Paternity and parental investment

The Economist:

MEN are doomed to uncertainty. Women know who their children are, but the ubiquity of sexual cheating makes it difficult for males of many species, humans included, to be sure which youngsters actually belong to them. If a male’s reproductive strategy amounts to little more than “Wham, bam, thank-you ma’am”, this may not matter to him much. But if, as in the human case, he takes an interest in his offspring, it matters a lot. There are few more foolish actions, from an evolutionary point of view, than raising another male’s progeny.
This line of reasoning led Alexandra Alvergne and her colleagues at the University of Montpellier, in France, to wonder if human fathers recognise features of children that might give away whose offspring they really are, and use those to guide the amount of attention doled out to each putative son and daughter. To find out, they established an experiment among villagers in the Sine Saloum region of Senegal, where polygynous marriages (ie, men with multiple wives) are common. In such societies the incentives for unmarried men and the opportunities for neglected women to engage in what zoologists who study other harem-forming species refer to as “sneaking” are particularly high. It gives the men a chance to reproduce and the women a chance to spread their bets.