Regarding the significance of ORP in gambling paradigms, Yeung & Sanfey [22] first demonstrated that this positive component was sensitive to the reward amount but insensitive to the loss/gain dimension. In contrast to this, our results showed that ORP was sensitive to both valence and amount dimensions (see Fig. 6). Further, as the difference waveform (see Fig. 5) indicates, this sensitivity of ORP could be time-bound: the valence (loss/gain) dimension was dominant around 300 ms and the pattern of separation switched to the amount (large/small) dimension after 400 ms. Therefore it can be speculated that the ORP component is more associated with the subjective evaluation of both valence and amount (i.e., what kind of and how much). In order to better understand the ORP, it is worth looking at the positivity in the error paradigms (Pe). In the research literature, the functional significance of Pe has been explained through several hypotheses (cf. Overbeek et al. [29] and Falkenstein [30]): 1) the affective-processing hypothesis [52], which suggests that the Pe reflects the emotional appraisal of the error or its consequences; 2)
