Alterations in Muller-Lyer Illusion Magnitude With Functional Fovea Placement Changes

2004 ◽  
Author(s):  
Clare K. Porac ◽  
Alan Searleman
Keyword(s):  
Illusion Magnitude ◽  
Lyer Illusion

Decrement and the Illusions of the Mueller-Lyer Figure

1994 ◽  
Vol 79 (2) ◽  
pp. 707-717 ◽  
Author(s):  
Clare Porac
Keyword(s):  
Perceptual Learning ◽  
Illusion Magnitude ◽  
Group Level ◽  
Illusion Decrement ◽  
Significant Time ◽  
Lyer Illusion ◽  
Significant Decrement ◽  
Level Data

Decrement, a time-related decrease in the magnitude of the Mueller-Lyer illusion, was measured separately for the wings-out and the wings-in variants of the Mueller-Lyer figure. There were significant reductions of wings-out illusion magnitude during the decrement period. Observers viewing the wings-in segment showed a non-significant decrement pattern. Analyses of individual decrement patterns showed that illusion magnitude did not decrease for a number of observers even when there were significant time-related trends at the group level. Data for 80 observers imply that the mechanisms of perceptual learning proposed by previous models of Mueller-Lyer illusion decrement are not sufficient explanations of the decrement process.

Iris Pigmentation and Visual-Geometric Illusions

Perception ◽  
1978 ◽  
Vol 7 (4) ◽  
pp. 473-477 ◽  
Author(s):  
Stanley Coren ◽  
Clare Porac
Keyword(s):  
Retinal Image ◽  
Scattered Light ◽  
Illusion Magnitude ◽  
Ebbinghaus Illusion ◽  
Image Degradation ◽  
Lyer Illusion ◽  
Iris Pigmentation ◽  
Line Elements

Blur or degrading of the retinal image has been shown to be a factor in the formation of visual-geometric illusions where intersecting line elements are present. Light irises allow more scattered light within the eye, which results in more image degradation than found in dark-eyed subjects. Measurements on 755 observers show that illusion magnitude varies as a function of iris pigmentation for a configuration with intersecting line elements (Müller — Lyer illusion), but not for a configuration devoid of such features (Ebbinghaus illusion).

Decrement of the Brentano Müller-Lyer Illusion as a Function of Inspection Time

Perception ◽  
1998 ◽  
Vol 27 (2) ◽  
pp. 183-192 ◽  
Author(s):  
John Predebon
Keyword(s):  
Visual Inspection ◽  
Illusion Magnitude ◽  
Inspection Time ◽  
Inspection Period ◽  
Illusion Figure ◽  
Illusion Decrement ◽  
Lyer Illusion ◽  
Time Period ◽  
Post Test ◽  
Time Periods

Two experiments are reported in which the decline or decrement in the magnitude of the Brentano Müller-Lyer illusion was measured. Observers made a pre-test judgment and, after a variable intervening time period, a post-test judgment of illusion magnitude. In experiment 1, the intervening time periods were 1, 2, and 3 min during which time the independent groups of observers allocated to each of the three time periods either systematically scanned the Brentano figure (inspection conditions) or waited until the intervening period had elapsed (no-inspection conditions). Experiment 2, which included an additional 5 min intervening time period, evaluated a response-bias explanation for the results of the inspection conditions of experiment 1. Taken together, the findings of the two experiments indicate that sheer inspection of the Brentano figure produces illusion decrement. However, illusion decrement was independent of the duration of the inspection period, with equivalent amounts of decrement occurring across the range of viewing times examined in the two experiments. The pattern of these results suggests that theories of Müller-Lyer decrement must incorporate a factor attributable to, or correlated with, inspection time, whose effect in reducing illusion magnitude is confined mainly to the first 1 or 2 min of active visual inspection of the Brentano illusion figure.

The Role of the Angle Components in the Wings-in and Wings-out Forms of the Müller-Lyer Illusion

Perception ◽  
1996 ◽  
Vol 25 (7) ◽  
pp. 773-781 ◽  
Author(s):  
John Predebon
Keyword(s):  
Illusion Magnitude ◽  
Paired Comparisons ◽  
Lyer Illusion ◽  
Psychological Continuum ◽  
Method Of Paired Comparisons ◽  
Good Agreement

The effect of selective amputations of the angle components in the wings-in (underestimated) and wings-out (overestimated) forms of the Müller-Lyer illusion was examined in two experiments. The stimulus figures consisted of one, two, or four angles. In experiment 1 the method of paired comparisons was used to scale the figures on the psychological continuum of length, and in experiment 2 the method of reproduction was used to obtain quantitative measures of illusion magnitude. There was good agreement between the scaling and the length-reproduction measures of the illusion. The illusory effects in all figures were significant, and the extent of the underestimation and overestimation of the wings-in and wings-out figures, respectively, increased as the number of angles increased. In general, selective amputation of the angle components produced similar patterns of illusory effects in the wings-in and wings-out figures. These findings are discussed with reference to the issue of whether the two forms of the conventional (ie four-angle) Müller-Lyer illusion are similar or distinct illusion types.

People Are Less Susceptible to Illusion When They Use Their Hands to Communicate Rather Than Estimate

2021 ◽  
pp. 095679762199155
Author(s):  
Amanda R. Brown ◽  
Wim Pouw ◽  
Diane Brentari ◽  
Susan Goldin-Meadow
Keyword(s):  
American Sign Language ◽  
Sign Language ◽  
English Speakers ◽  
American Sign ◽  
Estimation Task ◽  
Sign Languages ◽  
Lyer Illusion ◽  
Description Task ◽  
The Way

When we use our hands to estimate the length of a stick in the Müller-Lyer illusion, we are highly susceptible to the illusion. But when we prepare to act on sticks under the same conditions, we are significantly less susceptible. Here, we asked whether people are susceptible to illusion when they use their hands not to act on objects but to describe them in spontaneous co-speech gestures or conventional sign languages of the deaf. Thirty-two English speakers and 13 American Sign Language signers used their hands to act on, estimate the length of, and describe sticks eliciting the Müller-Lyer illusion. For both gesture and sign, the magnitude of illusion in the description task was smaller than the magnitude of illusion in the estimation task and not different from the magnitude of illusion in the action task. The mechanisms responsible for producing gesture in speech and sign thus appear to operate not on percepts involved in estimation but on percepts derived from the way we act on objects.

scholarly journals The Influence of Exploration Mode, Orientation, and Configuration on the Haptic Müller-Lyer Illusion

Perception ◽  
10.1068/p5269 ◽  
2005 ◽  
Vol 34 (12) ◽  
pp. 1475-1500 ◽  
Author(s):  
Morton A Heller ◽  
Melissa McCarthy ◽  
Jennifer Schultz ◽  
Jayme Greene ◽  
Melissa Shanley ◽  
...  
Keyword(s):  
Index Finger ◽  
Spatial Position ◽  
Lyer Illusion ◽  
Free Exploration ◽  
And Control ◽  
The Impact ◽  
Practical Implications

We studied the impact of manner of exploration, orientation, spatial position, and configuration on the haptic Müller-Lyer illusion. Blindfolded sighted subjects felt raised-line Müller-Lyer and control stimuli. The stimuli were felt by tracing with the index finger, free exploration, grasping with the index finger and thumb, or by measuring with the use of any two or more fingers. For haptic judgments of extent a sliding tangible ruler was used. The illusion was present in all exploration conditions, with overestimation of the wings-out compared to wings-in stimuli. Tracing with the index finger reduced the magnitude of the illusion. However, tracing and grasping induced an overall underestimation of size. The illusion was greatly attenuated when stimuli were felt with the index fingers of both hands. Illusory misperception was not altered by the position in space of the Müller-Lyer stimuli. No effects of changes in the thickness of the line shaft were found, but there were effects of the length of the wing endings for the smaller, 5.1 cm stimuli. The theoretical and practical implications of the results are discussed.

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