  Do theories of the evolution of biological altruism apply to humans? This is part of the broader question of whether ideas about the evolution of animal behaviour can be extrapolated to humans, a question that fuelled the sociobiology controversy of the 1980s and is still actively debated today (cf. Boyd and Richerson 2006, Bowles and Gintis 2011, Sterelny 2012). All biologists accept that Homo sapiens is an evolved species, and thus that general evolutionary principles apply to it. However, human behaviour is obviously influenced by culture to a far greater extent than that of other animals, and is often the product of conscious beliefs and desires (though this does not necessarily mean that genetics has no influence.) Nonetheless, at least some human behaviour does seem to fit the predictions of the evolutionary theories reviewed above. In general, humans behave more altruistically (in the biological sense) towards their close kin than towards non-relatives, e.g. by helping relatives raise their children, just as kin selection theory would predict. It is also true that we tend to help those who have helped us out in the past, just as reciprocal altruism theory would predict. On the other hand, humans are unique in that we co-operate extensively with our non-kin; and more generally, numerous human behaviours seem anomalous from the point of view of biological fitness. Think for example of adoption. Parents who adopt children instead of having their own reduce their biological fitness, obviously, so adoption is an altruistic behaviour. But it does not benefit kin—for parents are generally unrelated to the infants they adopt—and nor do the parents stand to gain much in the form of reciprocal benefits. So although evolutionary considerations can help us understand some human behaviours, they must be applied judiciously.