Figure-ground perception and random geometry

Abstract

Constructs of random geometry were applied to the problem of figure-ground perception. Random-dot images of black and white dots with various area fractions and tesselations (square and triangular lattices) were used as stimuli. The constructs of random geometry are correlation functions of n-th order and some functionals defined on them. The only parameter which is independent of the tesselation used is the first-order correlation which is the area fraction. It was first conjectured and then experimentally verified that figure-ground perception is not affected by the various tesselations used. Thus, figure-ground phenomena depend only on the area fraction of the white and black dots in the stimulus. There is a perceptual bias for white, that is, figure-ground reversal is easiest at 40 percent white-black area fraction. It was also experimentally shown that size-constancy prevails in figure-ground perception, but brightness-constancy does not.