Effects of aging on switching the response direction of pro- and antisaccades.

The present study investigated effects of task switching between pro- and antisaccades and switching the direction of these saccades (response switching) on performance of younger and older adults. Participants performed single-task blocks, in which only pro- or only antisaccades had to be made as well as mixed-task blocks, in which pro- and antisaccades were required. Analysis of specific task switch effects in the mixed-task blocks showed switch costs for error rates for prosaccades for both groups, suggesting that antisaccade task rules persisted and affected the following prosaccade. The comparison between single- and mixed-task blocks showed that mixing costs were either equal or smaller for older than younger participants, indicating that the older participants were well able to keep task sets in working memory. The most prominent age difference that was observed for response switching was that for the older but not younger group task switching and response switching interacted, resulting in less errors when two consecutive antisaccades were made in the same direction. This finding is best explained with a facilitation of these consecutive antisaccades. The present study clearly demonstrated the impact of response switching and a difference between age groups, underlining the importance of considering this factor when investigating pro- and antisaccades, especially antisaccades, and when investigating task switching and aging.