How did humans come to dominate the Earth?

How did humans come to dominate the Earth?

Humans have the unique ability to organise and co-operate in large groups and have “a complex morality emphasising responsibility to others that is enforced through reputation and punishment”. Such co-operation has deep evolutionary roots and De Waal and others have been studying this in chimpanzees and bonobos, our closest living relatives.

Studies of co-operation among primates reach three main conclusions. Firstly, primates co-operate widely with each other and not only with direct kin. Secondly, co-operation is often a reciprocal arrangement and favours received are remembered: a chimp is more likely to share food in the afternoon with another chimp who groomed him that morning. Thirdly, co-operation can be motivated by empathy. De Waal describes an interesting experiment: two monkeys sit together, and one selects a coloured token from a choice of two colours; one colour rewards only that monkey, the other colour rewards both monkeys. After a little experience of the game, the choosing monkey mostly picks the colour that rewards both monkeys. …

Co-operation brings great benefits. Mutualistic co-operation – working together for a goal that benefits all – is the most widespread form of co-operation, and it brings immediate benefits (for example, a pack of hyenas bringing down a zebra). Mutualistic co-operation encourages more subtle co-operation such as sharing; if one animal reaped all the rewards mutualistic co-operation would collapse. Animals and humans are very sensitive to fair sharing and De Waal quotes experiments showing monkeys, dogs and social birds rejecting rewards smaller than those offered to companions doing the same task. …

By William Reville, for The Irish Times

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