of the resource does not necessarily diminish the potential for use by another. Public radio stations, scientific knowledge, and world peace are public goods in that we all enjoy the benefits without reducing the quantity or quality of the good. The problem is that, in a large group, an individual will enjoy the benefits of the public good whether or not he or she contributes to producing it. You can listen to public radio whether or not you pledge and make a contribution. And in a large population, whether or not you contribute has no real impact on the quantity of the public good. So a person following the dictates of narrow self-interest will avoid the costs of contributing. Such a person can continue to enjoy the benefits from the contributions provided by others. But if everyone follows this logic, the public good will not be supplied, or will be supplied in less quantity or quality than is ideal.
Here we see the importance of the tragedy of the commons and its kin. All of the analyses just sketched presume that self-interest is the only motivator and that social mechanisms to control self-interest, such as communication, trust, and the ability to make binding agreements, are lacking or ineffective. These conditions certainly describe some interactions. People sometimes do, however, move beyond individual self-interest. Communication, trust, the anticipation of future interactions, and the ability to build agreements and rules sometimes control behavior well enough to prevent tragedy. So the drama of the commons does not always play out as tragedy.
This volume examines what has been learned over decades of research into how the drama of the commons plays out. It should be of interest to people concerned with important commons such as ecosystems, water supplies, and the atmosphere. In addition, commons situations provide critically important test beds for addressing many of the central questions of the social sciences. How does our identity relate to the resources in our environment? How do we manage to live together? How do societies control individuals’ egoistic and antisocial impulses? Which social arrangements persist and which do not? In looking at the long sweep of human history and the thousands of social forms spread across it, these questions may become unmanageable to study in a systematic manner. The commons, however, provides a tractable and yet important context in which to address these questions. Just as evolutionary and developmental biology progressed by studying the fruitfly, Drosophila melanogaster, an organism well suited to the tools available, we suggest that studies of the commons and related problems are an ideal test bed for many key questions in the social sciences.2
As is evident in the chapters of this volume, commons research already draws on most of the methodological traditions of the social sciences. There are elegant mathematical models, carefully designed laboratory experiments, and meticulous historical and comparative case studies. The statistical tools applicable to large or moderate-sized data sets also are being brought to bear. As we will detail, research on the commons attracts scientists from a great diversity of disciplines and from all regions of the world. Advances in the social sciences are likely to come