EFFECTS OF AGE AND TASK SIMILARITY ON DUAL-TASK PERFORMANCE

When a dual tracking task consisting of two incoherent (uncorrelated) subtasks is partly integrated, such that it is characterized by incomp atibility of similarity, or when axis similarity of subtasks is high, it may be difficult to map subtask stimuli to the proper responses. Es pecially for older adults, an increase in mapping demands may be a sou rce of confusion (cross talk). In the present experiment this issue wa s addressed with a dual task consisting of two unrelated one-dimension al compensatory tracking tasks with position dynamics. Task performanc e was measured in terms of root mean square tracking error and cross-a xial correlations. Tracking error data were consistent with the hypoth esis that older subjects are penalized when there is incompatibility b etween control and display integration. In general, negative effects o f incompatibility of integrality were the greatest when partial integr ation involved integration of the response component. Both performance measures indicated that with increasing incoherent similarity, task p erformance of the old subjects was more hampered than was that of thei r young counterparts.