Open AccessLuminance differences between the figures and background are not necessary for parallel search of a Kanizsa illusory square 1
Author(s) -
TAKAHASHI SHIN’YA,
OHYA KAZUO,
ARAKAWA KEIKO,
TANABE YURI
Publication year - 2007
Publication title -
japanese psychological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 30
eISSN - 1468-5884
pISSN - 0021-5368
DOI - 10.1111/j.1468-5884.2007.00331.x
Subject(s) - luminance , illusion , optical illusion , visual search , psychology , illusory contours , flicker , computer vision , artificial intelligence , optics , mathematics , cognitive psychology , computer science , physics , computer graphics (images)
In order to examine the role of differences in luminance in the early visual processing of the Kanizsa illusion, two experiments employing a visual search task were conducted. In the first experiment, 18 participants detected the target (a configuration generating the Kanizsa illusory square) among a variable number of non‐targets in either a luminance difference (LD) condition or a color difference (CD) condition. In the CD condition, luminance of the green figures and red background were equalized. Participants detected the target as efficiently in the CD condition as in the LD condition, showing the “pop‐out” of the isoluminant Kanizsa illusion. In the second experiment, the possible effect of residual luminance differences in the CD condition was examined. Three participants performed the same visual search task as in Experiment 1 under two isoluminant conditions; one with the equalization of the CIE luminance as in Experiment 1, and the other with equalization by means of minimum flicker photometry. The results showed no difference between the search efficiency in the two conditions. Overall, these results are consistent with previous findings and support the view that the primary generating factor of the Kanizsa illusion is figural information, specifically the two figural cues of alignment and incompletion, not the luminance difference between the figures and the background.