Economics majors were less likely to donate money to charity than students who majored in other fields. After majors in other fields took an introductory economics course, their propensity to give also fell… Think of the person who orders the most expensive entree at a restaurant, knowing that the check will be shared equally among companions… economics students showed a much higher propensity to free ride than other students.

“Secrets of the Economist’s Trade” from The Wall Street Journal.