Showing papers on "Visual perception published in 1980"
TL;DR: These results appear to provide an important model system for the study of the relationship between attention and the structure of the visual system, and it is found that attention shifts are not closely related to the saccadic eye movement system.
Abstract: Detection of a visual signal requires information to reach a system capable of eliciting arbitrary responses required by the experimenter. Detection latencies are reduced when subjects receive a cue that indicates where in the visual field the signal will occur. This shift in efficiency appears to be due to an alignment (orienting) of the central attentional system with the pathways to be activated by the visual input. It would also be possible to describe these results as being due to a reduced criterion at the expected target position. However, this description ignores important constraints about the way in which expectancy improves performance. First, when subjects are cued on each trial, they show stronger expectancy effects than when a probable position is held constant for a block, indicating the active nature of the expectancy. Second, while information on spatial position improves performance, information on the form of the stimulus does not. Third, expectancy may lead to improvements in latency without a reduction in accuracy. Fourth, there appears to be little ability to lower the criterion at two positions that are not spatially contiguous. A framework involving the employment of a limited-capacity attentional mechanism seems to capture these constraints better than the more general language of criterion setting. Using this framework, we find that attention shifts are not closely related to the saccadic eye movement system. For luminance detection the retina appears to be equipotential with respect to attention shifts, since costs to unexpected stimuli are similar whether foveal or peripheral. These results appear to provide an important model system for the study of the relationship between attention and the structure of the visual system.
3,559 citations
TL;DR: A method for discovering how the defining values of forthcoming body movements are specified is presented, consistant with a distinctive-feature view, rather than a hierarchical view, of motor programming.
Abstract: This article presents a method for discovering how the defining values of forthcoming body movements are specified. In experiments using this movement precuing technique, information is given about some, none, or all of the defining values of a movement that will be required when a reaction signal is presented. It is assumed that the reaction time (RT) reflects the time to specify those values that were not precued. With RTs for the same movements in different precue conditions, it is possible to make detailed inferences about the value specification process for each of the movements under study. The present experiments were concerned with the specification of the arm, direction, and extent (or distance) of aimed hand movements. In Experiment 1 it appeared that (a) specification times during RTs were longest for arm, shorter for direction, and shortest for extent, and (b) these values were specified serially but not in an invariant order. Experiment 2 suggested that the precuing effects obtained in Experiment 1 were not attributable to stimulus identification. Experiment 3 suggested that subjects in Experiment 1 did not use precues to prepare sets of possible movements from which the required movement was later selected. The model of value specification supported by the data is consistant with a distinctive-feature view, rather than a hierarchical view, of motor programming.
925 citations
838 citations
TL;DR: The approach of the present paper is to suggest that the basic data structure of perceptual coding consists of two-dimensional laminar mapping, and that successive stages of remapping, along with columnar architecture, may provide important computational functions.
616 citations
TL;DR: When a group of dots within a random-dot array is discontinuously displaced, it appears as a moving region perceptually segregated from its stationary surround, illustrating the interaction of relatively stimulus-constrained and relatively autonomous processes invisual perception.
Abstract: When a group of dots within a random-dot array is discontinuously displaced, it appears as a moving region perceptually segregated from its stationary surround. The spatial, temporal and other constraints governing this effect are markedly different from those classically found for the apparent motion of isolated stimulus elements. The random-dot display appears to tap a low-level motion-detecting process, distinct from the more interpretive process elicited by the classical displays. The distinct contributions of these processes can be identified in 'multi-stable' displays which yield alternative percepts of apparent motion depending on which one or both of the processes is activated. Such experiments illustrate the interaction of relatively stimulus-constrained and relatively autonomous processes in visual perception. Two contrasting approaches dominate much recent work on visual perception. One is to explore how properties of the stimulus may be decoded in the patterns of activity of neural channels or detectors, each of which has its own selective tuning (Braddick et al. 1978). The other approach (exemplified by Gregory I970) considers perception as a problem-solving process that must interpret the sensory input as evidence for some external object or event, and has tended to cast its explanations in functional terms rather than as hypothetical neural mechanisms. Generally these two approaches have been adopted to attack rather different problems. However, the perception of smooth continuous motion from discontinuous stimulation (vari
474 citations
TL;DR: It is concluded that ‘expectancy’, based on experience in both the long and the short term, has a profound influence on driver perception and assessment of risk.
Abstract: Recent research is reviewed and its implications discussed. "On-the-Spot" accident investigations have confirmed that errors of perception by the driver are a major contributory factor to accidents. However, the available evidence suggests that few of these are attributable to reduced or defective vision, since at best only a weak relationship has been found between a driver's level of vision (or visual performance) and his accident rate. A number of reasons for this general finding are considered, including driver compensation. For all drivers, the rapid fall in visual acuity with angular distance from the centre of vision presents particular problems, giving special significance to eye-movement patterns and the problems of visual search. Numerous physical and psychophysical restrictions on visibility could lead to the "looked, but failed to see" type of accident, but their relative importance requires evaluation. There is now much evidence that the driver is quite often operating beyond his visual or perceptual capabilities in a number of key driving situations, including overtaking, joining or crossing a high-speed road, and a number of nighttime situations. It is concluded that "expectancy", based on experience in both the long and the short term, has a profound influence on driver perception and assessment of risk. For all drivers, serious errors of judgment from time to time would seem inevitable. In general, these do not lead to accidents because of, among other things, the safety margins added by the driver and adjustments made by other road users. Thus, despite his limitations and fallibilities, the average driver is involved in surprisingly few serious incidents, particularly in view of the rapid rate of decisionmaking that is required. However, the present accident rate should not be accepted as inevitable and various countermeasures are discussed.
421 citations
TL;DR: In this paper, the problem of visual perception of the three-dimensional shape of moving objects is examined, and a case study of the problem is presented to illustrate some of the inherent shortcomings of the immediate perception framework.
Abstract: Central to contemporary cognitive science is the notion that mental processes involve computations defined over internal representations. This view stands in sharp contrast to the “direct approach” to visual perception and cognition, whose most prominent proponent has been J.J. Gibson. In the direct theory, perception does not involve computations of any sort; it is the result of the direct pickup of available information. The publication of Gibson's recent book (Gibson 1979) offers an opportunity to examine his approach, and, more generally, to contrast the theory of direct perception with the computational/representational view. In the first part of the present article (Sections 2–3) the notion of “direct perception” is examined from a theoretical standpoint, and a number of objections are raised. Section 4 is a “case study”: the problem of perceiving the three-dimensional shape of moving objects is examined. This problem, which has been extensively studied within the immediate perception framework, serves to illustrate some of the inherent shortcomings of that approach. Finally, in Section 5, an attempt is made to place the theory of direct perception in perspective by embedding it in a more comprehensive framework.
419 citations
TL;DR: In this paper, a U-shaped relationship between magnitude of cardiac response and loudness was found, indicating that the infants were responding to the auditory stimuli in terms of their similarity to the previously presented visual stimulus.
Abstract: It has been proposed that young infants are attentive to quantitative variations in stimulation to the exclusion of qualitative ones. To the extent that this is so, young infants should ignore differences between lights and sounds and should instead respond to auditory and visual stimuli as more or less similar depending on their intensity. To examine this hypothesis, a cardia c habituation/dishabituation method with a test for stimulus generalization was employed . Three-weekold infants were repeatedly presented with white-light followed by white-noise stimuli of different intensities. A U-shaped relationship between magnitude of cardiac response and loudness was found. In view of previous findings that without prior visual stimulation a monotonic increase in cardiac response to the same range of auditory stimuli results, this finding of a significant quadratic relationship with loudness suggests that the infants were responding to the auditory stimuli in terms of their similarity to the previously presented visual stimulus. A separate group of infants presented with a more intense visual stimulus exhibited a shift in the intensity at which a minimal cardiac response occurred. Results of a study with adults did not show any systematic relationship between cardiac response and loudness, indicating that unlike infants, adults do not spontaneously make cross-modal matches of intensity. Our perception of the world is based to a
343 citations
TL;DR: Three experiments are reported which aim to distinguish between mechanisms that might serve joint visual attention between human infants and adults and various explanations of this phenomenon and of the capacity for jointVisual attention.
Abstract: Three experiments are reported which aim to distinguish between mechanisms that might serve joint visual attention between human infants and adults. Between 6 and 18 months of age, the infant will adjust his (or her) line of gaze contingent on a change in the adult's focus of attention but behaves as if the adult is referring to loci within the infants' visual space. Thus, if the adult looks behind the infant, the infant scans the space in front of him. Various explanations of this phenomenon and of the capacity for joint visual attention are discussed.
339 citations
330 citations
TL;DR: A nonlinear function is derived to describe the contrast transduction process for human visual mechanisms, having an accelerating non linearity at low contrasts and a compressive nonlinearity at high contrasts.
Abstract: A nonlinear function is derived to describe the contrast transduction process for human visual mechanisms. This function is sigmoid in form, having an accelerating nonlinearity at low contrasts and a compressive nonlinearity at high contrasts. The resulting formulation is consistent with both signal detection theory and with Quick's (1974) equation for probability summation. Similarities between the present description of human vision and properties of complex cells in cat visual cortex are noted.
01 Aug 1980
TL;DR: The results suggest that word recognition entails activation of multiple codes and priming of orthographically and phonologically similar words.
Abstract: A discrete-trials color naming (Stroop)’paradigm was used to examine activation along orthographic and phonological dimensions in visual and auditory word recognition. Subjects were presented a prime word, either auditorily or visually, followed 200 msec later by a target word printed in a color. The orthographic and phonological similarity of prime-target pairs varied. Color naming latencies were longer when the primes and targets were orthographically and/or phonologically similar than when they were unrelated. This result obtained for both prime presentation modes. The results suggest that word recognition entails activation of multiple codes and priming of orthographically and phonologically similar words.
TL;DR: Fields within which attention can be distributed in imagery were measured by having subjects make judgements of resolution on pairs of dot patterns imagined simultaneously on opposite sides of the point of eye fixation, suggesting that peripheral acuity in visual imagery is limited by the same types of neural constraints that limit peripheral acute in visual perception.
Abstract: Subjects made judgements of resolution on two small dots that they either imagined or acutally observed at horizontal and vertical positions away from the point of eye fixation. As the distance between these two dots increased, the size of fields of resolution in imagery increased, in proportion to increases in the size of fields of resolution in perception. For vivid imagers, fields of resolution in imagery were the same size as those in perception, whereas for nonvivid imagers, fields of resolution in imagery were smaller than those in perception. In addition, fields of resolution in imagery and perception were virtually identical in shape, exhibiting similar horizontal eccentricity and vertical asymmetry. Fields within which attention can be distributed in imagery were also measured by having subjects make judgements of resolution on pairs of dot patterns imagined simultaneously on opposite sides of the point of eye fixation. These fields were smaller than fields of resolution for images of single dot patterns and were circular, as opposed to elliptical. These results suggest that peripheral acuity in visual imagery is limited by the same types of neural constraints that limit peripheral acuity in visual perception.
TL;DR: The results indicate that the source of the class 2 oblique effect obtained in RT paradigms is a greater confusability between the 45° oblique lines than between the horizontal and vertical lines when identification of orientation is required.
Abstract: Two classes of oblique effects are proposed. Oblique effects demonstrated in paradigms reflecting the basic functioning of the visual system are termed class 1, and those obtained in paradigms reflecting stimulus encoding and memory are termed class 2. The present experiments examine the class 2 oblique effect that has been obtained on reaction time (RT) tasks. Three RT tasks with different response requirements (identification, detection, and classification) were conducted to determine the basic conditions necessary for the production of the class 2 RT oblique effect. The results indicate that the source of the class 2 oblique effect obtained in RT paradigms is a greater confusability between the 45 degrees oblique lines than between the horizontal and vertical lines when identification of orientation is required.
TL;DR: It is suggested that the Korsakoff and Huntington patients have a severe deficit of associative learning combined with abnormal sensitivity to interference, whereas the Huntingtons are impaired primarily in visually-based associativeLearning.
TL;DR: A visual analog of auditory selective attention paradigms is described and the amount of processing required to monitor unattended information was examined, finding no evidence that any processing capacity was required.
Abstract: A visual analog of auditory selective attention paradigms is described. Using that analog, we examined the amount of processing required to monitor unattended information. With the materials used, there was no evidence that any processing capacity was required to monitor the unattended information. Memory for the unattended information and the recognition of one’s name were examined to provide additional evidence concerning the fate of the unattended information.
TL;DR: Visual experience is necessary for the normal stabilization of juvenile callosal connections, since some callosal neurons form connections in the absence of vision, and other influences capable of stabilizing juvenilecallosal neurons also exist.
Abstract: Counts of callosal neurons retrogradely labeled by horseradish peroxidase (visualized using multiple substrates) were obtained in areas 17 and 18 of five kittens reared with their eyelids bilaterally sutured and of three kittens which had undergone bilateral enucleation on postnatal days 1–4. These counts were compared with those obtained in normal adult cats. The normal adult distribution of the callosal neurons results from the gradual postnatal reduction of a more widespread juvenile population. Binocular visual deprivation by lid suturing dramatically decreases the final number of callosal neurons and narrows their region of distribution (callosal zone) in areas 17 and 18. A less severe reduction in the final number of callosal neurons is caused by bilateral enucleation, which also increases the width of the callosal zone compared to that of normal cats. Thus, visual experience is necessary for the normal stabilization of juvenile callosal connections. However, since some callosal neurons form connections in the absence of vision, other influences capable of stabilizing juvenile callosal neurons also exist. These influences are probably antagonized by destabilizing influences or inhibited, when the eyes are intact.
TL;DR: The visual perception of movement is a very important factor in the maintenance of the equilibrium, peripheral vision playing the major role, and foveal vision only a supplementary one.
Abstract: In a previous report (Amblard & Cremieux, 1976) we demonstrated that the maintenance of postural equilibrium, measured with the subject in Mann's stance on a foam rubber support, was significantly more difficult under stroboscopic rather than normal lighting conditions. The most plausible cause of the difficulty is the subject's loss of visual perception of movement as a result of the stroboscopic lighting. The present study was designed to look at this factor under normal lighting conditions. Also, the relative contributions of foveal and peripheral vision were assessed. During stance, the subjects (5 women and 6 men, aged from 25 to 55 yr.) viewed either a horizontal or a vertical rectangular grating. With horizontal lines, the visual perception of lateral movement is minimized. Lateral acceleration was measured at three anatomical levels: ankles, hips, and head. The horizontal stripe condition was significantly less effective than the vertical stripe one for maintenance of balance, both for measurements at the head level only and for values averaged from all three levels. Balance was significantly impaired with foveal vision alone compared to full vision or to peripheral vision alone, for measurements from each of the three levels. We conclude that the visual perception of movement is a very important factor in the maintenance of the equilibrium, peripheral vision playing the major role, and foveal vision only a supplementary one.
TL;DR: Three experiments are reported in which the salience of visual stimuli is assessed by finding which of two competing peripheral stimuli elicit a saccade when both are presented simultaneously with the use of a paradigm due to Lévy-Schoen, suggesting that salience might be accountable for in terms of the activation of transient channels in the visual system.
Abstract: Three experiments are reported in which the salience of visual stimuli is assessed by finding which of two competing peripheral stimuli elicit a saccade when both are presented simultaneously with the use of paradigm due to Love-Schoen The first experiment shows how salience is affected by position in the visual field A strong effect of retinal eccentricity is found which is compared with the cortical magnification factor Additionally directional biases occur The second experiment shows that temporal change appears to be significant in eliciting a saccade rather than any specific properties related to movement The third experiment shows that contour at high spatial frequencies does not affect salience An area of 4 cycles deg-1 high-contrast square-wave grating possesses the same salience as an equivalent area with identical, constant, space average luminance Taken together, the results suggest that salience might be accountable for in terms of the activation of transient channels in the visual system
TL;DR: Human observers detected the global three-dimensional organization of visual patterns consisting of only two successive frames of randomly positioned dots, corresponding to projections of a rotating sphere.
Abstract: Human observers detected the global three-dimensional organization of visual patterns consisting of only two successive frames of randomly positioned dots, corresponding to projections of a rotating sphere. A perfectly coherent sphere yielded a stable perceptual organization that was detected more accurately than other slightly less organized patterns.
TL;DR: In the presence of bilateral destruction of area 17, visual evoked potentials are mediated by extrageniculocalcarine pathways to secondary visual cortices, but this system is not capable of providing conscious visual perception in humans.
Abstract: • A 72-year-old woman, blind for more than two years, had normal evoked potentials to visual stimulation. Destruction of both areas 17 and relative preservation of areas 18 and 19 was demonstrated. We concluded that in the presence of bilateral destruction of area 17, visual evoked potentials are mediated by extrageniculocalcarine pathways to secondary visual cortices, but this system is not capable of providing conscious visual perception in humans.
Journal Article•
TL;DR: Findings are interpreted as indicating that infants can perceive subjective contours, however, the age of this accomplishment probably varies with both the characteristics of the array and the abilities of the observer.
Abstract: This study examines the development of infants' sensitivity to the organization of a subjective-contour stimulus array. 5- and 7-month-olds were sequentially shown 3 stimulus arrays of elements, only 1 of which was capable of producing subjective contours. Only the orientational relations among elements was varied. An infant habituation control procedure was used to test infants' abilities to discriminate these arrays. The results indicated that (1) only 7-month-olds showed consistent differential responsiveness to changes from an illusory array to a nonillusory array or vice versa, (2) 5-month-olds showed a weaker tendency to respond similarly and only when they had prolonged experience with the illusory array, and (3) neither age group showed much response recovery to a change from one nonillusory array to another. These findings are interpreted as indicating that infants can perceive subjective contours. However, the age of this accomplishment probably varies with both the characteristics of the array and the abilities of the observer.
TL;DR: It can be shown that a structured visual background is important in the treatment of sensory data concerned with the movement and in target localization, and that this effect is absent in rapidly executed pointing responses.
Abstract: In a visuo-motor pointing task, the accuracy of response was measured in situations which differ in the visual information available and the speed of execution of movement. Results confirm the role of visual cues received from self-produced movement in the control of the trajectory of a limb. Furthermore, it can be shown that a structured visual background is important in the treatment of sensory data concerned with the movement and in target localization. This effect is absent in rapidly executed pointing response.
TL;DR: It is concluded that the sensitive period of the kitten visual cortex to the effects of monocular deprivation lasts at least twice as long as previously thought, to between 6 and 8 months of age.
TL;DR: Patients who suffer from unilateral damage to the geniculostriate system were asked to make a voluntary blink response whenever they guessed that a light stimulus was presented in their perimetrically blind hemifield and the results indicate that there is a common extrastriate visual pathway subserving the performance in registration and localization of visual stimuli.
TL;DR: Recent work suggests that iconic memory is a property of some relatively late stage in the visual information-processing system, rather than being a peripheral sensory buffer store, which raises some fundamental theoretical issues concerning the psychology of visual perception.
Abstract: Human observers continue to experience a visual stimulus for some time after the offset that stimulus. The neural activity evoked by a visual stimulus continues for some time after its offset. The information extracted from a visual stimulus continues to be registered in a visual form of memory ('iconic memory') for some time after its offset. We may thus distinguish three distinct senses in which a visual stimulus may be said to persist after its physical offset: there is phenomenological persistence, neural persistence and informational persistence. Various assumptions have been made about the relation between these forms of visual persistence. The most frequent assumption is that they correspond simply to three different methods for studying a single entity. Detailed consideration of what is known about the properties of these three forms of persistence suggests, however, that this assumption is not correct. It can reasonably be proposed that visible persistence is the phenomenological correlate of neural persistence occurring at various stages of the visual system: photoreceptors, ganglion cells and the stereopsis system. Iconic memory on the other hand, does not correspond to visible persistence, nor to neural persistence in any stage of the visual system. Recent work, in fact, suggests that iconic memory is a property of some relatively late stage in the visual information-processing system, rather than being a peripheral sensory buffer store. This suggestion raises some fundamental theoretical issues concerning the psychology of visual perception, issues with which cognitive psychology has yet to come to grips.