In an experiment, a group of strangers was randomly divided in pairs to play a prisoners' dilemma; this process was indefinitely repeated. Cooperation did not increase when subjects could send public messages amounting to binding promises of future play

This paper studies how groups resolve disagreement when they must reach unanimity after submitting individual proposals and exchanging text-form messages via a chat window in lottery choice experiments. We find that the majority proposal does not always prevail. The minority proposal prevails...

We study the emergence of norms of cooperation in experimental economies populated by strangers interacting indefinitely and lacking formal enforcement institutions. In all treatments the efficient outcome is sustainable as an equilibrium. We address the following questions: can these economies...