What does it mean to be kind? After the past year and a half, many of us will feel we have a clear idea: helping out friends and family as well as mere acquaintances left high and dry by the pandemic; carrying out small acts of help or devoting huge resources of time and patience, sometimes for people we barely know.

Perhaps now, as we talk hopefully of a return to normality, such connections, newly enriched by kindness, are not something we wish to chill, atrophy or go back to how they were before.

"Kindness has been so talked about during the pandemic with people seeing examples of kindness in their community, on their street and in WhatsApp groups," says Claudia Hammond, a presented at BBC and a professor of psychology. "I think people have been thinking about their values and what really matters to them; taking stock and asking what they want the world to be like next."

And yet if we feel that recent trials have brought us closer to understanding kindness, for researchers it remains something of an enigma. Even the OED definition stretches on and on, encompassing the obvious – gentle, benevolent, warm-hearted, ready-to assist, obliging, considerate – and the intriguing, "a natural fondness for one’s family and high quality of social rank or character".

Is kindness then not just about altruism but also about in-groups and social status? Do performative acts of charity count? Or making a great song and dance about clapping for carers?

Kindness, answers Prof Robin Banerjee, Head of the School of Psychology at the University of Sussex, is indeed a tricky, elusive term, its malleability reflecting a highly subjective quality. "There’s so much about it we don’t know, it means something different to everyone," he says. "That’s the point of this survey."

‘This survey’ is a giant online questionnaire, open to all, conducted by Banerjee’s team at the University of Sussex, in partnership with Hammond and Radio 4. Results of the research will be aired on the BBC station next spring.

The survey starts by encouraging users to note the three words that they most closely associate with kindness. I put in "selfless; generous; altruistic", which tallies, Banerjee, tells me, with the stock conception of the term, as "a behaviour intended to benefit someone else. It’s just all the complexity we have to get a handle on."

That complexity is bound up in the ‘Why?’ Why behave kindly to others? Do we do it with some expectation of future benefit to ourselves, even if that benefit is hugely delayed or deferred – like giving up a seat on the bus to an elderly passenger knowing somewhere in the back of your mind that one day you will be hoping for the same to happen to you? Banerjee says yes, kindness can certainly comprise an element of expected reciprocity, "but the altruism [to give up a seat, say] is genuine in that moment, driven by compassion for another person". In other words, selflessness is not incompatible with self-interest.

The short-term and long-term jostle in other expressions of kindness, too, Hammond explains. It can seem kind in the short term to offer children a lolly, for example. But long-term lolly donations – of the ice cream or financial variety – may do more harm than good. So should we measure kindness not in the moment, but over time? Perhaps that’s what has been driving various billionaires recently to cut off their offspring from the full inheritance. Cruel to be kind? "Maybe in the long term," admits Banerjee, "an act of kindness is really not going to be helpful and might be counterproductive."

Yet, we all know some saintly people who just ‘are’ kind. So what about the evolutionary background to kindness, I ask? Has kindness been hard-wired into certain brains from the days we were cavemen, looking out for threats and helping our gang to survive? "The evolution of being kind to other people is something that many, many people have described," says Banerjee. Perhaps this explains why, he says, evidence from neuroscience shows something happening in the brain when we perform acts of kindness. "That sense of a warm glow when people do kind acts, there is a biological connection." That angelic halo I sense hovering over me as I carry the neighbour’s shopping up her stairs, it turns out, is nothing more than little hits of dopamine or the like, lighting up my sense of self-satisfaction and well-being. Who cares! It feels good to be good.

Yet still I’m stumped. Does this evolutionary connection mean that kind acts are usually performed to support our own groups, our own mates – possibly suppressing the chances of others? That doesn’t sound so kind, and suddenly that dictionary proximity of kin and kind seems important. Because those caveman concepts – what Banerjee calls "kindness in relation to your family, your group, adapted for survival" – endure today. The financial leg-up given to a child; the workplace internship offered to the son of an old friend... is this kindness? What starts out as a simple investigation into the nature of a lovely quality soon starts to burrow into fiendishly tricky aspects of human relationships. No wonder Hammond and Banerjee reveal that, as a subject of academic inquiry, kindness-studies have exploded in recent years, from a wistful diversion before the turn of the century, to the target of thousands of papers in the past decade.

It is why their survey digs into not just what individuals think it is to be kind, but also what kind of individuals we are to think that way in the first place. Those filling it in will find social relationships (loneliness and connectedness); demeanour (sunny or gloomy); political leaning (Left or Right); attitude to money, all probed. As I fill the questions in, I begin to suspect that the researchers might be wondering whether kindness in a person depends on what they think of themselves. This might explain some conundrums. "I can think of many examples of people who absolutely are not rich, absolutely don’t have the most resources, who are doing the kindest acts and being most generous," says Banerjee. But of course there are poor people who feel themselves rich – and the reverse.

And yet, do not give up yet, you hard-hearted Scrooges. For kindness, it turns out, is blissfully contagious.

"There have been experiments done in the lab where if people observe others being kind they are more likely to be so," says Hammond. Which is why the test, having asked for your definitions of kindness, quickly moves on to asking when someone was last kind to you; then when you were last kind to someone else. When I stopped and thought about it, I realised that I was constantly being bombarded with little doses of kindness, from the cup of tea brought to the keyboard while I scratch out this piece, to the thoughtful friend who somehow secured a first ticket to Lord’s for my cricket-mad eight-year-old. The stuff is out there everywhere once you open your eyes. "We need to look up and notice the kind acts that are going on around us," says Hammond.

Taking the Kindness Test, I realise, is one way of doing just that. So it might not only help researchers to pin down the essence of this slippery sensibility, but also help us tune in to kindness more – and feel better about life, the world, and ourselves.

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