The Average Pigouvian Tax (APT) was proposed by Suter et al. (2008) to reduce the financial burden of the standard ambient tax. This instrument consists in a standard ambient tax divided by the number of firms, which requires polluters to cooperate in order to achieve the social optimum. To enable polluters to cooperate, communication is allowed. We introduce different types of communication: cheap talk, exogenous costly communication (communication is imposed), and endogenous costly communication (conducted on a voluntary basis after a vote). Our experiment confirms that the instrument induces polluters to reduce their emissions under cheap talk. However, we find that group emissions are less reduced when communication is costly. This result still holds even when we endogenize communication by introducing a voting phase.
