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Results for “Figural Aftereffect”

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At least 19 recordsLinked to original sources

PubMed1978

Orientation detectors in the human visual system and figural aftereffects.

Figural aftereffects were measured by using square patches of high-contrast grating on a dark background as inspection and test figures. The orientation of the outer square border and the enclosed grating were varied independently in order to evaluate their relative influence on the strength of the induced change of overall apparent size of the test figure. The largest effect is obtained when inspection and test figures are identical in the orientation of both outer border and enclosed grating. The strength of the aftereffect is reduced as a difference in orientation is introduced between inspection and test figure for either the outer contour or the contained grating, although the former is a more potent factor than the latter.

Figural Aftereffect↗

PubMed1975

Kinesthetic figural aftereffects in acute schizophrenia: a style of processing stimuli.

The Kinesthetic Figural Aftereffect test was administered to 106 psychiatric inpatients to assess styles of stimulus processing in schizophrenia. Three conditions were used: (1) standard stimulus conditions at the acute phase; (2) standard conditions, 7 wk. later, to evaluate stability over time; (3) reversed stimulus conditions to assess kinesthetic figural aftereffect generality under different stimulus conditions. Results indicated that: (1) schizophrenics reduced stimuli, but differences between patient groups were not significant. (2) Kinesthetic figural aftereffect stability over time was shown by nonschizophrenics (p less than .01) but not by schizophrenic and borderline patients. (3) All diagnostic groups reversed kinesthetic figural aftereffect responses under reversed stimulus conditions, e.g., former "augmenters" tended to reduce more under agumenting conditions, suggesting the importance of the specific stimulus conditions. (4) Acute schizophrenics showed a stimulus-governed style. (5) The results raise questions about kinesthetic figural aftereffects as a measure of response style.

Acute Disease↗

PubMed1977

Feature analysers, optical illusions, and figural aftereffects.

Simple displacement models cannot explain some aspects of optical illusions and figural aftereffects. The orientation-detector interaction model proposed by Blakemore and others is more suitable to explain many aspects of the Zöllner illusion, positive and negative illusions, the effect of gap between the inducing and test lines, and the anisotropy of illusions. If we hypothesize size detectors whose tuning width and distribution steps are proportional to logarithmic size, interactions between them explain well the fact that the Delboeuf illusion and figural aftereffects of circles are determined by the size of the inducing to test circle, not by the absolute distance between the contours of these circles.

Figural Aftereffect↗

PubMed1978

The effects of dextroamphetamine on kinesthetic figural aftereffects.

The effect of dextroamphetamine, primarily a central stimulant, on kinesthetic figural aftereffects (KFAEs) was examined. The subjects were selected after preliminary testing with the Eysenck Personality Inventory and were classified into three groups: extraverts, ambiverts, and introverts. d-Amphetamine was used at three dose levels and a control group was included for purposes of comparison. The 3 X 4 randomized block design was replicated ten times. KFAEs were measured under two sets of conditions, i.e., before and after the induction experience. The results support the following conclusions: (1) neither personality grouping nor drug treatment during preinduction trials significantly affected KFAE; (2) both types of variables were, however, significantly related to behavior during the postinduction trials; (3) the extraverted subjects showed larger KFAEs than ambiverted and introverted subjects under placebo condition; (4) the extent of KFAE was reduced in extraverted and enhanced in introverted subjects under the influence of the drug; (5) there were significant interactions between the drug treatments and personality variables in effects on KFAE.

Adolescent↗

PubMed1975

Anchor effects and figural aftereffects: a comparative psychophysical investigation.

Perceptual contrast effect was studied from two points of view, as a special anchor effect and as a special figural aftereffect. Two experiments were conducted to investigate the influence of stimulus onset asynchrony on contrast and assimilation effects, induced and measured by different psychophysical methods. Stimuli were circular beams of light projected on screens (Delboef type of illusion). When anchor and series stimuli were shown and the latter were judged by means of a rating scale, stimulus onset asychrony had no substantial influence on the contrast effect (Exp. I). When the constant method was applied, however, the asynchrony altered the shape of the contrast effect considerably (Exp. II).

Adaptation, Ocular↗

PubMed1992

Attentional modulation of a figural aftereffect.

Evidence is reported that indicates that adaptation of the Schroder staircase is affected by attention. In previous work it has been shown that if subjects adapt to an unambiguous staircase, responses to an ambiguous test figure are biased towards the opposing perspective. In the current work, subjects adapted to superimposed upright and inverted Schroder staircases. Both staircases were centered on a common fixation point and were of different sizes and colors. Attention to each staircase was controlled by asking subjects to detect color changes in the line segments that defined one or the other staircase. Responses to an ambiguous test figure depended on which of the adapting staircases was attended.

Adaptation, Ocular↗

PubMed1978

Different loci suggested to mediate tilt and spiral motion aftereffects.

Interocular transfer of two figural aftereffects was examined in orthotropes and strabismic subjects. Within both groups there were persons with an appreciable degree of stereoacuity and others who had little or none. Experimental evidence from a variety of sources has suggested that stereopsis depends upon binocularity of units in the geniculostriate system. For the tilt aftereffect, interocular transfer correlated with stereoacuity among both orthotropes and strabismics. For the spiral motion aftereffect, interocular transfer did not correlate with stereoacuity; it was present among orthotropes and absent among strabismic individuals. The correlation of stereoacuity with interocular transfer of the tilt aftereffect agrees with previous observations and is consistent with the interpreation that this effect is mediated at a cortical level. The lack of a correlation between stereoacuity and interocular transfer of the spiral motion aftereffect suggests that this effect is mediated by units other than those responsible for stereopsis. Richards and Smith, on the basis of certain phenomenal differences between the spiral motion aftereffect and other figural aftereffects, have suggested that the former is mediated at a midbrain level. If strabismic persons lack binocular units in midbrain, the present results are consistent with their hypothesis.

Afterimage↗

PubMed1976

Satiation in cutaneous saltation.

The extent of cutaneous saltation (the illusory displacement of a tap presented to one skin locus by another tap occurring close in time at another locus) was modified by a "preconditioning" stimulus presented prior to and at a site distant from the saltatory test pattern. The 10-sec vibratory preconditioning (PC) stimulus appears to be analogous to inspection figures that "satiate" the perceptual field in experiments on figural aftereffects, producing changes in the perceived size, position, or shape of subsequent stimuli. The direction of displacement of the saltatory phantom was always away from the locus of the prior PC stimulus, consistent with results observed in studies of visual and kinesthetic aftereffects. Th- amount of repulsion and the rate at which the saltatory phantom returned to its initial position depend on the intensity, locus, and number of PC stimuli. As with figural aftereffects, these results resist explanation by peripheral mechanisms such as adaptation.

Adult↗

PubMed1979

Perceptual reactance and task performance.

57 female subjects participated in a study in which perceptual reactance was assessed by the kinesthetic figural aftereffects test. Subjects identified as augmenters were quicker than reducers on a disjunctive reaction time task and a significant interactive effect was found on a paired-associate task. Augmenters performed better on a similar list while reducers were more effective on a dissimilar list.

Female↗

PubMed1978

Obesity and perceptual reactance.

Similarities in anomalous perception of internal gastric states and sensitivity to distraction among the obese to variations in perceptual reactance suggest that the obese tend to augment the intensity of visceral cues associated with hunger. It was hypothesized that the obese would be overrepresented at the augmenter end of the perceptual reactance continuum. Thirteen obese (six male, seven female) and 14 nonobese (eight male, six female) college students participated in a study in which perceptual reactance was assessed by degree of Kinesthetic Figural Aftereffect (KFA). A highly significant relationship in the predicted direction was observed for perceptual reactance category and mean percent weight deviation. Additionally, there was a highly significant interaction of sex by category, with the hypothesized relationship intensified for the female Ss. Results supported interpretation of obesity as a consequence of animalous perception of cues associated with consuming behavior.

Attention↗

PubMed1976

Evoked response and kinesthetic measures of augmenting/reducing in schizophrenics: replications and extensions.

This study represents an attempt to replicate the central results of earlier work on stimulus intensity control. It uses a diverse sample of 40 hospitalized schizophrenic subjects, both chronic and acute. Two measures of stimulus intensity control were used: the Petrie kinesthetic figural aftereffects procedure (KFA), and the EEG method of average evoked response (AER). Finding the earlier results generally applicable, it presents a model of the function of stimulus intensity control in schizophrenia, which suggests that acute schizophrenics are particularly vulnerable to being inundated by stimuli, and therefore, that in order to protect themselves, they tend to reduce the perceived intensity of stimuli. Chronic schizophreniics have higher AER amplitudes and reduce less than acutes, suggesting that among chronics, the reducing mechanism either never was present or failed, whereas paranoid schizophrenics tend to be augmenters--a response style consistent with vigilant scanning.

Acute Disease↗

PubMed1977

Perceived exertion and stimulus intensity modulation.

Perceptual augmentation and reduction were considered contrasting styles of Stimulus Intensity Modulation. Differences in perceived exertion between augmenters and reducers were determined for three cycle ergometer work loads. Subjects were 20 males having similar physiological characteristics. Stimulus Intensity Modulation was determined by kinesthetic figural aftereffect. Augmenters rated their perceptions of physical exertion to be more intense than reducers at 450, 750 and 1050 kpm/min. Differences in physiological responses between augmenters and reducers were not significant at the three work loads. Style of Stimulus Intensity Modulation appeared differentially to influence perceived exertion at the work levels studied.

Blood Chemical Analysis↗

PubMed1975