Priming by motivationally salient distractors produces hemispheric asymmetries in visual processing

Stimuli that reliably herald the availability of rewards or punishers can acquire value associations, potentially imbuing them with emotional significance and attentional prioritization. Previous work has shown that an emotional stimulus (prime) presented just prior to an attention-demanding task disrupts performance in a lateralized manner that is independent of the prime's emotional valence. Here, we asked whether neutral stimuli with acquired value associations would similarly disrupt attention. In two experiments, adult participants first learned to associate specific face or chair stimuli with a high or low probability of either winning or losing points. These conditioned stimuli then served as primes in a speeded letter-search task. Primes with high versus low outcome probability, regardless of valence, slowed search for targets appearing in the left but not the right visual hemifield, mirroring previous results using emotional primes, and suggesting that motivational mechanisms that compete for control with non-emotional cognitive processes are right-lateralized in the human brain.