In this regard, a further notable point is that reductions in delta-P300 as a function of externalizing proneness were evident for both gain and loss feedback, indicating a global reduction in P300 response rather than an effect localized to one type of feedback or the other. However, along with a main effect for externalizing proneness, a small but significant Externalizing × Gain/Loss interaction was evident, indicating that amplitude reductions were slightly larger for responses to gain feedback. One possible explanation is that this simply reflects greater variance in response for Gain as compared to Loss trials (i.e., because delta-P300 responses were greater to Gain than Loss), affording greater opportunity to detect an effect of externalizing proneness in this condition. Another possibility is that the motivational impact of the gain feedback was diminished for individuals higher in externalizing proneness. Although the direction of this finding contrasts with the notion of high externalizing individuals as hypersensitive to reward, it is notable that the reward stimulus in the current context (i.e., gain feedback cue) was highly symbolic. Thus it may be that individuals
