Thursday, June 11, 2015

Chimpanzees Cooking

What do you have to say to this statement by psychologist Felix Warneken ?

“The logic is that if we see something in chimpanzees’ behavior, our common ancestor may have possessed these traits as well. If our closest evolutionary relative possesses these skills, it suggests that once early humans were able to use and control fire they could also use it for cooking.”

I would say that one has to be very careful in drawing general implications about ancestral abilities from the behavior of chimpanzees. They are not some frozen Pliocene ape. The human-chimpanzee split from our common ancestor may have occurred 7-8 million years ago. Since divergence,  the lineage that led to chimpanzees has been evolving for the same amount of time as our lineage. Many aspects of modern chimpanzee behavior may not reflect the ancestral condition but instead may have evolved later in their evolutionary history.

What the study that is described in the Guardian shows is that chimpanzees prefer cooked food to raw food and have abilities to defer instant gratification for later preferred reward. This though need not be restricted to cooked food. You could conceivably show that they for example behave the same way if given a choice between a raw and a ripe fruit. Or for that matter something not to do with food at all. There is no evidence that chimpanzees throw raw meat in natural forest fires and come back and eat the cooked meat. Awaiting for cooked food does not mean they posses "most of the intellectual abilities required for cooking"

And nor did our very early human ancestors. One implication drawn from these chimpanzee "cooking" experiments is that our ancestors may have developed a taste for grilled meats early on (possible) and the timeline for cooking may have to be shifted to an earlier date. I don't see the latter connection at all. The oldest confirmed evidence for cooking is about 1 million years ago, although some scientists like Richard Wrangham based on changes in physiology (larger brain, smaller molars)  seen in the fossil record push it back to around 2 million years ago.  Even assuming that the chimpanzees preference for cooked food reflects the ancestral state, one can't draw a connection between that and cooking appearing earlier in our lineage. It took 4-5 million years after our lineage split from the chimpanzee for us to evolve the ability to control fire and the addition of deliberately cooked food as part of our regular diets. That is hardly "early". It took a long time, in fact cooking has been absent for most of the time of our lineages existence, and it was contingent on a host of other unique changes in our cognition, social evolution and our abilities to use our limbs to manipulate objects.

There was nothing inevitable about it.. one just has to look at the chimpanzees. In fact, this precaution taken during the experiments gives the game away-

“Originally we thought of setting up a camping cooker in their sleeping area, but you could imagine them getting hold of a gas tank or burning themselves,” said Warneken. “This was not a viable option.”

It was not a viable option because chimpanzees don't even come close to possessing most of the required abilities to cook.

That is one of the problems of drawing sweeping evolutionary implications about behavior from contrived experimental situations.  They just don't bear any resemblance to behavior in the natural state.

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