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Results for “SIZE PERCEPTION”

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At least 415 records · Page 23Linked to original sources
PubMed2001

Recognition of self-generated actions from kinematic displays of drawing.

Five experiments addressed the question of whether individuals can distinguish between self-generated and other-generated actions when seeing their visual effects. Each experiment consisted of a recording session in which participants drew familiar and unfamiliar characters without receiving visual feedback and a recognition session in which they provided self-or-other judgments (SOJs) to indicate whether a kinematic display reproduced the visual effects of their own actions. The main results were that self-generated and other-generated drawing can be distinguished, that the familiarity of character shapes does not influence the accuracy of SOJs, and that velocity information is crucial for the identification of self-generated drawing. The ability to determine authorship from kinematic displays of drawing provides evidence for the contribution of action-planning structures to perception.

Adult↗
PubMed1979

A demonstration of selection of analyzers for integral dimensions.

Three experiments investigated the integrality of height and width of rectangles and the ability of observers to selectively attend to only one dimension. In Experiment 1, redundancy gain and orthogonal interference were demonstrated in a same/different task. Orthogonal interference was due to the output of the "irrelevant" analyzer interfering with the output of the "relevant" analyzer. These results indicated that height and width are integral, but they can be most parsimoniously explained by assuming that rectangles are initially processed by separate dimensional analyzers. Experiment I demonstrated that with sufficient practice (160 trials), observers are able to selectively attend to the more frequently relevant dimension. Performance for the stressed dimension increased, whereas performance for the unstressed dimension declined. Experiment 3 also demonstrated that with sufficient practice (192 trials), observers are able to selectively attend to the relevant dimension and ignore the irrelevant dimension. Orthogonal interference disappeared. The results are discussed in terms of the ability of observers to modify the perceptual process.

Attention↗
PubMed1981

Separation relative to length determines the organization of two lines into a unit.

The probability that two lines will form a perceptual unit, in the sense of reversing together under conditions of depth ambiguity, decreases as their separation is increased. In these studies, the critical separation for perceptual grouping is shown to be neither the retinal nor distal separation, but the ratio of separation to line length.

Depth Perception↗
PubMed1984

Terrestrial passage theory of the moon illusion.

Theories of the celestial, or moon, illusion have neglected geometric characteristics of movement along and above the surface of the earth. The illusion occurs because the characteristics of terrestrial passage are attributed to celestial passage. In terrestrial passage, the visual angle subtended by an object changes discriminably as an essentially invariant function of elevation above the horizon. In celestial passage, by contrast, change in visual angle is indiscriminable at all elevations. If a terrestrial object gains altitude, its angular subtense fails to follow the expansion projected for an orbital course: Angular diminution or constancy is equivalent to distancing. On the basis of terrestrial projections, a similar failure of celestial objects in successive elevations is also equivalent to distancing. The illusion occurs because of retinal image constancy, not--as traditionally stated--despite it.

Astronomical Phenomena↗
PubMed1965

Seeing in depth.

Explore the source record for details and available documents.

Depth Perception↗
PubMed1987

[Fusion amplitude and aniseikonia. Experimental studies of aniseikonia tolerance in unilateral aphakia].

The fusion amplitude of image pairs with aniseikonia was measured using the synoptophore. Aniseikonia was produced in five subjects by alteration of slide drawings. The subject's right eye was in cycloplegia after paralysis with cycloplegic eye drops. To compare these measurements with aniseikonic pictures to those using the same image pairs without aniseikonia the fusion amplitude achieved was expressed as a percentage of the aniseikonia-free fusion amplitude. The relation between aniseikonia, eccentricity of the image borders and percent fusion amplitude was described using a mathematical approach. The experimental results reveal that a minimal increase in overall aniseikonia with greater eccentricities (greater than 5 degrees) leads to a rapid decrease in the fusion amplitude and the occurrence of diplopia. The aniseikonia tolerance level of images with greater eccentricities achieved experimentally and theoretically are in good agreement with results found in unilaterally aphakic patients.

Accommodation, Ocular↗
PubMed1980

An invariant for wheel-generated motions and the logic of its determination.

Observers appear to perceive the paths of abstract centers of point-light configurations in making judgments about movement. For configurations on rolling wheels a metric was derived that described the relative vertical motion of this point. It was hypothesized that the smaller the metric the more the stimulus should appear to move in a wheel-like manner with linear translation. In two experiments observers viewed pairs of stimuli and were asked to select either the event that appeared most wheel-like or the one that hopped the most. Viewers consistently selected the stimulus with the smaller metric as being more wheel-like, with a frequency that increased with the difference between metrics. The inverse of this pattern was found for those observers requested to select the stimulus that hopped most. In a second set of two experiments observers drew the translational paths of these stimuli. Their drawings corresponded to the motion paths of configural centroids. Together, these results strongly suggest that observers perceive the translational component of the motion of the configurations as the path described by their centroids, or geometric centers. We propose that this description of the stimulus event is determined by the logical ordering of information extraction provided by the perceptural system, and discuss this logic and cases where it seems evident.

Form Perception↗
PubMed1993

Information processing by tree fellers: signal detection analysis.

Eighteen experienced tree fellers and eighteen forestry students watched video recordings of mature eucalypts being felled by a man using a chain saw, and then rated whether each tree had fallen normally or abnormally. Signal-detection analysis showed that the tree fellers were more accurate than the forestry students in predicting eventual outcome. Further, the tree fellers achieved peak accuracy in discrimination by the time the logger had completed cutting the scarf (typically several minutes before the tree hit the ground), whereas the forestry students predicted outcome most accurately only when a tree was falling (and about 1 s from hitting the ground). Study of the bases for information processing and decision making by tree fellers has implications for personnel selection and training, as well as for formulation of effective work practices.

Adult↗