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At least 163 records · Page 9Linked to original sources
PubMed1990

Moon illusion in pictures: a multimechanism approach.

The existence of the moon illusion in pictorial representations was demonstrated in 6 experiments. Ss either judged the size of the moon in pictures, depicted as on the horizon or high in the sky, or drew horizon and elevated moons. The horizon moon was consistently judged to be larger than the elevated moon, independent of the angle at which the pictures are viewed. The distance paradox usually observed with the moon illusion (horizon moon apparently closer than the elevated moon) also exists in pictures. The magnitude of both size and distance effects depends on the salience of depicted depth cues. The pattern of results suggests that the moon illusion is caused by several interacting mechanisms and that use of pictorial stimuli may allow the separation of various cognitive from physiological contributions to the illusion.

Attention↗
PubMed1990

A simple but powerful theory of the moon illusion.

Modification of Restle's theory (1970) explains the moon illusion and related phenomena on the basis of three principles: (1) The apparent sizes of objects are their perceived visual angles. (2) The apparent size of the moon is determined by the ratio of the angular extent of the moon relative to the extents subtended by objects composing the surrounding context, such as the sky and things on the ground. (3) The visual extents subtended by common objects of a constant physical size decrease systematically with increasing distance from the observer. Further development of this theory requires specification of both the components of the surrounding context and their relative importance in determining the apparent size and distance of the moon.

Distance Perception↗
PubMed1977

Contextual influences on judgments of linear extent.

A series of experiments was performed to test the predictions of adaptation level, efferent readiness, and framing explanations of illusions of extent. The framing notion, that the ratio of total figure length to shaft length (i.e., the framing ratio) determines the magnitude of illusions, was supported for the Müller-Lyer, Baldwin, and divided line illusions. Peak overestimation of shaft length obtained when the framing ratio was 3:2. Variation of proximal figure size, achieved by altering either viewing distance or distal figure size, was found to be directly related to the magnitude of the illusions. A model was proposed to account for the effects of both the framing ratio and proximal shaft length on judgments of focal length.

Cues↗
PubMed1978

An investigation of the cues responsible for figure impossibility.

Two different perceptual confrontations produced by two different cues (sides that seem to twist and apparent levels of depth), which were thought to influence the perception of the degree of possibility of impossible torus figures, were examined in two experiments. In Experiment 1 it was found that net change in depth experienced with one scan around the figure was inversely related to magnitude estimates of possibility, whereas the number of apparently twisted sides was not. These results were verified in Experiment 2, a replication of Experiment 1 using stereograms of the figures, in which an interpretation of multiple levels of depth was more difficult.

Cues↗
PubMed1979

Levels of processing in visual illusions: the combination and interaction of distortion-producing mechanisms.

In order to assess the mode and sequence of interaction of visual-geometric illusion mechanisms, responses to simple and composite overestimation configurations were measured in 72 observers. Analysis suggests that some illusion mechanisms add their distortions to the outputs of others and that other mechanisms average. A logarithmic or near-logarithmic transformation seems to occur when illusory effects combine. A path analysis of the results suggests that some illusory mechanisms combine in a serial manner and that others operate on separate parallel channels. Notions based on simple addition of illusory effects and on serial linear processing are not supported by these analyses.

Discrimination Learning↗
PubMed1980

Principles of perceptual organization and spatial distortion: the gestalt illusions.

In five interleaved experiments, conducted with 94 observers, it is shown that organization of the visual field according to gestalt principles results in measurable spatial distortions. Using the principles of proximity, similarity, good continuation, and two types of closure, it was found that interior distances (within a perceptual unit or group) are underestimated relative to exterior distances. The relationship between these spatial distortions and the resultant perceptual organization are discussed.

Distance Perception↗
PubMed1980

The Poggendorff illusion: consider all the angles.

In the Poggendorff display, which consists of parallel lines interrupting a transversal, one of the two transversal segments was replaced by a dot lying along the parallel. The angle between the remaining transversal segment and the parallels was varied in 15 degree increments, as was the orientation of the transversal with respect to the subject. Subjects set the dot to appear collinear with the transversal. Judgmental errors can be partitioned into additive components, one linearly related to the size of the obtuse angle between transversal and parallels and the other a sinusoidal function of transversal and parallels and the other a sinusoidal function of transversal orientation (collinearity settings err toward the horizontal or vertical, whichever is closer), plus a meridional effect, an interaction term that magnifies the errors of a given obtuse angle as the transversal approaches an oblique orientation.

Discrimination Learning↗
PubMed1981

Mistracking in alignment illusions.

A number of anomalies have been pointed out in opposition to attempts to account for the Poggendorff illusion in terms of the expansion of small or medium-sized acute angles. A principle under which these anomalies could be subsumed was proposed and subjected to experimental testing using simplified displays. The following theory emerged from these experiments. If a straight line (the pointer) is aligned with a do (the target) situated at the end of a second line (the induction line) and lying in a different orientation from the pointer, then (depending on the angle between pointer and induction line) the pointer will appear to be aligned with a point further along the induction line. The amount of misalignment varies inversely with increase in size, up to about 135 degrees, of the angle formed by the pointer with the induction line, after which there is no displacement attributable to the induction line. The effect appears not to be due to neural interaction. An explanation in terms of eye movement is discussed.

Discrimination Learning↗
PubMed1982

The moon illusion: II. A reference theory.

The present theory provides explanations for the moon illusion and related issues involving size and distance perception in natural, outdoor settings. Although some assumptions of previous theories are rejected, other pivotal aspects are retained in this formulation. In particular, the present theory states that both the sky and ground are important referents in judging the spatial extent of the moon. Neither factor alone can account for all the available data, but quantitative models incorporating both factors do quite well when applied to the parametric findings of Holway and Boring, as well as to the results obtained by Kaufman and Rock. The reference theory and its associated class of specific models suggest new theoretical directions and experimental tests to narrow yet further the selection of appropriate explanations for one of visual perception's oldest unsolved puzzles.

Astronomical Phenomena↗
PubMed1985

Size illusion, distance illusion, and terrestrial passage: comment on reed.

Two assumptions of Reed's (1984) terrestrial passage theory are questioned. First, Reed assumes that the moon's failure to increase in visual subtense while elevating is accounted for strictly by perceptual distancing. This allows a formal account of the moon distance illusion, but at the expense of a compelling explanation of the moon size illusion. Second, in order to explain the distance illusion, Reed assumes that all objects, regardless of their perceived altitude, are perceived to start from a common point at the horizon. Several alternative application of Reed's terrestrial-passage foundation to the actual illusions are suggested.

Astronomical Phenomena↗
PubMed2005

Naive optics: acting on mirror reflections.

It is known that naive observers have striking misconceptions about mirror reflections. In 5 experiments, this article systematically extends the findings to graphic stimuli, to interactive visual tasks, and finally to tasks involving real mirrors. The results show that the perceptual knowledge of nonexpert adults is far superior to their conceptual knowledge. Whereas conceptual errors include the assumption of left-right reversals in mirror images and often blatant extensions of the boundary of mirror space, the perceptual context prevents most such errors. However, a consistent bias to misjudge objects in mirrors too far to the outside is demonstrable in all cases including tasks with real mirrors. The authors present a 2-stage hypothesis consisting of an implicit bias of judging the mirror surface to be turned toward the observer's line of sight followed by a normalization that becomes explicit.

Adult↗
PubMed2003

Conflicting directional and locational cues afforded by arrowhead cursors in graphical user interfaces.

Task-irrelevant features of arowhead cursors may generate conflict during cursor placement within graphical user interfaces. Arrowheads can signify location, but also cue direction and feature in optical illusions. To address the influence of conflicting cues, 14 participants used arrowhead cursors (standard, oversized) pointing upward or downward to move to targets (7.5, 15-mm diameter) situated at the top or bottom of the screen. Compatible arrowhead orientation improved response initiation. Cursor size, orientation, direction of motion, and target size interacted during cursor movement. Overshooting occurred for oversized cursors in the direction the arrow pointed for larger targets. Larger compatible arrowhead cursors elicit less efficient cursor positioning movements that are more susceptible to illusory processes, posing implications for design of cursors and graphical user interfaces.

Adult↗