Strategic control and medial frontal negativity: Beyond errors and response conﬂict BRUCE D. BARTHOLOW, a MELANIE A. PEARSON, b CHERYL L. DICKTER, a KENNETH J. SHER, c MONICA FABIANI, b and GABRIELE GRATTON b a Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA b Department of Psychology and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA c Department of Psychological Sciences, University of Missouri and Midwest Alcoholism Research Center, Columbia, Missouri, USA Abstract Errors in timed choice tasks typically produce an error-related negativity (ERN) in the event-related potential (ERP). The error speciﬁcity of the ERN has been challenged by studies showing a correct response negativity (CRN). Forty- ﬁve participants engaged in a ﬂanker task in which both compatibility between ﬂankers and target and the probability of compatible ﬂankers were manipulated. Correct responses elicited a CRN, the amplitude of which increased with the degree of mismatch between the presence of conﬂict and conﬂict probability, even on low-conﬂict (compatible) trials. The fronto-central N2 component was larger on high-conﬂict (incompatible) correct response trials. However, in contrast to some recent accounts, this N2 was largest for highly probable stimuli. These ﬁndings suggest revision to models of the effects of conﬂict on response-related negativity to account for strategic adjustments made in preparation for the response. Descriptors: Error-related negativity, Correct-related negativity, Strategic control, Conﬂict detection Monitoring performance and adjusting behavior appropriately is an adaptive, critical function for the human information- processing system (e.g., Holroyd & Coles, 2002). A negative de- ﬂection has been identiﬁed in the event-related brain potential (ERP) occurring shortly after an erroneous response (e.g., Falkenstein, Hohnsbein, Hoormann, & Blanke, 1990, 1991; Gehring, Goss, Coles, Meyer, & Donchin, 1993), known as the error-related negativity (ERN) or error negativity (Ne), which appears to serve this action-monitoring function (e.g., Luu, Flaisch, & Tucker, 2000). A later-occurring positive component (the error positivity; Pe) also has been identiﬁed, although its functional relationship to the ERN/Ne remains somewhat un- clear (e.g., Falkenstein, Hoormann, Christ, & Hohnsbein, 2000; Vidal, Hasbroucq, Grapperon, & Bonnet, 2000). Initial accounts linked the ERN/Ne to the operation of an error detection mechanism (e.g., Bernstein, Scheffers, & Coles, 1995; Falkenstein et al., 1990). This view recently has been chal- lenged by studies showing small-amplitude ERN-like activity on correct trials (correct response negativity; CRN), leading some to propose that the ERN/CRN reﬂects a response comparison process (Vidal et al., 2000) or an emotional reaction to the re- sponse (e.g., Luu, Collins, & Tucker, 2000) rather than error detection per se. Proponents of the error detection view have argued that the CRN occurs when participants are unsure of the correctness of a given response, or when a stimulus elicits sub- threshold incorrect response activation before the correct re- sponse is emitted (Coles, Scheffers, & Holroyd, 2001). Consistent with this view, several studies have reported an association be- tween small CRNs and the presence of coactivation of correct and incorrect responses (Luu, Flaisch, et al., 2000; Scheffers, Coles, Bernstein, Gehring, & Donchin, 1996; Vidal et al., 2000). Thus, as noted by Coles et al. (2001), there should be no ERN- like activity (i.e., CRN) if a correct response is executed under conditions where stimuli are unambiguous. A related explanation has been offered by Cohen and col- leagues (e.g., Botvinick, Braver, Barch, Carter, & Cohen, 2001; Carter et al., 1998), who posit that the ERN reﬂects a response conﬂict monitoring function performed by the anterior cingulate cortex (ACC). This hypothesis is based largely on brain imaging data showing ACC activation following both erroneous respons- es and correct responses on tasks involving high response conﬂict (e.g., the word RED shown in blue font during the Stroop task; Stroop, 1935), but not on tasks involving low response conﬂict (e.g., the word RED shown in red font). According to this view, errors are simply an extreme form of response conﬂict but are not uniquely associated with the neural activity responsible for the Bruce D. Bartholow is now with the Department of Psychological Sciences, University of Missouri-Columbia. Melanie A. Pearson is now with the School of Public Health, Emory University. Support for this research was provided by Grants P50 AA11998 and R01 AA7231 from the National Institute on Alcohol Abuse and Alco- holism. We thank Mike Coles for helpful comments on early drafts of this article and Leighann Wieman for assistance with data collection. Address reprint requests to: Bruce D. Bartholow, Department of Psychological Sciences, 10 McAlester Hall, University of Missouri, Columbia, MO 65211, USA. E-mail: BartholowB@missouri.edu; or to Gabriele Gratton, Beckman Institute, 405 N. Mathews Ave., Urbana, IL 61801, USA; e-mail: grattong@uiuc.edu. Psychophysiology, 42 (2005), 33–42. Blackwell Publishing Inc. Printed in the USA. Copyright r 2005 Society for Psychophysiological Research DOI: 10.1111/j.1469-8986.2005.00258.x 33