Does Altruism Actually Exist?

Picture this: a man in his 80s trying to cross the street, but the traffic doesn't pause for long enough for him to cross. A young woman notices his difficulty, and runs over to help. Does the young woman get any kind of benefit from her action, or is it entirely thankless? Today, Dr. Bart Ehrman and I are talking about altruism. Is it possible to do a good deed without experiencing some kind of benefit?