The Use of Signal Detection Theory in Research on Age-Related Differences in Movement Control
Neff Walker David A. Philbin Christopher Spruell Georgia Institute of Technology
One truism about the effects of aging on performance is that physical movement skills decline from middle age onwards. A passing knowledge of professional sports makes clear that few people can function at the same high level of performance after age 35, and those that do tend to rely on "guile" to compensate for their "lost physical abilities."
Though we know that age-related differences in movement performance exist, the exact nature of the differences, much less their cause, is far from clear. One explanation for lower performance is based on loss of strength or muscle mass as one ages. An extensive body of research exists showing that for average adults muscle mass and strength drop off after age 40 ( Aniansson, Sperling, Rundgren, & Lehnberg, 1983; Fisher & Birren, 1947; Norris & Shock, 1960). For many movement skills, this loss in strength could explain performance differences, but this explanation is far from complete. Research has also shown that even though loss of strength is normal with aging, this loss can be reduced or even stopped with increased exercise. Research shows, however, that even with increased exercise, performance seems to suffer as age increases ( Frontera, Meredith, O'Reilly, Knuttgen, & Evans, 1988; Moritani & deVries, 1980).
Movement performance decrements also occur for tasks in which strength does not seem to be a limiting factor. In golf, for example, even though strength plays some role in determining performance, the age-related drop in performance is more often ascribed to nonstrength decrements. The execution of "Yips" in putting (a task related more to fine motor control than to strength) rather than of "driving" the shorter