Awareness is necessary for attentional biases by location-reward association.

Many studies have reported attentional biases based on feature-reward associations. However, the effects of location-reward associations on attentional selection remain less well-understood. Unlike feature cases, a previous study that induced participants' awareness of the location-reward association by instructing them to look for a high-reward location has suggested the critical role of goal-driven manipulations in such associations. In this study, we investigated whether the reward effect occurred without goal-driven manipulations if participants were spontaneously aware of the location-reward association. We conducted three experiments using a visual search task that included four circles where participants received rewards; one possible target location was associated with a high reward, and another with a low reward. In Experiment 1, the target was presented among distractors, and participants had to search for the target. The results showed a faster reaction time in the high-reward rather than the low-reward locations only in participants aware of the location-reward association, even if they were not required to look for the association. Moreover, in Experiment 2, we replicated the main findings of Experiment 1, even when the target had an abrupt visual onset to restrict goal-driven manipulations. Furthermore, Experiment 3 confirmed that the effect observed in Experiment 2 could not be attributed to the initial eye position. These findings suggest that goal-driven manipulations are unnecessary for inducing reward biases to high-reward locations. We concluded that awareness of the association rather than goal-driven manipulations is crucial for the location-reward effect.