Dissonance and the Brain

Dissonance proves human nature. People love that for which they suffer as Leon Festinger observed and the suffering starts with inconsistencies. You love your child who then pukes all over your laptop computer. When these inconsistencies arise, dissonance inflates, producing tension. And, as the theory predicts, often you resolve that tension by loving your puking child more. You resolve the suffering by valuing that which provokes the suffering.

But, how does this actually occur in people?

Consider this interesting fMRI study (pdf) that explored how the brain reacts during dissonance arousal and reduction. We’ll put people in the brain scanner, an experience most people find uncomfortable and claustrophobic. It’s not fun. We give them attitude statements (Target) that ask for their reaction in the scanner along with other attitude statements (Neutral) not related to the scanner. Start with the Control Group.

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 were actually enjoying the experience. Furthermore, they were informed that they would receive an additional dollar for each sentence that they responded to in this way. They were instructed to respond honestly to the other (neutral) sentences.

And, now for the Treatment Group.

Participants in the dissonance group were also instructed on how to respond to the stimuli. They were then told that a patient had been scheduled to be scanned after them and was to perform a similar task in the scanner. This patient, the participants were told, was now in the scanner control room, watching the screen of the experimental control computer, and was very nervous and uncomfortable about the upcoming scanning session. The participants were then told that several of the sentences were about their attitudes toward the scanner and the task and were asked if they would be willing to respond as though they were enjoying being in the scanner and performing the task, regardless of how they actually felt about the experience. This, they were told, might put the patient’s mind at ease, as the patient in the control room could see the responses on screen. We reasoned that this would be analogous to making a counter-attitudinal argument.

This is a sweet little manipulation for a scanner dissonance experiment. Rather than try to replicate past dissonance studies, this experiment makes the experiment itself part of the dissonance manipulation. People are asked to fake it for another person – in other words, performing a counter-attitudinal behavior (I’m acting like I enjoy this unpleasant experience). The control group also pretends, but in a direct, obvious, and compensated fashion. Past research has strongly demonstrated that this manipulation creates an external attribution (Why am I suffering? They paid me to act!).

The researchers also included a technical manipulation that was handled through a Solomon Four Group Design, which, it turns out, didn’t matter that much, so I’ll just note that and glide on.

The two key outcomes are how the two groups, Dissonance and Control, 1) reacted to those attitude statements, both Target and Neutral, and 2) showed any variation in brain activity. Consider the attitude statements.

Analysis of composite final attitude scores by means of an experimental group (dissonance, control) by pretest presence (present, not present) ANOVA verified a main effect of experimental group (F1,39 = 12.36, P = 0.001). This showed that scanner enjoyment was greater for the without-pretest dissonance group (M = 6.3, s.d. = 0.8) and withpretest dissonance group (M = 6.0, s.d. = 1.1) than for the withoutpretest control group (M = 5.1, s.d. = 1.3) and the with-pretest control group (M = 4.5, s.d. = 1.3). Individual t tests verified this effect for both the without-pretests groups (t22 = 2.51, P = 0.020) and the with-pretest groups (t17 = 2.43, P = 0.026). These results verified the basic cognitive dissonance finding.

Okay, I know some of you struggled through that and I appreciate the effort. Quite simply, the attitude difference between the Dissonance and Control groups was quite Large in Windowpane terms. That t(22) = 2.51, translates into a d over 1.00, roughly a 20/80 Windowpane. Dissonance really messes with your attitudes. Now, what about brain activity?

The research team measured brain activity in a variety of different areas, but expected the Dissonance only in specific locations. As the authors put it:

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, such as between the color and the meaning of a word in the Stroop task. dACC activation is consistently related to the amount of conflict occurring in such tasks.

And, indeed this is what they find. They offer a variety of statistical tests and figures to demonstrate the outcome. I’ll just share one.

These correlation plots display the relationship between activation and attitude for the key brain areas. The visual display in this case actually does a poor job of showing just how large the difference between the Dissonance and Control groups is. Note that the correlations in the Control group are around r = .10 to .30 and often in the wrong direction while for the Dissonance group they are all around r = .60 and in the right direction. These are Huge Windowpane effects.

This is pretty good evidence that the experiment did produce dissonance arousal and reduction and we’ve got good evidence that links dissonance to brain activation in areas related to conflicted information processing.  I’ll quote the authors.

These findings are consistent with a number of prior observations. Both cognitive dissonance and dACC and anterior insula activation have been associated with negative affect and autonomic arousal. These regions might therefore be responsible for representing or triggering the negative affect and related autonomic arousal associated with the dissonance . . . In short, our results are consistent with theories of cognitive dissonance that emphasize conflict between different cognitions, such as the original theory.

Realize the quality of the science here that again replicates key elements of Dissonance Theory. We’ve got a well done experiment with randomization, comparison, control, and counting. It connects a growing body of evidence in the neurosciences with behavioral studies going back to the 1950s. In other words, Dissonance is not some brand name magic sold by the gypsy boys and girls trying to make a buck. It is a well documented fact of human nature that describes, predicts, and explains how people change.

Dissonance is a play for genuine persuasion masters who truly know how to make change. Inconsistencies make people vulnerable to persuasion plays. They provoke intense, fast, and deep reactions both in physiology and psychology. Most of the time, people in the throes of Dissonance have no awareness of the effect. They just have an inconsistency problem to solve or so they think.


van Veen V, Krug MK, Schooler JW, and Carter CS. (2009). Neural activity predicts attitude change in cognitive dissonance. Nature Neuroscience, 12(11), 1469-74. Epub 2009 Sep 16.