No abstract

When adults reach for an object, kinematic measures of their approach movement are affected by what they intend to do after grasping it. We examined whether such future intended actions would be reflected in the approach-to-grasp phase of infant reaching. Twenty-one 10-month-old infants were encouraged to either throw a ball into a tub or fit it down a tube. Kinematic measures of the approach phase of the reach toward the ball were obtained using a motion analysis system. Infants, like adults, reached for the ball faster if they were going to subsequently throw it as opposed to using it in the precision action. The perceptual aspects of the ball were the same and cannot account for these kinematic differences. Infants appear to be planning both segments of their actions in advance. Our findings provide evidence for a level of sophistication in infant motor planning not reported before.

No abstract

Routine activities performed while standing and walking require the ability to appropriately and continuously modulate postural movements as a function of a concurrent task. Changes in task-dependent postural control contribute to the emergence, maturation, and decline of complex motor skills and stability throughout the lifespan.

Toddlers grasp a tool more effectively when it is self-directed (e.g., spoon) than other-directed (e.g., hammer), possibly because the consequences of self-directed actions are more obvious. When the negative consequences of an inefficient grip were made equally salient, the self-versus other-directed differences remained.