Alterations in Movement Dynamics in a Tool-Use Task

Abstract

This research evaluated how the inertial properties of a tool influence tool-using actions. Grip patterns and movements of 3-, 4-, and 5-year-old children and adults were recorded while hammering. Results revealed that both number of pegs driven and movement amplitude increased developmentally and changed as a function of inertial properties of the tool but other aspects of motor control (i.e., period, grip position) did not. This suggests that both children and adults were able to discriminate and modulate only those parameters that had the largest impact on performance (i.e., the delivery of force with the hammer). Even though the ability to adjust tool movements as tool characteristics change is evident during preschool years, the ability to do so did not reach adult levels and appears to continue to develop beyond preschool.