Error awareness and the error-related negativity: evaluating the first decade of evidence

Abstract

From its discovery in the early 1990s until this day, the error-related negativity (ERN) remains the most widely investigated electrophysiological index of cortical error processing. When researchers began addressing the electrophysiology of subjective error awareness more than a decade ago, the role of the ERN, alongside the subsequently occurring error positivity (Pe), was an obvious locus of attention. However, the first two studies explicitly addressing the role of error-related event-related brain potentials (ERPs) would already set the tone for what still remains a controversy today: in contrast to the clear-cut findings that link the amplitude of the Pe to error awareness, the association between ERN amplitude and error awareness is vastly unclear. An initial study reported significant differences in ERN amplitude with respect to subjective error awareness, whereas the second failed to report this result, leading to a myriad of follow-up studies that seemed to back up or contradict either view. Here, I review those studies that explicitly dealt with the role of the error-related ERPs in subjective error awareness, and try to explain the differences in reported effects of error awareness on ERN amplitude. From the point of view presented here, different findings between studies can be explained by disparities in experimental design and data analysis, specifically with respect to the quantification of subjective error awareness. Based on the review of these results, I will then try to embed the error-related negativity into a widely known model of the implementation of access consciousness in the brain, the global neuronal workspace (GNW) model, and speculate as the ERN's potential role in such a framework. At last, I will outline future challenges in the investigation of the cortical electrophysiology of error awareness, and offer some suggestions on how they could potentially be addressed.

Keywords: ERN; cognitive control; consciousness; error awareness; event-related potentials; performance monitoring.

Figure 1

Typology of transitive consciousness, based on different theoretical accounts from the philosophy of mind (see text for further details). Right column outlines defining properties of the different types of consciousness.

Figure 2

Testing the error-correction hypothesis of ERN amplitude in the AST. Depicted are the combined data from both experiments in Wessel et al. (2011), limited to the 24 subjects that exhibited enough errors to warrant statistical comparison. (A) Difference between reported and non-reported errors in this sample. (B) Difference between corrected and non-corrected reported errors. (C) Difference between reported errors with fast corrections and reported errors with slow corrections.

Figure 3

A putative model schematic of emerging error awareness in the human brain, based on the accumulating evidence account of error awareness and the global neuronal workspace model. Information about the accuracy of an action is processed in parallel in different areas that comprise the “network of processors,” which feeds forward into the GNW. Note that the flow of information indicated by the arrows is only depicted if potentially meaningful for error awareness. Additional exchange of information is also probable (especially attentional modulation from the GNW to the network of processors). Be aware that the potential functions of the performance monitoring network outlined here represent the main branches of theories that have been put forward, and it doesn't mean that the ERN is a correlate of all these computations, but probably only a subset of them. ERN, error-related negativity; BG, basal ganglia; dACC, dorsal anterior cingulate cortex; RCZ, rostral cingulate zone; PES, post-error slowing; DA, dopamine.