Handedness in infants' tool use.

In this study, we investigated whether hand preference influences infants' choice of what hand to use in grasping a new tool presented at the midline, and whether this will change in the course of learning the functionality of a tool. The tool was a rake within reach placed beside an out-of-reach toy presented either to its right or to its left. Forty-eight infants from 16 to 22 months of age were tested. The results show that use of the right-preferred hand to grasp the rake is strong as of 16 months of age and does not change significantly with age in the condition where using the right hand leads to a better outcome than using the left hand. In the condition where using the left-non-preferred hand makes toy retrieval easier, infants increasingly use the left hand with age. Thus, when grasping the tool, younger infants are more influenced by their hand preference than older infants, who are better at anticipating the most successful strategies.