Abstract
Reward-related midbrain dopamine is thought to guide animal behavior, motivating approach towards objects associated with reward and away from objects unlikely to be beneficial. We have recently conducted a series of experiments that suggest the dopamine system implements a similar principle in the deployment of covert attention in humans. This work shows that participants automatically attend to an object characterized by features recently associated with monetary reward. We call this reward priming. Using event-related potentials, we have demonstrated that the strength of reward priming in a given subject is predicted by the magnitude of neural response to positive feedback in anterior cingulate cortex (ACC), a brain area known to be a part of the dopamine reinforcement circuit. Those subjects who show a strong ACC response to reward are also those who show a strong bias to select reward-conditioned stimuli. This has led us to suggest that reward priming may be determined by reward-seeking or reward-sensitivity personality traits; some participants may attribute positive feedback with greater motivational valence, resulting in a stronger bias to select reward-conditioned stimuli. Here we present results that confirm this hypothesis. We had participants complete a personality inventory, the BIS/BAS scale, prior to completing a visual search task designed to measure reward priming. High scores on a reward-seeking subscale of the BIS/BAS strongly and reliably predicted the magnitude of the subsequent reward priming effect. These results both link trait reward-seeking to the dopamine reward circuit, and ACC specifically, and illustrate the important role reward plays in attentional control.