Cognitive Dissonance, Willpower, and Your Brain

Neuropsychology shows why cognitive dissonance is key to building willpower.

Posted Sep 14, 2018

With the expanding knowledge of neuropsychology, what was previously speculation is now being confirmed through the use of imaging studies such as functional magnetic resonance (fMRI) to track brain changes while experimental subjects perform specific cognitive activities. For example, we now have fMRI evidence that the brain’s prefrontal cortex (PFC) is involved in decision-making. However, it is less known precisely how the process of decision-making is carried out on a neuropsychological level, and even less known how the brain resolves cases of cognitive dissonance

Cognitive dissonance occurs when you are caught between trying to decide between two conflicting options. One of these options is irrational; nevertheless, you are emotionally inclined to choose it. On the other hand, the second option is more rational, but you are not inclined to choose it.

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"Snickers," by Bodo
Source: CC by 2.0

The first investigator to have looked carefully at cognitive dissonance appears to be the namesake of this blog, Aristotle, who offered the following illustration in his classic treatise on Ethics (Book 7):  Suppose you see something sweet. You think about how sweet it is and want to eat it. On the other hand, you realize that it is not healthy for you. So there you are, torn in two directions. If you suffer from weakness of the will (what the Greeks called Akrasia), you will succumb to the desire and eat the sweet. However, if you do have the willpower, you can resist the inclination, and choose the healthy option.

Now, were Aristotle alive today, he would have been able to apply neuropsychology to explain what brain activities support a person’s ability to overcome cognitive dissonance. So, how would he have fleshed out his theory of cognitive dissonance from a neuropsychological perspective? This blog will discuss some key PFC studies that bear on this question, and explore the implications for overcoming potentially self-destructive kinds of cognitive dissonance.

The Role of the Ventromedial Prefrontal Cortex in Cognitive Dissonance

One fMRI study conducted by Goel and Dolan, which focused on the ventromedial part of the human PFC (vmPFC), may have profoundly important implications for the neural basis of cognitive dissonance. The latter researchers found that the vmPFC was (bilaterally) active when subjects drew inferences from syllogisms with emotional content. Aristotle himself referred to such syllogisms as practical syllogisms and his analysis of cognitive dissonance proceeded in terms of them. For example, in developing his illustration of cognitive dissonance, cited above, Aristotle gave this example of a practical syllogism:

Syllogism A

(1)   If this is sweet, then I should eat it.

(2)   This is sweet.

So, I should eat it.

According to Aristotle, when you accept premise 1, which is a rule, and premise 2, which is a factual claim, and nothing prevents you from eating the sweet, you will actually go ahead and eat it. However, you may also entertain another more rational syllogism that conflicts with the above irrational syllogism, such as this one:

Syllogism B

(1’) If I will probably gain weight if I eat the sweet, then I shouldn’t eat it.

(2’) I will probably gain weight if I eat it (because that’s what happened in the past).

So, I shouldn’t eat the sweet.

In Syllogism B, (1’) is a rule that bids you not to eat the sweet; whereas (2’) is a factual claim, which is supported by an inductive (probabilistic) inference from past experience (That’s what happened in the past”).  

In generating the conclusion of Syllogism B, alongside that of Syllogism A, you may now be vacillating between these contradictory conclusions. While the latter bids you to eat the sweet, the second tells you not to eat it. Now, states Aristotle (Ethics, Book 7), “when appetite happens to be present in us,” the rational conclusion (in Syllogism B) bids us not to eat the sweet, but “appetite leads us towards it (for it can move each of our bodily parts).”  In other words, when you add “appetite” (desire) to the network of conflicting syllogisms, the irrational syllogism wins out over the rational syllogism and you end up eating the sweet.

Here, what Aristotle describes sounds remarkably like the neural representation of the syllogistic activity occurring bilaterally on the vmPFC, as discussed in the aforementioned research by Goel and Dolan. Interestingly, one further study of the right vmPFC suggests that the right vmPFC is associated with impulse control. As such, one possible hypothesis is that the right vmPFC is where rational syllogisms like Syllogism B are active, while the left hemisphere is associated with affective or impulsive ones like Syllogism A. In fact one lesion study has identified the left vmPFC, in contrast to the right, as associated with affect.

Significantly, the vmPFC interacts with another part of the brain called the amygdala, which is also active during emotional episodes. So this is the part of the brain that is active when, as Aristotle says, “appetite leads us towards it [the sweet thing]," which “can move each of our bodily parts.” In fact, according to a University of Michigan study, “sweet tasty food...can be extremely attractive when this brain structure [the amygdala] is triggered.”

So how is it even possible for you to exercise self-control in avoiding eating the sweet when you are under the influence of the irrational syllogism and the “appetite” activated by the triggered amygdala?

The Role of the Dorsolateral Prefrontal Cortex in Cognitive Dissonance

It is here that the plot thickens because there is further evidence that another part of the PFC, the dorsolateral prefrontal cortex (dlPFC), can also be activated in cases of cognitive dissonance.  According to a Caltech study, individuals with strong willpower confronted with a tasty food such as a Snickers bar have dlPFC activity when they resist the temptation. In contrast, individuals who succumb to the temptation do not have similar activity in this area of the brain.  In both cases, however, the vmPFC is activated, thus suggesting that the dlPFC may serve as a “willpower muscle” to regulate irrational inclinations, and resolve cognitive dissonance in favor of the rational syllogism—the one that incorporates health considerations, in the present example.

Strengthening The Brain’s Willpower Muscle

There is also evidence that the act of making a choice can itself change self-report preferences as well as their neural representations. This, in turn, suggests that the habit of self-control is formed through practicing the rational behavior, thereby strengthening the brain’s natural willpower muscle. Here Aristotle is again accurate, for he unequivocally states that we become …temperate by doing temperate acts…” After all, you lift weights and work out to strengthen your heart muscle and bodily muscles.  Now there is evidence that weakness of will can also be strengthened. And when confronted with cases of cognitive dissonance, you have an opportunity to make such cognitive brain changes.

Cognitive dissonance can therefore provide the occasion for increasing your brain’s willpower muscle, which is actually a good thing!  In a recent article in Trauma Psychology, I have suggested that cognitive-behavior therapy, especially Logic-Based Therapy, may be useful in encoding irrational syllogisms neurologically represented on the vmPFC in cases of depression and other emotional states, including post-traumatic stress disorder (PTSD). Such replacement of syllogisms requires the juxtaposition of the more rational syllogism proximately with the irrational syllogism, and an effort of will to overcome the tendency to act on the irrational syllogism. Hence, such a state of cognitive dissonance provides the opportunity to overcome your irrational syllogism, and, therefore, to strengthen your brain’s natural willpower muscle. 

Here, the goal is to, eventually, execute the rational behavior (exhibit temperance) without exercising willpower (so that your dlPFC no longer lights up). That’s when you have successfully replaced your irrational tendency with the rational habit!