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Results for “Size Perception”

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At least 19 recordsLinked to original sources
PubMed1979

Perception of size of one object among many.

Adaptation to a grating of properly chosen frequency may lead to two apparently conflicting observations: Another grating may then appear to be of increased frequency (compared with its "unadapted" frequency) while the individual bars of the grating appear to have widened. This perceived widening parallels previous results with single bars. By attending to only one grating bar, the subject effectively seems to change the grating frequency spectrum to that of a single bar.

Adaptation, Physiological↗
PubMed1977

Pictorial perspective: perception of size, linear, and texture perspective in children and adults.

Perception of size, linear, and texture perspective was investigated in third-grade and sixth-grade children and in college adults in three separate studies. A matching task required the observer to choose from a set of four alternative real scenes the correct match for the test stimulus, which was either a picture or a real scene. Correct performance required that the subject utilize perspective information for both size and distance distance relations. Erroneous choices available to the subject indicated errors in size judgement, in distance judgment, or in both simultaneously. View was either restricted at the correct station point or was free, with head motion. There were no significant effects of grade level. For all three groups, mean percent correct was nearly 100% with the real-scene test stimuli, and significantly below the chance level with the picture test stimuli. Errors in size judgment occurred most frequently, indicating that the geometrically correct rate of perspective convergence was too rapid to be seen by the subjects as perceptually acceptable. With size-perspective information alone, the number of size plus distance errors also increased significantly. There was no significant effect of viewing condition.

Adult↗
PubMed1979

Shifts in perception of size after adaptation to gratings.

After viewing a suitable grating of vertical stripes for 5 minutes, subjects overestimated the width of a rectangle by 6 percent. The shifts in perception of size occurred whether individual stripes in the grating were narrower than, equal to, or wider than the rectangle. Rectangle width was underestimated only if the grating stripes were extremely wide, with a spatial frequency lower than most of the effective amplitude spectrum of the rectangle. These findings (and complementary ones with horizontal gratings) suggest that the visual system codes size on the basis of spatial frequency components, rather than directly in terms of width.

Adaptation, Physiological↗
PubMed1977

Field dependence and the role of visual frameworks in the perception of size.

The extent to which apparent size is relationally determined has been studied by Rock and Ebenholtz and by Wenderoth, who came to widely differing conclusions as to the magnitude of this phenomenon. In both studies, a large range of individual differences was observed. In the present study, an attempt was made to account for variations in the influence of visual contexts on the perception of size by relating them to the cognitive style dimension of field dependence/independence. In two situations, relativelyfield-dependent observers made size judgments which were influenced by a frame surrounding the target figure, while relatively field-independent observers made size judgments which were influenced by a frame surrounding the target figure, while relatively field-independent observers tended to be less influenced by the frame, making their judgments approximate the retinal size of the target. The results suggest that assessment of the magnitude of the relational determination of apparent size must consider the cognitive style of the observers as well as situational variations.

Field Dependence-Independence↗
PubMed1978

Pictorial depth and related constancy effects as a function of recognition.

It is argued that while pictorial cues must be fundamental in the perception of an extended ground plane in daily life (and, by definition, in the perception of depth in pictures), the traditional pictorial cues such as perspective or texture gradients are neither a necessary nor a sufficient basis for it. That they are not necessary was shown by experiments in which such cues were eliminated from pictures representing a scene in depth. Illusory size perception based on localization of objects in depth in such pictures nonetheless occurred. That they are not sufficient was shown by experiments in which photographs of grassy fields did not yield impressions of depth or related size illusions when conditions were such that the scene was not recognized. Once recognized, however, these same pictures did yield such perceptions. It is suggested that a critical step in perceiving depth based on pictorial information is recognition of the scene.

Art↗
PubMed1978

Body awareness in anorexia nervosa: disturbances in "body image" and "satiety".

Patients with anorexia nervosa have been shown previously to display distortions in body image perception. Bruch has postulated that these disturbances as well as disturbances in interoception are meaningfully related to the development of the syndrome. We hypothesized that disturbances in body image, as measured by a distorting photograph technique, and interoception, as measured by a satiety-aversion to sucrose test, should be demonstrable in anorexic patients vs. normal controls. Furthermore, these disturbances should be modifiable by external cues (looking at one's image in a mirror and ingesting isocaloric "high" and "low" calorie connotation meals). We also hypothesized that body image and interoceptive disturbances would be interrelated in the same individuals. Results indicated that patients with anorexia nervosa (N = 26) differed from normal controls (N = 16) in overestimating their body sizes (p = 0.06) and in failing to develop an aversion to the sucrose tastes (p less than 0.001). However, neither viewing one's image in a mirror nor ingesting both "high and "low" calorie connotation meals altered body size perception. Intrasubject body size estimates were very stable from week to week for the anorexic subjects (r = +0.75, p less than 0.001) but less for the controls (r = +0.45, p less than 0.05). The data revealed that overestimation of body size was closely related to the failure to develop an aversion to sucrose tastes in anorexic patients.

Adult↗
PubMed1978

Effect of perspective and slant on perception of apparent size and distance.

An experiement was performed to re-examine the role of linear perspective and floor slant on apparent size and distance scales. Misleading perspective cues did not alter the observers' apparent distance scales but did influence the absolute magnitude of distance judgments; floor slant exerted little influence on apparent distance scales or the absolute magnitude of distance judgments. Neither perspective nor slant manipulation reliably affected apparent size scales or exerted more than a minor influence on the absolute magnitude of size judgments.

Cues↗
PubMed1979

[The role of the pupil's size in the perception of other persons].

Studies by Hess (1975) show that the pupil serves as a source of information in perception of the emotional state of another person. Large pupils are interpreted in a positive sense. Basing on the results of Hess, the hypothesis that pupil size does not become a relevant variable in person perception until after puberty, was formed. The following result would be interpreted as supporting the hypothesis: since girls reach puberty before boys, more girls should react to pupil size than boys of the same age. 121 students between the ages of 11 and 16 years judged in several statements which of two face photos of a teacher expressed a greater degree of positive attention and esteem towards the students. The two face photos were identical with the exception of pupil size. All age groups rated the photos with larger pupils more positively. Sex differences occurred in the ratings of the 11 to 12-year-olds. Some basic differences between this experiment and that of Hess are discussed.

Adolescent↗
PubMed1979

Accessing similarity and dimensional relations: effects of integrality and separability on the discovery of complex concepts.

A series of studies investigated how stimulus integrality and separability impact the cognitive accessibility of similarity and dimensional relations. A good deal of previous work has established that stimulus integrality and separability differentially determine perception; here, the question is whether they also have differential effects on conception. Are the principles that govern perception also principles that can be readily discovered in concept learning tasks? Is a similarity-based rule especially easy to abstract from integral stimuli and a dimensionally-based rule especially easy to abstract from separable stimuli? In Experiments 1 and 2, we measured the relative ease with which the two types of rules (similarity and dimensional) are discovered by adults with the two types of stimuli (integral and separable). In experiment 1, the two rules were made redundant and we asked which rule the subjects learned. In Experiment 2, one rule was made relevant and the other irrelevant, and we compared relative speeds of learning. The results from the studies led us to conclude (a) that dimensionally based rules are more accessible from separable than from integral stimuli; (b) that similarity-based rules are more accessible from integral than from separable stimul; and (c) that, in general, subjects have a bias to access dimensional relations in this type of task. Experiment 3 pursued an additional suggestion from Experiments 1 and 2 that the dimensional relations within integral stimuli are sometimes accessible, more so when larger interstimulus differences are encountered. In confirmation, Experiment 3 demonstrated that adult subjects are more successful in applying a dimensional rule to pairs of integral stimuli that differ by a small amount if they also have exposure to pairs of integral stimuli that differ by a large amount. In a later discussion, it was argued that such a finding is consistent with the notion that the "dimensions" of integral stimuli are merely arbitrary directions in the integral stimulus space, and some relevant pilot data to that effect were presented. Finally, Experiment 4 took up a developmental issue. Young children have sometimes produced perceptual responses governed by similarity relations when presented with stimuli that are separable for adults. Will they more readily access similarity-based or dimensionally-based relations from such stimuli in the concept learning tasks here? The results showed that both kindergarteners and fifth graders more readily access the dimensional relations. A final discussion integrated the findings from the several experiments, taking up the following issues: (a) the relation between the perception and the conception of stimulus relations and (b) the nonprimacy of the dimensional axes in the integral stimulus space.

Adult↗
PubMed1978

[Two kinds of apparent size distortion in the Ponzo illusion (author's transl)].

It was proposed that there are two kinds of apparent size distortion to be distinguished in the Ponzo illusion. The apparent size of the single line in the converging lines (CL) became larger as it was located nearer to the apex. However, this distortion could not predict the obtained illusion sufficiently. Hence there should be assumed another kind of size distortion in the perception of the size relation as a result of comparison of two paralle lines (PL). In this comparison process, breaking of the continuity of CL and elimination of the oblique components from CL had a slight decreasing effect on the illusion. Moreover, it was found in the various contour figures that the greater the separation of PL was, the larger the illusion was.

Adolescent↗