underlying such acts? Will people rely on "excuses" to avoid acting on costly punishment intentions, as with other costly pro …-social acts? In a laboratory experiment, we find that third parties punish reluctantly: they state a preference to punish, but … differences in motives underlying second- and third-party punishment. …

We study the stability of voluntary cooperation in response to varying group growth rates. Using a laboratory public … cooperation. We then study the effect of exogenously varying growth rates on cooperation. Slow growth yields higher cooperation …-reinforcing beliefs persisting under slower growth. Allowing incumbent group members to select growth rates also sustains high cooperation …

We study how the willingness to enter long-term bilateral relationships affects cooperation even when parties have … little information about each other, ex ante, and cooperation is otherwise unenforceable. We experimentally investigate a … research, longer interactions facilitate cooperation. However, many individuals avoid long-term commitment, with uncooperative …

-play messages. In a laboratory experiment, we modify communication by making the sending of messages optional and costly. Even small …

monetary contexts. -- Altruism ; generosity ; harm ; experiment …

explore the effectiveness of two policies intended to facilitate such integration, using a laboratory experiment that models …

environments, we use a laboratory experiment in which we form groups and assign leadership roles at random. We study an environment … behavior. Moreover, appointing leaders who are likely to have acted dishonestly in a preliminary stage of the experiment yields …