning Reading.

Abstract: PRESENTS THE FINDINGS of a comparison of the reading progress, through third grade, of pupils identified as having high visualhigh auditory, high visual-low auditory, low visual-high auditory, and low visual-low auditory abilities when they entered first grade. Subjects were identified among 232 in 12 classrooms from two school systems using a sight approach to reading and 216 in 10 classrooms from two school systems using the HayWingo approach. Subjects with both visual and auditory modalities high scored highest on tests of reading at the end of first and third grades; those with both modalities low scored lowest; those with one strong and one weak modality scored between the two extremes. Neither method for teaching reading surpassed the other among pupils with strong or weak modalities. Regardless of method, auditory discrimination made a significant contribution to all reading while visual perception did not.