SENSITIVITY TO TEXTURAL STATISTICS AFFECTS THE PERCEIVED SIZE OF A VISUAL OBJECT
Human vision exhibits peculiar sensitivity to specific global properties of visual stimuli. Visual objects are characterised by statistical textural properties, resulting in their surface appearance Texture grain provides information on the material composition of a visual object and can affect its perceived size. According to the Oppel-Kundt illusion, an area articulated in subparts appears larger than an empty one. Adopting a quantitative approach, we tested the perceived extension of and articulation of subparts (checkboards vs. random order) systematically varied. An illusory increment of area extension was generally found with textured stimuli. The perceptual enlargement increased with spatial frequency and decreased independent analysis of the two basic properties. An ordered arrangement of subparts (as in checkboards) provided a larger effect than a random articulation. Those results demonstrate the relevance of processing textural statistics on perceiving the size of visual objects.