What Is Cognitive Dissonance?

The definition of cognitive dissonance is the mental discomfort people feel when trying to hold two conflicting beliefs in their mind.

cognitive dissoancne

The definition of cognitive dissonance is the mental discomfort people feel when trying to hold two conflicting beliefs in their mind.

The ground-breaking social psychological experiment of Festinger and Carlsmith (1959) provides a central insight into the stories we tell ourselves about why we think and behave the way we do.

The experiment is filled with ingenious deception so the best way to understand it is to imagine you are taking part. So sit back, relax and travel back.

The time is 1959 and you are an undergraduate student at Stanford University…

(Alternatively, you can skip straight to what is cognitive dissonance.)

As part of your course you agree to take part in an experiment on ‘measures of performance’.

You are told the experiment will take two hours.

As you are required to act as an experimental subject for a certain number of hours in a year – this will be two more of them out of the way.

Little do you know, the experiment will actually become a classic in social psychology.

And what will seem to you like accidents by the experimenters are all part of a carefully controlled deception.

For now though, you are innocent.

Cognitive dissonance: the set-up

Once in the lab you are told the experiment is about how your expectations affect the actual experience of a task.

Apparently there are two groups and in the other group they have been given a particular expectation about the study.

To instil the expectation subtly, the participants in the other groups are informally briefed by a student who has apparently just completed the task.

In your group, though, you’ll do the task with no expectations.

Perhaps you wonder why you’re being told all this, but nevertheless it makes it seem a bit more exciting now that you know some of the mechanics behind the experiment.

So you settle down to the first task you are given, and quickly realise it is extremely boring.

You are asked to move some spools around in a box for half an hour, then for the next half an hour you move pegs around a board.

Frankly, watching paint dry would have been preferable.

At the end of the tasks the experimenter thanks you for taking part, then tells you that many other people find the task pretty interesting.

This is a little confusing – the task was very boring. Whatever. You let it pass.

Effects of cognitive dissonance

Then the experimenter looks a little embarrassed and starts to explain haltingly that there’s been a cock-up.

He says they need your help.

The participant coming in after you is in the other condition they mentioned before you did the task – the condition in which they have an expectation before carrying out the task.

This expectation is that the task is actually really interesting.

Unfortunately the person who usually sets up their expectation hasn’t turned up.

So, they ask if you wouldn’t mind doing it.

Not only that but they offer to pay you $1.

Because it’s 1959 and you’re a student this is not completely insignificant for only a few minutes work.

And, they tell you that they can use you again in the future.

It sounds like easy money so you agree to take part.

This is great – what started out as a simple fulfilment of a course component has unearthed a little ready cash for you.

You are quickly introduced to the next participant who is about to do the same task you just completed.

As instructed you tell her that the task she’s about to do is really interesting.

She smiles, thanks you and disappears off into the test room.

You feel a pang of regret for getting her hopes up.

Then the experimenter returns, thanks you again, and once again tells you that many people enjoy the task and hopes you found it interesting.

Then you are ushered through to another room where you are interviewed about the experiment you’ve just done.

One of the questions asks you about how interesting the task was that you were given to do.

This makes you pause for a minute and think.

Now it seems to you that the task wasn’t as boring as you first thought.

You start to see how even the repetitive movements of the spools and pegs had a certain symmetrical beauty.

And it was all in the name of science after all.

This was a worthwhile endeavour and you hope the experimenters get some interesting results out of it.

The task still couldn’t be classified as great fun, but perhaps it wasn’t that bad.

You figure that, on reflection, it wasn’t as bad as you first thought.

You rate it moderately interesting.

After the experiment you go and talk to your friend who was also doing the experiment.

Comparing notes you found that your experiences were almost identical except for one vital difference.

She was offered way more than you to brief the next student: $20!

This is when it first occurs to you that there’s been some trickery at work here.

You ask her about the task with the spools and pegs:

“Oh,” she replies. “That was sooooo boring, I gave it the lowest rating possible.”

“No,” you insist. “It wasn’t that bad. Actually when you think about it, it was pretty interesting.”

She looks at you incredulously.

What the hell is going on?

What is cognitive dissonance?

What you’ve just experienced is the power of cognitive dissonance.

Social psychologists studying cognitive dissonance are interested in the way we deal with two thoughts that contradict each other – and how we deal with this contradiction.

In this case: you thought the task was boring to start off with then you were paid to tell someone else the task was interesting.

But, you’re not the kind of person to casually go around lying to people.

So how can you resolve your view of yourself as an honest person with lying to the next participant?

The amount of money you were paid hardly salves your conscience – it was nice but not that nice.

Your mind resolves this conundrum by deciding that actually the study was pretty interesting after all.

You are helped to this conclusion by the experimenter who tells you other people also thought the study was pretty interesting.

Your friend, meanwhile, has no need of these mental machinations.

She merely thinks to herself: I’ve been paid $20 to lie, that’s a small fortune for a student like me, and more than justifies my fibbing.

The task was boring and still is boring whatever the experimenter tells me.

Examples of cognitive dissonance

Since this experiment numerous studies of cognitive dissonance have been carried out and the effect is well-established.

Its beauty is that it explains so many of our everyday behaviours.

Here are some examples provided by Morton Hunt in ‘The Story of Psychology:

  • When trying to join a group, the harder they make the barriers to entry, the more you value your membership. To resolve the dissonance between the hoops you were forced to jump through, and the reality of what turns out to be a pretty average club, we convince ourselves the club is, in fact, fantastic.
  • People will interpret the same information in radically different ways to support their own views of the world. When deciding our view on a contentious point, we conveniently forget what jars with our own theory and remember everything that fits.
  • People quickly adjust their values to fit their behaviour, even when it is clearly immoral. Those stealing from their employer will claim that “Everyone does it” so they would be losing out if they didn’t, or alternatively that “I’m underpaid so I deserve a little extra on the side.”

Once you start to think about it, the list of situations in which people resolve cognitive dissonance through rationalisations becomes ever longer and longer.

If you’re honest with yourself, I’m sure you can think of many times when you’ve done it yourself.

I know I can.

Being aware of this can help us avoid falling foul of the most dangerous consequences of cognitive dissonance: believing our own lies.

→ This post is part of a series on the best social psychology experiments:

  1. Halo Effect: Definition And How It Affects Our Perception
  2. Cognitive Dissonance: How and Why We Lie to Ourselves
  3. Robbers Cave Experiment: How Group Conflicts Develop
  4. Stanford Prison Experiment: Zimbardo’s Famous Social Psychology Study
  5. Milgram Experiment: Explaining Obedience to Authority
  6. False Consensus Effect: What It Is And Why It Happens
  7. Social Identity Theory And The Minimal Group Paradigm
  8. Negotiation: 2 Psychological Strategies That Matter Most
  9. Bystander Effect And The Diffusion Of Responsibility
  10. Asch Conformity Experiment: The Power Of Social Pressure


Author: Dr Jeremy Dean

Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology. He has been writing about scientific research on PsyBlog since 2004.

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