A shocking result – people are more willing to hurt themselves than others for profit

You wait in a cubicle, electrodes strapped to your body. In a room nearby, a stranger is confronted with a series of decisions. They can choose a smaller cash reward and avoid an electric shock, or a larger sum that comes together with an unpleasant zap. The twist is that in half of the trials, the stranger knows the associated shock punishment is for them, but in the others they know it's you who will suffer. You glance nervously at the electrodes.

It's a tough spot. Surely you will receive many shocks – after all why wouldn't the deciding stranger opt for more money when they know it poses no personal risk? As a psychology nerd, you grimly recall experiments showing we're more prepared to hurt others financially than ourselves. Then you cast your mind wider and recall more hopefully how empathy research suggests humans are highly motivated to prevent suffering in others. Maybe the stranger won't put you at more risk than they put themselves?

This is the scenario that was explored in research carried out at University College London by Molly Crockett and her colleagues. Across two experiments, the 80 participants who played the role of the decision-makers were in fact more careful with another person's pain than with their own. They were prepared to receive higher shocks for modest extra rewards, but rejected the same deals when the shocks were for another unknown person. Specifically, the participants needed about twice the financial return before they would raise the pain levels for a stranger.

One fact of note is that when a trial involved choosing shocks for another person, the participants took more time over their decision – and the more they slowed down, the more likely they chose the kinder option. This is surprising because previous research on generosity suggests that faster decisions lead to more altruistic actions. The current research complicates this account, suggesting that snap decisions may be more altruistic in positive situations, but less altruistic in negative ones. Essentially, the research calls for us to recognise that being "thoughtful" is also a component of altruism.

The empathy literature explains how witnessing others' pain affects our own pain networks, so this would imply that we could treat it as seriously as our own. But these findings go further, to something Crockett likens to Adam Smith's notion of "moral sentiment", where human beings are driven by a principled aversion to benefiting through the suffering of another. By contrast with the selfishness seen in economic trading games, this research shines a light on how the direct physical suffering of others triggers empathic responses that are altogether different from responses to other people's purely financial disadvantage – even though lack of money may result in suffering too. We respond most humanely – most humanly – to human conditions of need: tired eyes, thin limbs, a body in pain.

Further reading

Crockett, M., Kurth-Nelson, Z., Siegel, J., Dayan, P., & Dolan, R. (2014). Harm to others outweighs harm to self in moral decision making. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1408988111