Prior research demonstrates a willingness to incur costs to punish norm violators. But, how strong are the motives 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...

Development of human societies requires cooperation among unrelated individuals and obedience to social norms. Although punishment is widely agreed to be potentially useful in fostering cooperation, many recent results in psychology and economics highlight punishments' failures in this regard....