Abstract
The role of associative reward learning in guiding feature-based attention and spatial attention is well established. However, no studies have looked at the extent to which reward learning can modulate the direction of saccades during visual search. Here, we introduced a novel reward learning paradigm to examine whether reward-associated directions of eye movements can modulate performance in different visual search tasks. Participants had to fixate a peripheral target before fixating one of four disks that subsequently appeared in each cardinal position. This was followed by reward feedback contingent upon the direction chosen, where one direction consistently yielded a high reward. Thus, reward was tied to the direction of saccades rather than the absolute location of the stimulus fixated. Participants made an average 80.5% and 73.8% of saccades in the high reward direction, collapsed across all trials, for Experiment 1 and 2 respectively, demonstrating robust learning of the task contingencies. In an untimed visual foraging task that followed, which was performed in extinction, participants fixated on disks until a hidden target was revealed (Experiment 1). Early saccades were reliably biased in the previously rewarded-associated direction. However, no directional bias was found in a speeded, shape search task where participants had to fixate a target that could appear in one of four cardinal positions (Experiment 2). Our findings suggest that rewarding directional eye movements biases search patterns in a foraging context in which the location of the target is unknown, but such biases do not effectively compete with feature-based attentional guidance during goal-directed visual search.