Time and intensity as determiners of perceived shape.

The purpose of the present study is to analyze the role of exposure duration and luminance as determiners of the extent to which constancy occurs. To this end, the functional relation between the matched shape of an obliquely viewed disc and the exposure duration is determined. The effect of luminance is investigated in view of the reciprocal relation between exposure time and luminance below the critical duration of about .1 sec. and the general importance of luminance as a variable in vision. The results indicate that an exposure longer than the critical duration is required for maximum shape constancy. As a check on the possibility that this may be the result of an experimental artifact, eye-movement records were taken while subjects were making shape judgments. (PsycINFO Database Record (c) 2006 APA, all rights reserved)