Abstract
Dakin and Herbert (1998) showed that symmetry detection relies predominantly on stimulus information from a limited region around the symmetry axis. Rainville and Kingdom (2002) showed that this so-called integration region (IR) scales with stimulus density such that the amount of information in the IR is constant. We investigated whether this constancy applies to the amount of raw stimulus information or to the amount of nonredundant information that, from an information-theoretic perspective, remains after perceptual processing. We tested the effect of global redundancy using stimuli featuring one, two, or four symmetry axes, and we tested the effect of local redundancy by introducing local correlations such as co-orientation of elements. Results show that the IR scales with both local and global redundancy. This suggests that the visual system is capable of integrating more information if the information is redundant.