The Difference Between Americans and Humans?

The academic psychologist Joseph Henrich brought the Ultimatum game to the Amazon jungle and found that the Maschiguenga people of southeastern Peru make decisions like economists: “[T]hey felt rejecting was absurd, which is really what economists think about rejection. It’s completely irrational to turn down free money.” This led him to hypothesize that maybe they’re not the outliers — but that we Western, educated, industrialized, rich, democratic (weird) folks are. His new paper in Behavioral and Brain Sciences asks a trenchant question: since 96% of the test subjects in behavioral science are from the West, with the U.S. owning 70% of all journal citations, can such experimental results really speak for the entire human race? [%comments]

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  1. Gary says:

    My intuition is that how cultural groups see this (and the world in in general) is correlated to availability of calories. Where calories are scarce, it would be foolhardy to reject even a little bit that can sustain your survival. Group cooperation also is advantageous. Where calories are abundant, you easily can afford much more altruistic generosity and individuality.

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  2. Brian S says:

    My understanding was formerly that the ultimatum game was played with an extremely diverse population. If the above is true, then the question “can data primarily gathered on Americans be applied to wider ranges of people?” is an emphatic NO.

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  3. Eric M. Jones says:

    Since 98% of the books on human psychology are written by men, I have always suspected that women’s psychology has not been well represented in the literature.

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  4. KevinH says:

    Valid question, but it doesn’t mean we should evenly distribute our subjects across the globe. Obviously the west has more incentive to learn how westerns think than a hypothetical average human. If we want to solve the west’s economic and political problems, or make projections about behavior in the west, we need to study westerners.

    The biggest impact I see this having is on developmental econ, where you might want to do some testing on the population in the area you are trying to develop and adjust your strategies based on how they interpret signals/incentives.

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  5. Ian Kemmish says:

    Isn’t that sample also hugely skewed towards undergraduate students? I’ve only twice been asked to take part in psychology experiments, both times while I was at Cambridge. And if you watch a documentary about this stuff on TV, the experimental groups are almost always exclusively composed of students.

    As a layman (and mathematician and software engineer), I’ve always ASSUMED that these experiments only describe the behaviour of undergraduates. If the experts really are assuming that the results are universal, it would be a rare example of the scientists being less cautious than the laymen!

    I’d even wager a modest amount that if you played the Ultimatum Game with middle-aged people, a significant number would refuse to play at all, suspecting a scam. Avoiding scams is one situation in which turning down “free money” is indeed rational.

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  6. Ryan says:

    Assuming that people only care about money is rather unjustified. If you value punishing the greedy more than whatever money you would have gotten, then the ‘correct’ response is to reject the offer.

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  7. KevinM says:

    Ian: Not turning down free money is also the explanation for the undergraduates’ participation in psych experiments – further skewing the pool. Not to mention that a lot of those undergraduates are serial study participants who may themselves have studied psychology.

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  8. Jay says:

    I’d bet that there is a pretty strong correlation between the level of competition in a society and the rejection rate in the game. In more competitive societies, people are more likely to measure their own wealth relative to their peers and the rejection point is likely to be higher. In more cooperative societies the participants are less likely to worry about what the other person gets, thus a lower rejection point.

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