Aging and executive control in task switching

Theories of cognitive control have proposed a dissociation between automatic or procedural processes that carry out well learned tasks and executive processes that control novel behaviors and coordinate multiple processes and tasks. In the present study we examined age-related differences in an executive control process(es), the ability to rapidly and accurately switch between multiple tasks. Young and old adults were presented with a row of digits and required to judge either the number of elements or the digit value. The RTs after a switch between tasks were compared with RTs obtained in the absence of a switch (i.e. when the same task was performed sequentially for several trials). During the first experimental session the older adults displayed a substantially larger switch cost than did the young adults. However, surprisingly, the old adults showed switch costs equivalent to the young adults after a relatively small amount of practice. These age-equivalent switch costs were maintained over a two month retention period. These results are discussed in terms of general and process-specific conceptualizations of cognitive aging.