Mathew Iredale: «SciPhi Issue 33»

«We are used to be being told by the latest scientific research how similar we are to our ape cousins, especially chimpanzees.

Tool use, once thought to be a uniquely human activity, has been observed many times in wild chimpanzees. More extraordinary is the fact that captive chimpanzees have been taught sign language, and in some cases have taught it to their offspring. And research into the chimpanzee genome has just been published which suggests that we share as much as 99% of our functional DNA with chimpanzees.

But despite all these examples, significant differences still exist between humans and chimps. Humans are a very social species. Experimental evidence indicates that people willingly incur costs to help strangers in anonymous one-shot interactions, and that altruistic behaviour is motivated, at least in part, by empathy and concern for the welfare of others. But such behaviour does not appear to be shared by chimpanzees, in which cooperative behaviour is mainly limited to family members and reciprocating partners, and is virtually never extended to unfamiliar individuals.

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It might have been a different matter if chimp behaviour were also influenced by indirect reciprocity. Indirect reciprocity can be summed up by the principle: “You scratch my back and I'll scratch someone else's” or “I scratch your back and someone else will scratch mine”. But there is little or no evidence of indirect reciprocity amongst chimpanzees.

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Direct reciprocity does not require the same intellectual or linguistic abilities as indirect reciprocity. Imagine that chimp A has some food and chimp B does not. If A gives some of his food to B then he will expect to get something in return. Most obviously, at a later date when B has some food and A does not, A will expect B to give him some. This is a basic reciprocal relationship. If B decides not to reciprocate, then A may try to punish him in some way, either through the use of physical force or simply by not cooperating with him in the future. The point to note here is that even though the chimps are unable to speak it does not affect the outcome, for better or worse, of the relationship between them. Nor does this relationship require any intellectual skills beyond remembering that “I gave B some food” (for chimp A) and “A gave me some food” (for chimp B).

Indirect reciprocity, by contrast, does require significant intellectual and linguistic skills. It requires linguistic skills because it is based upon reputation, and for my reputation to be established and to grow requires that individuals are able to tell each other what I did.

It requires significant intellectual skills because instances of indirect reciprocity are far more complex than instances of direct reciprocity. As Nowak and Sigmund state:

• Indirect reciprocity requires information storage and transfer as well as strategic thinking and has a pivotal role in the evolution of collaboration and communication. The possibilities for games of manipulation, coalition-building and betrayal are limitless. Indirect reciprocity may have provided the selective challenge driving the cerebral expansion in human evolution.

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From this we can see the beginnings of a possible explanation as to why it is humans who have developed a sense of morality and not other species. Direct reciprocity does not require any moral judgement to be made. It is, in a sense, just a very sophisticated variation of a symbiotic relationship. But indirect reciprocity is another matter entirely.

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(Retirado do The Philosopher´s Magazine Online; ler na íntegra.)