“Ireally enjoy doing it: it makes me feel good about myself. It gives me a boost, mentally and physically.” If these were your reactions to an activity, you’d surely be inclined to do it as often as you could. After all, aren’t a lot of us looking for ways to find more meaning in life and to be happier and healthier? What, then, is the act that elicits such positive responses? The answer: being kind. A growing body of evidence from the fields of psychology and neuroscience demonstrates that performing kind acts increases mental wellbeing, enhances physical health and might even improve life expectancy. Kindness is not just beneficial for the recipient, but also for the giver. In 2021 I worked with a team at the University of Sussex to create the Kindness Test. This online study was launched on BBC Radio 4, and more than 60,000 people took part. We found that the more acts of kindness people told us they carried out, the greater their wellbeing. At Christmas, if someone really loves the gift you’ve chosen for them, the pleasure of giving can be even stronger than the pleasure of receiving a present. But such feelings don’t always sit comfortably with us. Shouldn’t true kindness be selfless? Traditionally, it is tied up with notions of self-sacrifice and putting other people’s welfare ahead of your own. Indeed, some of those researching kindness argue that a defining element is that the person performing the act must give up something in order to help someone else – and not gain personally. This may physically be the case. If I give up my seat to an older person on a crowded tube, she ends up sitting and I end up standing. I’ve lost out by my kindness. Similarly, if you give up several hours a week to volunteer at your local food bank, you are sacrificing time in order to help others. You are not directly benefiting from your kindness. Yet when I surrender my seat, or you volunteer your time, we tend to feel a warm glow of self-satisfaction, a glow that shows up in brain scans, a glow that is distinct from the pleasure that registers when we win something for ourselves. We can also benefit through reciprocity. We can act kindly now, even if it’s at some cost to us, in the knowledge that at some point in the future someone will act in a kind way towards us when we need help. Reciprocity has helped humans to work together, survive and thrive for many thousands of years. Being kind has such evolutionary benefits that our brain rewards us for it, pushing us towards that behaviour. But the biological push doesn’t mean the joy is tainted. It’s a bit like sex. The evolutionary point of sex is to reproduce, but that doesn’t mean sex shouldn’t be fun when you’re not trying to make babies. So why try to suppress the advantages we gain from our kindness? Why not just celebrate the fact that the giver of kindness, as well as the recipient, has something to gain? Kindness isn’t simply a transactional activity: one person gives, the other takes. Rather, it is a shared, two-way endeavour. Only in extreme situations does kindness involve the complete or near complete abnegation of self, such as when people risk or sacrifice their life to save the lives of others. And even in these situations, if the hero survives, they can personally gain from their action through a huge enhancement to their reputation. Less elevated acts of kindness, meanwhile, tend to have mixed motivations, including feeling positive about ourselves and looking good in the eyes of others. There is, in other words, an element of self-interest in being kind to others – and there’s nothing wrong with that. This is not to argue that selfless kindness should be replaced by selfish kindness. If, for example, the only reason you want to help cook Christmas lunch for homeless people is so that you can post on social media and get lots of likes from your friends and followers, you probably need to check your motivation. Kind acts shouldn’t be done entirely cynically in search of praise or in an attempt to appear more attractive. They need to be authentic. No one wants to be accused of virtue signalling or of tainted altruism, but if the result of enjoying your kindness is that you do it more often and the sum of kindness in the world increases, then surely that’s a good thing. Acting kindly can be difficult: it requires effort and isn’t always fully appreciated. But it’s because this is true that you shouldn’t feel guilty about experiencing that warm glow or believe that it diminishes your act of kindness. There is plenty of evidence, for example, that donating to a charity appeal makes us feel good, but the money we give at Christmas genuinely helps the recipients. In the Kindness Test, people were asked which words they would use to describe how they felt after receiving an act of kindness. In the main, they told us they felt happy, loved, relieved, supported or warm. If this is the positive impact that we can have by being kind, we shouldn’t get too hung up on the purity of our motivation. Kindness can be entirely selfless, but more often we’ll have a mixture of intentions. Why not lean into those benefits and be kinder more often? This year, maybe take extra trouble to find that special gift for a loved one, or make the effort to check on a neighbour who might be spending Christmas alone. The chances are it will make the festive season not just happier for them, but for you too. And that’s fine: everyone wins. Claudia Hammond is visiting professor for the Public Understanding of Psychology at the University of Sussex, and the author of The Keys to Kindness (Canongate). Further reading Mindful Compassion by Paul Gilbert and Choden (Little, Brown, £12.99) Heroes of Postman’s Park: Heroic Self-Sacrifice in Victorian London by John Price (History Press, £16.99) The Social Instinct by Nichola Raihani (Vintage, £9.29)