Dissociable effects of reward on attentional learning: from passive associations to active monitoring.

Visual selective attention (VSA) is the cognitive function that regulates ongoing processing of retinal input in order forselected representations to gain privileged access to perceptual awareness and guide behavior, facilitating analysis ofcurrently relevant information while suppressing the less relevant input. Recent findings indicate that the deployment ofVSA is shaped according to past outcomes. Targets whose selection has led to rewarding outcomes become relatively easierto select in the future, and distracters that have been ignored with higher gains are more easily discarded. Althoughoutcomes (monetary rewards) were completely predetermined in our prior studies, participants were told that higherrewards would follow more efficient responses. In a new experiment we have eliminated the illusory link betweenperformance and outcomes by informing subjects that rewards were randomly assigned. This trivial yet crucial manipulationled to strikingly different results. Items that were associated more frequently with higher gains became more difficult toignore, regardless of the role (target or distracter) they played when differential rewards were delivered. Therefore, VSA isshaped by two distinct reward-related learning mechanisms: one requiring active monitoring of performance and outcome,and a second one detecting the sheer association between objects in the environment (whether attended or ignored) andthe more-or-less rewarding events that accompany them.