Electrophysiological correlates of decision making under varying levels of uncertainty

When making decisions we are often faced with uncertainty about the potential outcomes of a choice. We therefore must rely upon a stimulus–response–outcome (S–R–O) rule learned from previous experiences of gains and losses. Here we report a study that used event-related potentials (ERP) to examine the neural and cognitive mechanisms involved in decision making when S–R–O rules are changing in a volatile manner. Thirty-one participants engaged in a reward-based decision-making task in which two contextual determinants of decision uncertainty were independently manipulated: Volatility (i.e. the frequency of changes in the S–R–O rules) and Feedback validity (i.e. the extent to which an S–R–O rule accurately predicts outcomes). Results of stimulus-locked ERPs showed that volatility of S–R–O rules was associated with two well-known neural signatures of cognitive control processes. First, increased S–R–O volatility in a high FV context was associated with frontally-based N2 (200–350 ms) and N400 (350–500 ms) components. Second, in a low FV context, volatility was associated with an enhanced late positive complex (LPC, 500–800 ms) largest on frontal sites. Feedback-locked ERPs showed an enhanced Feedback-Related Negativity (FRN) and P300 for losses compared to wins as well as a volatility driven FRN. These results suggest that, in a high FV context, coping with volatility might involve conflict monitoring processes. However, in a low FV context, coping with frequent changes in the S–R–O rule might require greater attentional and working memory (WM) resources.

► We independently manipulate volatility and feedback validity (FV) in a decision task.
► In high FV conditions, volatility is associated with N2/N400 ERPs.
► In low FV conditions, volatility is associated with an LPC.
► We suggest dissociable modes of cognitive control in different forms of uncertainty.