Shared spatial attention for action selection and action monitoring

• Main Author: Mahon, Aoife
• Published: University of Aberdeen 2017
• Subjects: 150; Perceptual-motor processes
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731612

Dual-task studies have shown higher sensitivity for stimuli presented at the targets of upcoming actions. Generally, movement outcome feedback is also obtained at action targets. This thesis examined whether attention is directed to action targets for the purpose of action selection, as previously concluded, or if attention is directed to monitor feedback about movement outcomes as supported by skilled-action research. Across seven experiments, participants executed either a pointing movement (Experiments 1 – 5) or a saccade (Experiments 6 and 7), while simultaneously identifying a discrimination target ('E' or '3') among distractors (2s and 5s). Action targets were generally cued by a central arrow. Discrimination target identification accuracy measured attention allocation. Crucially, movement accuracy feedback was presented at a spatially separate location from the action target. It was found that during the planning of goal-directed actions, attention is allocated to monitor movement outcomes, even if this information is provided at a spatially separate location from the action target. Attending the separate feedback location resulted in slower reaction times and less accurate pointing. Clear and consistent perceptual enhancement was also demonstrated at the action target location, even when no intrinsic or extrinsic feedback about the action could have been gained from attending there. Specific to saccades, it was found that attention is allocated before saccade execution to both the saccade goal and to the predicted future retinal location of feedback information. Lastly, perceptual performance is greater in general when participants perform the dual-task visually open-loop, that is without visual feedback from the moving hand. These results are novel in showing that attention appears to be required for action target selection, independently of the need to monitor expected locations of feedback.