Preprogramming, programming and reprogramming of aimed hand movements as a function of age.

The present experiments were conducted to investigate the relationship between age and the response programming operations underlying the execution of a ballistic motor act. In an initial experiment, two separate age groups of female subjects (mean ages of 21.9 and 69.1 years) performed aimed-movements of the right hand and arm in one of two movement directions (left or right), under preprogramming, programming, and reprogramming conditions. These operations were examined by providing advance information about the direction of an impending movement and manipulating the degree of correspondence between the advance information and a subsequent reaction signal. The results indicated that subjects in the older age group reacted and moved more slowly than subjects in the younger age group, however, there was no interaction between age and the three response programming conditions. Such findings indicated that the basic operational characteristics of these processes remain unaffected with advancing chronological age. Also, irrespective of age and response programming condition, responses to the right were initiated faster than responses to the left. This difference was especially accentuated for reprogramming. A second experiment, using a new stimulus-response mapping, replicated the left-right difference in initiation time; this difference was reversed when the left hand was used to execute the designated movement, indicating that this finding is indeed a response programming phenomenon. Further discussion focused on the possible operations underlying reprogramming.