Abstract
Research using the antisaccade task, in which participants are requested to look away from a visual stimulus, has demonstrated that the ability to control eye movements may be affected by aging. For correct antisaccades it is essential to inhibit a prepotent response towards a stimulus and to select a saccadic response away from it. When pro- and antisaccades are tested within the same block (mixed-task), task switching between pro- and antisaccades and response switching, e.g., a saccade to the left on one trial and a saccade to the right on the next, are required. We investigated the effects of task switching and response switching on performance of younger and older adults, with a focus on response switching. Participants performed single-task blocks, which required only pro- or only antisaccades and mixed-task blocks, in which pro- and antisaccades were assessed. The most important results were that specific task switch costs were observed for error rates of prosaccades in the mixed-task blocks 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 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 facilitation of consecutive antisaccades. Taken together, the present study clearly demonstrated the impact of response switching and a difference between age groups. This finding underlines that it is important to consider this factor in the antisaccade task, especially when investigating task switching and aging.