Why do we produce errors of commission? An ERP study of stimulus deviance detection and error monitoring in a choice go/no-go task.

The present study investigated event-related brain potential (ERP) reflections of stimulus deviance detection and error monitoring recorded during a go/no-go auditory oddball task. The mismatch negativity and error negativity were analysed as indices of these processes, respectively. We examined whether errors of commission occurred because of failures to detect stimulus deviance. On error trials the mismatch negativity amplitude did not differ between big and small deviant stimuli and was clearly reduced as compared with mismatch negativity amplitude on correct trials. Following an error response an error negativity was elicited, the amplitude of which was unaffected by stimulus deviancy. This pattern of ERP results was interpreted as supporting the defective deviance detection hypothesis.