tors. We argue elsewhere (Richerson et al., 2001) that the transition from the harsh, highly variable climate regime of the last ice age to the much more benign regime of the Holocene set off a competitive footrace that consistently has favored more efficient subsistence and better organization of social systems. The fact that the human race has not yet reached equilibrium with the economic and social-organizational potential made possible by the benign climate of the Holocene (Richerson and Boyd, in press) is testimony to the relatively stately pace of cultural evolution. Even if equilibrium is at hand (Fukuyama, 1992), 10 millennia is a long time to get here! The pace of institutional evolution seems to have accelerated toward the present, no doubt because of the spread of literacy, mass communications, and science and social science. Foreign customs are much more transparent than they once were, and scholars often make more or less sophisticated comparative appraisals of the diversity of social experiments that come to their attention. Even so, institutional revolutions are apt to be frustratingly slow. For example, the conversion of Russia from a socialist one-party state to a market economy and elective democracy is far from a success after more than a decade of work.
The study of the rates of cultural evolution prevailing in the modern world and a sophisticated dissection of the processes that regulate those rates is a project in its infancy. In evolutionary biology, the coin-of-the-realm study of evolution is a quantitative estimate of the rate of evolution of a character and an attribution of the causes of change to particular processes such as natural selection and migration (e.g., Endler, 1986). Although such experiments are not commonly done by social scientists, plenty of examples exist to indicate that the project is perfectly feasible (Weingart et al., 1997:292-297). One of the most sophisticated literatures of this sort is the “policy learning/advocacy coalition” approach to studying policy change (Sabatier and Jenkins-Smith, 1993). Several of the studies applying this approach have been studies of commons policy issues. Obviously, applied institutional development agencies would benefit enormously from a sound knowledge of the comparative natural history of institutional evolution. The practical problem is to help a society with weak institutions acquire more functional ones of a specific orientation. The record indicates that inept interventions can do more harm than good, but good interventions also occur (Baland and Platteau, 1996:243-245, 279-283).
Societies have political institutions of varying degrees of complexity for aggregating individual-level beliefs and desires to produce collectively desired outcomes (Boehm, 1996; Turner, 1995). In the limit, collective decision-making systems cause us to endow institutions such as the state with many of the attributes of an individual rational actor, although both theory (Arrow, 1963) and practical experience suggest that reaching sensible collective decisions is fraught with prob-