Developmental aspects of the control of manual aiming movements in aligned and non-aligned visual displays.

The goal of the present study was to determine for children and adults whether practice of a manual aiming task performed on a vertical computer display by moving a mouse facilitates performance of the same task but with a different display orientation. Children (6, 7-8, and 9-10 year olds) and adults practiced a video aiming task using a vertical display. Prior to and after this practice phase, they performed the same task but this time using a horizontal display simulating aiming performance in a normal environment. For all age groups, the results indicated that, on the amplitude component of the task, what has been learned with a vertical display transferred positively to performance of the same task with a horizontal display. No transfer, either positive or negative, was noted on the direction component of the task. A kinematic analysis of the participants' aiming movements revealed that the positive transfer noted on the amplitude component of the task resulted from positive transfer occurring for both the response planning and the motor control processes. Also differences in aiming performance noted between the children and the adults were caused by both more efficient movement planning and online control processes. Finally, the kinematic analysis revealed that both children and adults were able to modulate online their initial movement impulse, providing evidence of continuous or pseudo-continuous movement control based on visual afferent information.