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