Intelligence level as a variable in the perception of shape

The relation between shape constancy and intelligence was investigated by determining the functions relating matched shape to the angle of inclination of a circular test-object for groups at four levels of intelligence. Subjects were obtained from groups of institutionalized mental defectives, slow learners from the public schools, unselected undergraduates, and undergraduates who had been awarded scholarships. With increasing intelligence level the matches tend to approach the prediction based on the law of the retinal image thus demonstrating an inverse correlation between intelligence and the extent to which constancy is demonstrated. Since it is known the instructions given to the subject are a variable in shape constancy, it is suggested that the present data are the result of different attitudes adopted by the subjects at the various intelligence levels. The more intelligent subjects are assumed to adopt an analytic attitude in the experimental situation, while the less intelligent tend to maintain their everyday, non-analytic modes of perceiving.     

An analytic comparison of Herrnstein's equations and a multivariate rate equation

Herrnstein's equations are approximations of the multivariate rate equation at ordinary rates of reinforcement and responding. The rate equation is the result of a linear system analysis of variable-interval performance. Rate equation matching is more comprehensive than ordinary matching because it predicts and specifies the nature of concurrent bias, and predicts a tendency toward undermatching, which is sometimes observed in concurrent situations. The rate equation contradicts one feature of Herrnstein's hyperbola, viz., the theoretically required constancy of k. According to the rate equation, Herrnstein's k should vary directly with parameters of reinforcement such as amount or immediacy. Because of this prediction, the rate equation asserts that the conceptual framework of matching does not apply to single alternative responding. The issue of the constancy of k provides empirical grounds for distinguishing between Herrnstein's account and a linear system analysis of single alternative variable-interval responding.     

The perception of rotated shapes: A process analysis of shape constancy

Ss made objective shape judgments of circular objects rotated in depth to provide a process analysis of shape constancy. The significant finding was that task difficulty, as reflected by proportion errors and correct reaction times; increased with increases in rotation from the frontal-parallel plane. This effect was located at the perceptual encoding stage of the shape judgment process. It was demonstrated that, in contrast to true shape information, the time to interpret slant and two-dimensional projected shape information was not critically dependent on degree of rotation. These results and a number of other additional observations demonstrate that the invariance hypothesis does not provide a sufficient account of shape constancy. Although projected shape and’ slant judgments can be made easily, perception of true shape involves encoding a figure-ground relationship by a process that does not rely exclusively on the discrete values of projected shape and slant.     

Probability matching

The class of symmetric path-independent models with experimenter-controlled events is considered in conjunction with two-choice probability learning experiments. Various refinements of the notion of probability matching are defined, and the incidence of these properties within this class is studied. It is shown that the linear models are the only models of this class that predict a certain phenomenon that we call stationary probability matching. It is also shown that models within this class that possess an additional property called marginal constancy predict approximate probability matching.This research grew out of questions posed by William K. Estes. We are also indebted to Professor Estes for his encouragement and assistance at all stages of this research. During the course of this research J. I. Y. received support from the U. S. Public Health Service (N. I. M. H.). M. F. N.'s present address is the University of Pennsylvania. J. I. Y.'s present address is the University of Minnesota.     

Size constancy in extended haptic space

When a stick is used to extend the boundaries of the world perceived by touch, haptic parallels to visual angle and size constancy appear. In a pilot study, Ss using a stick to feel an out-of-reach gap were more likely to underestimate its size than were Ss feeling a nearby gap with the index finger, but size constancy was relatively high with the stick. The main study, comparing judgments of gaps at intermediate and far positions, confirmed these findings. Errors were greater for the more distant gap, but constancy was high in both positions. Correlations between far and intermediate judgments indicated that Ss were consistent in the type of error made. Similar findings emerged from a partial replication with blind and partially sighted Ss.     

Influence of exploration time on haptic and visual matching of complex shape

The time adult Ss were allowed to explore stimuli was varied during intra- and cross-model equivalence matching involving vision and touch. Increasing time to explore either each standard, each comparison, or both standard and comparison from 4 to 16 sec significantly improved haptic intramodel matching. However, cross-modal matching, from either vision to touch or touch to vision, improved significantly only when time to explore each standard was increased. Videotape recordings of Ss’ hand movements revealed use of a greater variety of haptic scanning strategies by Ss in groups where increased exploration time enhanced accuracy. The difference in effects of exploration time on intra- compared to cross-model shape matching was discussed in terms of possible differences in requirements between the two tasks.     

Adaptation in the constancy of visual direction tested by measuring the constancy of auditory direction

Modification of the constancy of visual direction was produced by partially adapting Ss to the displacements of the visual field caused by magnifying lenses during 1 h of continuous head turning. The adaptation effects were measured by determining the range of perceived target immobility before and after this adaptation period. A method for measuring the range of apparent immobility of an auditory signal during head movements was developed and employed to test whether a modification of the constancy of visual direction transfers to the constancy of auditory direction. No such transfer was found, and it was concluded that a modification of the constancy of visual direction does not consist in an altered evaluation of kinesthetic cues for head turning. The method and the equipment used in the investigation of the constancy of visual direction are described; knowledge of the previous brief publications on this topic is not needed.     

Contrast constancy revisited: The perceived contrast of sinusoidal gratings above threshold

The contrast sensitivity function of the human visual system, measured with sinusoidal luminance gratings, has an inverted U shape with a peak around 2–4?c/deg. Above threshold, it is thought that luminance gratings of equal physical contrasts but of distinguishably different spatial frequencies are all perceived as having similar contrasts, a phenomenon that has been termed contrast constancy. However, when suprathreshold contrast matches were measured for pairs of luminance gratings whose spatial frequencies were indistinguishable, the matching curves were not flat and followed a similar inverted U shape form as the contrast sensitivity function at threshold. It was therefore suggested that contrast constancy may only be revealed when matching the contrasts of clearly distinguishable spatial frequencies. Here, observers matched the perceived contrasts of suprathreshold luminance gratings of similar but visibly different spatial frequencies between 0.25 and 16?c/deg. The results show that, much like the contrast sensitivity function at threshold, observers are more sensitive to intermediate spatial frequencies (1–6?c/deg) than they are to either higher or to lower spatial frequencies. This tuning is evident when matching reference contrasts of 30–80%, implying a significant role in everyday vision. To demonstrate that these results were not due to local adaptation, the experiment was repeated with shorter stimulus duration, producing the same results. The extent of departure from contrast constancy found in the present study is compared to previously reported suprathreshold measurements. The results are also discussed with consideration to limitations with display apparatus such as monitor blur.     

Brightness contrast in the cat

Using both the method of paired comparisons and the method of constant stimuli, degree of brightness contrast was determined for two cats. Brightness contrast varied with relative luminance of various parts of the stimulus configuration in a manner comparable to that found in human Ss; brightness constancy was not obtained. The data indicate a fixed, nonadaptive basic visual process rather than a cognitive or adaptive perceptual constancy.     

The locus of masking shape-at-a-slant

Twelve subjects provided shape and orientation judgments for a set of projectively equivalent, variously rotated rectangles under three viewing conditions—monoptic, dichoptic, and binocular—with and without the presence of a pattern mask. In the absence of the mask, partial constancy was exhibited under the first two conditions and near perfect constancy under the binocular condition. Orientation was discriminated. Presence of the mask produced projective shape matching and diminished orientation discrimination. It is argued that the site of masking was postchiasmal, and the results are related to previous work with pattern masking of projectively equivalent ellipses.     

Edge-Assignment and Figure–Ground Segmentation in Short-Term Visual Matching

Eight experiments examined the role of edge-assignment in a contour matching task. Subjects judged whether the jagged vertical edge of a probe shape matched the jagged edge that divided two adjoining shapes in an immediately preceding figure–ground display. Segmentation factors biased assignment of this dividing edge toward a figural shape on just one of its sides. Subjects were faster and more accurate at matching when the probe edge had a corresponding assignment. The rapid emergence of this effect provides an on-line analog of the long-term memory advantage for figures over grounds which Rubin (1915/1958) reported. The present on-line advantage was found when figures were defined by relative contrast and size, or by symmetry, and could not be explained solely by the automatic drawing of attention toward the location of the figural region. However, deliberate attention to one region of an otherwise ambiguous figure–ground display did produce the advantage. We propose that one-sided assignment of dividing edges may be obligatory in vision.     

The retrieval of abstract and concrete materials as functions of imagery,mediation, and mnemonic aids

Department of Educational Psychology, The Pennsylvania State University, University Park, Pennsylvania 16802 This study is a report of an investigation of the interaction between imagery ability and processes employed for facilitating recall. The tasks were assumed to involve contrasting processes through the use of imaginal or verbal mediators and concrete or abstract jingles (mnemonic aids) in memorizing two concrete and two abstract lists of 10 words in each list. The dependent variables were latencies in arriving at an association, number of errors and omissions on immediate recall, and number of errors and omissions on delayed recall. The main effects of imagery ability, favoring high imagers, and of kind of lists favoring concrete lists were significant. In delayed recall there was a significant interaction of mnemonic aid and kind of list. Imagery ability interacted with mediators to influence Ss’ recall. The results were discussed as supporting Paivio’s two-stage association model.     

Shape from shading from images rendered with various surface types and light fields

Shape constancy is referred to as the tendency for the perceived shape of an object to remain unchanged even under changed viewing and illumination conditions. We investigated, in two experiments, whether shape constancy would hold for images of 3-D solid objects defined by shading only, whose renderings differed in terms of surface material type (bi-directional reflectance distribution functions), light field, light direction, shape, and specularity. Observers were presented with the image of a sphere or an ellipsoid and required to set perceived orientation and cross-section profile on designated points of the image. Results showed that shape judgments varied with all the aforementioned variables except specularity. Shape estimates were more precise with specular than asperity scattering surfaces, collimated than hemispherical diffuse lighting conditions, lower than higher elevations, spherical than ellipsoidal shapes, but not different between surfaces having differing specularity. These results suggest that shape judgments are made largely on the basis of the overall intensity distribution of shading, and that the portions of intensity distribution that are due to nonstructural variables such as surface material type or light field are not excluded in the process of shape estimation, as if being due to structural components. It is concluded that little constancy is expected in the perception of shape from shading.     

Idiosyncratic exceptions to the probability-matching decision-rule in visual discrimination

Human “Yes-No” signal-detection performance was tested under a modified perceptual-defense procedure. A majority of Ss tended to match the relative frequency with which they gave affirmative responses to the relative frequency at which signals were presented. These Ss thereby replicated the “probability-matching” behavior found in previous signal-detection and discrimination studies. However, in marked contrast to those previous results, another large set of Ss showed a tendency toward preponderant use of one of the two responses (typically, of “No”) rather than toward probability-matching. The evidence failed to suggest that the latter effect was related to a lesser ability to make the requisite sensory discrimination or to response inhibition induced by taboo stimuli.     

Global shape cannot be attended without object identification.

Whether the global shape of objects can be processed without accessing semantic or identity information was tested. Ss judged which of 2 fragmented forms had the same global shape as a reference stimulus. Matching stimuli could be physically identical, semantically related, or unrelated. The reference stimulus and nonmatching (distractor) form could be semantically related or unrelated. Similarity effects in the related condition were unconfounded with matches nameable and nonnameable forms. For nameable forms, related matching forms facilitated performance; a related distractor disrupted performance. Semantic interference was eliminated when nameable distractors were replaced with nonnameable partners; semantic similarity effects on matching were eliminated with a nonnameable reference stimulus and with inverted targets and distractors. Access to information concerning global shape does not normally occur without object identification.     

The effects of books and gender constancy development on kindergarten children's sex-role attitudes

The effects of symbolic models and level of gender understanding on children's sex-role attitudes was investigated. Kindergarten boys and girls heard and discussed books whose characters depicted either traditional or nontraditional sex-role behaviors. Attitudes toward males and females were measured before and after the picture book treatment. When the study began, children were screened for gender understanding so that half were able to make other-gender constancy judgments, and half were not able to make other-gender constancy judgments. Prior to the treatment, boys and children who had attained gender constancy were slightly negative toward males and neutral toward females, whereas girls and children who had not attained gender constancy were very negative toward males and very positive toward females. Exposure to traditional books had the effect of enhancing attitudes toward males and decreasing attitudes toward females. Exposure to nontraditional books had the opposite effect of decreasing attitudes toward males and enhancing attitudes toward females. The effects of the picture book treatment on attitudes toward females were more pronounced for children who had attained other-gender constancy. Implications for social learning and cognitive-developmental theories of sex-role development are discussed.     

THE PERCEPTION OF A VISUAL SHAPE AND OF ITS FRAME-SURFACE DURING CONTINUOUS TRANSFORMATION

The procedure differed from that of traditional shape constancy experiments in that cues for the slant of the total frame-surface containing the main figure, a shadow rectangle, were given. The impression of slant was determined by gradients of continuous perspective transformations caused by movable elastic material casting its shadow on a translucent screen. The following hypothesis was confirmed: the tendency to see a shape in its original proportions (i.e., those it has when shown in a frontal-parallel orientation) increases with the increasingly strong impression of the slant of its plane surface.     

The constancy of object orientation: Compensation for ocular rotation

When a thin horizontal line is displaced, either left or right of straight ahead, or when a vertical line is displaced up or down, systematic changes occur in the binocular disparity associated with the target. In threeexperiments, Ss matched the orientation of displaced targets with a variable comparison line. Estimates of apparent displacement with a pointing technique were also made. Since head position was fixed, apparent displacement was mediated by the angle of ocular rotation. Near perfect matches were made with vertical targets, but horizontal targets produced errors suggestive of underestimation of apparent displacement. However, the pointing data did not yield clear evidence for this view. Control data denien the possible role of the induced effect (IE) in matching the horizontal targets, and the result were discussed in the context of orientation constancy based upon compensation for displacement.     

Persistent effects of information about internal reactions: Ineffectiveness of debriefing

A process of self-persuasion has been advanced to account for the effects of information about internal reactions on attitudes toward emotional stimuli. To determine whether the results of this cognitive activity would be resistant to debriefing, Ss were shown slides of female nudes while hearing their alleged heart-rate reactions and were subsequently informed that these reactions were part of a deception manipulation. It was found that, although Ss accepted the debriefing, the false information continued to exert an infleunce on their attitudes toward the nudes. The attitudes of these Ss toward the nudes were the same as those of Ss who were not debriefed.     

Persistent Effects of Information about Internal Reactions: Ineffectiveness of Debriefing

A process of self-persuasion has been advanced to account for the effects of information about internal reactions on attitudes toward emotional stimuli. To determine whether the results of this cognitive activity would be resistant to debriefing, Ss were shown slides of female nudes while hearing their alleged heart-rate reactions and were subsequently informed that these reactions were part of a deception manipulation. It was found that, although Ss accepted the debriefing, the false information continued to exert an influence on their attitudes toward the nudes. The attitudes of these Ss toward the nudes were the same as those of Ss who were not debriefed.