Serotonin and aversive processing in affective and social decision-making

The effects of the neuromodulator serotonin on affect and behavior are so diverse and wide-ranging that characterizing its function has faced substantial challenges. Here we review recent work investigating how serotonin shapes affective and social decision-making in humans, focusing in particular on serotonin's influence on aversive processing. We consider the evidence that serotonin plays a key role in linking so-called Pavlovian aversive predictions with behavioral inhibition, a proposal derived from computational models of value-based decision-making. We evaluate the extent to which a core mechanism connecting serotonin with Pavlovian inhibition can explain diverse effects of serotonin on affective and social decision-making and highlight critical questions for future research.