What is cognitive dissonance?

The discomfort of holding two conflicting beliefs, or a belief that clashes with your behaviour, which we tend to resolve by changing the belief rather than the behaviour.

Who developed the theory?

Psychologist Leon Festinger, in 1957.

Why does it lead to bad reasoning?

Because the easiest way to remove the discomfort is to rationalise — editing your beliefs to justify what you’ve already done, instead of rethinking the action.

Cognitive dissonance

Also called the discomfort of two clashing truths · Social psychology

Cognitive dissonance is the mental discomfort of holding two beliefs — or a belief and an action — that clash. To ease it, we usually don’t change the behaviour; we change the belief, quietly rewriting what we think so it fits what we’ve already done.

How it works

The mind seeks internal consistency, so a contradiction between what we believe and how we act creates tension. Since the action is often already taken and hard to undo, the cheaper repair is to adjust the belief — rationalising, discounting, or reinterpreting until the conflict dissolves.

How to use it

Noticing when a new opinion conveniently justifies something you already did or bought.
Reducing dissonance honestly — by changing the action — rather than editing your beliefs to excuse it.
Understanding why people dig in harder after being shown they’re wrong.

Worked example

After choosing between two similar job offers, people rate the one they picked as much better and the one they rejected as worse than they did before deciding — resolving the “did I choose right?” tension by inflating the choice they made.

Where it fails

The discomfort is real and useful — it’s a signal that something doesn’t fit. The failure mode isn’t feeling it but resolving it dishonestly, bending beliefs to protect an action instead of letting the clash prompt a genuine rethink.

The deeper point

Its most useful reframe is to treat the discomfort as data, not noise: the itch of dissonance points precisely at the place where your story and your evidence disagree. Most people scratch it by editing the story; the discipline is to let it edit you.

Frequently asked

What is cognitive dissonance?: The discomfort of holding two conflicting beliefs, or a belief that clashes with your behaviour, which we tend to resolve by changing the belief rather than the behaviour.
Who developed the theory?: Psychologist Leon Festinger, in 1957.
Why does it lead to bad reasoning?: Because the easiest way to remove the discomfort is to rationalise — editing your beliefs to justify what you’ve already done, instead of rethinking the action.

Confirmation bias The sunk cost fallacy Second-order thinking Inversion Wikipedia: Cognitive dissonance

The books behind better thinking

Thinking, Fast and Slow — Daniel Kahneman
The Art of Thinking Clearly — Rolf Dobelli
The Great Mental Models, Volume 1 — Shane Parrish
Poor Charlie’s Almanack — Charlie Munger
Super Thinking — Gabriel Weinberg & Lauren McCann
Seeking Wisdom — Peter Bevelin

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Editorial synthesis © ReadGlobe 2026, drawing on the mental-models tradition (Charlie Munger, Farnam Street) and the primary sources for each model. · Last reviewed 2026-07-01.