Competing Norms and Social Evolution: Is the Fittest Norm Efficient?

Paul Mahoney, University of Virginia
Chris William Sanchirico, University of Pennsylvania Law School & Wharton School, Business and Public Policy Department

Abstract

An influential theme in recent legal scholarship is that law is not as important as it appears. Social control, many scholars have noted, is often achieved through social norms - informal, decentralized systems of consensus and cooperation - rather than through law. This literature also displays a guarded optimism that social evolutionary processes will tend to favor the adoption of efficient norms. Using concepts from evolutionary game theory, we demonstrate that efficient norms will prevail only in certain settings and not in others: survival of the fittest does not imply survival of the efficient. In particular, we show that in many games of interest to legal scholars - games describing fundamental interactions in property, tort, and contract - evolutionary forces lead away from efficiency. We also describe how law rights the trend.