Friday, October 28, 2005

intruiging monkey behavior studies

Two very interesting studies of primate behavior that I want to mention! Both have interesting and amusing parallels with human behavior, of course...

Both were also reported by Science Now, which is the journalism wing of the journal Science. (Not to be confused with the military wing...)

First, researchers at Harvard looked at when different species of monkey would be willing to forsake an immediate food reward for the opportunity to get a larger food reward later. They compared marmosets and tamarins, which have interestingly different lifestyles. Marmosets apparently spend a lot of time chewing on trees to get at sap, which takes a while, while tamarins grab bugs and eat them, which is fast. They found that marmosets will wait longer than tarmarins for a larger reward, but will move less far than tamarins for the reward. So you might say that marmosets are lazy, but not greedy, while tamarins are impatient, but active. I, for one, am definitely with the marmosets on this one...

I'm not so much with the chimps, though. Selfish bastards, really. A team at UCLA built this setup where they had two chimps in adjacent cages. Chimp A had two levers in its cage. One lever gave it a pellet of food, while the other lever gave a pellet of food to both it and to chimp B. That is, chimp A could see that it could give food to chimp B, or not, without affecting how much food it itself got. Alas, they found that the chimps weren't altruistic at all, and wouldn't give the other chimp food at a rate higher than chance. And this was true regardless of who the other chimp was -- even if it was a sibling or other close relative! And even if the other chimp was noisily complaining! This is, to me, quite surprising, given that chimps live in social groups with family, use tools and have at least some basic communication. Sociobiology would also predict that an animal should at least help out its relatives. Apparently even human teenagers, a selfish lot by and large, will give the reward very consistently, but one of our closest non-human relatives don't seem to. One wonders if bonobos, which are well known for their, uh, kindness towards their troop-mates, would respond differently in this task...


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