The effect of knowledge of reversibility on the reversibility of ambiguous figures

Abstract

The role of knowledge of the reversibility of reversible figures was tested in four experiments. Two ambiguous figures, the vase-face figure and a depth-reversing pyramid-hallway figure were shown to high school students. In the Uninformed condition, subjects were not told that the figures were reversible. A sampling procedure was used in which subjects reported what they perceived at 5-sec intervals. Viewing durations of up to 3 min were used, and approximately half of all subjects did not reverse at all during the Uninformed condition, whereas virtually all subjects reversed quickly and frequently once they knew that the figures were reversible. These results are not consistent with neural fatigue models of perceptual reversal.Ambiguous figures and the perceptual alternations which occur when viewing them are of interest because their explanation would appear to require central dynamic factors. Previous reports and theories have repeatedly stressed the spontaneous character of the reversals in which voluntary control neither causes nor prevents reversal. This apparent spontaneity of reversals has played an important role in the theoretical interpretation of the phenomena. The most widely investigated theory, the cortical satiation theory of Kohler and Wallach (1944), proposed that cortical' events produce their own resistance and bring about their automatic replacement by the opposing cortical events that then result in the perceptual reorganization. But all fatigue or satiation theories of reversal, including those based on contemporary neurophysiological constructs, posit an inexorable effect due to continuous passive stiniulation.This kind of theory of reversal implicitly defines ambiguity purely in stimulus terms. The stimulus can represent two (or more) possible objects, and when one such percept is satiated another automatically replaces it. Of course, this presupposes that the observer can identify these alternatives either because each is a familiar object (e.g., "cube," "face," "vase," etc.) or because each is a member of a different category or distinctive in some way in the observer's repertoire (e.g., "cube tipped up or on edge," "two-dimensional line pattern," etc.) But one might ask the further question of whether the meaning of ambiguity presupposes awareness by the observer that the figure is ambiguous. This is the issue with which we are concerned here. There is nothing in the literature to suggest that such awareness is part of 'the meaning of ambiguity and, in fact, it seems to be implicit that such knowledge is not a necessary part of the meaning. Certainly such an assumption is alien to the satiation model for the reasons 550 suggested above.Nonetheless, experiments on figure reversal are performed with informed subjects. The method typically employed in studying this problem seems necessarily to entail informing the subject about the possible alternative perceptions of a given figure, and that the figure reverses. It is understandable why investigators have believed that only in this way ...

Preattentive and cognitive effects on perceptual completion at the blind spot

“…It is clear from the results of Experiment 4 that a marked decrease in latency to reversal occurred for the instructed condition, which was consistent across stimuli and remarkably stable regardless of the order of presentation. Based on the data obtained on figure reversal by Girgus et al (1977), it is probable that this facilitation was in fact due to the acquired knowledge that reversal is possible. One could argue, however, that the difference in reversal latency observed between the two conditions was perhaps due to an inhibition of reversal during the passive condition that was released during the instructed condition.…”

“…Figure reversal was believed to be due to the saturation of cortical neurons (Koehler & Wallach, 1944), but it is now clear that the phenomenon has much more complex determinants. For instance, it has been demonstrated that the subjective occurrence of figure reversal depends largely on being informed of its possibility (Girgus, Rock, & Egatz, 1977), that the frequency of the reversal process is a direct function of the ambiguity of the design (Riani, Tuccio, Borsellino, Radilova, & Radil, 1986), and that the reversal process is subject to conscious control (Liebert & Burk, 1985;Pelton & Solley, 1968;Washburn & Gillette, 1932).…”

Mental images can be ambiguous: Reconstruals and reference-frame reversals

“…Reisberg and Chambers (1991) argue that, in response to these instructions, subjects substitute one image for another, rather than reverse the original image. They argue further that this reversal process differs from the reversal processes operating in perception, where reversals occur spontaneously (although research by Rock and his colleagues [Girgus, Rock, & Egatz, 1977;Rock & v.C. top, "rabblt-to~ Mitchner, in press] demonstrates that the reversals of many figures may not be perceived spontaneously).…”

As the cube turns: Evidence for two processes in the perception of a dynamic reversible figure

“…These include the findings that observers have some volitional control over reversal rate (e.g., Pelton & Solley, 1968), that an observer's prior knowledge of the reversible character of the stimulus affects reported reversals (Girgus, Rock, & Egatz, 1977), and that significant practice effects across sessions have been reported (e.g., Ammons, 1954;Mefferd, Wieland, Greenstein, & Leppman, 1968).…”