9319835 Ostrom Common Pool Resources (CPRs) have been the focus of extensive research in the social sciences. In particular, there has been an ever-growing policy debate regarding the ability of diverse institutions to cope with the allocation issues that surround CPRs. Individuals jointly using a CPR are assumed to face a social dilemma - - often called the tragedy of the commons - - in which individually rational resource users ignore the external harm they impose on other users, leading to outcomes that are not rational from the perspective of the group. Using a theoretical and empirical approach with foundations in game theory, field studies, and experimental methods, the authors' previous research addressed numerous questions related to the allocation issues that surround CPRs. The current investigation extends this previous work by examining behavioral regularities in more complex (more realistic) laboratory and field environments. In particular, the proposed research begins the process of examining behavior in environments with the following attributes: time dependencies; multiple equilibria; heterogeneities; and, local/global nesting. Each of these attributes will be investigated with a specific focus on how the institutional setting interacts with individual and group behavior. In the laboratory, time-dependent settings will be investigated in which subjects' current decisions have significant consequences on the characteristics of the decision setting they face in future plays of the game. Settings will be investigated where subjects make decisions facing exogenously imposed "rules of the game: and settings where subjects have flexibility in choosing the rules. A principle focus will be the potential conflict that arises due to heterogeneities in input endowments, costs, technology, and information. In the field, the focus will also address issues of time dependency and appropriator heterogeneity in relation to variations in physical a nd institutional conditions. The filed research will focus principally on forestry resources. As part of prior NSF funding, the authors developed and pretested a series of data collection instruments that can be used to record systematic data about forests and forest institutions on a repeated basis over time. This current project is crucial for extensive scientific analyses of this evolving database. ***
