Two perspectives on response monitoring: Perfectionism-related variations and post-response adaptation

The cognitive system needs to monitor actions to ensure that the intended actions are successfully executed and to intervene when deviations from the intended actions are detected. In two studies, we investigated systematic variations of response monitoring between (Study 1) and within (Study 2) individuals. We assessed response monitoring using electrophysiological markers. The error/correct negativity (Ne/c) and the error/correct positivity (Pe/c) are both components of the event-related potential that occur within 300 ms after a motor response. Usually, they have higher peak amplitudes following errors compared to correct responses. In Study 1, we related these indicators of response monitoring to two dimensions of perfectionism and found that individuals who strive for flawlessness purely because they are afraid of being evaluated negatively by others (evaluative concern perfectionists) displayed less error-specific early response monitoring (indicated by the Ne/c) than non-perfectionists and individuals who set themselves high goals and are internally motivated to perform flawlessly (personal standards perfectionists). In Study 2, we linked the single-trial peak estimates of the Ne/c and Pe/c amplitudes to indicators of post-response adaptation derived by a diffusion model decompo¬sition of post-response times and accuracies. We found that early response monitoring reflected by the Ne/c was associated with a higher decision threshold and a greater focus on task-relevant features on the subsequent trial. The Pe/c, on the other hand, was associated with a lower decision threshold when speed was relevant. The interplay of Ne/c- and Pe/c-related processes may thus ensure that subsequent responses are as fast and as accurate as possible by adjusting the decision threshold. The thesis points out how future research could benefit from integrating both levels of response monitoring by investigating how individual differences as described in Study 1 modulate basic post-response adaptation mechanisms as delineated in Study 2