The effect of monetary punishment on error evaluation in a Go/No-go task.

Little is known about the effects of the motivational significance of errors in Go/No-go tasks. We investigated the impact of monetary punishment on the error-related negativity (ERN) and error positivity (Pe) for both overt errors and partial errors, that is, no-go trials without overt responses but with covert muscle activities. We compared high and low punishment conditions where errors were penalized with 50 or 5 yen, respectively, and a control condition without monetary consequences for errors. Because we hypothesized that the partial-error ERN might overlap with the no-go N2, we compared ERPs between correct rejections (i.e., successful no-go trials) and partial errors in no-go trials. We also expected that Pe amplitudes should increase with the severity of the penalty for errors. Mean error rates were significantly lower in the high punishment than in the control condition. Monetary punishment did not influence the overt-error ERN and partial-error ERN in no-go trials. The ERN in no-go trials did not differ between partial errors and overt errors; in addition, ERPs for correct rejections in no-go trials without partial errors were of the same size as in go-trial. Therefore the overt-error ERN and the partial-error ERN may share similar error monitoring processes. Monetary punishment increased Pe amplitudes for overt errors, suggesting enhanced error evaluation processes. For partial errors an early Pe was observed, presumably representing inhibition processes. Interestingly, even partial errors elicited the Pe, suggesting that covert erroneous activities could be detected in Go/No-go tasks.