Structuring communication effectively for environmental cooperation

Many environmental problems represent social dilemma situations where individually rational behaviour leads to collectively suboptimal outcomes. Communication has been found to alleviate the dilemma and stimulate cooperation in these situations. Yet, the knowledge of what type of information needs to be shared to ensure the beneficial effect is still incomplete. Previous research relies on ex post methods, i.e. after conducting an experiment researchers analyse what information was shared during the communication phase. By nature, this ex post categorization is endogenous. In this study, we aim to identify the elements of effective communication ex ante and evaluate their impact in a more controlled way. Based on the findings of previous studies, we identify four cooperation-enhancing elements of communication: (i) problem awareness, (ii) identification of strategies, (iii) agreement, and (iv) ratification. In a laboratory experiment with 560 participants, we implement interventions representing these components and contrast the resulting levels of cooperation with the outcomes under free (unstructured) or no communication. We find that the intervention facilitating agreement on a common strategy (combination of (ii) and (iii)) is particularly powerful in boosting cooperation. And if this is combined with interventions promoting problem awareness and ratification, similar cooperation levels as in settings with free-form communication can be reached. Our results are relevant not only from an analytical perspective, but also provide insights for effectively structuring communication in participatory processes aimed at improving environmental outcomes.