Dissociating absolute and relative reward- and punishment-related electrocortical processing: An event-related potential study.

The meaning of reward and punishment signals depends on context. Receiving a small reward where a larger reward could have been obtained can be considered a punishment, while a small loss in the context of avoiding a larger loss can be experienced as a reward. The aim of this study was to investigate the electrophysiological processes associated with absolute and relative reward and punishment signals. Twenty healthy right-handed volunteers performed a decision-making task and were instructed to judge which of two neutral objects was the most expensive. The received outcome was presented together with the non-received outcome for the alternative choice. The feedback-related potentials P200, FRN and P300 were recorded in response to absolute (i.e., received) outcome and relative (i.e., received in the context of the alternative) outcome. Absolute rewards yielded higher P200 amplitudes as compared to relative rewards, while the P200 amplitude was largest for relative as compared to absolute punishments. The P300 amplitude showed a main effect of valence with larger amplitudes for more positive relative and absolute outcomes. No effect of absolute or relative outcome was observed for the feedback-related negativity (FRN). Our findings suggest distinct processes associated with context-dependent and context-independent processing during feedback processing.