Reader Mark Spahn points us to this book review on the Gene Expression blog of Moral sentiments and Material Interests, edited by Herbert Gintis, Samuel Bowles, Robert Boyd, and Ernst Fehr.

The book's starting point is an empirical look at the actual economic behavior of individuals, in order to see whether it matches the rational-self-interest assumed by economic theory. It is found that it doesn't, and the actual behavior observed is next interpreted in terms of evolutionary psychology. Finally, the political and social significance of these new observations is sketched.

...The authors define three mechanisms leading to altruism and social cohesion: strong reciprocity, conformity, and "costly signaling". These are made possible by innate dispositions evolved in two steps -- simple reciprocity first at the early primate small group level, and the more complex behaviors next at the early human. Altogether they make possible genetic selection for altruism, via net fertility advantages for all members of organized social groups (not simply biological groups or kinship groups) which are successful because their members behave altruistically. Biological competition within the group is suppressed by non-innate social and cultural mechanisms, giving an advantage to members of the group on the average, but not to every individual. This way, with gene-culture coevolution and mutualism, there can be genetic selection for a degree of innate altruism in a way that there could not be without culture and society, which form a kind of artificial environment.

"Strong reciprocity" is what replaces "rational self-interest". It consists of the weak reciprocity described by Axelrod (initial cooperation, continued until the partner defects) plus an additional altruistic propensity to punish defectors even if there's no personal advantage in doing so. In a society of strong reciprocators (altruists both in giving and in punishment), defectors do not have an advantage, whereas in a society of non-punishing altruists, the defectors have an advantage which causes the defector gene to drive out the altruist gene.

Two other behaviors are mentioned. "Conformity" is a weaker principle explaining social uniformity in the absence of the threat of punishment, and mostly applies to cases in which there is no clearly-perceptible advantage or disadvantage for the individual, so he just does what everyone else does. "Costly signaling" only appears in one chapter, which uses the biological concept to explain generosity of the potlatch / largesse / big man type. To me these are less immediately interesting than strong reciprocity, though "costly signaling" is a step on the way toward defining a more complex heirarchal society extending beyond the face-to-face level.

A significant advantage of this book is that it describes a social world which, like the world observed and described by historians, has "multiple equilibria and tipping points" and is thus less stable and less predictable than the imaginary world of equilibrium economics.

Readers of my blog know that I have no sympathy for the simplistic ways that economists apply the apparent axioms of economics to complex real-world problems. Yet I find the fundamental assumption of "rational self interest" nevertheless a completely compelling axiom. We can argue about what is meant by "self" -- is it an individual, a family, a social collective, a gene? -- but regardless, assuming self interest somehow defined is a practical necessity: somehow, we have survived and prospered, so whatever it is we have been doing all these years must be rational self interest.

I fear that many who attack the science of economics for its embedded exaltation of "selfishness" are really engaging in culture warfare, not science. They start with the ethical commandment that individual's interests should be sacrificed to some greater good, and seek to undermine any purported science that seems to achieve reasonable explanatory and predictive power by assuming selfishness. If the nature of selfishness is more complicated that economics typically assumes, if it is indeed tied up in considerations of family, friends, nation, species -- whatever -- then let the science of economics try to adopt itself to those complexities. But those complexities merely redefine and broaden the meaning of selfishness, they do not overturn it. They do not even begin to justify systematic self-sacrifice or coerced altruism. Nor do they lead to scientific rationales for why particular collectivist policies touted in the name of the greater good are either moral or effective.