The classical P3(00) is probably the most studied ERP component (e.g., Donchin, 1981; Donchin and Coles, 1988; Nieuwenhuis et al., 2005; Verleger, 1997), not least because of its omnipresence across ERP paradigms and study groups (although to a different degree) and its resilience to masking by common reference choices, all of which may have contributed to its early discovery (Sutton et al., 1965). Its hallmark characteristic is a mid-parietal maximum, but other ERP positivities with similar peak latencies and different topographies have since between identified, together forming a family of ERP components often referred to as the late positive complex (Sutton and Ruchkin, 1984). Two subcomponents, termed P3a and P3b, have generated a considerable amount of research interest: P3b, which is synonymous to the classical P300, is hypothesized to reflect effortful allocation of attention and subsequent memory processing, while P3a, which peaks earlier than P3b and has a relatively more frontal midline maximum, is assumed to reflect stimulus-driven attentional processes (e.g., reviewed by Polich, 2007). Because of their temporal and spatial overlap, it may be difficult to disentangle these two
