In the course of researching my next novel, I happened upon this old paper by Robert H. Frank, Thomas Gilovich, and Dennis T. Regan, "Does Studying Economics Inhibit Cooperation?" Its conclusions: Economics grad students are more likely to free ride than the general public. Economists are less generous than other academics in charitable giving. Economics undergrads are more likely to defect in prisoner's dilemma problems. Students are less likely to return found money after studying economics but not after studying another subject like astronomy.