MEASURING SIZE CONSTANCY AND THE MOON ILLUSION

  • Helen E. Ross

Abstract


Improvements in measuring size constancy and the moon illusion have come with developments in apparatus and statistics, producing better agreement on the factors affecting size perception. However, there is little agreement on whether size and distance are processed in parallel or whether distance is processed before size. Recent developments include the interpretation of measures of variability in addition to mean values. It has been argued that lower variability implies fewer stages of brain processing, but experimental results are hard to interpret. Neurophysiological studies using fMRI and evoked potentials suggest that the perceived size enlargement caused by geometrical illusions is represented in the primary visual cortex. This is consistent with other evidence that observers with normal binocular vision do not have access to information about true angular size.
Section
Full Articles