As you give, so shall ye get: Psychological experiments
show that
altruism
has indirect benefits:
They invented a laboratory game in which volunteers passed money to each
other. The rules prevented a player from directly returning the favour to
the donor - they had to give their cash to a third party.
But as the game developed, the researchers noticed that the most generous
players actually began to accumulate the most money. The scientists conclude
that doing good deeds increases the likelihood that someone else will treat
you better.