It pays to be nice

Can evolution explain why we would give to a beggar?

Being nice to other people can bring real rewards over and above a warm satisfied glow, say scientists.

Swiss psychologists have been trying to figure out why human beings have evolved to co-operate rather than act in a mostly selfish manner.

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.

Selfish genes

Claus Wedekind and Manfred Milinski of the University of Bern were testing a hypothesis known as altruistic behaviour for indirect reciprocity. This is used to describe situations where the rewards for unselfish behaviour come from sources that are not immediately obvious.

Claus Wedekind explained to the BBC how this works: "If I observe you giving money to a beggar then this theory would predict that I am more likely to give you something later if you are in need just because I've seen that you are generous to others.

"This is called indirect reciprocity because you don't benefit from the person to whom you gave the money and I don't benefit from you."

Such research could help us explain why altruism exists in a Darwinian world of apparently "selfish genes".

"Most of us understand evolution as a struggle, a competition where everyone fights everyone else," Dr Wedekind said. "There doesn't seem to be much place for altruistic behaviour. But there are different hypotheses that could explain why it pays for an individual to be nice to others in the long term."

Swiss francs

Most research has focussed on two ideas. The first explains altruism with regard to our close relations: helping our nearest and dearest promotes our own genes. The second deals with direct reciprocity: if you help me, I will help you.

The idea of indirect reciprocity was only modelled two years ago by game theoreticians and the lab work done by Drs Wedekind and Milinski is among the first research to test it.

They got almost 80 first-year students to play a game of give and take using virtual Swiss francs. The students sat in a semicircle and handed money to each other through a bizarre contraption of buttons, tangled cables and lights.

The guinea pigs had no idea of the true identity of the person to whom they were giving the money; the only information that was displayed at each interaction was a player's history of giving and non-giving.

"We found that the students in a controlled lab situation behaved as predicted. They're generous to those that were generous to others before them," Dr Wedekind said.

The research is reported in the journal Science.