THE stereotypes about economists are well known: that we’re selfish Grinches; that we don’t read human interest stories because they don’t interest us; that the only reason we don’t sell our children is that we think they’ll be worth more later.

But are the stereotypes true? And if so is the cause nature or nurture? In other words, are selfish people disproportionately likely to become economists? Or is there something about being an economist (or being on the receiving end of economics education) that makes people selfish?

Academic research suggests that there’s a good deal of truth to the stereotype. Many studies have looked at how economists behave in what are called public goods situations. A key feature of these situations is that you can benefit from public goods even if you don’t contribute to them. You can watch PBS without making a donation; you can enjoy clean air even if you drive a car that pollutes. Such goods, however, give rise to the so-called free-rider problem: acting selfishly makes sense for each individual (why sacrifice if you don’t have to?) but as more and more people choose to act selfishly, the good disappears and everyone loses.

Public goods run counter to Adam Smith’s “invisible hand” theory in that self-interested behavior by individuals does not, as the theory would have it, lead to good outcomes for society as a whole. These situations flummox just about everybody — look at all the trouble that nations and individuals are having in dealing with climate change — but economists and economics students appear to be especially likely to free-ride and act in ways that are “anti-social” rather than “pro-social.”