Reaching movements are attracted by stimuli that signal reward

Abstract

When presented with a set of possible reach targets, the movement trajectory can reveal aspects of the underlying competition for action selection. Current goals and physical salience can affect the trajectory of reaching movements to be attracted towards a distractor. Some studies demonstrated that stimuli associated with reward can also cause an attraction when reaching towards the reward stimulus was previously rewarded and the reward stimulus was physically salient. Here we demonstrate that a non-salient stimulus that signals the availability of reward attracts reaching movements even when moving towards it was never necessary nor rewarded. Moreover, the attraction by reward is particularly evident with short-latency movements. We conclude that neither physical salience nor reinforcing the movement towards a stimulus is necessary for reward to gain priority in the selection for action.