Value-based decision-making between affective and non-affective memories.

Affective biases can change how past events are recalled from memory. To capture mechanisms underlying affective memory formation, recall, and bias, we studied value-based decision-making (VBDM) between reward memories encoded in different mood states. Our findings suggest that following discrete affective events, created by large magnitude wins and losses on a Wheel of Fortune (WoF), healthy volunteers display an overall positive memory bias [favoring higher probability shapes learned after a WoF win compared with those learnt after a WoF loss outcome]. During this VBDM process, participants' pupils constrict before decision-onset for higher-value choices, and remained dilated for a sustained period after choice. Sustained pupil dilation was particularly sensitive to the reward values of abstract memories encoded in a positive mood. Taken together, we demonstrate that experimentally induced affective memories are recalled with a positive bias, and pupil-linked central arousal systems are actively engaged during VBDM between affective and non-affective memories.