Younger and older adult participants performed a dynamic multiple-task requ
iring concurrent processing of 4 independent tasks. Component-task performa
nce emphasis (i.e., task priorities) was biased by differential point alloc
ations across task components. After training, the point structure was modi
fied. Older adults exhibited larger multiple-task performance deficits comp
ared with younger adults; however the age-related gap in multiple-task perf
ormance decreased with practice. The age-related performance difference inc
reased again when task emphasis was changed, but not when demands were chan
ged. Consistent with the training data, the age-related differences diminis
hed again with additional experience on this new task-component emphasis. T
he data suggest that higher-order; strategic processing may be an important
source of age-related differences in complex multiple-task performance. Ac
tual or potential applications of this research include the facilitation of
techniques for age-related comprehensive usability testing for products of
even moderate complexity.