Visual control of manual aiming movements in 6- to 10-year-old children and adults

Recent results indicate that adults modulate their initial movement impulse toward a stationary visual target by processing visual afferent information. The authors investigated whether the mechanisms responsible for those modulations are already in place in young children or develop as the children grow older. Adults (n = 10) and 6-, 8- and 10-year-old children (ns = 6, 7, and 7, respectively) performed a video-aiming task while vision of the cursor they were moving was (acquisition) or was not (transfer) visible. The results indicated that within-participant variability of the initial impulse trajectory of the children's aiming movement leveled-off in acquisition between peak extent deceleration and the end of the initial impulse, whereas it increased linearly as movement unfolded in transfer. The results also indicated that children modulate their initial movement impulse when visual afferent information is available, although to a lesser extent than adults do, and strongly imply that contrary to past suggestions, the initial impulse of an aiming movement is not ballistic.