Effect of Psychophysical Method on Measurement of the Müller-Lyer Illusion

1984 ◽  
Vol 58 (3) ◽  
pp. 822-822 ◽  
Author(s):  
Stuart J. Mc Kelvie
1994 ◽  
Vol 13 (4) ◽  
pp. 323-333
Author(s):  
Richard P. Atkinson

This study investigated the differential influences of hypnotic susceptibility on Muller-Lyer illusion difference thresholds in waking and hypnosis using the psychophysical method of constant stimuli. As assessed by the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) and the Group Stanford Hypnotic Susceptibility Scale, Form C (GSHSS:C), sixteen high (scores = 9–12) and sixteen low (scores = 0–3) hypnotizables participated. In counterbalanced sessions of waking and hypnosis, each subject was sequentially exposed to 110 computer-generated Muller-Lyer illusion pairs of comparison stimuli and a standard stimulus. Difference thresholds for high and low hypnotizables did not differ significantly in waking, but were significantly lower for high than low hypnotizables in hypnosis. Difference thresholds were also significantly lower for high hypnotizables in hypnosis than in waking. Low hypnotizables performed similarly in waking and hypnosis.


2021 ◽  
pp. 095679762199155
Author(s):  
Amanda R. Brown ◽  
Wim Pouw ◽  
Diane Brentari ◽  
Susan Goldin-Meadow

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.


2005 ◽  
Vol 22 (3) ◽  
pp. 389-399 ◽  
Author(s):  
Marc Pouliot ◽  
Simon Grondin

One of the features of the auditory system is its ability to efficiently process events that occur in rapid succession. The aim of the present study is to propose a new way of investigating sensitivity to auditory tempo changes. More specifically, it proposes to compare the relative sensitivity (bias) to acceleration and deceleration in both musical and monotonal conditions. Bias was measured with (1) a conventional psychophysical method known as the method of constant stimuli (MCS) and (2) a so-called method of dynamic stimuli (MDS). The latter method consists in responding with a finger press as soon as a near-continual tempo change is detected. With the MCS, there was no preference, as estimated by the point of subjective equality, between acceleration and deceleration in the monotonal condition, but there was a preference in the musical condition that indicated more facility for estimating decelerations than accelerations. The results obtained with the MDS are consistent with the MCS results, given that the response time was faster for decelerations than accelerations in the musical condition but not in the monotonal condition. We conclude that the MDS is a sensitive tool for investigating slight tempo variations.


Perception ◽  
10.1068/p5269 ◽  
2005 ◽  
Vol 34 (12) ◽  
pp. 1475-1500 ◽  
Author(s):  
Morton A Heller ◽  
Melissa McCarthy ◽  
Jennifer Schultz ◽  
Jayme Greene ◽  
Melissa Shanley ◽  
...  

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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