Cognitive dissonance

Cognitive dissonance is the unpleasant inner tension we feel when our beliefs, values and actions do not match. When we do something that contradicts what we believe, the brain registers it as discomfort and wants to get rid of it as quickly as possible. What is interesting is how it usually does that. It rarely changes the behaviour. Far more often, it adjusts the opinion or finds an excuse so that the contradiction disappears. In other words, we bend our thoughts more easily than our deeds. That is exactly why cognitive dissonance is one of the most powerful drivers of human behaviour and also a very rewarding tool in marketing, especially in the post-purchase phase.

Cognitive bias classification

• Cause (Cognitive Bias Codex): Not enough meaning
• Mental area: Beliefs and emotions
• Marketing function: Ego and beliefs (and retention)
• Customer journey: Post-purchase
• Cialdini’s principles: Consistency and commitment
• System 1 / System 2: System 1 (and post-hoc rationalisation)

In a nutshell

• What it is: tension between what we do and what we believe.
• How we resolve it: usually by changing our opinion or making an excuse, not by changing our behaviour.
• Where you will encounter it: after an expensive purchase, with bad habits, in relationships, after a difficult decision.
• How to use it: after the purchase, reassure customers that they made the right choice.

A real-life story

The term was introduced by the American psychologist Leon Festinger in his 1957 book A Theory of Cognitive Dissonance. Even earlier, in 1956, in the book When Prophecy Fails, he described the story of a sect that believed the world would end on a certain date and that its members would be saved by aliens. When the end of the world did not come, the members did not abandon their faith. On the contrary, they told themselves that it was their devotion that had saved the world, and they began spreading their faith even more zealously. The conflict between reality and belief was so strong that it was easier to rewrite their interpretation of the world than to admit a mistake.

The classic proof came from a 1959 experiment by Festinger and his colleague Carlsmith, published in the Journal of Abnormal and Social Psychology. Participants performed a boring task and were then asked to lie to another participant that it had been fun. Some were paid twenty dollars for the lie, others only one. And lo and behold, those who got one dollar later rated the task as more enjoyable. Twenty dollars was a sufficient excuse for lying, so they felt no contradiction. One dollar, however, was not enough, so they had to convince themselves that they had actually enjoyed the work.

Imagine Peter, who has bought expensive headphones for 10,000 CZK (about 410 EUR). At home he discovers that his friend’s cheaper model sounds almost the same. Instead of admitting he overpaid, he starts highlighting details he had not noticed before. “But the sound really is cleaner, and the materials are in a different league.” That is not a lie to his friend, it is consolation for himself. Classic post-purchase dissonance, which is also closely familiar to the sunk cost fallacy.

Fun fact: Cialdini’s principle of consistency is also built on dissonance. Once we publicly commit to something, we behave accordingly so that we are not inconsistent in our own eyes. That is why a small first step, such as a signature or a like, often leads to a bigger commitment later.

How cognitive dissonance works

The brain craves inner harmony. When it encounters a contradiction, unpleasant tension kicks in and the brain looks for the easiest way to remove it. Changing deep-seated behaviour is hard, so it prefers to adjust an attitude, play down the importance of the contradiction or add a new reason that makes everything fit. Dissonance is strongest where our ego is at stake and where decisions cannot be reversed. It is closely related to loss aversion, because we perceive admitting a mistake as a loss, and to the IKEA effect and the endowment effect, where we defend all the more strongly whatever we have put ourselves into.

Use in marketing

1. Post-purchase reassurance. Right after buying, customers waver between joy and doubt. A thank-you email along the lines of “you made a great choice” and a guide to getting the most out of the product will calm the dissonance and reduce returns.
2. Building consistency in small steps. A small first commitment, such as subscribing to a newsletter or completing a profile, leads to greater willingness to continue, because people want to stay true to themselves.
3. Community and brand identity. When customers publicly identify with a brand, they will defend it so as not to be inconsistent. That is where the power of fans and ambassadors comes from.
4. Returns and guarantees. Easy returns reduce the initial dissonance before purchase, but once customers have the product and have settled in with it, the dissonance of returning it tends to make them keep it.
5. Content that confirms the choice. Guides, tips and stories from other satisfied customers give customers ammunition to justify their purchase to themselves and to others.
6. The ethical line. Exploiting dissonance to keep customers tied to something that does not serve them does not pay off in the long run. The disillusionment tends to be all the harsher.

How to deal with cognitive dissonance in yourself

1. Acknowledge the contradiction. When you feel unpleasant tension, ask yourself whether you are resolving it with an excuse instead of a change.
2. Change the action rather than the truth. With bad habits, it is more honest to adjust your behaviour than to keep telling yourself it is not a problem.
3. Be careful after big purchases. Praising your own purchase is natural, but do not turn it into a rule for next time.

Cognitive dissonance is proof that people are not logical machines but beings who long to make sense of the world and stay in harmony with themselves. Anyone who understands this can support customers after a purchase and admit their own mistakes before cementing them with excuses.

Frequently asked questions

What is cognitive dissonance?

An unpleasant inner tension that arises when our actions, opinions and values contradict each other. The brain usually resolves it by changing an attitude or making an excuse.

Who described the theory of cognitive dissonance?

The American psychologist Leon Festinger, who introduced it in his 1957 book A Theory of Cognitive Dissonance.

What is an example of cognitive dissonance?

A smoker who knows smoking is harmful but, instead of quitting, tells themselves “I wouldn’t be able to quit anyway”, or defending an expensive purchase that did not pay off.

How does cognitive dissonance show up in a relationship?

We explain away and excuse inconsistencies in our partner’s behaviour so that we do not feel the contradiction between reality and our idea of the relationship.

Euro amounts are approximate, converted at the Czech National Bank rate of 24.34 CZK per EUR on 29 October 2026.

Patrik Pilous

I am a marketing strategist and SEO consultant. I love the world of marketing, the internet and AI. I am at my best when planning business growth, setting and executing marketing strategy and optimising websites (SEO, GEO and, above all, sales).