The influence of error detection and error significance on neural and behavioral correlates of error processing in a complex choice task.

Error detection and error significance form essential mechanisms that influence error processing and action adaptation. Error detection often is assessed by an immediate self-evaluation of accuracy. Our study used cognitive neuroscience methods to elucidate whether self-evaluation itself influences error processing by increasing error significance in the context of a complex response selection process. In a novel eight-alternative response task, our participants responded to eight symbol stimuli with eight different response keys and a specific stimulus-response assignment. In the first part of the experiment, the participants merely performed the task. In the second part, they also evaluated their response accuracy on each trial. We replicated variations in early and later stages of error processing and action adaptation as a function of error detection. The additional self-evaluation enhanced error processing on later stages, probably reflecting error evidence accumulation, whereas earlier error monitoring processes were not amplified. Implementing multivariate pattern analysis revealed that self-evaluation influenced brain activity patterns preceding and following the response onset, independent of response accuracy. The classifier successfully differentiated between responses from the self- and the no-self-evaluation condition several hundred milliseconds before response onset. Subsequent exploratory analyses indicated that both self-evaluation and the time on task contributed to these differences in brain activity patterns. This suggests that in addition to its effect on error processing, self-evaluation in a complex choice task seems to have an influence on early and general processing mechanisms (e.g., the quality of attention and stimulus encoding), which is amplified by the time on task.

Error significance but not error expectancy predicts error-related negativities for different error types.

Violations of outcome expectancies have been proposed to account for error-related brain activity in the medial prefrontal cortex. The present study investigated whether early error monitoring processes are sensitive only to the expectancy of errors, or whether these processes also evaluate the significance of errors. To this end, we considered the error-related negativity (Ne/ERN), an electrophysiological marker of early error monitoring, in a modified flanker task in which errors could occur because participants responded to the flankers instead of the target (flanker error) or because a response unrelated to the stimulus was given (nonflanker error). By manipulating the onset of the flankers relative to the target, we manipulated two variables: the probability (and thus the expectancy) of flanker errors and the proportion of significant attention errors among each error type. Contrary to the predictions of outcome expectancy accounts, we found that the Ne/ERN was larger for flanker errors than for nonflanker errors only in the condition in which flanker errors were particularly frequent. Consistent with the error significance account, however, Ne/ERN amplitude mirrored the estimated proportion of significant attention errors as estimated by multinomial modeling. These results provide support for the idea that early performance monitoring as reflected by the Ne/ERN involves an evaluation of error significance.