Two coincident-timing experiments examined the role of three different target velocities and display extents and three age levels of normal and retarded children. Subjects made a ballistic response to a target moving horizontally across their visual field. In the first experiment there were generally no clear differences between normal and retarded children on the task, with subjects having difficulty for both the slow and fast target speeds. In the second experiment, with target velocity held constant, no significant differences were reported between normal and handicapped children, although the longer the subjects were allowed to view the target the more accurate they were. The data were discussed in terms of the response strategies to perform anticipatory ballistic movements. An ecological issue was raised which suggested that children as well as adults make their most accurate anticipations when confronted with velocity problems that have been experienced in their everyday world.
Bibliographical noteFunding Information:
This research was supported by NICHHD Program Project Grant No. HD05951 to the Center for the Study of Reading, University of Illinois at Urbana-Champaign. The author would like to thank Karl Newell and Stephanie Blackett for comments on earlier drafts of· this paper and the anonymous reviewer and editor of the Journal of Motor Behavior for help with the revision. Reprint requests should be sent to Dr. M.G. Wade, Leisure Behavior Research Laboratory, #1 Institute for Child Behavior and Development, 51 Gerty Drive, University of Illinois, Champaign, I L 61820.