Illusory Perceptions Research Articles

The Importance of Orienting Attitudes in the Perception of the Hering and Zollner Illusions

AbstractBy analyzing descriptions of illusory and nonillusory figures, Richer (1978) called into question the common assumption that illusory and nonillusory perceptions were experientially the same and differed only in terms of their accuracy. The present study attempted to replicate Richer's work with a focus on identifying within the subjects' descriptions any orienting attitudes corresponding to these two forms of perception. Nineteen student volunteers were asked to describe two illusory figures (the Hering and the Zollner figures) and a nonillusory control of similar complexity. The descriptions revealed consistent differences between the two forms. However, the Hering and Zollner figures were not always described in illusory terms, and surprisingly, several subjects described the control as if it were illusory. Further, perceptual accuracy was not guaranteed by nonillusory experience. Subjects described the figures from within one of three different orienting attitudes-atomizing, representational, and geometrical-organizing. The latter attitude appeared necessary for the phenomena of illusory perception and experience. Though the present findings confirmed Richer's distinction between illusory and nonillusory experience, they also indicate the need for further differentiation- illusory perception versus illusory experience. Finally, the findings also supported Luria's (1976) and Segall, Campbell, and Herskovits's (1966) position on the importance of particular cultural and educational experiences and codes in relation to perceptual illusions.

Controlling the uncontrollable: Effects of stress on illusory perceptions of controllability.

Controlling the uncontrollable: Effects of stress on illusory perceptions of controllability.

Controlling the uncontrollable: effects of stress on illusory perceptions of controllability.

Individuals' failure to exercise actual control over an event might be compensated for by trying to bolster a generalized, subjective sense of control. Control might then be sought by undertaking acts the effect of which on the environment is illusory. This observation led to the hypothesis that stress, which undermines persons' sense of control, would engender illusory perceptions of controllability. The hypothesis was tested in 3 experiments that required Ss to choose between 2 gambling forms. Although the 2 forms were essentially identical, 1 was designed to instill an illusion of control. The results showed that highly stressed Ss, compared with those who experienced low stress, preferred gambling forms that heightened perceptions of controllability.

The Purposeful-Action Sequence and the "Illusion of Control"

This study examined how features of both the situation and the target's behavior may lead observers to infer that a target has exerted control over a random event-in this case a roll of the dice in a game of backgammon. Observers read stories about a game of backgammon in which the male target either strongly wished for one particular outcome of the roll of the dice or was indifferent and in which either the target rolled the dice himself or a third party rolled the dice for him. Results showed that when the target desired a particular consequence of the dice roll in advance and rolled the dice himself, observers were more likely to see him as having exerted influence over the dice roll, were willing to wager more that he could roll the same number again, and rated luck as less influential in producing the dice roll outcome. These results are discussed from the perspective of illusory perceptions of control that might explain why observers inferred an actor's intentions from the actor's production of an event generally regarded as random.

A theory of phenomenal geometry and its applications

The geometry of perceived space (phenomenal geometry) is specified in terms of three basic factors: the perception of direction, the perception of distance or depth, and the perception of the observer's own position or motion. The apparent spatial locations of stimulus points resulting from these three factors thereupon determine the derived perceptions of size, orientation, shape, and motion. Phenomenal geometry is expected to apply to both veridical and illusory perceptions. It is applied here to explain a number of representative illusions, including the illusory rotation of an inverted mask (Gregory, 1970), a trapezoidal window (Ames, 1952), and any single or multiple point stimuli in which errors in one or more of the three basic factors are present. It is concluded from phenomenal geometry that the size-distance and motion-distance invariance hypotheses are special cases of the head motion paradigm, and that proposed explanations in terms of compensation, expectation, or logical processes often are unnecessary for predicting responses to single or multiple stimuli involving head or stimulus motion. Two hypotheses are identified in applying phenomenal geometry. It is assumed that the perceptual localization of stimulus points determines the same derived perceptions, regardless of the source of perceptual information supporting the localizations. This assumption of cue equivalence or cue substitution provides considerable parsimony to the geometry. Also, it is assumed that the perceptions specified by the geometry are internally consistent. Departures from this internal consistency, such as those which occur in the size-distance paradox, are considered to often reflect the intrusion of nonperceptual (cognitive) processes into the responses. Some theoretical implications of this analysis of phenomenal geometry are discussed.

Motion sickness caused by rotations about Earth-horizontal and Earth-vertical axes

Rotation at constant angular velocity about the head's Z-axis, with the rotational axis horizontal (barbecue-spit rotation), causes motion sickness and illusory perceptions of bodily movement. To determine whether such rotations about the head's X- and Y-axes cause similar effects, and to test the validity of the mismatch theory of motion sickness, more than 200 tests (using vertical axes as well as horizontal axes) were administered to 14 subjects. Three different visual conditions were also investigated: normal external vision, vision of only the inside walls of the rotating capsule, and eyes closed in the dark. In Earth-horizontal rotation, the X- and Y-axis stimuli were found to be equally as effective in provoking sickness as was the original Z-axis stimulus, and a comparable loss of perception of gravity occurred for all three stimuli. The horizontal axis stimuli were found to be very effective in producing sickness in all the three visual conditions, but the external vision condition was significantly less effective than the other two conditions. The findings were generally inconsistent with the mismatch theory.

The Myth of the Cavern Revisited: Are Large-Scale Behavioral Models Useful?

The building of large-scale quantitative simulation models, which has been made possible by advances in computing technology over the last ten or fifteen years, remains a controversial issue in the social sciences. Criticisms are often voiced, either of the construction of these in general, or of the approach followed by particular models.1 This paper attempts to summarize both the attributes and failings of such models, with particular reference to of economic-demographic systems. Although the authors have an interest in the field,2 we do not attempt to simply rationalize our particular modeling work, or in general, in this article. To anticipate our conclusions somewhat, we consider that large-scale systems have uses that cannot be provided by any other analytical tool. They can provide an explicit and more rigorous representation of real world relationships than the mental models that would otherwise guide analysis and decisionmaking. At the same time we would argue that there are many limitations on their use. We consider below some of the implications of these limitations, together with the balance of advantages and disadvantages in using large-scale for particular purposes in the social sciences. Our title comes from Plato's allegory, in which shadows on the wall of a cavern represent the illusory perceptions we have of reality. A model is only a shadow of reality, and the question is whether it too is illusion or whether it can help us understand the real world.

Gestalt Principles, Illusory Perceptions, and Traffic Problems (Letter to the Editor)

Gestalt Principles, Illusory Perceptions, and Traffic Problems (<i>Letter to the Editor</i>)

ILLUSORY PERCEPTION AS A CONSTANCY PHENOMENON.

GREGORY1 offers a general account of visual illusions, relating the apparent distortions in them to the perceptual process of size constancy. He observes that Tausch is the only previous writer to have considered constancy in relation to illusions. However, Gibson2 has incorporated illusory perceptions within the context of size constancy, and suggests that perception of size is a by-product of a constant scale, which Gregory calls ‘constancy scaling’, at different distances. Arguing that illusory figures are “flat projections of typical views of objects lying in three-dimensional space”, Gregory notes that “the parts of the figure corresponding to distant objects are expanded and the parts corresponding to nearer objects reduced”. He states the same principle more simply when he writes: “Those parts of the figures which would normally be further away in 3-D space appear too large in the illusion figures”3. These principles are applied to a series of illusions, including those of Müller-Lyer, Ponzo and Hering. Gregory therefore postulates a common process modifying retinal images in constancy scaling and in the perception of illusory figures.

Some stimuli and aptitudes determining apparent parallelism.

Apparent parallelism was studied to determine spatial relations of S, standard, and variable which might be sufficient for veridical and illusory perceptions of parallelism. Relationships between Ss' aptitude for spatial visualization (paper-and-pencil tests) and the measures of parallelism were assessed. Different spatial relations of S, standard, and variable resulted in veridical and illusory perceptions of parallelism. The magnitude of the illusory effects was inversely related to S's aptitude for spatial visualization, the highest r being –.98. The two tests correlated +.92. A theory of apparent parallelism is proposed.

The illusory perception of movement caused by angular acceleration and by centrifugal force during flight. II. Visually perceived motion and displacement of a fixed target during turns.

oculo-gyral and oculo-gravic illusions were studied in flight using three Ss who observed a fixed luminous target in the dark. The observations were made in the rear cockpit of an SNJ-6 aircraft while the pilot executed turns with different degrees of bank… . In the first series the turns were carried out by using a constant power setting and changing the angle of attack of the wing to maintain the proper altitude. In the second series the angle of attack was held constant while the power was increased to maintain altitude. The third series was a repetition of the first for 3 selected angles of bank… . there was no significant evidence of any difference in the illusory perceptions during the 2 types of banks nor was there any evidence of habituation within the limits of this experiment. The illusory motion and displacement upward occurred at all angles of bank studied. There was a clear positive relation between the accelerative forces and the occurrence of the illusions. There was also an increase in the magnitude and duration of the illusions observed as the accelerative forces increased. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

The illusory perception of movement caused by angular acceleration and by centrifugal force during flight. I. Methodology and preliminary results.

Abstract : Experiments were carried out on three subjects using five basic maneuvers in addition to control periods of straight and level flight. It was shown that angular acceleration and g during flight induce illusory perceptions of motion and displacement of an objectively motionless object. The magnitude of the illusory effects may be great, the fixation object appearing to be displaced as much as 60 degrees from its actual position. The significance of this finding for aviation is evident. The method is adaptable to a number of types of studies concerned with the influence of angular acceleration and g on visual perception. (Author)