Selfless acts of generosity activate the brain’s reward regions, making the warm glow of kindness a very real thing, according to British researchers.

By analysing the brain scans of over a thousand people making kind decisions, psychologists at the University of Sussex have confirmed that even when there’s nothing in it for you, being nice really does make you feel good.

The study, published in NeuroImage, analysed scans from existing research, but for the first time, it differentiated between true altruism and strategic kindness – nice acts that also happen to give you something to gain in return.

“This major study sparks questions about people having different motivations to give to others: clear self-interest versus the warm glow of altruism,” said Dr Daniel Campbell-Meiklejohn, the study’s lead and Director of the Social Decision Laboratory at the University of Sussex, in a statement.

“The decision to share resources is a cornerstone of any cooperative society. We know that people can choose to be kind because they like feeling like they are a ‘good person’, but also that people can choose to be kind when they think there might be something ‘in it’ for them such as a returned favour or improved reputation.

“Some people might say that ‘why’ we give does not matter, as long as we do. However, what motivates us to be kind is both fascinating and important. If, for example, governments can understand why people might give when there’s nothing in it for them, then they can understand how to encourage people to volunteer, donate to charity or support others in their community.”

Campbell-Meiklejohn and his team found that acts of kindness that gave us something to gain made us happier, with the reward areas of the brain using up more oxygen when people acted out of strategic kindness. But these areas also lit up for acts of altruism and specific regions in the subgenual anterior cingulate cortex were more active for altruism than strategic kindness. So there’s something uniquely satisfying about being altruistic.

The research suggests that rewarding people for behaviour they anticipated as altruistic might actually be detrimental.

“Given that we know there are these two motivations which overlap in the brain, charities should be careful not to offer something which feels like a token gesture, as this might undermine a sense of altruism. Sending small gifts in return for a monthly donation could change donors’ perceptions of their motivation from altruistic to transactional. In doing so, charities might also inadvertently replace the warm glow feeling with a sense of having had a bad deal,” said Jo Cutler, co-author of the study.

“The same issues could also apply when we think about interactions between family, friends, colleagues or strangers on a one-to-one basis. For example, if after a long day helping a friend move house, they hand you a fiver, you could end up feeling undervalued and less likely to help again. A hug and kind words however might spark a warm glow and make you feel appreciated.”