BIMANUAL ROLE-DIFFERENTIATED TOY PLAY DURING INFANCY

Role-differentiated bimanual manipulation requires each hand to perfor m different, but complementary, actions on one or more objects. It is usually considered to be a late-developing high-level motor and cognit ive skill involving the coordination of the two hemispheres of the bra in. The frequency of role-differentiated bimanual manipulations was re corded in a longitudinal sample of 24 infants tested at 7, 9, 11, and 13 months during play with 10 different toys. Role differentiation was observed as early as 7 months, and its frequency was unaffected by to y characteristics. Role-differentiated bimanual actions increased with age, and the type of toy did influence the likelihood of eliciting ro le differentiation between 9 and 13 months.