Ultimatums Again

Today we have a new slant on the games that are designed to examine people’s response to unfair or fair play when playing the ultimatum game. You’ll recall that this is the game where a “proposer” offers to split the change in his/her pocket with you, the “responder”. If you accept, you get your share. If you reject the offer the government takes the lot and you both loose out.

What makes the game a test is that the offers may be “fair” (50:50, 40:60) or “unfair” (30:70, 20:80 or 10:90). Those deep in game theories will know that the winner of the group playing the game should take all offers as something is better than nothing. Punishing someone who makes an unfair offer by turning down 10% so that the proposer looses their 90% is letting emotion run over your theoreticians logic.

The latest twist that we have this week is from Takahashi et al whose study is published in the Proceedings of the National Academy of Science (1).  They took 20 young men and presented them with a stacked ultimatum game whereby a pre-programmed computer and not the other players made the offers to them.

But that’s not all. They were all given a PET scan where the interest was focused on the serotonin receptors in the Raphe nucleus (that’s at the top of the brain stem.) And there’s more. They were all given a psychiatric assessment of their personalities. Agreeableness or neurotic were the pigeonholes that their personalities were shoehorned into.

To put this together, low levels of serotonin meant the guys were honest and trustful, that is generally agreeable. High levels meant that they were more Machiavellian and consequently on the neurotic side.

What are your prejudices, I wonder? Agreeable guys would just take the hits and accept the offers, while our Machiavellian friends would do a bit of punishing if it was only going to cost them a 10% offer, but would deny the proposer their 90%, maybe?

Well, no. The nice guys were more outraged at being short-changed and punished hard because it was patently unfair. The Machiavellians just shrugged as it was just business and what’s fairness got to do with business? Guess they’re destined for Wall Street

  1. http://www.pnas.org/content/early/2012/02/13/1118687109.full.pdf

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