There is much debate as to why economics students display more self-interested behavior than other students: whether homo economicus self-select into economics or students are instead “indoctrinated” by economics learning, and whether these effects impact on preferences or beliefs about others’ behavior. Using a classroom survey (n\u3e500) with novel behavioral questions we show that, compared to students in other majors, econ students report being: (i) more self-interested (in particular, less compassionate or averse to advantageous inequality) already in the first year and the difference remains among more senior students; (ii) more likely to think that people will be unwilling to work if unemployment benefits increase (thus, assuming others are motivated primarily by self-interest), but only among senior students. These results suggest self-selection in preferences and indoctrination in beliefs
