I'm not alone in this self-defined failure. Lots of people I know, my own age and younger, also admit to feeling like failed adults: "I haven't grown up" is merely the tense-shifted version of "I don't want to grow up". But what does this really mean?

I turn 52 next week, and I have a confession to make: I feel like a complete failure at "adulting". Adulting, loosely defined, is that set of activities and behaviours which we judge to be characteristics of grown-ups. You can stop now and make your own list: what I'm going to suggest, speculatively, is that you probably feel like a failure at adulting too. (If you don't, you can stop reading here.)

Well, in addition to formal educational processes, we humans learn like most mammals—by observing and imitating. Play in young mammals is all about practicing life skills, but unlike most animals we have a huge load of cultural skills to acquire, stuff we aren't born knowing more or less how to do and just need some practice to get right. And we work out what an adult is, and does, by observing the adults around us.

To say I feel like a failure at adulting doesn't mean I am a failure. I'm a middle-aged novelist who lives in an apartment he owns, has a car, is married, and so on. If I make a checklist of things grown up humans do (as I suggested in the first paragraph above) I actually come out pretty well insofar as the things I don't do are mostly optional. But I still feel like I'm missing stuff. So ... why?

Like most of us, my first experience of observing adults in the wild was as an infant, watching my parents. And—I mentioned that I'm nearly 52?—I'm not giving the game away if I say that my parents are not youngsters. They grew up and came of age in the 1930s and early 1940s; they, in turn, will have internalized their own models of adult behaviour from my grandparents, (only one of whom I ever met). And they came of age during or prior to the first world war.

So here's the thing: I suspect that when I was a pre-teen I internalized a model of adult behaviour that is familiar to anyone under 30 today mostly from TV shows like Mad Men. Men wore suits and hats and went out to work, women wore dresses and stayed home to raise kids, the trappings of material success included cars and maybe a black and white television and a vacuum cleaner (a luxury item in 1950s UK) and air travel was exotic. People went to church (or in the case of my family, synagogue) and society was determinedly homogeneous and a little bit bigoted on the side. And because I don't wear a suit and tie and smoke a pipe while surrounded by my nuclear family in our suburban house I feel kind of slightly like a giant overgrown kid who never managed to grow up and attain the complete grown-up checklist.

This is of course complete bullshit. It's imposter syndrome for grown-ups, and about as valid as imposter syndrome ever is. The reality of being an adult was never like that for everyone, except perhaps the rich and famous role models; it's just that the image of middle class success in the prevailing cultural narrative supplied a template, and insecure, frightened people who are trying to convince themselves that they're adults try to conform to what they perceive as the expectations of everyone around them. The generation that lived in 50's suburbia in turn had inherited their mental map of adult behaviour from their parents. They probably felt like adulting failures too—as witness the sky-high rate of tranquiliser use and alcohol and tobacco addiction in real-world mid-20th century suburbia. And you can trace it back further. The conformist parents of the 1920s were probably trying and failing and feeling like utter failures at being a Victorian paterfamilias or home-maker, or faintly inadequate because they couldn't afford to employ a cook, a maid, and a butler (the Victorian equivalent of a microwave oven, a vacuum cleaner, and a broken metaphor).

We base our vision of an aspirational lifestyle on our parents, who in turn got it by looking at the culture they grew up in (and their parents in turn). The rich are okay; they can afford to buy whatever trappings they think they're supposed to have—butlers for the mansion, finishing school for the kids, whatever. "Downton Abbey" was popular for the worked example of the classical lifestyle of the rich that it supplied: a place for everyone and everyone in their place, including the viewers sitting in front of the TV and wondering if that was why mum was always so fussy about positioning the cutlery just so when laying the table for family dinner. (It's not like the silver spoon novel doesn't have a history.) But the rest of us are struggling to find relevance in a slew of anachronistic cultural detritus that we'd be a lot happier if we simply learned to let go of.

So if you're slouched in front of your laptop wearing a hoodie and joggers while listening to 80s bubblegum pop on a streaming audio channel, and if you've got a collection of bobble-heads or models of the Starship Enterprise on your desk, and your kids (assuming you have any) are wearing retro fashions that remind you of photos of your parents back when they were dating, relax: you are not a failure! Cultural change happens over generations and you're going with the flow rather than trying to cling onto the past like these folk. As Terry Pratchett said, "inside every 80 year old man there's a bewildered 8 year old boy wondering what the hell just happened to him." Give that 8 year old a hug, and tell him he's doing just fine.