Journals of Gerontology Series B: Psychological Sciences and Social Sciences, Vol 52, Issue 1 P40-P52, Copyright © 1997 by The Gerontological Society of America
Age-related differences in movement control: adjusting submovement structure to optimize performance
N Walker, DA Philbin and AD Fisk
School of Psychology, Georgia Institute of Technology, Atlanta 30332- 0170, USA.
In this experiment older and younger adults were compared on their ability
to position a cursor with an electromechanical mouse. Distance of the
movement, size of the target, and relative emphasis on the speed or
accuracy of the movement were manipulated. The study was designed to
isolate and evaluate the effects of age-related differences in the
noise-to-force ratio, perceptual feedback efficiency, strategy differences,
and the ability to produce force as explanations for age- related
differences in movement control. This was done by using two types of
movement tasks and by analyzing movement performance according to stages of
movement. The study showed that all four factors, when isolated, are
significantly different for the two age groups. However, in the task
component where all factors could simultaneously affect performance, the
age-related difference in performance was less than the difference in
either the measure of noise-to-force ratio or perceptual efficiency.
Analysis of the submovement structure revealed how older adults compensated
for the greater noise and less perceptual efficiency by adjusting the
velocity and number of submovements. These findings are discussed in light
of the optimized submovement model.
