Time-frequency (TF) approaches to assessing event-related potential (ERP) activity have provided evidence that many common ERP components contain a mixture of overlapping TF components which can index separable underlying processes. Substantial work has focused on ERPs from target detection tasks, where theta (3-7 Hz) and delta (0-3 Hz) TF activity have been shown to underlie common time-domain ERP components such as the P3 (Başar-Eroglu and Demiralp, 2001; Başar et al., 1999; Başar et al., 2001; Demiralp et al., 2001a; Demiralp et al., 2001b; Porjesz et al., 2005; Yordanova et al., 2000; Makeig et al., 2002). Additional work has demonstrated that the error-related negativity (ERN; Gehring et al., 1993; Falkenstein et al., 1991) is well characterized by theta TF measures (Gehring and Willoughby, 2004; Trujillo and Allen, 2007; Yordanova et al., 2004; Cavanagh et al., 2011; Cavanagh et al., 2009a; Cohen and Cavanagh, 2011). Using a recently developed approach based on principal components analysis (PCA) of reduced interference distributions (RID) from Cohen's class of TF transforms (Bernat et al., 2005), recent work has provided improved TF specificity for indexing theta and
