Effects of Gap Size between Shaft and Fins and of Angle of Fins on the Müller—Lyer illusion

Perception ◽  
1977 ◽  
Vol 6 (4) ◽  
pp. 435-439 ◽  
Author(s):  
Alexander W Pressey ◽  
Vincent Di Lollo ◽  
Robert W Tait
Keyword(s):  
Assimilation Theory ◽  
Gap Size ◽  
Comparison Line ◽  
Lyer Illusion ◽  
Apparent Length

Assimilation theory was employed to generate quantitative predictions relating the ingoing Müller—Lyer illusion to both angle of fin and gap between shaft and fin. Gap sizes were varied from zero to 18 mm in steps of 2 mm, and angles of fins were varied from 30° to 180° in steps of 30°. Five subjects adjusted the length of a comparison line to match the apparent length of the shaft at each combination of gap size and angle of fin. It was predicted that the gap necessary for a reversed illusion to occur, and the gap at which the maximal reversed effect occurred, would be inversely related to angle of fins. Empirical functions verified the predictions.

Evidence for the Role of Attentive Fields in the Perception of Illusions

1974 ◽  
Vol 26 (3) ◽  
pp. 464-471 ◽  
Author(s):  
Alexander W. Pressey
Keyword(s):  
Ponzo Illusion ◽  
Assimilation Theory ◽  
Comparison Line ◽  
Lyer Illusion ◽  
Correct Direction ◽  
Perception Of Illusions

On the basis of the concept of attentive fields, it was predicted that the position of the comparison line would systematically affect the amount of illusion displayed in the Ponzo configuration and in two impoverished forms of the Müller-Lyer illusion. Ten of 12 predictions which seemed to be unique to assimilation theory were verified statistically and the remaining two predictions were in the correct direction. A reversed Ponzo illusion which was expected from the concept of attentive fields was not exhibited. This latter result was explained on the basis of the fact that the Müller-Lyer illusion of elongation is normally greater than the Müller-Lyer illusion of shrinkage.

Assimilation Theory, Attentive Fields, and the Müller—Lyer Illusion

Perception ◽  
1978 ◽  
Vol 7 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Michael Bross ◽  
Richard Blair ◽  
Paul Longtin
Keyword(s):  
Field Size ◽  
Assimilation Theory ◽  
Unitary Theory ◽  
Attentive Field ◽  
Lyer Illusion

The assimilation theory of geometric illusions was employed to predict changes in the outgoing and ingoing forms of the Müller—Lyer illusions as a function of attentive field size. It was found that the theory predicted correctly the form of the function relating amount of illusion and size of attentive field only for the outgoing Müller—Lyer. For the ingoing illusion the prediction was opposite to the empirically obtained results. The findings are seen as additional evidence for the untenability of a unitary theory, such as assimilation theory, for both versions of the Müller—Lyer illusion as they fail to account for substantial differences between them.

Attention and the Müller-Lyer Illusion: Simulation of an Experiment by Larsen and Garn

1989 ◽  
Vol 68 (3_suppl) ◽  
pp. 1323-1329 ◽  
Author(s):  
Alexander W. Pressey ◽  
Bernd Kersten
Keyword(s):  
Computer Simulation ◽  
Assimilation Theory ◽  
Visual Distortion ◽  
Lyer Illusion ◽  
Separate Effect ◽  
Close Relationship

An assimilation theory of visual distortion which emphasizes the role of attention was used to explain results obtained by Larsen and Garn (1988). A computer simulation of their experiment showed a close relationship ( r = .81) between obtained and predicted patterns of results in Müller-Lyer configurations. It was deemed unnecessary to postulate a separate effect in which fins of Müller-Lyer figures interfere with the ability to make a veridical comparison between shafts.

Apparent Depth and the Müller—Lyer Illusion

Perception ◽  
1973 ◽  
Vol 2 (2) ◽  
pp. 225-234 ◽  
Author(s):  
M A Georgeson ◽  
C Blakemore
Keyword(s):  
Three Dimensional ◽  
Apparent Depth ◽  
Size Constancy ◽  
Comparison Line ◽  
Perspective View ◽  
Lyer Illusion ◽  
Classical Size

The Müller–Lyer illusion was presented stereoscopically as either a flat or a three-dimensional figure. When the flat figure was made to appear closer or further than a comparison line, the illusion persisted along with large changes in overall size due to classical size constancy. When the fins of the figure were tilted in depth the illusion was somewhat reduced for both forward and backward tilts. It is argued that the size-constancy theory of illusions should predict an enhancement when stereopsis and the typical perspective view' reinforce each other, and abolition or reversal of the illusion when they are in opposition. These results therefore pose some problems for the theory.

scholarly journals Visual search for apparent-length targets is modulated by the Müller-Lyer illusion

2004 ◽  
Vol 17 (4) ◽  
pp. 417-441 ◽  
Author(s):  
Hermann Müller ◽  
Astrid Busch
Keyword(s):  
Visual Search ◽  
Lyer Illusion ◽  
Apparent Length

Influence of Instructions and Cognitive Articulation on Reducing the Müller-Lyer Illusion with a Repeated Trial

1984 ◽  
Vol 59 (3) ◽  
pp. 791-796 ◽  
Author(s):  
Santo Di Nuovo
Keyword(s):  
Female Students ◽  
Assimilation Theory ◽  
Illusory Effect ◽  
Repeated Trial ◽  
Lyer Illusion ◽  
Geometrical Illusions ◽  
Trial Analysis ◽  
Significant Difference

The role of specific, suggestive instructions and of the subject's cognitive articulation in fostering modifications of Müller-Lyer illusory effect was studied. 60 female students were divided into four subgroups on the basis of (a) Witkin's GEFT scores and (b) instructions given to the subjects for the repeated trial. Analysis shows no statistically significant difference between the more and less articulated subjects on the first trial, for influence of both cognitive articulation and instructions or their interaction on the reduction of the illusion. Data are interpreted in terms of some theoretical explanations of geometrical illusions, such as ‘centration theory’ and ‘assimilation theory’.

Effects of Figure Context on the Apparent Length of a Line

1997 ◽  
Vol 85 (2) ◽  
pp. 551-558 ◽  
Author(s):  
Chun R. Luo ◽  
Su Wang
Keyword(s):  
Significant Influence ◽  
Context Effect ◽  
Visual Illusions ◽  
Standard Line ◽  
Comparison Line ◽  
Apparent Length ◽  
Stretching Effect

This study investigated the effects of figure context on the apparent length of a line. In Exp. 1, ten participants were asked to adjust the length of a comparison line to match a standard line enclosed within a rectangle. The participants consistently overestimated the length of the standard line, demonstrating the stretching effect of figure context on the apparent length of a line. In Exp. 2 (12 participants), the size of the context figure was varied and it had no significant influence on the magnitude of the context effect. In Exp. 3 (nine participants), the context effect was shown not only for squares and rectangles but also for other shapes of figures such as circles and 5-pointed stars. We discuss the possible mechanism of the figure-context effect within Gregory's (1970, 1978) misapplied constancy theory of visual illusions.

Assessment of Apparent Length and Angle Explanations of the Poggendorff Effect

1983 ◽  
Vol 57 (2) ◽  
pp. 539-546 ◽  
Author(s):  
A. E. Wilson
Keyword(s):  
Angular Distortion ◽  
Assimilation Theory ◽  
Substantial Portion ◽  
Apparent Length ◽  
Poggendorff Effect

Explanations of the Poggendorff effect were assessed by comparing the degree of angular distortion induced by modified and traditional configurations. Assimilation theory predicted that the traditional effect would be reversed in modified configurations. Analysis showed that the effect, although reduced in magnitude, was not reversed. Comparison of the degree of the effect induced by modified and traditional configurations indicated that a substantial portion of the Poggendorff effect was due to processing of areas between the long vertical lines of the display. This finding is not consistent with theories based on subjective distortion of angles. It was concluded that a theory of the Poggendorff effect must include processing of internal areas of the configuration.

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