摘要:We compare two devices previously found to increase contributions to
public goods in laboratory experiments: communication, and punishment (allowing
subjects to engage in costly reductions of one another’s earnings after learning of their
contribution decisions). We find that communication increases contributions more
than punishment, and, taking into account the cost of punishment, only
communication significantly increases subjects’ earnings and thus efficiency. We study three forms of communication to understand what elements of
communication are essential to this result: exchanges of numerical messages,
exchanges of verbal messages through a computer chat room, and face-to-face
communication. Compared with a baseline of no communication and no
punishment, we find that chat room communication increases cooperation and
efficiency substantially, and when coupled with punishment opportunities nearly as
much as face-to-face communication, even though the chat room environment does
not communicate cues of facial expression, tone of voice, and body language. Face-to-
face communication is so effective that adding a punishment option to it does not
significantly change the level of contributions or earnings. In contrast, communication
limited to sending numerical messages has no net effect on contributions or efficiency.