Chimps more “rational” than humans

Chimps play the ultimatum game more "rationally," that is to say more in line with standard economic models, than do humans.  I’m not sure whether this says more about chimps or economists.

Thanks to Jeff Smith for the pointer.


researchers concluded chimpanzees do not show a willingness to make fair offers and reject unfair ones. In this way, they protect their self interest and are unwilling to pay a cost to punish someone they perceive as unfair

reputation must not matter to chimps

Chimps love Ayn Rand!

Game theory is for chimps?

We are inclined to punish unfairness because we recognize that very few things are one-time deals, and punishing unfairness is perfectly rational if this is something that will be repeated again and again. While punishing someone for an unfair share may be irrational in this case (I assume that it's framed such that this is a one-time thing), the fact they still do is perfectly understandable because this one-time-thing is rare and unrealistic in real life and thus we instinctively pursue fairness. Irrational? Yes. Understandable? Yes, because in most real-life cases, it is perfectly rational.

As for the person doing the dividing, as long as there is a reasonable expectation that there will be punishment for unfairness (even if it is irrational), the person doing the dividing will have an incentive to divide fairly.

"Has anyone ever conducted this experiment with real money? I mean it's one thing to reject an "unfair" proposal when someone offers you $.50 out of $5. Not too costly to send a message. What would happen if the proposal was $500 out of $5000? would the fairness bug still bite people? I kind of doubt it. I think the fact that grapes are important to chimps, $.50 not so important to most people can help explain these results."

The traditional way to test this hypothesis is to run your experiment in a poor country, so that your experimental budget can allow for stakes that are large relative to local wage rates.

Here is one such study of the ultimatum game, played in the Slovak Republic, with maximum stakes equal to 62.5 hours of work.

They found that initially, (1) offers were similar between low and high stakes versions of the game and (2) rejection rates of low offers were slightly lower in the high stakes version. But as the game was repeated (with different partners, to avoid repeated game effects), the average offers went down.

It means economists are nothing but monkeys

I gather that the interesting question is whether there are more one-time deals now, in modern society, than there were in the past.

It doesn't really matter if the deal is one-time in the sense that you'll never make a deal with that person again. If the deal is merely observed or is public knowledge (or may become public knowledge), then reputation matters. In modern society, it is much harder to escape a bad reputation -- you can't just move where nobody knows you or switch into a different line of business, because it's too easy for people in the new place or industry to find out about you now.

Brian Hollar,

Uh oh! I can see TV network executives coming up with the next variation of "Dancing with the Stars".

I think when they do these sorts of tests in "primitive" societies the results are very much in line with the chimp tests.

Chimpanzees have a rule. This rule is it doesn't matter who you are or what your position is in the group, you can't take away food from another chimpanzee. You can ask to be given some food (beg) but it's entirely up to the other chimp how much food to give, if any, and the begging chimp has to be satified with what they get no matter how small. The results of the study are entirely consistant with normal chimpanzee behaviour. This behaviour appears common to all chimp societies. Human however make more complex rules about what can be taken and what should be given. These are formalized by tradition or, since the advent of civilization, by law. These rules exist in all human societies including those of hunters and gatherers.

Sorry, it's figure 1 in the Blount paper (above) not table 1.

To be fair, there is a "3rd party treatment" in the Blount paper and the acceptances do shift from the typical results (also replicated by Blount, although less extreme than the results that are usually cited). The "third party" treatment does not generate the same acceptances as the "randomly generated" proposals treatment because in the third party treatment the subjects expect that the third party (human) will have some notion of "fairness" (I hate that word - it has 31 meanings on or "equal splits" (this is table 1). Again, I would think that chimps would view the appearance of food in a pot as a random division, not a 3rd party division, but I can't speak intelligently on the thoughts of chimps.

Another resource for pondering from Scientific American Mind

Is Greed Good?
Economists are finding that social concerns often trump selfishness in financial decision making, a view that helps to explain why tens of millions of people send money to strangers they find on the Internet
By Christoph Uhlhaas

i like it!

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