درباره برخی از مفاهیم روانشناسی تکاملی برای مطالعه ترجیحات و موسسات

In many economic interactions, for instance in firms, the standard approximation of strict self-interest is inadequate to modeling human behavior. A scientific theory of preferences, grounded in evolutionary psychological and biological theory, can avoid resort to ad hoc assumptions. Evolutionary theory is supported by a growing body of data including new results in experimental economics. It holds that the evolved human nature includes an ability to solve social dilemma problems through reciprocity and punishment of cheaters. Treating realized preferences as phenotypic expressions with both environmental and genetic causes will also allow economists to study the impact of institutions on preferences.

Darwinism was once taken to imply that the process of biological competition can spare no sentimentality for unselfishness or indeed, for sentiment itself. The most ruthless, self-seeking, and rational organisms will survive, while weaker members of their species will fall by the wayside. Darwinism and the economics of the century that followed The Origin of Species appeared to entail kindred social theories, in which human moral pretensions were set aside and the natural competitiveness of the species claimed its full due. Edgeworth’s dictum that “The first principle of economics is that every agent is actuated only by self-interest”1 was thought by many to be Darwin’s as well. Darwin (1871) himself had been interested in both sentiment and altruism. But while this fact was known to some careful readers, it took many decades before the cooperative dimension of social interaction emerged as a central focus of biology and allied social sciences. This new focus is exemplified by the work of biologist Robert Trivers in the 1970s, political scientist Robert Axelrod and biologist William Hamilton in the 1980s, and psychologist Leda Cosmides and anthropologist John Tooby in the 1990s, although other important contributors could be cited.2 Theorists of sociobiology and evolutionary psychology take as their starting point the idea that it is genes, rather than the organisms that bear them, that engage in the struggle for survival. From an evolutionary standpoint, survival of several replicas is better than survival of any one copy. Organisms not predisposed by their genes to invest resources in bearing and (where immaturity at birth requires it) nurturing offspring will make poor agents for “replication-minded” genes. Any undue propensity to shirk on investments in reproduction and nurturing, should it appear by the serendipity of mutation, will be selected against, since the genes in which the new propensity is encoded will leave fewer copies in future generations. More broadly, propensities to invest resources in helping close kin, who share a significant fraction of one’s own genes, will pay off in evolutionary terms.3

Economists are often heard to complain that the attempt to explain some behavior which appears to defy standard neoclassical theory by appeal to additional arguments in the utility function are ad hoc in character. The goal of economics, to such practitioners, is to take the assumptions of strict self-interest and rationality and to explain as much of actual behavior as possible with them. To allow for extendedness of preferences is viewed, from this standpoint, as an instance of “cheating by changing the rules of the game.” While this game could well go on for many years into the future, we think that in the long-run, the economics discipline as a whole will recognize that the old assumption of rational, strictly self-interested individuals is not only an inexact and special approximation, but also inconsistent with a scientific view of human nature as the product of an evolutionary process. Models of rational, self-interested behavior are likely to persist and be put to many uses, but they will be recognized as special cases. What the evolutionary sciences are providing is the foundation for a nonarbitrary reformulation of individual choice theory along scientific lines. As psychologist Donald Campbell put it a decade ago, “Rationality in economic theory is primarily a rationality of means … While it is a maximization of self-interest, the contents of self-interest are usually not specified by the theory. Merging such self-interest theory with evolutionary biology offers the promise of theoretical grounds for predicting such contents, that is, predicting what sorts of interest the products of biological evolution would be apt to have.”13