The neural mechanisms of affect infusion in social economic decision-making: A mediating role of the anterior insula

► We assessed the neural basis of how sad mood biases interactive economic decisions. ► Receiving unfair monetary offers in a sad mood activated the anterior insula. ► Receiving such offers in a sad mood also activated the anterior cingulate cortex. ► Sad mood was associated with diminished sensitivity in the ventral striatum. ► Insular activation mediated the relationship between sadness and decision-making.