Recognition of Shapes across Modalities by Infants

HUMAN adults and children as young as four years can recognize two identical objects as equivalent when they touch one and see the other 1–3 . It is not yet known what mechanisms underlie this cross-modal ability. One suggestion 4–6 has been that humans are able to match identical objects cross-modally because they can give the visual and tactual objects the same name. This hypothesis has recently been questioned 7 , and an experiment which showed that chimpanzees and orang-outangs can to some extent match shapes cross-modally 8 makes it improbable that cross-modal mechanisms need always be based on language. But it may still be true that humans have to be able to attach common verbal labels to visual and tactual inputs in order to treat them as the same.