Abstract: stability and constancy in visual perception mechanisms and processes wiley series in behavior. Book lovers, when you need a new book to read, find the book here. Never worry not to find what you need. Is the stability and constancy in visual perception mechanisms and processes wiley series in behavior your needed book now? That's true; you are really a good reader. This is a perfect book that comes from great author to share with you. The book offers the best experience and lesson to take, not only take, but also learn.

Abstract: In 48 patients with multiple sclerosis sine-wave gratings were used to test visual sensitivity for coarse, medium, and fine detail rather than measuring visual acuity for fine detail only, as in conventional clinical tests. In 20/48 patients the test revealed a visual defect of neural origin, qualitatively different from that caused by refractive error. In 11 of these 20 patients, visual sensitivity to detail of medium coarseness was markedly degraded, even though sensitivity to both coarse and fine detail was unimpaired. In 3 of these 20 patients visual sensitivity to coarse detail was selectively degraded. These visual defects could not be detected by the Snellen test, yet the patient might experience visual problems in everyday life and also experience distorted visual perception. Possible neural bases for these visual impairments are discussed. Since 8 of the 14 patients with selective loss showed no clinical evidence of visual involvement, the test can aid the earlier diagnosis of multiple sclerosis.

Abstract: THE approximate form of the projection of visual space on the striate cortex in man has long been established from neurological evidence1–3 and estimates of cortical magnification M (the extent of striate cortex in millimetres corresponding to a degree of arc in visual space) have been derived from studies on cortical phosphenes and visual acuity4, and migraine scotoma dimensions5. The possibility that M could be estimated from the density of retinal ganglion cells which provide the output from the eye to the brain has received support from studies on monkeys6–8. It has been shown that M is proportional to √Dc (where Dc is the projected ganglion cell density in cells per solid degree of visual space) for peripheral angles (θ) greater than 10°. More centrally, where Dc is maximal, this relationship breaks down because the cells are displaced from their receptive fields by an amount which is difficult to determine8. If data on ganglion cell receptive field density, Dr (in receptive fields per solid degree) were available, they might be expected to relate to M at every point in the visual field. I report here that I have obtained such estimates of Dr and examined their usefulness as predictors of M. The results are summarised in three basic equations.

Abstract: The focus of this paradigmatic review of the effects of imagery on children's learning is the specification of conditions under which imagery increases children's learning of verbal materials. In particular, this paper examines the recurrent speculation tha t imagery is more effective at some developmental levels than at others. The paradigmatic nature of the children's learning l i terature dictates Ihe paradigmatic organization of this article. Pairedassociate learning is discussed first and most extensively be­ cause the bulk of experimental work on imagery and children's l ea rn ing has been conducted wi th in a pa i red-associa te framework. The remainder of the paper reviews other popular paradigms used to investigate imagery effects. The discussion proceeds from simple tasks (recognition and recall) to more difficult tasks (prose learning). Because of space limitations the review of research in these latter paradigms will not be as exhaustive as the discussion of imaginal effects on pairedassociate learning. Instead, the emphasis will be on topics of recent interest to researchers in these paradigms. Each section

Abstract: The problem about visual discrimination between seeing objects in motion and perception of motion of the perceiver (locomotion) was taken up. A flow of vertical motion was presented to limited areas of the far periphery (45 degrees-90 degrees) of the retina simultaneously with optical information about a stationary room over the rest of the retina. The result was that most subjects perceived themselves as sitting in an elevator continuously moving upward or downward. Thus, peripheral motion stimulation over a few percent of the retinal area determines locomotion perception in apparent competition with information about a static state over the rest of the retina. The same type of stimulus presented to the central part of the retina always brought about perception of object motion and a static perceiver. Effects of size and localization of the area stimulated with the motion flow was studied. Theoretical consequences and problems for further experimental analyses are discussed.

Abstract: Preface Introduction 1. The background to Molyneux's question 2. Cataract operations 3. Diderot's Letter on the Blind 4. Berkeley and Condillac 5. Thomas Reid and the new nativism 6. Lotze and Kant: the theory of local signs Afterword Index.

Abstract: Environmental objectives and human needs. The process of visual perception. The design of the luminous environment. Case studies.

Abstract: This chapter describes recent theory and research in one limited area of social-cognitive development, namely, the childhood acquisition of knowledge about visual perception. The author and his co-workers have hypothesized that there are two developmental levels of such knowledge. At earlier-developing Level 1, the child understands that others as well as the self see objects, and is also able to infer correctly what objects they do or do not currently see if provided with adequate cues. At later-developing Level 2, the child understands not only that people can see objects, but also that they can have differing visual experiences while seeing the same object; most notably, they can have different spatial perspectival views of it when looking at it from different positions. Arguments and evidence for the developmental distinction between Level 1 and Level 2 knowledge are briefly presented in Section I. A more detailed model of Level 1 knowledge is presented in Section II, together with an account of several studies of its development during the first four years of life. During these early years, children appear to learn a great deal about how to produce visual percepts in others (showing and pointing to things), how to deprive others of percepts (hide objects), and how to diagnose the percepts they currently have (follow others' direction of gaze and pointing gestures). Section III similarly reviews recent theory and research on the development of Level 2 perspective-taking knowledge in older children. This work is focused mainly on the acquisition and use of very general perspective-taking rules, such as the rule that two observers who look at an object array from the same spatial position must on that account necessarily have identical perspectival views of the array. Section IV described further developmental research that could be or is being done on Level 2 knowledge, Level 1 knowledge, and on the Level 1-Level 2 distinction.

Abstract: The research reported herein was designed to assess whether the presence of noise elements in a visual display affects the detection of target letters at the perceptual or feature extraction level of processing, as well as at the decision level, and more specifically, whether (a) input or processing channels operate in an independent or interactive fashion and (b) how the spatial relation between signal and noise items affects detection performance. In order to distinguish among current theories proposed to account for the influence of noise items on visual processing, a forced-choice detection task was modified to incorporate a cueing procedure, which permitted the independent variation of signal-noise similarity, confusability, and proximity. The results provide evidence for feature-specific inhibition at the perceptual level, and a theory is proposed that assumes hierarchically organized, limited-capacity feature detectors and feature-specific inhibitory channels. There is now considerable evidence that the detectability of a designated signal is impaired by the presence of noise elements in the same visual display. The degree of impairment has been shown to vary as a function of the confusability of noise elements with the set of alternative targets (Estes, 1972; Gardner, 1973; Mclntyre, Fox, & Neale, 1970) and the spatial proximity of target and noise (Strangert & Brannstrom, 1975; Wolford & Rollingsworth, 1974). However, whether the effects of signal-noise similarity on target detection might be different than the effects of signalnoise confusability and how either of these variables might interact with signal-noise proximity has not been established; nor is it clear at what level of processing noise items impair the visual detection of signals. Evidence Edward E. Smith acted as Guest Editor for this article. The research reported was supported by Grant

Abstract: : The mechanisms underlying effects of ionizing radiation on visual-motor tasks in combat are not understood but definitely involve some disruption of visual perception. The degree of involvement is not known and must be studied and quantified in animal models. It is possible to identify those parts of the central nervous system necessary for visual perception. Once these areas have been identified, their sensitivity to irradiation can be studied more precisely. Visual responses of area 18 neurons were studied in the awake, behaving monkey. Cells were divided into six different classes on the basis of their stimulus preferences and spatial characteristics. Orientation cells were sensitive to the orientation of elongated stimuli. Color cells had nonoriented receptive fields with spatially coextensive opponent color inputs. Direction cells preferred moving stimuli, giving the greatest response to movement in some direction and no response or inhibition to movement in the opposite direction. Spot cells preferred a properly positioned small spot of light and responded equally well to all directions of stimulus movement. Border cells responded best to a stimulus that filled an excitatory region without encroaching on a powerful suppressive flank. Lightinhibited cells had high maintained spontaneous activity that was reduced or abolished by light.

Abstract: Three chronometric experiments, each comparing vision and kinesthesis, were conducted to study visual dominance. The time required to switch attention from vision and from kinesthesis was equal, while switching to kinesthesis was faster than switching to vision (Experiment 1). Responses to a combined visual-kinesthetic stimulus were slower than responses to a kinesthetic stimulus alone when the subject was expecting the bimodal stimulus. The visual dominance effect was shown to depend on the subject knowing the modality of the stimulus in advance (Experiment 2). When subjects were instructed to attend one modality they had equal difficulty with conflicting visual and kinesthetic information (Experiment 3). These findings suggest that visual dominance results from a bias to attend vision when that modality seems adequate for the task. Te bias to attend vision may develop to overcome a deficiency in visual alerting. Language: en

Abstract: Cluster analyses of intercorrelation of scores on tests of sensory integrative, language, auditory, intellectual, and academic tests administered to young learning-disabled school children demonstrated a close relationship between academic achievement, the right ear score on dichotic listening, language expression, and auditory memory. Visual perception tests and the Auditory Association sub-test of the Illinois Test of Psycholinguistic Abilities showed a close association with IQ. Others associations were consistent with the view that when the two cerebral hemispheres do not corroborate, both hemispheres tend to develop similar motor and language functions. Analyses of the intercorrelation of scores on the sensory integration, auditory, and language tests resulted in four major factors: auditory-language functions, postural-ocular reactions, eye-hand coordination, and somatosensory and motor planning or praxis. A fifth factor, visual perception, contributed less to the final factor structure.

Abstract: Reaching and retrieving, with and without visual feedback of the hand, were observed in 50 infants ranging in age from 2 1/2 to 6 1/2 months. Failure, to see the hand did not completely inhibit reaching and retrieving, although reaching and retrieving were reduced in this situation for infants 5 1/2 months and older. It was hypothesized that infants of this age expected to see their hands within their visual fields. When this expectation was not met, the infant's ongoing behavior was disrupted.

Abstract: To what extent is simultaneous visual and auditory perception subject to capacity limitations and attentional control? Two experiments addressed this question by asking observers to recognize test tones and test letters under selective and divided attention. In Experiment 1, both stimuli occurred on each trial, but subjects were cued in advance to process just one or both of the stimuli. In Experiment 2, subjects processed one stimulus and then the other or processed both stimuli simultaneously. Processing time was controlled using a backward recognition masking task. A significant, but small, attention effect was found in both experiments. The present positive results weaken the interpretation that previous attentional effects were due to the particular duration judgment task that was employed. The answer to the question addressed by the experiments appears to be that the degree of capacity limitations and attentional control during visual and auditory perception is small but significant.

Abstract: I begin obliquely. Doty,] following the work of Downer,2 has studied the relation between visual gnostic functions and fear reactions in the split-brain macaque. In one of his preparations a unilateral amygddectomy is combined with sectioning of the optic tract on the contralateral side. Then all of the forebrain commissures are transected, except for the posterior one-third of the corpus callosum. This remaining tissue, the splenium, is ensnared by a ligature that is brought to the skull surface and left protruding. Allowing several months for the bone flap t o knit, the animal is then placed in a large enclosure. Now if a man enters this enclosure the monkey behaves normally: that is, it takes flight. However if the splenium snare is pulled-which takes only a few minutes and causes n o reaction other than a slight blink-a dramatic change occurs in the same animal’s behavior. It n o longer runs from the man. In fact it will approach him, let him touch its snout, will sniff, nuzzle or very gently bite his outstretched fingers. This is precisely the point at which conceptual problems arise. For suppose someone, trying t o explain the change in the monkey’s behavior, asks if this animal can still see the man in the enclosure. The answer must be “yes,” because completion of the neocommissural transection did not add to its blindness: it was already homonymously hemianopic due to sectioning of the optic tract on one side, i.e., both eyes were blind for that half visual field. And in fact it displays normal visual behavior, at least for one half the visual field. It blinks and dodges rapidly approaching objects, jumps accurately from perch to perch, and fixates-with conjugate eye movements-on the man as he enters the enclosure. Now suppose we are asked if this monkey can still feel fear. Again the answer must be “yes,” because disruption of the splenium did not affect the remaining intact amygdala. Indeed if this animal is touched elsewhere than on the snouton its body or limbs, for example-it will be provoked to violent flight or attack. But then why does the monkey run when it sees the man in the enclosure? If it can see him, and can feel fear, why has it lost its visual fear reactions? The short and simple explanation for this, the kind of answer I would expect from Geschwind,3 is that what we are witnessing here is just another “disconnection syndrome.” By pulling the splenium snare, we have disconnected the visual cortex of one cerebral hemisphere from the other cerebral hemisphere, which includes an intact amygdala. So the part of the monkey that sees but cannot feel fear is cut off from the part of the monkey that is blind but fearful. Thus we have provoked what might be called a functional bilateral amygdalectomy with regard to visual stimuli. I find this explanation attractive for its simplicity, but ultimately unsatisfying. The reason I find it unsatisfying is that if we persist in thinking of this as a single conscious organism, the fact remains that “it,” the monkey, both sees and is fearful, yet does not react fearfully to what it sees. HOW can this be if it is the same monkey that sees and is fearful? And if one says that only a part of the monkey sees, another part is fearful, and these two parts were disconnected by