The study found the act of donating money to save a life produced happiness at first, but the effects didn’t last. After a month, students who donated money were less happy than those who choose to keep the money for themselves.

“Prosocial behavior does not unequivocally increase happiness,” the study authors wrote,”because prosocial spending naturally requires giving up something else, which may decrease happiness in its own right.”

“Wow, definitely a surprising result and one that is inconsistent with previous research,” said happiness researcher Sonja Lyubomirsky, author of “The How of Happiness: A Scientific Approach to Getting the Life You Want,” who was not involved in the study.