Age-related changes in task-switching components: The role of task uncertainity

The present study examined age differences in executive functioning, using an externally cued task-switching paradigm. Two components of task switching were assessed: the ability to maintain and select among task sets (general switch costs) and the ability to switch between task sets (specific switch costs). In contrast to previous findings, we found large age-related differences in specific switch costs, especially when the number of potentially relevant task sets is increased from two to four. Age-related differences in general switch costs were absent when external task cues subserved executive processing in task switching. Generally, the find-ings suggest that age-related impairments in task-switching components vary as a function of task uncertainty, such as the presence of environmental prompts to behavior. ª 2002 Elsevier Science (USA) Key Words: aging; executive control; attention; task switching; cognition; environmental prompts; task uncertainty. In recent years, cognitive aging researchers have become increasingly interested in whether age-related differences in executive functioning may contribute to an un-derstanding of age-related decline in various intellectual abilities such as fluid intelli