Touch and vision in normal and Down's syndrome babies.
Two experiments are reported with young Down's syndrome and normal children matched for mental age, sex, and social class. In one, Down's syndrome children performed at chance level on two tactual--visual cross-modal tasks, and only the oldest succeeded with one of two visual--visual within-modal tasks. The modal children performed at above chance level on the visual--visual tasks, and on the tactual--visual tasks the oldest succeeded on two and the youngest on one of the tasks. These results suggest that Down's syndrome children may have some sort of difficulty involving tactual perception. The second experiment examined the effect of touch on visual behaviour. Down's syndrome children and their matched controls looked at pairs of shapes which sometimes could be touched and sometimes could not. In the former condition the Down's syndrome children touched less, and looking and touching was less coordinated than that of normal children. However, both groups made fewer but longer looks when they could touch the shapes. In the light of these results the role of tactual perception in Down's syndrome children is discussed.