你好，我在校内数据库外文知网搜的。所以你打不开。就不给地址了，希望对你有用。 Cooperation and the CommonsSustainably managing common natural resources， such as fisheries， water， and forests， is essential for our long-term Many analysts have assumed， however， that people will maximize short-term self-benefits—for example， by cutting as much firewood as they can sell—and warned that this behavior will inevitably produce a “tragedy of the commons” (1)， such as a stripped forest that no longer produces wood for But in laboratory simulations of such social dilemmas， the outcome is not always Instead， a basic finding is that humans do not universally maximize short-term self-benefits， and can cooperate to produce shared， long-term benefits (2， 3) Similar findings have come from field studies of commonly managed resources (6–7) It has been challenging， however， to directly relate laboratory findings to resource conditions in the field， and identify the conditions that enhance On page 961 of this issue， Rustagi et (8) help fill this In an innovative study of Ethiopia's Oromo people， they use economic experiments and forest growth data to show that groups that had a higher proportion of “conditional cooperators” were more likely to invest in forest patrols aimed at enforcing firewood collection rules—and had more productive They also show that other factors， including a group's distance to markets and the quality of its leadership， influenced the success of cooperative Researchers have translated social dilemmas into economic games in which the players—typically college students in the United States or Europe—can earn real money， depending on whether they and others “invest” in a common good， or become “free riders” who benefit without paying their fair Cardenas (9) was the first to translate a game carried out with students using computers in a lab (5) into a pen-and-paper version that was played by actual users of local forests in C This field effort essentially replicated the lab findings， but the levels of cooperative behavior observed were more Other field experiments examined how people who relied on forests， fisheries， and grazing lands responded to experimental designs that enabled them to impose sanctions on free riders， including varying monetary penalties (10， 11) Several examined whether rules established by an external authority—such as a government—“crowded out” a group's motivation to cooperate In Ethiopia's Bale Mountains， Rustagi et took these experiments a step There， high livestock density poses a major threat to forests， because the animals browse on young To address this and other problems， officials launched a forest management program that gave Bale Oromo groups common ownership of woodlands， and responsibility for maintaining forest To explore the role of cooperation in the success of these efforts， Rustagi et first set up “field labs” in a number of villages， and invited residents to play games designed to measure their propensity to cooperate (conditional on others' cooperation) They also conducted surveys that gathered socioeconomic data and information about resource monitoring Finally， they compared the game results and the survey data from 49 groups to measurements of potential crop trees， an indicator of forest Overall， they found that the groups with the larger shares of conditionally cooperative members were more likely to be successful in managing their forest They also invested more in “costly” enforcement of cooperation (participating in forest patrols， which promote cooperation by sanctioning free riders) By establishing this link between the levels of cooperation observed in field labs with local forest conditions， Rustagi et have increased the confidence that scholars can have in the external validity of results from previous experiments carried out all over the world， with student and nonstudent In addition， by adding to findings showing diverse levels of cooperation in social dilemmas， rather than no cooperation， they support the growing acceptance of a behavioral theory of human action (14): Individuals facing dilemmas， who learn from experience and adopt a norm of conditional cooperation， achieve levels of cooperation that increase over time—if a sufficient number of conditional cooperators are If a group is composed of a substantial number of free riders， however， cooperation levels fall over One way of interpreting Rustagi et 's findings is that learning and norm-adopting individuals are attracted to certain situations， and then are affected by the behavior of other actors facing the same situation (see the figure) Initially， this leads to some degree of cooperation (， acceptance of rules of the forest group， monitoring other users， and helping to maintain their forest) If enough individuals initially cooperate， they slowly obtain benefits from the forest， and levels of cooperation Alternatively， initial cooperation rates can be low， and then can continue to decline over Rustagi et identify a number of well-known variables that can influence cooperation， including the size of the forest group， its leadership， and the heterogeneity of the Other， broader， variables include village elevation and market access， with villages closer to markets for wood products more likely to invest in cooperative Other field studies have found that prior experience in cooperative management increases the likelihood of groups successfully managing a Rustagi et also found that the share of conditional cooperators in a group is affected by clan affiliation and the leader， who needs to have sufficient prestige to change the norms of the Other recent evidence from field experiments shows that resource users responded prosocially to environmental appeals made by park rangers (15) More details of cultural effects on cooperation are provided by Prediger et (16)， who use a socioecological framework (17) to identify main differences between two populations before performing field They show that historical events that interfere with self-governance， as well as subtle ecological differences， can affect the propensity to More research is needed to explain the factors that produce variation in Using multiple methods (18) to identify the relevant “microsituational” and broader contextual variables， and using robust econometric methods to link these variables with differences in behavior and real-world outcomes， will constitute a major step in advancing a behavioral theory of human
