‘So what are you working on?’ people would ask. ‘Fun’, I would tell them, and see the curiosity fade to incomprehension or even horror. It seems that even uttering the word ‘fun’ is to become an advocate of hedonism and frivolity and forfeit any claim to seriousness – an attitude I understand because it was just this sort of dismissive scepticism that got me interested in the subject. For decades, whenever there was a mention of weddings, holidays or parties, my wife and daughter would take a look at my face, throw back their heads, roll their eyes and cry, ‘Oh God, the man who hates fun’ - and eventually this got me wondering: what is fun, do I hate it and if so, why? Is it fun or is it me?

I began to pay attention to contemporary manifestations of fun and these generated another host of questions. Why has dressing up become such an obsession? In particular, why do so many want to dress as zombies? Why are swinger clubs and BDSM so popular? Why is much of the younger generation covered in tattoos? Why have dance events, festivals and stand-up comedy clubs proliferated? Why, when spending on holidays plummeted after the crash of 2008, did spending on cruises continue to rise? Why has football become the world sport when it seemed in terminal decline a few decades ago? Why has fun become such a crucial feature of serious movements, from radical protest on the left to evangelical Christianity on the right? And why did most of these developments begin in the seventies? Why the seventies?

There were even some startling Irish connections. A headline jumped out at me: Swingers Groups in Ireland Are Growing at a Massive Rate. Then there was a prominent advertisement in an English broadsheet newspaper: PACKAGE HOLIDAYS TO HALLOWEEN IN DERRY. Apparently my cynical, apathetic hometown now hosts the largest Halloween carnival in Europe. And it turned out that the World Naked Bike Ride, an annual international event where thousands ride through cities naked, is celebrated in Cork. Naked paddies and colleens on bicycles! I doubt if my old heart could stand the shock. So Derry is dressing up, Cork is stripping off and everywhere Mother Ireland is swinging. If fun has conquered even puritanical Ireland it must indeed be well on the way to world domination.

Finally there came the meta question, the question about questions – why is there such an apparent lack of curiosity about these developments? Why does no one ask what fun is or what the experience is supposed to provide? One reason is that fun is assumed to be so simple, obvious and changeless that it requires no explanation. And there is also a near-universal reluctance to think about fun. For the practitioners, the funists, part of the attraction of fun is its escape from the burden of thought. And for those who abhor fun, the afunists, the phenomenon is too vulgar even to mention, much less analyse.

Fear of a contemptuous response made me reluctant to start writing - but a fun folder insisted on being opened, and it quickly filled up with cuttings, references and notes. Themes and sub-headings emerged. Research revealed fascinating historical connections. It became clear that here was a social phenomenon developing right under everyone’s noses but somehow invisible – the writer’s dream of virgin territory. And exploring this territory could even be intellectually respectable. I could found a new academic discipline, Fun Studies, and be the first Emeritus Professor of Fun, not to mention executive editor of the Journal of Fun Studies.

Far from being simple, obvious and changeless, fun turns out to be complex, paradoxical and constantly changing. To begin with, fun is social. It is possible to have pleasure alone but not fun. And fun tends to take predictable forms – the same activities in the same places at the same times with the same people. So fun is ritualised – a group ritual, or, rather, a set of group rituals. And these group rituals seek not just sensual pleasure but often some combination of belonging, solidarity, transcendence, experience, re-enchantment, comedy, play, authenticity and transgression. Then there is the paradox that fun, the most profane of activities, can even be a quasi-religious provider of meaning. And while fun is essentially a modern phenomenon, it has recreated many of the elements of early ritual (festivals, intoxicants, costuming, face and body painting, group dancing to rhythmic music). The post-postmodern is turning out to be the pre-premodern.

And considering all this produced a personal revelation. It came to me that my problem with fun is its social nature. I’m averse to most forms of group activity because I’m an old-fashioned twentieth-century individualist, and investigating the roots of individualism led to the wider conclusion that the exclusive pursuit of individual freedom is not as fulfilling as it promised to be, and may not be the terminus of civilisation but a temporary over-reaction against social constraints, a lurch from one extreme to the other that is now correcting itself. We may well be entering a post-individualist age. In much of the Western world there seems to be a new interest in social connection and group activity of every kind.

Does this mean that I have become a funist? It’s a bit late in the day for that. But I would definitely describe myself as a recovering afunist, less inclined to be dismissive of group activity, though still reluctant to participate, and this in itself is an extraordinary change. If anyone had told me years ago that I would be sympathetic to ravers, cosplayers, swingers and gamers, I would have laughed myself into a double hernia.

Isn’t This Fun? Investigating the Serious Business of Enjoying Ourselves is published by Simon and Schuster, £9.99