The present article analyzes the differences between economists and non‐economists with respect to observed corruption behavior used as a proxy for selfishness. For this purpose, I analyzed real world data of relating to the 109th–111th US Congress between 2005 and 2009, including 695 representatives and senators. I show that those who hold a degree in economics are significantly more prone to corruption than ‘non‐economists’. These findings hence support the widespread, but controversial hypothesis in the ‘economist vs. non‐economist literature’ that economists lack what Frey and Meier (2004) call ‘social behavior’. Moreover, by using real world data, these findings overcome the lack of external validity, which impact on the (low cost) experiments and surveys to date.