 (2005) demonstrated that older people were able to distinguish the motion of high-contrast stimuli quicker than younger adults, and that inhibition was responsible for differences in spatial suppression.Karas and McKendrick (2009) used the Chubb illusion to test whether high contrast backgrounds affected the visual perceptions of older participants lesser than the younger participants owing to reduced inhibition.The stimuli used for the experiments were based on the parameters used by Dakin, Carlin and Hemsley (2005), who used the Chubb illusion to check for reduced inhibition in schizophrenics.