The distribution of spatial attention changes with task demands during goal-directed reaching

Goal-directed movements are commonly used to allow humans to interact with their environment. When making a goal-directed movement in a natural environment, there are many competing stimuli. It is therefore important to understand how making a goal-directed movement could be impacted by the need to divide attention between the movement and competing stimuli. We used a dual-task paradigm to investigate the sharing of attentional resources between a search task in central vision and a peripheral pointing task completed concurrently. Results suggest some degree of shared attentional resources between these two tasks with performance on both central and peripheral tasks degraded under dual-task conditions. Movement latency, but not movement time, was also affected by dual-task conditions. Altogether, the results suggest that there is a cost to reach performance if attention is engaged away from the movement goal. Interestingly, this cost is associated with movement planning rather than execution.