Recent years have seen an explosion of research on the N2 component of the event-related potential, a negative wave peaking between 200 and 350 ms after stimulus onset. This research has focused on the influence of ''cognitive control,'' a concept that covers strategic monitoring and control of motor responses. However, rich research traditions focus on attention and novelty or mismatch as determinants of N2 amplitude. We focus on paradigms that elicit N2 components with an anterior scalp distribution, namely, cognitive control, novelty, and sequential matching, and argue that the anterior N2 should be divided into separate control-and mismatch-related subcomponents. We also argue that the oddball N2 belongs in the family of attention-related N2 components that, in the visual modality, have a posterior scalp distribution. We focus on the visual modality for which components with frontocentral and more posterior scalp distributions can be readily distinguished.Descriptors: N2, N200, Cognitive control, Error-related negativity, Feedback-related negativity, NoveltyThe P300 may be the most studied component of the event-related potential (ERP). Its amplitude is sensitive to stimulus probability and task relevance of the eliciting stimulus, and its latency reflects stimulus evaluation time (Johnson & Donchin, 1980, Chapter 12;Verleger, 1997). The P300 is commonly divided into two subcomponents with different scalp distributions and different functional correlates: a frontally maximal P3a that reflects the orienting of attention to unexpected or significant events in the environment and a parietally maximal P3b that indexes the updating of working memory (Courchesne, Hillyard, & Galambos, 1975;Debener, Makeig, Delorme, & Engel, 2005;Dien, Spencer, & Donchin, 2004;Donchin, 1981;Friedman, Cycowicz, & Gaeta, 2001;Goldstein, Spencer, & Donchin, 2002;Na¨a¨ta¨nen & Gaillard, 1983;Polich & Comerchero, 2003;Spencer, Dien, & Donchin, 1999, 2001Squires, N. K., Squires, & Hillyard, 1975).Commonly observed in combination with the P3a and P3b is the smaller, earlier N2. The label ''N2'' refers to the second negative peak in the averaged ERP waveform and is labeled as such because it follows a prominent frontocentral negative peak at around 100 ms in the auditory modality or a prominent temporooccipital negative peak at around 180 ms in the visual modality. So linked were the N2 and P3 in early research that they were often referred to as the ''N2-P3 complex,'' and some studies measured them in combination for purposes of correlation with stimulus probability (Squires, K. C., Petuchowsky, Wickens, & Donchin, 1977;Squires, K. C., Wickens, Squires, & Donchin, 1976).Recent years have seen a renewed interest in N2 components of the ERP as functionally distinct from P3 components and useful for understanding the nature and sequence of cognitive processes. For instance, a large literature has emerged focusing on the role of anterior N2s in cognitive control. Cognitive control is partly defined as the monitoring or regulation of ...
