Event-related potentials and the decision making under risk and ambiguity

The aim of this study is to contrast the neural temporal features of decision making in context with risk and ambiguity. Facing stimulus of risk or ambiguity in a monetary gambling, 13 participants were ask to decide to bet or not, while the event-related potentials (ERPs) were recorded. The ERP components, identified as the P200 and N200 were found. The P200 amplitude elicited by the risky condition was significantly larger than the amplitudes for the ambiguous condition. Yet, the N200 amplitude triggered by the risky condition was significantly smaller than the ambiguous condition. The smaller P200 amplitude in the ambiguous condition was likely indicative of rapid feature detection process attending to the negative stimuli. The larger N200 amplitude evoked by the ambiguous condition was associated with perceptual conflict. These findings indicated that the decision under ambiguity may relate to a more complex cognitive process than decision under risk, and the amplitude of P200 and N200 can be viewed as a reference measure to reflect the difference between the ambiguity and the risk.