Event-related potentials in response to early terminated and completed sequential decision-making.

The process of outcome evaluation effectively navigates subsequent choices in humans. However, it is largely unclear how people evaluate decision outcomes in a sequential scenario, as well as the neural mechanisms underlying this process. To address this research gap, the study employed a sequential decision task in which participants were required to make a series of choices in each trial, with the option to terminate their choices. Based on participants' decisions, two outcome patterns were classified: the "reached" condition and the "unreached" condition, and the event-related potentials (ERPs) were recorded. Further, in the unreached condition, we investigated how the distance (i.e., the position interval between the actual outcome and potential outcome) modulated outcome evaluation. Behavioral data showed a higher emotion rating when people got a reward rather than a loss (i.e., the reached condition), while the opposite was true in the unreached condition. ERP results showed a larger feedback-related negativity (FRN), a smaller P3, and a larger late positive potential (LPP) when people got a loss compared to a reward. Importantly, a hierarchical processing pattern was found in the unreached condition: people processed separately the potential outcome and the distance at the early stage, manifested in the FRN amplitude; subsequently, the brain focused on the distance-a lower distance elicited an enhanced P3 amplitude. Finally, the potential outcome and distance were processed interactively in the LPP amplitude. Overall, these findings shed light on the neural underpinnings of outcome evaluation in sequential decision-making.