Are children with Down syndrome susceptible to visual illusions?

Abstract

We know surprisingly little about how the perception of visual illusions develops on children with intellectual disabilities (ID). The aim of the present study was to determine the specificity of the visual perception deficit to different groups of children with ID. We compared 23 children with Down syndrome (DS) and 42 mental age-matched children with non-specific ID on two classes of illusory perception, one involving visual illusions of perceptual constancy, and the other ambiguous figures. The results clearly showed that children with DS performed more poorly than the children with non-specific ID only on the ambiguous figures tasks. The findings are discussed in terms of the specificity of the etiology-related cognitive profiles of ID groups.