Effects of adult aging on the movement complexity factor of response programming.

The interaction effects between adult aging and incremental levels of movement complexity were studied in young, middle-aged, and older healthy females. Utilizing a two-choice reaction time (RT) paradigm, movement complexity as a factor of response programming was varied in a microswitch pressing task by altering the number of sides of the body and the number of fingers controlled. The speed of response programming was found to be age dependent and to interact with movement complexity across age groups. The results confirmed that as movement complexity increases, the effects of adult aging on RT increase. This study further emphasizes the robustness of the movement complexity x age effect, in that older individuals were found to be much more sensitive to small changes in movement complexity than younger subjects. The comparison results of three adult age groups suggested this sensitivity to movement complexity is progressive over the adult life span.