Experiment finds most people are willing to pay to spare others pain

No pain, no gain. People who gladly underwent electric shocks for cash in an experiment were more willing to sacrifice money to reduce others' pain than they were to reduce their own.

The findings, published in the journal Proceedings of the National Academy of Sciences, tested the limits of people's willingness to inflict pain on others for their own benefit - and reveals human behaviour to be, at least in this case, surprisingly altruistic.

Research into "prosocial" behaviour - that is, behaviour that's intentionally meant to help others - leads to different conclusions, depending on the experiment. Studies show that people do put a value on other people's "monetary outcomes" - they're willing to donate money to total strangers - but they care far less about others' financial gain than they care about their own.

Other research indicates that people empathise with others' pain, but value it no higher than their own. So how altruistic are people, really?

To get at that question, scientists at University College London set up two experiments involving more than 160 participants in anonymous pairs, randomly assigned the ominous sounding roles of "decider" and "receiver".

The decider would get to choose between more money and more electric shocks, or less money and fewer electric shocks - say, seven shocks for £10 (HK$121) or 10 shocks for £15. But even though the decider always got the money, there was a twist: half the time, the decider would get the shocks; the other half, the receiver would get the shocks.

The researchers found that people were "hyper-altruistic" - that is, the deciders were less likely to harm the receivers for a little more cash than they were to harm themselves.