A review of Mathematical Models of Social Evolution: A Guide for the Perplexed by Richard McElreath and Robert Boyd. The University of Chicago Press (2007), 432 pages, £16.00 ($25.00), ISBN: 0226558274 (paperback); and Why Humans Cooperate: A Cultural and Evolutionary Explanation by Natalie Henrich and Joseph Henrich. Oxford University Press (2007), 272 pages, £20.00 ($35.00), ISBN: 0195314236 (paperback)
We discuss theoretical and empirical arguments for a human bias to acquire information individually rather than socially. In particular, we argue that when other people can be observed, information collection is a public good and hence some of the individual variation in the choice between individual and social learning can be explained by variation in social value orientation. We conducted two experimental studies, based on the game Explore & Collect, to test the predictions that (1) socially and individually acquired information of equal objective value are treated differently, and (2) prosocial subjects tend to spend more effort than selfish subjects on individual acquiring of information. Both predictions were supported.
Over-punishment often occurs in anonymous peer-to-peer punishment in public goods game experiments where punishment is free for all. We report a public goods game experiment in which a condition where punishment rights were restricted to one other player per player yielded higher total welfare than a condition with unrestricted punishment. In the restricted punishment condition, there was much less punishment but high levels of cooperation were achieved nonetheless. This indicates that it may be beneficial to groups to restrict punishment rights. In a second study we presented respondents from many different countries with three scenarios constituting everyday social dilemmas of various kinds. Across countries, respondents tended to judge it as inappropriate for most involved parties to punish selfish individuals in the scenarios. Typically, only one party was judged to have the right to punish. Whereas much prior work has considered punishment as a public good that needs to be encouraged, these findings suggest that informal norms about sanctions tend to constrain punishment to certain individuals. Such norms may serve the function to harness the positive effects of punishment while containing the negative effects, and we suggest that they are likely to arise from learning.