Laboratory Experiments

In this section we present results from laboratory experiments we have performed since 2005. These experiments aim to study the conditions of self-governance in commons dilemmas. In contrast to traditional economic experiments we include more complexity of the environment in which decisions are made since we aim to understand how ecological dynamics and information availability affect the outcomes. In order to pursue this research we have developed a number of open source software projects for those experimental environments.

Available Software


a general web-based experimental environment.


a spatial explicit and dynamic common resource experimental environment.


a computer based irrigation game.

A broader discussion on these experiments can be found in this publication:

Experimental platforms for behavioral experiments on social-ecological systems (pdf)

Janssen, M.A., A. Lee, and T. Waring
Ecology & Society 2014, 19 (4): 20.

Recently, there has been an increased interest in using behavioral experiments to study hypotheses on the governance of social-ecological systems. A diversity of software tools are used to implement such experiments. We evaluated various publicly available platforms that could be used in research and education on the governance of social-ecological systems. The aims of the various platforms are distinct, and this is noticeable in the differences in their user-friendliness and their adaptability to novel research questions. The more easily accessible platforms are useful for prototyping experiments and for educational purposes to illustrate theoretical concepts. To advance novel research aims, more elaborate programming experience is required to either implement an experiment from scratch or adjust existing experimental software. There is no ideal platform best suited for all possible use cases, but we have provided a menu of options and their associated trade-offs.

Foraging Games

A series of experiments are performed with a spatially explicit dynamics resource to study self-governance of participants who share a common resource. The current version of the software can be found here.

Synergistic effects of voting and enforcement on internalized motivation to cooperate in a resource dilemma (pdf)

DeCaro, D.A., M.A. Janssen and A. Lee
Judgment and Decision Making 2015, 10(6): 511-537.

We used psychological methods to investigate how two prominent interventions, participatory decision making and en- forcement, influence voluntary cooperation in a common-pool resource dilemma. Groups (N=40) harvested resources from a shared resource pool. Individuals in the Voted-Enforce condition voted on conservation rules and could use economic sanc- tions to enforce them. In other conditions, individuals could not vote (Imposed-Enforce condition), lacked enforcement (Voted condition), or both (Imposed condition). Cooperation was strongest in the Voted-Enforce condition (Phase 2). Moreover, these groups continued to cooperate voluntarily after enforcement was removed later in the experiment. Cooperation was weakest in the Imposed-Enforce condition and degraded after enforcement ceased. Thus, enforcement improved voluntary cooperation only when individuals voted. Perceptions of procedural justice, self-determination, and security were highest in the Voted- Enforced condition. These factors (legitimacy, security) increased voluntary cooperation by promoting rule acceptance and internalized motivation. Voted-Enforce participants also felt closer to one another (i.e., self-other merging), further contribut- ing to their cooperation. Neither voting nor enforcement produced these sustained psychological conditions alone. Voting lacked security without enforcement (Voted condition), so the individuals who disliked the rule (i.e., the losing voters) pil- laged the resource. Enforcement lacked legitimacy without voting (Imposed-Enforce condition), so it crowded out internal reasons for cooperation. Governance interventions should carefully promote security without stifling fundamental needs (e.g., procedural justice) or undermining internal motives for cooperation.

Experimental Protocol   Data Set (Excel file)  Key (Excel file)

The effect of constrained communication and limited information in governing a common resource (pdf)

Janssen, M.A., M. Tyson, and A. Lee
International Journal of the Commons 2014, 8(2): 617-635.

Allowing resource users to communicate in behavioural experiments on commons dilemmas increases the level of cooperation. In actual common pool resource dilemmas in the real world, communication is costly, which is an important detail missing from most typical experiments. We conducted experiments where participants must give up harvesting opportunities to communicate. The constrained communication treatment is compared with the effect of limited information about the state of the resource and the actions of the other participants. We nd that despite making communication costly, performance of groups improves in all treatments with communication. We also nd that constraining communication has a more signi cant effect than limiting information on the performance of groups.

Experimental Protocol            Data Set (Excel file)

The role of information in governing the commons: experimental results (pdf)

Janssen, M.A.
Ecology and Society 2013, 18(4): 4.

The structure and dynamics of ecosystems can affect the information available to resource users on the state of the common resource and the actions of other resource users. We present results from laboratory experiments that showed that the availability of information about the actions of other participants affected the level of cooperation. Since most participants in commons dilemmas can be classified as conditional cooperators, not having full information about the actions of others may affect their decisions. When participants had more information about others, there was a more rapid reduction of the resource in the first round of the experiment. When communication was allowed, limiting the information available made it harder to develop effective institutional arrangements. When communication was not allowed, there was a more rapid decline of performance in groups where information was limited. In sum, the results suggest that making information available to others can have an important impact on the conditional cooperation and the effectiveness of communication.

Experimental Protocol            Data Set (Excel file)

Lab Experiments for the Study of Social-Ecological Systems (Journal)

Janssen, M.A., R. Holahan, A. Lee, and E. Ostrom
Science 2010, 328: 613-617.

Governance of social-ecological systems is a major policy problem of the contemporary era. Field studies of fisheries, forests, and pastoral and water resources have identified many variables that influence the outcomes of governance efforts. We introduce an experimental environment that involves spatial and temporal resource dynamics in order to capture these two critical variables identified in field research. Previous behavioral experiments of commons dilemmas have found that people are willing to engage in costly punishment, frequently generating increases in gross benefits, contrary to game-theoretical predictions based on a static pay-off function. Results in our experimental environment find that costly punishment is again used but lacks a gross positive effect on resource harvesting unless combined with communication. These findings illustrate the importance of careful generalization from the laboratory to the world of policy.

Experimental Protocol            Data Set (Excel file)

Introducing Ecological Dynamics into Common-Pool Resource Experiments (pdf)

Janssen, M. A.
Ecology and Society 2010, 15(2): 7.

Case-study analysis shows that long-lasting social–ecological systems have institutional arrangements regulating where, when, and how to appropriate resources instead of how much. Those cases testify to the importance of the fit between ecological and institutional dynamics. Experiments are increasingly used to study decision making, test alternative behavioral models, and test policies. In typical commons dilemma experiments, the only possible decision is how much to appropriate. Therefore, conventional experiments restrict the option to study the interplay between ecological and institutional dynamics. Using a new real-time, spatial, renewable resource environment, we can study the informal norms that participants develop in an experimental resource dilemma setting. Do ecological dynamics affect the institutional arrangements they develop? We find that the informal institutions developed on when, where, and how to appropriate the resource vary with the ecological dynamics in the different treatments. Finally, we find that the amount and distribution of communication messages and not the content of the communication explains the differences between group performances.

Experimental Protocol            Data Set (Excel file)

TURFs in the lab: Institutional Innovation in dynamic interactive spatial commons (Journal)

Janssen, M.A., and E. Ostrom
Rationality and Society 2008, 20: 371-397.

Using a real-time, spatial, renewable resource environment, we observe participants in a set of experiments formulating informal rules during communication sessions over three decision rounds. In all three rounds, the resource is open access. Without communication, the resource is persistently and rapidly depleted. With face-to-face communication, we observe informal arrangements to divide up space and slow down the harvesting rate in various ways. We observe that experienced participants, who have participated in an earlier experiment where private property was used as one way of controlling harvesting in this renewable resource environment, are more effective in creating rules, although they mimic the private-property regime of their prior experience. Inexperienced participants need an extra round to reach the same level of resource use, but they craft diverse arrays of novel rule sets.

Experimental Protocol            Data Set (Excel file)

Effect of rule choice in dynamic interactive spatial commons (pdf)

Janssen, M.A., R.L. Goldstone, F. Menczer and E. Ostrom
International Journal of the Commons 2008, 2(2): 288-312.

This paper uses laboratory experiments to examine the effect of an endogenous rule change from open access to private property as a potential solution to overharvesting in commons dilemmas. A novel, spatial, real-time renewable resource environment was used to investigate whether participants were willing to invest in changing the rules from an open access situation to a private property system. We found that half of the participants invested in creating private property arrangements. Groups who had experienced private property in the second round of the experiment, made different decisions in the third round when open access was reinstituted in contrast to groups who experienced three rounds of open access. At the group level, earnings increased in Round 3, but this was at a cost of more inequality. No significant differences in outcomes occurred between experiments where rules were imposed by the experimental design or chosen by participants.

Experimental Protocol            Data Set (Excel file)

Irrigation Games

A series of lab experiments are performed with a computer based version of the irrigation game and as well as the paper and pencil versions from the field. The current version of the software can be found here.

The effect of information in a behavioral irrigation experiment (Journal)

Janssen, M.A., J.M. Anderies, I. Pérez and D.J. Yu
Water Resources and Economics 2015, 12: 14-26.

When governing shared resources, the level and quality of information available to resource users on the actions of others and the state of the environment may have a critical effect on the performance of groups. In the work presented here, we find that lower availability of information does not affect the average performance of the group in terms of their capacity to provide public infrastructure and govern resource use, but it affects the distribution of earnings and the ability to cope with disturbances. We performed behavioral experiments that mimic irrigation dilemmas in which participants need to maintain infrastructure function in order to generate revenue from the use of water. In the experimental design, there is an upstream–downstream asymmetry of access to water that may lead to unequal access to water. We find that inequality of investment in irrigation infrastructure and water appropriation across players is more pronounced in experiments where resource users have limited information about the actions of others. We also find that inequality is linked to the ability of groups to cope with disturbances. Hence a reduced level of information indirectly reduces the adaptive capacity of groups.

Experimental Protocol            Data Set (Excel file)

Irrigation experiments in the lab: trust, environmental variability, and collective action (pdf)

Baggio, J. A., N. D. Rollins, I. Pérez, and M. A. Janssen
Ecology and Society 2015, 20(4):12.

Research on collective action and common-pool resources is extensive. However, little work has concentrated on the effect of variability in resource availability and collective action, especially in the context of asymmetric access to resources. Earlier works have demonstrated that environmental variability often leads to a reduction of collective action in the governance of shared resources. Here we assess how environmental variability may impact collective action. We performed a behavioral experiment involving an irrigation dilemma. In this dilemma participants invested first into a public fund that generated water resources for the group, which were subsequently appropriated by one participant at a time from head end to tail end. The amount of resource generated for the given investment level was determined by a payoff table and a stochastic event representing environmental variability, i.e., rainfall. Results show that that (1) upstream users’ behavior is by far the most important variable in determining the outcome of collective action; (2) environmental variability (i.e. risk level in investing in the resource) has little effect on individual investment and extraction levels; and (3) the action-reaction feedback is fundamental in determining the success or failure of communities.

Experimental Protocol            Data Set (Stata file)

Social roles and performance of social-ecological systems: evidence from behavioral lab experiments (pdf)

Perez, I., D.J. Yu, M.A. Janssen and J.M. Anderies
Ecology & Society 2015, 20(3): 23 .

Social roles are thought to play an important role in determining the capacity for collective action in a community regarding the use of shared resources. Here we report on the results of a study using a behavioral experimental approach regarding the relationship between social roles and the performance of social-ecological systems. The computer-based irrigation experiment that was the basis of this study mimics the decisions faced by farmers in small-scale irrigation systems. In each of 20 rounds, which are analogous to growing seasons, participants face a two-stage commons dilemma. First they must decide how much to invest in the public infrastructure, e.g., canals and water diversion structures. Second, they must decide how much to extract from the water made available by that public infrastructure. Each round begins with a 60-second communication period before the players make their investment and extraction decisions. By analyzing the chat messages exchanged among participants during the communication stage of the experiment, we coded up to three roles per participant using the scheme of seven roles known to be important in the literature: leader, knowledge generator, connector, follower, moralist, enforcer, and observer. Our study supports the importance of certain social roles (e.g., connector) previously highlighted by several case study analyses. However, using qualitative comparative analysis we found that none of the individual roles was sufficient for groups to succeed, i.e., to reach a certain level of group production. Instead, we found that a combination of at least five roles was necessary for success. In addition, in the context of upstream-downstream asymmetry, we observed a pattern in which social roles assumed by participants tended to differ by their positions. Although our work generated some interesting insights, further research is needed to determine how robust our findings are to different action situations, such as biophysical context, social network, and resource uncertainty.

Experimental Protocol            Data Set (Zip file of Excel files)

Environmental variability and collective action: Experimental insights from an irrigation game (Journal)

Anderies, J.M., M.A. Janssen, A. Lee and H. Wasserman
Ecological Economics 2013, 93: 166-176.

Studies of collective action in commons dilemmas in social–ecological systems typically focus on scenarios in which actors all share symmetric (or similar) positions in relation to the common-pool resource. Many common social–ecological systems do not meet these criteria, most notably, irrigation systems. Participants in irrigation systems must solve two related collective action problems: 1) the provisioning of physical infrastructure necessary to utilize the resource (water), and 2) the asymmetric common-pool resource dilemma where the relative positions of “head-enders” and “tail-enders” generate asymmetric access to the resource itself (water). In times of scarcity, head-enders have an incentive to not share water with tail-enders. Likewise, tail-enders have an incentive to not provide labor to maintain the system if they do not receive water. These interdependent incentives may induce a cooperative outcome under favorable conditions. However, how robust is this system of interdependent incentives in the presence of environmental variability that generates uncertainty about water availability either through variation in the water supply itself or through shocks to infrastructure? This paper reports on results from laboratory experiments designed to address this question.

Experimental Protocol            Data Set (Excel file)

Coordination and Cooperation in Asymmetric Commons Dilemmas (Journal)

Janssen, M.A., J.M. Anderies and S. Joshi
Experimental Economics 2011, 14(4): 547-566.

In this paper we discuss laboratory experiments that address the problem of self-governance in an asymmetric commons dilemma. Small-scale irrigation systems that provide food for hundreds of millions of people around the world are probably the most common example of such dilemmas. Here, we formulate an abstract dilemma in which subjects make both a decision about investment in the provision of infrastructure associated with the use of a resource and about how much to extract from the common-pool resource made available by this infrastructure. The impact of inherent asymmetry in irrigation systems on the provision of a resource and the impact of communication on the capacity of the group to solve the two-level commons dilemma of cooperation and coordination based on the analysis of the experimental data are discussed.

Experimental Protocol          Data Set (Excel file)