Dopamine Bonuses

First, stimuli that are not associated with reward prediction are known to activate the dopamine system persistently,including in particular stimuli that are novel and salient, or that physically resemble other stimuli that do predict reward (Schultz, 1998). Second, dopamine release is associated with a set of motor effects, such as species-and stimulus-specific approach behaviors, that seem either irrelevant or detrimental to the delivery of reward. We call these unconditional effects. In this paper, we study this apparently anomalous activation of the OA system, suggesting that it multiplexes information about bonuses, potentially including exploration bonuses(Sutton, 1990; Dayan & Sejnowski, 1996) and shaping bonuses (Ng et al, 1999), on top of reward prediction errors. These responses are associated with the unconditional effects of OA, and are part of an attentional system.