A multiple-task environment requires an individual to perform two or more tasks at the same time, usually under a time limit for overall task performance. Everyday examples of multiple tasks include driving an automobile in an unfamiliar city and using various computer software programs. In this study, younger and older adult participants performed a dynamic multiple-task requiring concurrent processing of four independent tasks. Component-task performance emphasis (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.
Abstract