Abstract
While there is evidence that attention is deployed to a movement goal, it is not clear how deployment of attention changes with task demands or how it affects movement outcomes. We investigated the structure of attentional resources during rapid pointing with a dual-task paradigm. Each component of the dual-task was tested separately to establish baselines, enabling comparison of single and dual-task conditions. The perceptual task was an alphanumeric search task presented at central fixation. The target was a letter embedded within a letter string. The goal-directed movement consisted of a rapid point made to a touchscreen. The target was a small, high contrast dot presented briefly (100ms) at 4 or 8° eccentric to central fixation at one of 8 possible locations with equal probability. The dual-task conditions differed only in when the search task ceased, either at pointing stimulus onset (part reach), or after reach completion (whole reach). At the end of each trial, participants reported how many times the target letter was presented. We measured endpoint accuracy and precision, movement latency and movement time and search task performance. Dual-task conditions generally negatively affected search task performance, indicating a degree of shared resources during movement planning and perception, consistent with previous results. The greatest decrease in performance was observed between baseline and whole reach conditions, indicating that ending the search task during movement planning (part reach) had less impact on search performance than task continuation. Pointing accuracy and precision were not significantly different between conditions. Movement latency increased in the dual-task conditions, while there was no significant difference in reach times. Results suggest there is a cost to reach performance if attention is engaged away from the reach goal but this cost is associated with movement planning rather than execution.
Meeting abstract presented at VSS 2012