We study the decision whether to engage in costly punishment of a free rider in a survey-based experiment with 1423 students from seven study areas in the social sciences as well as medicine at Aarhus University, Denmark. Using a dictator game and a social dilemma game, that captures essential features of the public goods game, we replicate previous findings that economics students give significantly less than students from other disciplines. However, when subjects decide whether or not to punish a free rider, we find that economics students are just as likely to punish as students from other disciplines.