The Electrophysiological Distinctions Between Risky Decision-making And Ambiguous Decision-making

Resolving uncertainties is a central motivation for human decisions.A comprehensive,clear review of these uncertainties is necessary for promoting a better understanding on decision behaviors theoretically and empirically.Two kinds of uncertain decision-making are defined: decision-making under risk(known probabilities)and decision-making under ambiguity(unknown probabilities).It is still under debate whether these two types of decisions share the same neural mechanisms.The current research aims to find eletrophysiological indexes to distinguish between the two types of decisions using the event-related potential(ERP)method.As individuals show different behavioral preferences under a single-person and a social context,my study investigated the electrophysiological characterization between risky and ambiguous decisions under these contexts,respectively.Study 1 included reward magnitude as an experimental factor in a single-person context,and was a 2(uncertainty: risk and ambiguity)× 2(reward magnitude: large and small one)within-subject design.The ERP results showed the early P1 component being sensitive to magnitude but insensitive to the degree of uncertainty,while both the N2 and P3 components showing the opposite pattern.Specifically,small magnitude elicited a larger P1 than did large magnitude.Meanwhile,both the N2 and P3 amplitudes evoked in the risky condition were larger than those evoked in the ambiguous condition.In short,different neurophysiological activities are associated with risky and ambiguous decision-making in the single-person context,and such differences mainly emerged in the middle and late stages of the option characteristics processing.The related cognitive processes might be more complicated and abundant in risky decision-making than in ambiguous one.Study 2 included social incongruence as an experimental factor in social context,and was a 2(uncertainty: risk and ambiguity)× 5(the level of incongruence: 0-Incon,1-Incon,2-Incon,3-Incon,4-Incon)within-subject design.The ERP results showed that the uncertainty factor modulated early and middle processing stage while the social incongruence factor modulated the whole processing stage.Specifically,the risky condition elicited a smaller N1 than did the ambiguous condition,while the reverse was true for the FRN.Instead,I observed the levels of social incongruence were represented more elaborately as the cognitive processing went on.The results indicated that the neurophysiological differences between risky and ambiguous decision-making in the social context mainly emerged in the early and middle stages of option characteristics processing.Again,the sensitivity of the FRN to the uncertainty factor suggests that the cognitive processes underlying risky decision-making are more complex than ambiguous decision-making.To conclude,my research has found different eletrophysiological indexes for two types of uncertainty(i.e.,risk and ambiguity)in the single-person and the social context,respectively.The larger N2 and P3 amplitudes in the single-person context and the sensitivity of the FRN in the social context suggested that decision under risk has more complicated cognitive processes and consumes more resources than decision under ambiguity.Meanwhile,the electrophysiological patterns in temporal dimension depend on decision contexts: the differences between risky and ambiguous decision-making in the single-person context emerge in the middle and late stages of option characteristics processing,while their differences in the social context appear in the early and middle cognitive stages.These findings provide an insight into distinguishing between risky and ambiguous decision-making from an electrophysiological perspective.