Heterogeneity and cooperation in climate change mitigation: An experimental approach to common-pool resource games

The collective action problem associated with CO 2 reduction presents a global challenge that requires cooperation among actors. Two factors are often argued to hinder successful cooperation in this context: endowment heterogeneity and the time delay between environmentally harmful actions and their consequences. This study examines the effects of endowment heterogeneity and delayed feedback on cooperation in common-pool resource management at the individual and group levels. Using a Common-Pool Resource (CPR) game in a laboratory experiment, we simulated CO 2 emission dynamics under various conditions of heterogeneity and time-varying feedback. The results highlight that cooperation in common-pool resource dilemmas is shaped through complex micro-macro interdependence. Endowment heterogeneity primarily affects the internal distribution of behavior within groups rather than aggregate outcomes. Low-endowment participants tend to emit less, while high-endowment participants tend to emit more, indicating that endowment heterogeneity affects emissions in opposite directions across group members, largely offsetting each other at the group level. This suggests that heterogeneity may redistribute contributions to mitigation efforts within groups. In contrast, delayed feedback primarily operates by influencing how individuals process and respond to social information. Feedback timing affects how participants react to prior group behavior and the informational conditions under which conditional cooperation is expressed. At the group level, this translates into a modest but detectable effect, suggesting that feedback structure can influence collective outcomes even when individual-level effects are limited. This implies that the determinants of cooperation in CPR settings cannot be fully understood by looking only at either the micro or the macro level.