Figural Aftereffects Research Articles

Geometrical illusions and figural after-effects: The mechanism and its location

Previous experimental studies of figural after-effect phenomena are discussed. Particular reference is made to the general question of establishing the locations of perceptual mechanisms, to the possibility of the same mechanism being responsible for both after-effects and illusions and to difficulties arising when attempting to evaluate research in this field. The “distorting” and “distorted” components of Ponzo's illusion are distinguished and prepared as I- and T-figures. An apparatus is described employing which any after-effect due to the former can be determined accurately by adjustments made in the latter. Figural after-effects are measured following several periods of pre-exposure of the I-figure and allowing various timeintervals to elapse before the T-pattern is displayed. The extent of illusion is estimated also when both components are seen together. No significant differences obtain between monocular and binocular presentation. Accordingly, these data are merged and arranged along a single time continuum. This suggests strongly that the same mechanism underlies both forms of perceptual distortion. In a further experiment the I- and T-components are presented successively to alternate eyes. Extents of interocular transfer prove insignificant in comparison with monocular and binocular conditions. A schematic analysis of projections of I- and T-figures, however, reveals that they are represented topographically upon the cortex in essentially similar ways. It is concluded, therefore, that the mechanism concerned is located in sub-cortical regions, probably within the retina itself.

Comparison of normalization theory and neural enhancement explantation of negative aftereffects.

Proposes that neural inhibitory interaction underlies negative aftereffects as well as figural aftereffects, with the former occurring when nontopographic principles are used by the nervous system to signal stimulus values and the latter when topographic coding is involved. Relationships between aftereffect data and information available about feature analysis from electrophysiological measurement and contour masking studies are examined with emphasis on tilt and movement aftereffects. It is concluded that even though the neural enhancement position cannot be tested in detail until more is known about tuning characteristics in sensory systems and the way cells respond to abrupt changes in stimulus value, in its present form it offers a more satisfactory explanation of negative aftereffects than normalization theory. There is little to support the latter claim that negative aftereffects occur as by-products of a perceptual adaptation process. (3 p. ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved).

Perceptual processes in the coordinate system of the retina and the viewed space. Study on the problem of direction stability using figural aftereffects

Perceptual processes in the coordinate system of the retina and the viewed space. Study on the problem of direction stability using figural aftereffects

A Visual Spatial Aftereffect of Surface Slant

The long (binocular) inducing period required by Bergman and Gibson to generate a measurable slant aftereffect was not necessary for a highcontrast surface. The aftereffect for the black-on-white lattice pattern dissipated exponentially. The complex surface, however, produced concomitant interfering effects, possibly decreasing the precision of aftereffect measures. A simpler surface, of vertical contours, sufficed for relatively accurate binocular (but not monocular) adjustments to the vertical. This pattern also produced interfering effects, possibly accounting for the correlation of aftereffect variance with inducing-figure slant. The five studies suggest using a single vertical contour as both inducing and test figures to study a hypothesized relationship between tilt aftereffect and slant aftereffect. A sensory spatial aftereffect occurs when the judgment of some spatial property of a test stimulus is modified as a result of prolonged stimulation by an inducing stimulus. The aftereffect is assumed to be a simple additive component and is defined as the algebraic difference between a prestimulation judgment (pretest) and a poststimulation judgment of the test stimulus (posttest).' Spatial aftereffects in the third dimension of visual space were first demonstrated by KShler and Emery.2 They reported, for example, that a frontal-parallel cardboard strip was judged to be slanted in one direction following fixation of a similar strip slanted in the opposite direction. Later, Bergman and Gibson reported the occurrence of a slant aftereffect induced by an irregularly textured burlap surface with its edges obscured from view.3 The mean afterReceived for publication by Professor E. B. Newman, August, 1967. The research was part of a thesis awarded the M.A. at the University of Sydney, 1968. The author wishes to thank Professor R. H. Day for his assistance throughout the project. 1 J. J. Gibson, Adaptation after-effect and contrast in the perception of curved lines, J. exp. Psychol., 16, 1933, 1-31; W. Kbhler and H. Wallach, Figural aftereffects: An investigation of visual processes, Proc. Amer. phil. Soc., 96, 1944, 269-357. Later investigations have usually not departed from this convention. 2 W. Kdhler and D. A. Emery, Figural after-effects in the third dimension of visual space, this JOURNAL, 60, 1947, 159-201. 3 R. Bergman and J. J. Gibson, The negative after-effect of a surface slanted in the third dimension, this JOURNAL, 72, 1959, 364-374.

Relationship of kinesthetic figural aftereffect to masculinity-femininity and expectation for internal versus external control of reinforcement.

60 introductory psychology students (30 male, 30 female) were administered KFAE in ascending and descending trials, using both dominant and non-dominant hands, followed by an embedded-figures test and 145 items from personality tests (Masculinity-Femininity scale of Guilford-Zimmerman Temperament Survey, Rotter I-E Scale, and the combined self-actualization scale of Shostrom's Personal Orientation Inventory). Hand dominance but not sex affected KFAE. No stable relation appeared between the personality measures and spatial aftereffect from kinesthetic stimulation for men or women.

EEG-Averaged Evoked Response and Perceptual Variability in Schizophrenics

PERCEPTUAL and cognitive studies of schizophrenic patients characteristically reveal great variability. Not only does the performance of schizophrenics on psychological tests typically cover a much broader response range than that of nonschizophrenics, but individual performance shows great variability across time. 1 By selecting representatives of two schizophrenic subtypes as subjects for this study, we hoped to reduce interindividual variability, thus enabling ourselves to observe intraindividual variability more clearly. The two subtypes, nonparanoid long-term process and paranoid short-term reactive, have clinical characteristics often thought to be consistently associated with markedly different perceptual behavior patterns. 1 To test the hypothesis that the two groups show contrasting perceptual patterns, two psychophysical tasks and an average evoked response (AER) measure were administered. In previous researches, a correlation was demonstrated in normal waking-state subjects between reponsiveness on a kinesthetic figural aftereffects (KFA) procedure and responsiveness on an AER

Apparent properties of inspection figures as determiners of figural after-effects.

Figural after‐effects (FAE) were studied using the Hering, the Ehrenstein, and the Orbisson illusion, patterns in two ways. In one condition, the total pattern was used as inspection figure (IF), and that part of the pattern in which the illusion normally appears, as test figure (TF). The resulting FAE was in a direction opposite to that of the illusion. In the second condition, the illusion producing part of the total pattern served as IF, and the illusion suffering part as TF. This produced an after‐effect, the direction of which was the same as that of the illusion.

Figural aftereffect potency: A function of sex or field-dependence?

literature shows a greater abundance of field-independent Ss among unselected male groups as compared to females who typically yield a higher percentage of field-dependent measures, the experimental groups employed by Immergluck might have contained greater densities of male and female Ss, respectively, for the fjeld-independent and field-dependent groups. Actually, care was taken in those investigations to avoid an overloading of male or fern ale Ss for each of the experimental groups, although no separate analyses were made for the male and female Ss. The present investigation aims to clarify this issue by exploring specifically the potential effects of sex vs field-dependence in relationship to aftereffect potency. Both sex and field-dependence measures, then, have been controlled in the research design, thus permitting direct comparison of these two S attributes as they affect pereeptual aftereffect performance. Furthermore, in order to make the presently obtained data more directly relevant to the previously cited investigations, the identical aftereffect figures and the same experimental conditions were employed in the present study. METHOD

Geometrical illusions and figural after-effects. The distorting and distorted components of illusions

Qualitative observations indicate that illusions remain when their distorting and distorted components are brought into stereoscopic registration. The distortions evident in Poggendorff and Müller-Lyer figures are measured and compared with a registration reference. No differences are evident between stereoscopic and binocular conditions. The convention of distinguishing between “distorting” and “distorted” parts of illusions is queried. It is shown that both components of Ebbinghaus and Delboeuf illusions exert significant mutual influences. Previous research in this field is discussed. It is suggested that the question of what is being measured with respect to what when illusions are presented stereoscopically has not yet been determined satisfactorily. Until this problem is solved arguments favouring one or other locus of the mechanisms responsible for illusory distortions remain questionable.

The relationship of figural after-effects and geometrical illusions to successive and simultaneous contrasts.

The relationship of figural after-effects and geometrical illusions to successive and simultaneous contrasts.

Tactile and kinesthetic influences on visual figural aftereffects.

12 Ss were presented with a bent line I (inspection) figure followed by a straight line T (test) figure under four different conditions in order to produce a FAE of a bent line. In the visual condition S saw the I figure and then the T figure. In the tactile condition S held a curved bar and viewed the I figure simultaneously. The two kinesthetic conditions required S feel a straight or curved bar and view the I figure simultaneously. In both the kinesthetic and tactile curved-bar conditions Ss showed a strong tendency to perceive the visual T figure as curved. In the other conditions Ss perceived the T figure as bent (the usual effect produced by this combination of I and T figures). The results demonstrate the influence of kinesthetic and tactile stimulation on visual FAE.

Sex differences on tests of visual figural aftereffects

Three experiments were conducted to determine the nature of sex differences on tests of visual figural aftereffects (FAEs). In exp. 1, in which the method of adjustment was used, the FAE increased as a negatively accelerated function of inspection-time but no significant sex differences were exhibited. In exp. 2, in which a method of detection was employed, women reported significantly fewer occurrences of FAEs than men. Inspection-time, however, had no significant effect on the size of the FAE. In exp. 3 an adjustment technique was used and, once again, sex differences were not revealed. It was concluded that sex differences are dependent upon the method used to measure FAEs and that women exhibit smaller (or fewer) FAEs probably because they adopt a more conservative attitude in situations which have a high level of uncertainty.

Individual differences in figural aftereffects.

Discusses recent experiments which indicate that the magnitude of a figural aftereffect is dependent on decision processes in addition to stimulus variables. The influence of judgment time, expectation, and instructional criterion on figural aftereffect is examined. It is suggested that the lack of attention paid to these variables may be responsible for the discrepant findings that have been characteristic of research in the area. (32 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved).

Studies of movement aftereffects.

213 Ss participated in 4 experiments designed to identify relationships between figural aftereffects elicited by hand, limb, and total body movements. The measures obtained were reliable and highly task specific.

Size adaptation: a new aftereffect.

If, after prolonged observation of a striped pattern, one views a grating of the same orientation with somewhat narrower bars, then the bars seem even thinner than in fact they are. Broader bars seem broader still. This finding implies a system of size-detecting channels in humnan vision. The phenomenon may underlie many of the classical figural aftereffects.

A problem for Koehler's theory of figural aftereffects.

Consideration of Koehler's theory of figural aftereffects in the light of research on the alternation of Rubin's reversible figure indicates a serious problem for the theory which seems to have been overlooked. There is considerable evidence for the dominance of the narrower sector of the Rubin reversible figure. Yet, satiation theory would appear to predict the opposite effect under prolonged inspection.

A study of visual temporal size contrast

Stimuli exposed successively with an interpolated larger or smaller stimulus (IS) are subject to size-contrast effects to a highly significant degree. While stimuli nearer IS are, in general, more affected than stimuli farther away, there is some indication of paradoxical distance effect (PDE): Stimuli somewhat farther from IS are more affected than those nearest IS. Intermediate IS has a splitting effect in that stimuli above are judged larger, and those below are judged smaller, thus verifying the results with IS below and above the series stimuli. The relation of these results to figural aftereffects is stressed.

FIGURAL AFTER‐EFFECTS, SENSORY CODING, EXPECTATION AND EXPERIENCE

Eight experiments on figural after‐effects (FAEs) are reported. The roles of induced set, and of experience in making judgements in a set‐free environment, were analysed. It was found that set can play a dominant part in the generation, or pseudo‐generation, of FAEs. Unless exceptional precautions are taken, set is likely to contaminate most reports of FAEs, and this factor probably accounts for most of the conflicting reports in the literature. In particular, it was shown that attempts to assess the relative importance of apparent size and retinal size in FAE situations can be vitiated by failure to control set. Two attempts to measure orientation‐specific FAEs in experienced, but set‐free, subjects met with limited success, and tended to confirm the interpretation of FAEs as functions of the coding system inherent in mammalian visual receptive field organization.

Effects of luminance contrast and temporal factors upon a figural retroactive-effect

Abstract An experiment was designed to investigate the concentric circles figural retroactiveeffect, which differs from the corresponding figural aftereffect in that the order of presentation of the inducing and test figures is reversed. 2 conditions of luminance contrast of the stimulus components with the background were used in conjunction with 2 inducing figure exposure times and 3 conditions of test figure presentation. The 60 Ss in the experiment were replicated over inducing figure exposure time. For 2 conditions, in which the low contrast inducing figure and high contrast test figure were used, it was found that the apparent displacement of the test figure was towards, rather than away from, the inducing figure. These attraction effects showed that the figural retroactive-effect and figural aftereffect may be in opposite directions, and suggested a need for the modification of current theories of apparent displacement which seek only to explain a repulsion of the test figure away from the inducing...

Figural Aftereffects Elicited by Gross Action Patterns: The Role of Kinesthetic Aftereffects in the Arm-Shoulder Musculature

Abstract To differentiate between the influence of kinesthetic aftereffects in the arm-shoulder musculature versus ancillary gait and vestibular cues upon the production of figural aftereffects, 40 volunteer subjects were employed in tasks which required that they identify the shape of various pathways while walking through them blindfolded. During the initial and final traversals of a straight “test” pathway the subjects used a different hand to hold the guide stick than that used as they walked through the curved “inspection” pathways. It was found that 67.5% of the subjects reported aftereffects (perceived that the straight pathway was curved in a direction opposite to that walked in the curved pathway) under the conditions described. It was concluded that figural aftereffects of movement elicited by blindfolded walking may be independent of kinesthetic aftereffects in the arm-shoulder musculature—possibly because of the manner in which guide sticks were employed. Theoretical and methodological implications of the findings were discussed.