In response to fast offers (A), significantly larger P300 amplitude occurred when offers affected high-, than low-empathy targets (*P = 0.004). However, in response to slow offers (B), no differences in P300 amplitude occurred depending on target empathy (P = 0.53). Moreover (C), P300 amplitude was significantly larger prior to accepting, than rejecting offers (*P < 0.001), indicating that higher amplitude was associated prosocial decisions. These differences can also be observed from EEG scalp topography (D).