Feedback-related potentials are sensitive to sequential order of decision outcomes in a gambling task

The feedback negativity (FN) has been repeatedly linked to expectancies about decision outcomes. Sequential outcome order is likely to influence such expectancies but has been widely disregarded. We therefore investigated whether the three-trial order of decision outcomes in a gambling task influences the FN as well as the P200 and P300. All three deflections were not only influenced by the outcome valence of the current trial but also by the outcomes of the two preceding trials. In detail, the FN and P300 to any current trial outcome were largest when the outcomes in the two preceding trials had an opposite valence. The P200 was highest in the context of two directly preceding wins, indicating that it may reflect representations of local outcome history. Our findings demonstrate that neural systems involved in decision outcome processing dynamically and continuously integrate the local outcome history for the evaluation of present outcomes.