Human brain responses associated with subjective evaluation of error significance are sensitive to error inevitability

Abstract

This study examined whether error-related brain responses are sensitive to the degree of error inevitability, a factor which seriously affects the attribution of moral responsibility for an error. We were especially interested in error-related negativity (ERN), which is an electrophysiological marker of subjective evaluation of error significance and its motivational value. In addition, we focused on post-error slowing, which is a post-error behavioural adjustment. We hypothesized that the more avoidable the error, and consequently the greater its significance and motivational value, the larger the ERN amplitude, the shorter the ERN latency, and the greater the post-error slowing should be. To elicit errors whose inevitability varies, we used the stop-signal task. The inevitability of errors in this task depends on whether the stop signal is presented before or after a point beyond which the completion of the movement cannot be cancelled. Consistent with our hypotheses, we found that the higher motivational value of avoidable errors was indeed reflected in larger and earlier ERNs. Moreover, avoidable errors led to greater adjustments in subsequent behaviour aimed at preventing similar failures in the future. These findings show that early performance monitoring, as reflected by ERN, involves an evaluation of error inevitability. In a broader perspective, these results indicate that the elementary basis for distinguishing between culpable (avoidable) and non-culpable (unavoidable) errors may occur in the brain several dozen milliseconds after error commission.