NATURE NEUROSCIENCE VOLUME 12 | NUMBER 11 | NOVEMBER 2009 1469 ARTICLES 1 Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, California, USA. 2 Imaging Research Center, University of California at Davis, Sacramento, California, USA. 3 Department of Psychology, University of California at Santa Barbara, Santa Barbara, California, USA. Correspondence should be addressed to V.v.V. (vanveen@berkeley.edu) or C.S.C. (cameron.carter@ucdmc.ucdavis.edu). Received 29 July; accepted 8 September; published online 16 September 2009; doi:10.1038/nn.2413 One candidate region for the detection and processing of cognitive dissonance is the dorsal anterior cingulate cortex (dACC). We and others have proposed that one of the dACC’s functions in cognition is to detect conflicts between active, but incompatible, streams of information processing 13–15 , such as between the color and the meaning of a word in the Stroop task 16,17 . dACC activation is consistently related to the amount of conflict occurring in such tasks. Computational simulations of conflict in simple speeded response tasks have measured conflict as Hopfield’s energy and have shown that dACC activation in such tasks can be well modeled by this measure 13,18 . Likewise, conflict is an important component of the classic dissonance theory 1 , and computational models of cognitive dissonance have measured it as increased energy 19,20 . We hypothesized that the dACC’s conflict monitoring functions might generalize from detecting conflict in simple speeded-response tasks to detecting conflict between prior attitudes and counter-attitudinal behavior in cognitive dissonance 11,14 . To test this, we adapted the induced compliance procedure 2 into an event-related fMRI design. Participants first performed a rather long (45 min) and boring task in the uncomfortable environment of the magnetic resonance scanner. Participants then participated in a second task, during which they had to respond to sentences presented on a screen with their left or right ring, middle, or index finger, as on a 6-point Likert scale (1 = left ring finger, completely agree; 6 = right ring finger, completely disagree). We used two types of sentences: target sentences consisting of attitudes toward the scanner and task, and neutral sentences (Fig. 1). While participants were performing the initial task, they were randomly assigned to one of two groups, dissonance or control. Participants in the control group were told to respond to the target sentences as though they were enjoying the scanner and the task, regardless of whether they According to cognitive dissonance theory, people tend to strive to keep their knowledge, actions and attitudes consistent (consonant). Inconsistent (dissonant) behavior and attitudes result in a psychologically uncomfortable state that motivates people to reduce the dissonance, often by changing their attitudes to be more consonant with the displayed behavior. Since this theory was first proposed in the 1950s 1,2 , it has led to a large amount of fruitful research in social psychology 3 and is considered to be one of the most influential theories in psychology 4 . However, little is known about how cognitive dissonance is represented in the brain or what the cognitive mechanisms might be that mediate this process. We used functional magnetic resonance imaging (fMRI) to study how the brain responds to cognitive dissonance in a modified version of the classic ‘induced compliance’ procedure 2 . In this procedure, participants argue in favor of a position that is counter to their actual attitudes (counter-attitudinal argument). It has consistently been found that participants change their attitudes to be more consistent with the counter-attitudinal behavior. Dissonance has been shown to be a negative emotional state 5–7 accompanied by autonomic arousal 5,8 ; it has been shown that people change their attitudes and restore consonance to specifically reduce the negative affect 5–7 . When participants in control groups are able to attribute their counter-attitudinal behavior to payment 2 or coercion 3,9–11 , or when the counter-attitudinal behavior has no real- world consequences 10,12 , conflict between behavior and prior attitudes is reduced, and participants experience less cognitive dissonance and do not change their attitudes (see Supplementary Discussion). Notably, as dissonance theory has largely focused on what motivates attitude change rather than how that change comes about, we focused on the neural correlates of the actual dissonance, rather than the attitude change that follows it, which awaits future study. Neural activity predicts attitude change in cognitive dissonance Vincent van Veen 1,2 , Marie K Krug 2 , Jonathan W Schooler 3 & Cameron S Carter 2 When our actions conflict with our prior attitudes, we often change our attitudes to be more consistent with our actions. This phenomenon, known as cognitive dissonance, is considered to be one of the most influential theories in psychology. However, the neural basis of this phenomenon is unknown. Using a Solomon four-group design, we scanned participants with functional MRI while they argued that the uncomfortable scanner environment was nevertheless a pleasant experience. We found that cognitive dissonance engaged the dorsal anterior cingulate cortex and anterior insula; furthermore, we found that the activation of these regions tightly predicted participants’ subsequent attitude change. These effects were not observed in a control group. Our findings elucidate the neural representation of cognitive dissonance, and support the role of the anterior cingulate cortex in detecting cognitive conflict and the neural prediction of attitude change. © 2009 Nature America, Inc. All rights reserved.