Abstract: Three studies were done to test the hypothesis that there is a development in early childhood from a less advanced (Level 1) to a more advanced (Level 2) form of knowledge and thinking about people's visual experiences. Study 1 replicated and further validated a previous finding that 3-year-olds perform very well on tasks that call for Level 1 knowledge but very poorly on those that require Level 2 knowledge. Study 2 showed that children of this age did not perform better when critical aspects of Level 2 tasks were designed to be familiar to them and similar to what they might encounter in everyday life. Study 3 showed that most of the children who performed poorly on Level 2 tasks in Study 2 continued to perform poorly on a retest given 2-19 weeks later. In addition, a brief training period following the retest proved largely unsuccessful in inducing Level 2 knowledge and thinking in these children. The results of these three studies appear to provide strong support for the Level 1-Level 2 developmental hypothesis.

Abstract: Single-cell activity was recorded in the inferotemporal cortex of monkeys performing a task that requires perception and temporary retention of colored stimuli. Many cells reacted differentially to the stimuli. By changing the relevance of certain features of compound stimuli, it was found that the reactions of some cells to color depend critically on whether or not the task demands that the animal pay attention to color. A substantial number of cells showed color-dependent differences in frequency of discharge during the retention periods of the task. The temporal characteristics of differential discharge and its dissolution when memory is no longer required indicate that the cells that display it are involved in retaining visual information.

Abstract: Based on the author's thesis (Ph.D.--Massachusetts Institute of Technology) Includes indexes.

Abstract: The main factors limiting the performance of the peripheral parts of the visual system can be specified, and doing this clarifies the nature of the interpretive tasks that must be performed by the central parts of the system. It is argued that the critical factor that hinders development of better resolving power is the difficulty of confining light within the waveguide-like outer segment, and that for sensitivity this critical factor is the thermal decomposition of photosensitive pigments. Knowledge of these limits makes many surprising details of the eye intelligible. Understanding the difficulties posed by the narrow dynamic range of nerve fibres may give similar insight into the coding of the retinal image for transmission to the brain. Our level of understanding changes when we come to the visual cortex, for although we do not lack good anatomical and neurophysiological data, these do not make the principles of operation self-evident in the way that the structure of the eye immediately suggests that it is an image-forming device. The cortex converts the representation of the visual field that it receives into reliable knowledge of the world around us, and the trouble may be that we lack good models of how this can be done. A system that can respond to single quanta and resolve almost to the diffraction limit is unlikely to employ grossly inefficient methods for those higher functions upon which its whole utility depends, and so it is worth seeking out the limiting factors. The quality of human performance at certain higher perceptual tasks is high compared with the limit of reliable statistical inference; hence much of the sample of information available in a visual image must be effectively utilized. But there are strong limitations on the connectivity in the cortex, so that one is forced to consider how the relevant information can be collected together. Three stages of dealing with the visual image are proposed: the improvement of the cortical map in primary visual cortex by processes analogous to spatial and temporal interpolation; the detection of linking features in this map; and the concentration of this information by non-topographical mapping in adjacent visual areas.

Abstract: Several recent theories of visual information processing have postulated that errors in recognition may result not only from a failure in feature extraction, but also from a failure to correctly join features after they have been correctly extracted. Errors that result from incorrectly integrating features are called conjunction errors. The present study uses conjunction errors to investigate the principles used by the visual system to integrate features. The research tests whether the visual system is more likely to integrate features located close together in visual space (the location principle) or whether the visual system is more likely to integrate features from stimulus items that come from the same perceptual group or object (the perceptual group principle). In four target-detection experiments, stimuli were created so that feature integration by the location principle and feature integration by the perceptual group principle made different predictions for performance. In all of the experiments, the perceptual group principle predicted feature integration even though the distance between stimulus items and retinal eccentricity were strictly controlled.

Abstract: A magnitude estimation response procedure was used to evaluate the strength of visualauditory intersensory bias effects under conditions of spatial discrepancy. Maj or variables were the cognitive compellingness of the stimulus situation and instructions as to the unity or duality of the perceptual event. With a highly compelling stimulus situation and single-event instructions, subjects showed a very high visual bias of audition, a significant auditory bias of vision, and a sum of bias effects that indicated that their perception was fully consonant with the assumption of a single perceptual event. This finding reopens the possibility that the spatial modalities function as a transitive system, an outcome that Pick, Warren, and Hay (1969) had expected but did not obtain. Furthermore, the results support the model for intersensory interaction proposed by Welch and Warren (1980) with respect to the susceptibility of intersensory bias effects to several independent variables. Finally, a new means of assessing intersensory bias effects by the use of spatial separation threshold was demonstrated.

Abstract: Three experiments were performed involving the perception of surface texture. Experiment 1 indicated that when vision and touch are presented with discrepant information concerning texture, the two senses appear to weight the information about equally. Moreover, Experiment 2 showed that using touch, vision, or touch and vision, subjects performed a texture identification task with comparable matching accuracy and precision. Experiment 3 demonstrated that using the same three modes, subjects performed a magnitude estimation task similarly, in terms of magnitude estimates of roughness, the rates of growth of perceived roughness, and response precision. The comparability of the two senses in texture-related tasks may underlie the relatively equal compromise between discrepant sources of texture information demonstrated in Experiment (modality superiority interpretation). Such a compromise is somewhat different from that commonly reported in the sensory conflict literature. The relative weighting of multiple sources of sensory information about surface texture was also considered in terms of a directed-attention interpretation of intersensory organization.

Abstract: Originally published in 1981, this third volume deals with the empirical data base and the theories concerning visual perception – the set of mental responses to photic stimulation of the eyes. As the book develops, the plan was to present a general taxonomy of visual processes and phenomena. It was hoped that such a general perspective would help to bring some order to the extensive, but largely unorganized, research literature dealing with our immediate perceptual responses to visual stimuli at the time. The specific goal of this work was to provide a classification system that integrates and systematizes the data base of perceptual psychology into a comprehensive intellectual scheme by means of an eclectic, multi-level metatheory invoking several different kinds of explanation.

Abstract: The full-text of this book chapter is not available in ORA. Citation: Atkinson, J. & Braddick, O. J. (1981) Development of optokinetic nystagmus in infants: an indicator of cortical binocularity. In: Fisher, D. F., Monty, R. A. & Senders, J. W. (eds.) Eye movements: cognition and visual perception, Hillsdale, N.J: Lawrence Erlbaum, pp. 35-64.

Abstract: The effect of visual cortical and subcortical lesions on orienting behavior was assessed bu examining the rats' ability to interrupt an ongoing response and perform appropriate head and postural adjustments to repeatedly presented auditory or apparently moving visual stimuli. Large lesions of the entire superior colliculus (SC) or the deep layers of the SC did not result in visual agnosia or the inability to perform the motor responses involved in orienting. Rather, the orienting response simply ws not emitted to visual stimuli that the intact rat treated as less salient, but was to those it treated as more salient. Lesions of either the superficial layers of the SC or visual cortex also did not completely prevent orienting to very salient, apparently moving visual stimuli, but did produce changes in the number of responses made to such stimuli and in the occurrence of other components of orienting behavior. It was suggested that the SC and visual cortex play a modulatory role in orienting behavior and that stimulus characteristics must be considered in the development of neuronal models of orienting behavior.

Abstract: Multiple visual field representations are contained within the feline LP-pulvinar complex; regions differentiated by their afferent and efferent connectivity patterns as the striate-, tecto- and retino-recipient zones. Cell responses from these visuotopic zones were investigated in immobilized cats under N2O/O2 supplemented with pentobarbitone or Althesin, using spot, bar and textured stimuli.

Abstract: Descartes is probably the first known person to recognize the importance of eye movements in vision and visual perception, although Leonardo da Vinci may have recognized this before him.

Abstract: The massive visual projection to cortical areas 17 and 18 (striate and parastriate cortex) of the cat strongly suggests that these structures have a major role in visual processing. It is therefore paradoxical that ablation of these areas has been reported to result in very trivial deficits in their visual perception and behaviour1,2. In contrast to humans and monkeys, which show profound visual deficits after ablation of the visual cortex3–6, cats with similar lesions show essentially normal visual behaviour and are able to discriminate complex visual patterns. The only apparent effect of cortical lesions is a mild impairment of the visual acuity for gratings and a possibly greater reduction of vernier acuity7. In the past, the functional deficits resulting from lesions or ablations of various cortical structures have provided important clues to the function of many cortical areas, but recently a more detailed picture has emerged from electro-physiological studies of the properties of their constituent neurones. A striking aspect of most visual cortical cells in both cat and monkey is their specificity for horizontal retinal disparity8–10, the detection of which is a prerequisite for stereopsis11. This suggests that the visual cortex may play a major part in mediating stereopsis. We report here that ablation of cortical areas 17 and 18 in the cat results in severe selective deficits in binocular depth perception consistent with a loss of stereopsis.

Abstract: J. J. Gibson's approach to,the study of perception emphasizes the way an active observer picks up information from the environment. The central postulates of Gibson's approach are that (1) visual space is defined by information (such as texture gradients) contained on environmental surfaces, (2) the crucial information for perception is information that remains invariant as an observer moves through the environment, and (3) this invariant information is picked up directly, so that no intervening mental processes are necessary for visual perception. This paper summarizes Gibson's approach as it is stated in his three books, Perception of the Visual World (1950), The Senses Considered as Perceptual Systems (1966) and The Ecological Approach to Visual Perception (1979) and evaluates thefinalform of his approach described in his third, and last, book.

Abstract: Exploratory behaviors of rats with lesions of the visual cortex or superior colliculus (SC) were examined using a traditional open field and a smaller closed field. Animals with large bilateral lesions of the SC or lesions restricted to the deep laminae of the SC exhibited excessive locomotor activity in both experimental situations. The degree of habituation of this hyperactivity and other behaviors such as investigating rearing, exploratory nose poking, and self-initiated exposure to illuminated visual stimuli in the closed field were also examined. Consideration of the complete range of exploratory responses and the effect of lesions on them lead to a proposal that the hyperactivity of rats with SC lesions is an impairment adjunct to sensory neglect and orienting behavior impairments.

Abstract: In a study of visual dominance based on Rock and Victor's experiments, observers examined well-known objects while receiving conflicting tactual and visual information. In experiment 1 observers si...