The ‘seeing‐leads‐to‐knowing’ deficit in autism: The Pratt and Bryant probe

This study retests the findings by Leslie & Frith (1988) and Perner, Frith, Leslie & Leekam (1989) that children with autism have a specific difficulty in understanding the principle that ‘seeing leads to knowing’. It extends the earlier work by including a control group of subjects with mental handicap, and by using a simpler method, derived from Pratt & Bryant (1990). Despite these modifications, a very similar result was found: while 75 per cent of the subjects with mental handicap passed this test, only 33 per cent of the subjects with autism did so. This more stringent retest suggests this result is robust.