Field of Science

How normal is WEIRD?

It's a shocking fact, but pretty much everything we think we know about human behaviour derives from studies of US undergraduates - the psychologists' 'lab rat'! These people are WEIRD (Western, Educated, Industrialized, Rich, and Democratic) in more ways than one.

A paper from three psychologists at the University of British Columbia lays out in stark detail just how unusual the WEIRDs are, at least from a global perspective. First off, some stats to give you an idea of just how big the problem is. Of studies published in the top psychology journals:

  • 96% of subjects come from Western industrialized countries, which have only 12% of the world's population. And the USA alone accounts for 68% of all study subjects.
  • 99% of the investigators live in these countries, and 73% live in the USA.
  • 67% of US studies, and a staggering 80% of studies in other countries, use a study population comprised solely of psychology undergraduates!

Interestingly, this doesn't simply represent the US lead in science overall. Psychology is simply a much more popular (or well funded) subject in the USA. Whereas 70% of psychology studies come from the USA, only 37% of chemistry studies do.

Does this matter? It sure does!

When studies have been done of people outside the narrow group of WEIRDs, the results are often surprising - and conflict with some cherished theories about evolutionary psychology.

Take, for example, two games that are frequently used to try to understand how people share and co-operate - the Dictator Game and the Ultimatum Game. Studies done in the West have shown that people don't behave rationally in these games - they're more generous than they should be, and willing to take a hit in order to punish offenders.

Cue all sorts of theories about how we've evolved to operate in groups and, 'for the good of the group' are intuitively more trusting than hard rationality would predict.

But when you do these studies in people living in small-scale societies (foragers, subsistence farmers, and the like), you find that the US is a glaring outlier.

The figure shows how much people offer in the Dictator Game. Both players are totally anonymous strangers. The idea is that you need to offer as little as you think you can get away with without making the other player go off in a huff. In the USA, most players offer rather a lot - nearly 50% of what they have. But in small-scale societies, where dealings with strangers are rare, it tends to be much lower.

What these results suggest is that the pro-sociality shown by US undergraduates is not a consequence of evolution at all. Instead, it's something they learn, as a tool to help them exist in a complex society where you frequently have to interact with strangers.

So what do all these revelations mean for the psychology of religion? A couple of things, I think.

Firstly, the Dictator Game and the Ultimatum Game are standard tools to test the effects of religion. The idea is that religion - specifically the idea that a supernatural being is watching you - has an important effect in making people more honest.

So, for example, back in 2007 a study showed that religious priming did indeed increase the pro-sociality of Canadian students (whether or not they were religious themselves). But there was no effect in non-students (often older people). This suggests that the students were still learning the rule book for living in their complex world, and that's why religious priming worked.

And the second thing to consider (and this is something that I always wonder about when reading about studies on religion done in the USA) is that the USA is not typical even among Western industrialized nations.

The US is much more religious than other similar countries, and atheists are far more distrusted. What this means is that, in the US, being religious is a badge that shows you are normal and want to fit in. That you are prosocial, in other words.

So we have endless studies from the US showing that prosocial people tend to be religious. As a result, researchers have concluded that religion helps people to be prosocial. Well, maybe. But I'd like to see those studies conducted in a people other than US psychology undergrads before making my mind up!
Henrich, J., Heine, S. J., & Norenzayan, A. (in press). The Weirdest people in the world? Behavioral and Brain Sciences.

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.


  1. As so often, you have put me onto yet another fascinating study. Thanks a lot!

  2. I'm not sure the data is really a problem for evolutionary psychology. I have read only a few things about EP but my understanding is that EP would say that our deep time ancestors evolved a mental 'mechanism' for determining how to share and that 'mechanism' is then 'adjusted' by the socialization process. I don't see anything in the data that would show that view to be wrong.

  3. I agree that US population is over studied.How about sponsoring research in other parts of the globe.One could get more interesting data.Also get information from religious primed with non christian religions. When you study differences among religions in US,you get data corrupted by influence of modernity.This might not be the case if you study the same in developing world.For example you might find Indians to be less giving than Pakistanis.You might find Christians to be more giving than Hindus etc.Anybody interested in funding studies on Indians?:-)

  4. jdhuey, the full story (as they describe it in the paper) is that Martin Nowak, a leading computational modeller of these games, analysed the findings from the USA and showed that they are a long way from the rational response. But the findings from small-scale societies are much closer to what you would predict. The implication is that the US undergraduates have learned to be trusting of anonymous strangers as a result of the complex, law-bound society they live in.

  5. Dheeraj, I think there's increasing interest in studies outside the west. I've blogged a few over the past year or so. Although they are difficult to set up (because the researchers with the money live in the West), there are some benefits too.

    For example, Dan Ariel (author of predictably rational) has been studying how bonuses affect performance. He does a lot of this work in middle income countries because he can afford to pay participants there what they regard as a large sum of money!

  6. Crazy timing, I just for the first time read about the Dictator game and Ultimatum game not two days ago, reading Steven Pinker's The Blank Slate. This definitely is enlightening!

    One thing though, the entire range is 25%-50%, which is clearly significant, but I don't think it undermines the idea that at least some of the effect observed in the Ultimatum game is a result of evolution. 25% is still an awful lot to give if you assumed both participants were purely rational actors.

  7. Also, is there a typo in your post? Unless I am getting the two confused, the graph must be showing the Ultimatum game, not the Dictator game as it says in the prose to the left of the graph. My understanding was that even in the US, the Dictator game resulted in much much smaller sums being offered.

  8. A typo??? Impossible! Must be something wrong with your screen ;)

    Heh no I did check and it is the right graph. A purely selfish player should offer 0 in the Dictator game, so you're right - even the small-scale societies act irrationally.

    Apparently, however, the results of the Ultimatum Game (which I should've put instead, but anyway are in fact are pretty similar) are close to what you would predict from purely selfish behaviour.

  9. I don't see how the study undermines evolutionary psychology in particular. In fact, the authors (1) say they concur evolutionary explanations of behavior are important, and (2) explicitly praise evolutionary psychologists for doing more cross-cultural work than most.

    Also... 'for the good of the group'? That is practically heresy among evolutionary psychologists.

  10. Yeah I agree totally! Sorry if that wasn't clear.

    The problem is that evolutionary theory is at odds with the findings from psychology studies. This paper suggests that the reason for this is that the people psychologists are studying are WEIRD. That is, they've learned new behaviour to adapt to their unnatural, modern environment.

    If you accept this (and I guess not all psychologists would), then you don't need to turn to group theory to explain the apparent irrational altruism shown in psychology studies.


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