Why We All Stink as Intuitive Psychologists: The False Consensus Effect

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When we overestimate how much other people share our beliefs and behaviours.

Many people quite naturally believe they are good ‘intuitive psychologists’, thinking it is relatively easy to predict other people’s attitudes and behaviours. We each have information built up from countless previous experiences involving both ourselves and others so surely we should have solid insights?

No such luck.

In reality people show a number of predictable biases when estimating other people’s behaviour and its causes. And these biases help to show exactly why we need psychology experiments and why we can’t rely on our intuitions about the behaviour of others.

One of these biases is called the false consensus effect. In the 1970s Stanford University social psychologist Professor Lee Ross set out to show just how the false consensus effect operates in two neat studies (Ross, Greene & House, 1977).

False consensus

In the first study participants were asked to read about situations in which a conflict occurred and then told two alternative ways of responding. They were asked to do three things:

  • Guess which option other people would choose,
  • Say which option they would choose,
  • Describe the attributes of the person who would choose each of the two options.

The results showed more people thought others would do the same as them, regardless of which of the two responses they actually chose themselves. This shows what Ross and colleagues dubbed the ‘false consensus’ effect – the idea that we each think other people think the same way we do when actually they often don’t.

Another bias emerged when participants were asked to describe the attributes of the person who made the opposite choice to their own. Compared to other people who made the same choice they did, people made more extreme predictions about the personalities of those who made didn’t share their choice.

To put it a little crassly: people tend to assume that those who don’t agree with them have something wrong with them! It might seem like a joke, but it is a real bias that people demonstrate.

Eat at Joe’s!

While the finding from the first study is all very well in theory, how can we be sure people really behave the way they say they will? After all, psychologists have famously found little connection between people’s attitudes and their behaviour.

In a second study, therefore, Ross and colleagues abandoned hypothetical situations, paper and pencil test and instead took up the mighty sandwich board.

This time a new set of participants, who were university students, were asked if they would be willing to walk around their campus for 30 minutes wearing a sandwich board saying: “Eat at Joe’s”. (No information is available about the food quality at ‘Joe’s’, and consequently how foolish students would look.)

For motivation participants were simply told they would learn ‘something useful’ from the study, but that they were absolutely free to refuse if they wished.

The results of this study confirmed the previous study. Of those who agreed to wear the sandwich board, 62% thought others would also agree. Of those who refused, only 33% thought others would agree to wear the sandwich board.

Again, as before, people also made more extreme predictions about the type of person who made the opposite decision to their own. You can just imagine how that thinking might go. The people who agreed to carry the sandwich board might have said:

“What’s wrong with someone who refuses? I think they must be really scared of looking like a fool.”

While the people who refused:

“Who are these show-offs who agreed to carry the sandwich board? I know people like them – they’re weird.”

We’re poor intuitive psychologists

This study is fascinating not only because it shows a bias in how we think about others’ behaviours but also because it demonstrates the importance of psychology studies themselves.

Every psychologist has, at some point, been driven to distraction when trying to explain a study’s finding by one form of the following two arguments (amongst others!):

  1. I could have told you that – it’s obvious!
  2. No, in my experience that’s not true – people don’t really behave like that.

As this social psychology study shows, people are actually pretty poor intuitive psychologists. One of the few exceptions to this is when the answer is really really obvious, such as asking people whether it is OK to commit murder. But questions we can all agree on are generally not as interesting as those on which we are divided.

People are also more likely to assume someone who doesn’t hold the same views as them has a more extreme personality than their own. This is because people think to themselves, whether consciously or unconsciously, surely all right-thinking (read ‘normal’) people think the same way as me?

Well, apparently not. Although knowing that we don’t know other people is a great start.

And that is one good reason why we need psychology studies.

Image credit: Drew Leavy

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About the author


Dr Jeremy Dean is a psychologist and the author of PsyBlog. His latest book is "Making Habits, Breaking Habits: How to Make Changes That Stick". You can follow PsyBlog by email, by RSS feed, on Twitter and Google+.

Published: 6 November 2007

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Images: Creative Commons License