According to the latest theory by a doctor of psychology, the real reason people give their time and money to good causes is that they want to make themselves attractive to members of the opposite sex.
Dr Geoffrey Miller of the University of New Mexico has just published a hypothesis in the Journal of Personality and Social Psychology that claims acts of altruism are simply part of an elaborate mating ritual.
It has long been held that women often look for partners who can provide for them financially. Dr Miller argues that a man may demonstrate his ability to do so by making a donation to charity, because it shows that he has money to burn.
By contrast, men often look for a willingness to make sacrifices in a future wife, and what better way to prove this than to give up your free time to work at a charity?
Dr Miller concludes that both sexes are more than happy to be generous with their time and money, so long as there is a chance that their acts of altruism might be observed by someone fanciable.
Unfortunately, his paper did not discuss whether this means that those who work in the voluntary sector are luckier in love than others.