'In England', wrote the historian DW Brogan, "being a schoolboy is an end to itself". He was right. At the high tables of Cambridge University on every Sunday night, college fellows are offered a mouth-watering choice of desserts to close their meal, but almost all opt for rice pudding.
When once I summoned the courage (as I scoffed pavlova) to ask why, my dining partner smiled knowingly and said "It reminds us of matron and of school".
Not that our country seems very different. In rural Ireland, until recently, you remained "a boy" until you married, which could be late in life if you were waiting for parents to pass.
A Dáil deputy for Louth back in the 1950s made an emotional plea for the rights of "boys of 46 or 50 still waiting to inherit the land".
The outbreak of laddishness in the culture of the 1990s breathed new life into the phenomenon. From Nick Hornby to Hector
Ó hEochagáin, the various types may be seen on TV. Even as childhood seems to be rolled back and reduced, the idea of a boyhood lasting into late middle-age has taken further hold.
Some versions of the prototype are distinctly queasy: a current joke maintains that if Michael Jackson commits just one more infraction, the Pope will offer him a parish.
But most are viewed as examples of healthy high spirits - the sort of charming blokes who propelled many a PG Wodehouse novel with their amusing attempts to avoid entrapment by a Gladys, who represented the awful prospect of "settling down".
The image evoked by that phrase was of a corpse reclining into a coffin of complacency.
The cultural forces that have produced the "new boy" are probably not all that different from those which generated Bertie Wooster or the Louth bachelor lads.
If you are chronically "short of the readies" and cannot afford to pay the vast money now needed to secure a home of your own, the temptation is to go out and blow what money you have on cars, gadgets or gismos. Hence the strange, rather unnerving, poster which this month advertised a display of such items in the RDS: "Toys 4 Big Boys".
Meanwhile, estate agents report that many of those taking out mortgages on first-time houses or apartments are single women in their 20s, who do not necessarily see such a move as coinciding with marriage or cohabitation. And some young men, less adept at planning or saving, are choosing to stay living in the homes of their parents.
The romantic poet, Samuel Taylor Coleridge, said that people should never put away childish things: the wisdom of life, he maintained, was to learn how "to carry the feelings of childhood into the powers of manhood". That was a plea for people not to lose their sense of wonder.
And it's true that many artists are great by virtue of maintaining contact with their inner child. "A boy could have done that", mocked a harsh critic of one of Picasso's early abstract paintings. "Yes", the artist chortled, "but could a boy of 40 have done it?" I'm not sure that the 40-somethings who play Grand Theft Auto and read Superman comics are operating fully in the spirit of Coleridge and Picasso. But they are certainly haunted by the notion of a lost boyhood still to be recovered. A similar explanation may lie behind the success this year of The Dangerous Book for Boys.
This is a high-finish recreation for adult males by Conn and Hal Iggulden of the world of the old Victor and Wizard comics. It tells you how to make knots and treehouses or how to know the flags of all nations.
I happened to be clearing out the garage of my childhood home in the week that The Dangerous Book for Boys came my way. Every item I came upon - a blow football game, Subbuteo, a collection of Victorian pennies, a postage stamp album, a wooden drum - seemed to come out of the now-distant world reconfigured in the current best-seller.
It all bore in on me just how much the experience of boyhood has changed in the past 30 years. My father shared with me the pleasure of stringing a bow-and-arrow or of lacing a conker, as his father had done with him.
But I don't understand most of my son's PlayStation games (even the Fifa soccer seems designed for someone with different wiring from my own).
Frustrated in the attempt to pass on the lore of old boyhood, many men in their late 40s and 50s are choosing to recreate it privately in their reading. Hence the demand for The Dangerous Book for Boys or for Ben Schott's miscellanies. Meanwhile, those "big boys" still in their 30s commune with their lost (or never fully worked-through) youth in the hall of the RDS.
Perhaps the psychological truth behind much of this was captured in the Hugh Grant movie, About a Boy. Like the central character in that film, all seem shadowed and haunted by the image of a boy, who is not only mysterious and persistent in himself, but who seems to call men away from childish play back into the real world of grown-ups.