Age-related performance in a multiple-task environment.

Younger and older adult participants performed a dynamic multiple-task requiring concurrent processing of 4 independent tasks. Component-task performance emphasis (i.e., task priorities) was biased by differential point allocations across task components. After training, the point structure was modified. Older adults exhibited larger multiple-task performance deficits compared with younger adults; however, the age-related gap in multiple-task performance decreased with practice. The age-related performance difference increased again when task emphasis was changed, but not when demands were changed. Consistent with the training data, the age-related differences diminished again with additional experience on this new task-component emphasis. The data suggest that higher-order, strategic processing may be an important source of age-related differences in complex multiple-task performance. Actual or potential applications of this research include the facilitation of techniques for age-related comprehensive usability testing for products of even moderate complexity.