Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SIZE PERCEPTION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed1975

Information complexity and cross-modal functions.

Intra-modal and cross-modal presentations of a matching procedure were compared at two levels of information complexity in the same subjects. The modalities were visual and somatosensory. Sequence of information type and sex of experimenter and subject were systematically controlled. Pattern of accuracy among the several modality combinations and the effect of sequence varied as a function of information complexity. Sex of experimenter and subject yielded significant differences with simple information but not complex. The results, involving several detailed comparisons, confirmed generalizations derived from a review of prior studies in which only one type of information had been administered to any single group of subjects. Further examination of the relations between type of information and sensory modality is discussed.

Adolescent↗
PubMed1982

Central visual field representation in striate-peristriate cortex as the functional unit of pattern discrimination in the bushbaby (Galago senegalensis).

Bushbabies were trained on a battery of visual discrimination and localization tests and retested after serial lesions of the occipital and temporal lobes. The results of these experiments indicated that visual deficits following occipital lobectomy depend on the extent of damage to the central vision representation in both striate and peristriate cortices. If lesions involved both cortical representations of central vision, form and stripes discrimination capacities were lost. When the peristriate representation was spared, form vision was lost but vision for striped patterns was retained. The subsequent addition of middle or ventral temporal area lesions did not alter discrimination performance. Results are discussed in terms of a transcytoarchitectonic subdivision in striate and peristriate cortices as the functional unit of organization for pattern vision.

Animals↗
PubMed1976

Use of the Beery Visual-Motor Integration Test with partially sighted students.

The purpose of this research was to determine the difference in performance of partially sighted and sighted students on the Beery Visual-Motor Integration Test. Since this test is only standardized on sighted students, there are no norms for partially sighted students. 60 partially sighted students, ranging in age from 6 to 18 yr., were tested on Beery's Visual-Motor Integration Test. These students did not achieve as well as Beery's norms indicate his sighted population did. The average age of the partially sighted students was 3 yr., 8 mo. below that of Beery's seeing students. Partially sighted students had greater difficulty with certain test items than Beery's normal subjects. A special test which would rank geometric forms by development stages seems needed for partially seeing students.

Adolescent↗
PubMed1979

Nature of the representation for picture-recognition memory.

When distracting pictures are randomly selected from the same pool of pictures as the target pictures, performance with large numbers of pictures (1,000) is much poorer than has previously been reported. Further, performance drops quite substantially after 1 wk., a finding that differs from the conclusion that picture memory is relatively stable over time. Under conditions where the distractors were selected to reduce similarity between targets and distracting pictures, performance approximated levels previously reported in the literature. The results of the experiments seem to demand some type of categorization model of picture-recognition memory.

Discrimination Learning↗
PubMed1988

Contrast and assimilation in the Baldwin illusion.

Four experiments were conducted to investigate the role of "large" squares on the occurrence of assimilation and contrast in the Baldwin illusion. In Exps. 1 and 2, in which subjects reproduced the length of the test line, large squares induced illusions of assimilation. In Exp. 3, reproduction of the entire length of the test line also resulted in illusions of assimilation but bisection of the test line and reproduction of one-half the length of the test line resulted in contrast. Exp. 4 replicated the findings involving judgments of one-half the length of the test line. Over-all, the results indicate that judgments of one-half the length of the test line result in contrast, whereas judgments of the entire extent result in assimilation.

Adult↗
PubMed1995

Re-examination of evidence questions Christman's (1989) report of moderate experimental support for the visual spatial frequency hypothesis.

The visual spatial frequency hypothesis contends that perceptual characteristics of stimulus arrays can affect the magnitude and direction of hemispheric asymmetries in laterality experiments. In a 1989 literature review, Christman reported that 45 of 79 experimental comparisons yielded significant interactions for side of hemispheric advantage x perceptual characteristic which supported the visual spatial frequency hypothesis, a level of support he characterized as moderate. Re-examination of those 45 outcomes shows that in 20 of them either a significant interaction for side of hemispheric advantage x perceptual characteristic was not found or, if it was, the particulars do not agree fully with predictions of the visual spatial frequency hypothesis as presented by Christman in the 1989 paper. These findings suggest that experimental support for the visual spatial frequency hypothesis is weak, not moderate as characterized by Christman.

Attention↗
PubMed2000

The role of feedback in manual tracking of visual targets.

The role of visual feedback in manual tracking was investigated in 24 subjects who tracked 5-, 10-, and 40-mm/diameter targets, moving on a screen at 18 to 25 mm/sec., along various paths, by moving an unseen handle over a digitizing tablet. A cursor indicating instantaneous handle position was visible at all times on half the trials and hidden within a circle coaxial with the target but double its diameter in the other half. The handle had to be within the instantaneous target's digitizer-defined boundaries for the latter to keep moving. All tracking movements were segmented into small movement steps. A tendency to outrun the target was seen, indicating predictive control. Absence of visual feedback had negligible effect on movement velocity. Movement direction appeared to involve open-loop programming but improved significantly when subjects could see the cursor. Occasional corrective movements occurred only when visual feedback was given. Otherwise, a large positional error accumulates despite reasonable ability to control tracking direction.

Adult↗
PubMed1975

Figural after-effects of Köhler and Wallach reinterpreted.

A theory of perception is extended to figural after-effects which has been used already to rationalize the illusory phenomena of static visual illusions, fluctuating figures and visual illusions of motion. The theory proposes three laws of perception. All of the extensive observations of Köhler and Wallach are rationalized under these laws embodying the present theoretical orientation. The theory maintains that the experience of perception occurs only during the interaction of forces introduced by a pattern with the forces characteristic of the brain in order to produce the greatest equilibrium within the two systems of forces. A pattern is not reproduced in the brain. A pattern produces a system of forces. Neither the image of the pattern nor its forces impinging on the nervous system produce the perceptual experience. It is during the process of interaction of the forces of the pattern with the forces of the brain and only during this interaction that perception is experience. This interaction is a constant process to integrate the incompatibilities existing between the two system of forces.

Brain↗
PubMed1997

Encoding into working memory of spatial location, color, and shape: electrophysiological investigations.

Event-related potentials (ERP) were recorded while subjects memorized either the location, the color or the shape of stimuli which could be located in 1 of 4 positions relative to a central fixation point (top, bottom, left or right), be of 1 of 4 positions relative to a central fixation point (top, bottom, left or right), be of 1 of 4 colors (white, green, red or blue), and present 1 of 4 shapes (triangle, cross, circle or square). These ERP were compared to ERP recorded while subjects looked at the same stimuli but performed other control, nonmemory tasks. Only ERP corresponding to the memorization of spatial location showed a differential pattern which could be specifically attributed to memory encoding processes. This reveals an important difference in ERP modulation between a working memory subsystem for spatial location and other subsystem (or subsystems) for color or shape, which would provide evidence supporting the existence of different working memory subsystems for visual information in the brain.

Adolescent↗
PubMed2002

Visual perception of collinearity.

In a metrical space, there exists an intimate relation between collinearity and parallelity. In particular, in a Riemannian space collinearity is just a special case of parallelity. Is this true for visual space as well? We investigated the visual perception of collinearity by having subjects align two bars in the horizontal plane at eye height. The distances of the bars from the subject and the angles at which they were placed were varied. We found deviations of up to 22 degrees. The deviations of the left and right bars could be split into two independent components: namely, the sum and the difference of the deviations of the left and right bars. We found that the former depended only on the ratio between the distances of each bar from the subject, whereas the latter was largely independent of the positions of the bars. The difference in deviations corresponded to the deviation from parallelity. Compared with the results in the parallelity task (Cuijpers, Kappers, & Koenderink, 2000b), the deviations from parallel were much smaller. As a consequence, the results of the two experiments cannot be described by the same Riemannian geometry. This indicates that the intrinsic geometry of visual space differs across tasks. This is conceivable if the intrinsic geometry of visual space is operationally defined.

Adult↗
PubMed1990

Absolute and relative perceptual codes in young children.

Three experiments were conducted to ascertain whether young children's perceptual codes, as evidenced by choice reaction times, were related to either the absolute difference or the ratio between stimuli. In Experiments 1 and 2, children were shown pairs of line lengths and were asked to choose either the longer or shorter line within each pair. In Experiment 3, children chose which of two birds on a map was closer to themselves or to the experimenter. In all three experiments, children's reaction times were related to both the absolute differences and ratios between pairs of stimuli. The findings suggest that perceptual judgments in young children may be based on both absolute and relational codes.

Attention↗