Effect of practice versus information on the visual illusion.
OBJECTIVE
The Muller-Lyer illusion is a visual illusion in which a horizontal shaft with an inward-pointing chevron (fins-out) affixed to each end is perceived longer than a shaft with outward-pointing chevrons (fins-in). The goal of this study was to compare the effects of experience and knowledge about the Muller-Lyer illusion on participants' perceptual precision.


METHODS
Participants were undergraduate students (n = 108) who were not familiar with the Muller-Lyer illusion prior to the experiment. The task of participants was to adjust one movable line to make it equal to the other in Muller-Lyer figure. They received ascending and descending Muller-Lyer trials in three blocks with 20 trials each. The Experimental Group received information about the Muller-Lyer illusion prior to the third block.


RESULTS
For the Experimental Group, the amount of departure in Block 3 was reduced significantly compared with previous blocks.


CONCLUSIONS
Knowledge about the mechanisms underlying visual illusions may play an important role in helping individuals overcome them.
Khorasani
Abbas A
AA
Mashhad Medical Sciences University, Mashhad, Iran.
Fadardi
Javad S
JS
Fadardi
Marziyeh S
MS
Cox
W Miles
WM
Sharif
Jafar T
JT
D000328:Adult; D001921:Brain / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007088:Illusions / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation; D012727:Sex Characteristics; D014796:Visual Perception / Q000502:physiology*