Dr. Melayne McInnes, an associate professor in economics at The Darla Moore School of Business at the University of South Carolina, and her student, Erica Morgan, found that first-born siblings tend to be more risk-averse and more patient in making monetary decisions. Conversely, last-born siblings tend to be bigger risk takers, willing to gamble for a higher payoff and less willing to wait unless the rate of return was much higher.

To test the hypothesis, McInnes and Morgan devised different scenarios that offered participants the possibility of larger payoffs with higher risk, smaller payoffs with lower risk, larger payoffs with a longer time delay and smaller payoffs with a shorter time delay. The kicker: They used real money, provided through a National Science Foundation grant.

They found that older siblings were more averse to risk and more willing to wait to receive a higher payout. First-born siblings required more compensation if they were going to assume more risk, and younger siblings had to be offered a higher rate of return for them to be willing to wait for a payout.

Gender and race, which have been thought to affect one’s risk aversion, proved not to be as strong an indicator as birth order, McInnes said.