Congenital visual impairment and 'theory of mind'

On theoretical grounds, Hobson (1990) suggested that lack of vision might delay the emergence of so-called 'theory of mind' in congenitally blind children. This prediction was tested using tactile versions of theory of mind tasks devised by Perner, Leekam & Wimmer (1987) and Wimmer & Perner (1983). Twenty-one visually impaired children were group matched for chronological age and verbal intelligence with 21 sighted children. All of the children who participated in the study had mental ages over the age of 4 years. Visually impaired children's performance on the two theory of mind tasks was significantly poorer than that of their sighted peers, but most of the children could make some adjustment to another person's false beliefs. The possible sources and implications of these findings are discussed with reference to accounts of 'theory of mind' development.