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Cognitive dissonance - why it's so hard to change our minds


The great physicist Max Planck, widely regarded as the father of quantum theory, was a true scientist. Planck always respected what the evidence showed, even if it was the opposite of what he previously researched and believed. 

But he observed that it was far harder to change the minds of others. His observation, the Planck Principle, also has a shorter and more succinct version - "Science progresses one funeral at a time." 

Ok, a nice, warm and morbid start to our discussion. 


But Plank's observation should be quite familiar to us. How often do you succeed in changing someone's mind in real life, even when the evidence is overwhelming?  And you would also notice, it is especially difficult if someone had publicly stated his view, or if the belief is tied in part to identity - for example, ever tried changing someone' political affiliation? 

One of the big reasons for this is what we call cognitive dissonance. 


  • Cognitive dissonance occurs when we are presented with new information or (are forced to ) perform a behaviour that contradcits with ur prior beliefs, values, or feelings.

  • There is a tension that is created between what we think we should do, and what we are doing or seeing.

  • This tension, what we term as dissonance, creates a discomfort within us. 

  • And we try to reduce this discomfort by reducing how we think about should act, and how we actually act.

How does this happen? First a short 5 minute video. It seems like it was made a century ago, but the content is good, and it features Leon Festinger, the psychologist who came up with cognitive dissonance himself. 

The experiment

  • Participants were asked to perform a series of dull tasks for over an hour, (such as repeatedly putting pencils into drawers, turning things 90 degrees) intended to bore them.

  • When the tasks were completed, the experimenter appealed to the participant to do a short briefing for the next waiting subject.

  • Participants were promised either a $1 or $20 incentive (randomly assigned) if they told the next waiting subject that the tasks were really interesting. 

  • After the participants had done the briefing, they were asked about their own honest assessment of whether they found the tasks enjoyable:

    • Those paid $20 openly shared that they found the tasks terribly boring​

    • Those paid $1 shared that they enjoyed the tasks and found them interesting

  • What??​  What happened?? Why would people who were paid $1 lie that they enjoyed the tasks when they clearly didn't? And why did those paid more not lie about it? 

Understanding Cognitive Dissonance


  • All the participants didn't enjoy the tasks. 

  • So when they described the tasks to the next batch of subjects, everyone lied. 

  • They were then asked to share their honest review. If they had been asked what their opinion was before having to explain to the subjects, all their answers would have likely been the same.

  • But having taken action, humans naturally feel the need to justify we have done.

  • For those paid $20, the incentive was enough to justify their act of lying, i.e. "I was willing to tell the new subject it was enjoyable even when I didn't actually think so because I received a good incentive." The dissonance they feel is resolved from the money they received. 

  • But for those paid just $1, it's much harder to justify to themselves (and to the experimenter) why they had willingly told such a big lie for such a small incentive, i.e. "I thought the tasks were really boring; yet I told the subjects the tasks were interesting for just a small token of $1. There is a dissonance that causes them great discomfort.

  • And so these participant sought to resolve their dissonance. They convinced themselves that they really thought the tasks were enjoyable. This way, it it would not violate any existing beliefs. If they "really enjoyed" the tasks, then they did not lie, they did not succumb to doing something opposite of what they thought for just a meagre sum of $1. 

  • The dissonance is resolved. 

Or as Festinger puts even more starkly:

||    "The general principle seems that people come to believe in and to love the things they have to suffer for."

We see examples of cognitive dissonance very regularly in our lives

  • We want to lose weight
  • We end up eating far too much and exercising far too little
  • So we tell ourselves hat it's ok because diet starts next month, and we diet really hard the next month.  

It could be a change that we want to make in life:​

  • We're unhappy with our job​

  • but we're scared to make a change

  • So we convince ourselves that perhaps the opportunity that came wasn't right for us.

We see this in our interactions with friends and family:​

  • We want to spend more time with the people that matter​

  • But hey it's a busy period, colleagues are working hard, you don't want to look bad in comparison

  • So we console ourselves that we had the best intentions to spend time with friends and family, but this is just a bad month. 

In particular, cognitive dissonance is very evident in some of the most thorny issues today. Take this experiment for example:

climate change 2 groups.jpg

University College of London wanted to test how people's views are influenced by new evidence. They gathered a group of climate change deniers and believers and split them up into 2 groups (both groups had believers and deniers). 

Group A was told that recent evidence from scientists suggests that climate change will be much worse than originally forecasted. 
Group B was told the opposite, that recent evidence suggests climate is far less serious than originally forecasted.


So did new evidence influence the participants?

Climate change bad.jpg
climate change not so bad.jpg

The results can be seen in the 2 pictures above (if you're on mobile, click to magnify). 

It's not surprising since we have just gone through cognitive dissonance. New evidence only matters if it fits our original view:


In Group A, believers accepted the new evidence and were now more worried about the adverse impact of climate change. Deniers on the other hand rejected the new evidence, claiming that the scientists faked the data or had an agenda.


In Group B, the exact opposite. Deniers laughed off climate change as the hoax they always believed it to be, while it was now the belivers that claimed fake data or scientist agenda. 


And this experiment is a great example of how cognitive dissonance amkes it so difficult for us to change our minds, what Max Planck observed at the very top of the page. To avoid dissonance, our minds can still find ways to harmonise what we believe with what is reality by devising the most complicated justifications. 

To reduce dissonance, we often choose comforting lies to explain things away, rather than face unpleasant truths.

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