Paying people to protect the environment: A meta-analysis of financial incentive interventions to promote proenvironmental behaviors

What effect do financial incentive interventions have on initial and sustained proenvironmental behavior, how do different types of incentives (e.g., cash, transit tickets) affect proenvironmental behavior, and how does the effect of incentive interventions vary across different types of behaviors (e.g., recycling, travel behavior)? A meta-analysis of 22 studies (k = 30) addressed these questions. Incentive interventions had a small-to-medium effect on behavior while incentives were in place (d+ = 0.36) and after they were discontinued (d+ = 0.41). Moreover, certain financial incentives features tended to be more effective at changing behavior, such as incentives distributed on variable schedules as compared to fixed schedules. Finally, financial incentive types were more effective at changing specific proenvironmental behaviors; cash incentives had a stronger effect on recycling and non-cash incentives had a stronger effect on travel behavior. These findings suggest that financial incentives can change proenvironmental behavior, can contribute to sustained behavior, and are particularly effective in certain contexts.