I explore possible impacts of reciprocal preferences on participation in international environmental agreements. Reciprocal countries condition their willingness to abate on others' abatement. No participation is always stable. A full or majority coalition can be stable, provided that...

Why do people engage in costly cooperation with unknown others that they will never meet again? Answers to this evolutionary puzzle emphasize the role of indirect reciprocity (i.e., cooperation through reputation), whereby cooperation is not reciprocated by the recipient but by other members of...