Have you noticed? A sub-genre of films seems to be building up; for the sake of courtesy, let's use an imaginary example.

Writer J. Smith lived a hundred or so years ago, and wrote a considerable number of plays/novels/poems, all of which were really fine work that people are still enjoying today. Not unnaturally, being a human being, J. probably also had a personal life. Modern critics may know about this personal life, or it might be shrouded in mystery, but it doesn't altogether matter: unless they lived in a locked room, they probably fell in love somewhere down the line. So let's make a film about it!

Which would be fine. But when you actually go to see Smith, you'll discover something. Or, if you'd been reading the tagline - 'Love is the greatest inspiration', or something like that - you'll have worked it out in advance. According to the writers of the script, J. Smith wrote all those wonderful plays or novels, not because he or she was, um, talented, not because he or she was intelligent, not because he or she worked very hard to get good at it, not because he or she had something to say about the world ... but because a love affair sparked them all off.

Writing, according to this branch of entertainment, is entirely a matter of getting laid.

Would that were so, but the sad fact is that, even if you're a romantic with high ideals and a picky attitude, it's still easier to get laid than it is to write literature that people will still be reading centuries after your death. I write to the best of my abilities, but I suspect that if I want anyone to make a movie about me I've either got to drastically improve my fiction or worsen my love life, so maybe it's different if you're a Genius, but still. I've written single, I've written in relationships, I've written in love, out of love, crossed in love, and while your love life, like everything else in your life, affects your mood, which might affect what you write, love doesn't get you writing.

So whence these stories that say you do?

The simplest answer is possibly the literal-minded one. Writers do write about love a lot. I remember once doing some quote-hunting for a job, and, after reading about fifteen books of poetry a day, reading poetry until my eyes crossed and the letters started dancing on the page, exasperatedly concluding that poets only wrote about two things: their own sensitivity and getting laid. (I take it back, in retrospect, but you try searching the National Poetry Library for a month to find appropriate quotes for pictures of dogs in landscapes. It wears you out.) But poets do write about getting laid, about being in love. It's a marvellous excuse for descriptive writing, and descriptive writing is fun: you can get drunk on words without having to sort out a plot. But frankly, I wouldn't be prepared to bet that half the love poems in the world were written about real people. It's a subject, and you don't need to be in love to be able to describe beauty and emotion. There's probably a poem to be written about the ante-room of poetic beloveds, coral-lipped ghosts called into being by their poet lovers who left them at the end of the last stanza and philandered on to the next beloved the next time they wrote a sonnet, acres upon acres of casualties of a poet's romantic imagination, but I'm not a good poet so I think I'll just leave it as a prose idea.

And even the beloveds who are real aren't really the cause of the poem. Or at least, they're only a catalyst. Loved by someone who didn't write, they would have been brought flowers and chocolates instead of verse; without them, their lovers would have written about something else. Writers write whether you love them or not. If you don't, they write about how nobody loves them. And if they're blocked, then they don't write until they're unblocked, love or not. Loneliness is as much of a spur to the imagination as romance, and possibly more so, as it gives you more time to write. A blocked writer who falls in love might suddenly unblock, but it's more likely he'll just think, 'Hooray, something to think about other than how stuck I am, let's go make love and not talk about my poems, please.' And whatever gets his imagination working again, it's likely to be complicated, and to more to do with the depths of his psyche than the depth of his beloved's eyes.

One reason the idea plays well, I suspect, has to do with extroversion and introversion. There are more extroverts than introverts out there, but writers tend to be introverted. So you've got a movie about an introverted person, which is probably going to be watched by an extrovert-majority audience. To an extrovert, the idea that you could draw creative energy from within yourself, in isolation from other people, is just instinctively wrong, because extroverts draw their energy from contact with others. Of course, then, to an extrovert, a writer writes more when they're in love: they're having contact with someone else, which means they get an injection of energy. Now, to an introvert - which the writer very probably was - that's a fallacy: you get your ideas from within (where else do ideas come from?) so the presence of another person may be anything from a nice extra to a positive distraction. But what it's not is a source of energy. As a contented introvert who dislikes being poked by people convinced extroversion is the only healthy way to be, I rather resent the implication. We aren't all the same, you know. And, more generally, it's likely to be an inaccurate portrait, which is seldom good for biopics.

An innocent audience may not realise any of these things, of course, and so these lit-roms get away with silly handling of the imaginative arts.

Another factor that makes it go over with innocent audiences is the romantic trance theory. I mentioned a while ago that among the numerous unanswerable remarks a writer encounters, one of them is 'This should inspire you!' when pointing at a pretty landscape, a good concert, a painting, or anything else that either is artistic itself, or is the kind of thing that some poet or painter, somewhere, some time, has produced art about. People write about love, a lot, so exposure to love makes you write, right? But it's based on a fundamental misunderstanding of the artistic process. In this misunderstanding, art is produced in a kind of trance. You can be pushed into this trance by exposure to anything associated with art, and in the trance, you produce art yourself. Art doesn't require conscious thought, it just flows into your brain when a stimulus starts you mainlining the Muse, and anything that came from the Muse can open that channel. Again, would that were so, but it ain't.

But there's a problem with all these explanations. While it's possible that someone who doesn't write might assume that everything someone writes about love is based on personal experience, it's the assumption of someone who doesn't know how it's done: 'it must be based on real life, because nobody could, y'know, make stuff up like that!' So for the romantic trance theory: only someone who doesn't write thinks that everything vaguely romantic or artistic 'inspires' you. But that can't be what's going on here: it doesn't make sense. Because, let's remember, somebody actually has to write these scripts. Scripts don't write themselves. By definition, whoever is writing these scripts, they're writers themselves, and they must know that it takes more than a white rose, a glistening tear and an invigorating orgasm to make you write something brilliant.

Possibly screenwriters are unusually extroverted. I don't know any, so I cannot possibly say for sure; it's certainly a more collaborative process than most kinds of writing, and films are more comfortable about taking ideas from external sources: it's supposed to be a rule in Hollywood that you keep your ideas to yourself or somebody will nab them, and adaptations, remakes and sequels are all big business. It might be, I suppose, that extroverted screenwriters are remaking writers' lives to make them seem more instinctively correct, but if that's the case somebody needs to go and poke them, because introverts are misrepresented enough as it is.

Cynical marketing ploys to get people reading might be another explanation - read the author's books, which are just like the movie! - but I don't think the publishing industry is funding them, and if the aim is to make people consume more art, it would be more in Hollywood's interests to do romanticised biopics about directors and screenwriters, which I've yet to see. More probably, they're casting their nets out, assuming that fans of writer Smith will come to see the movie, and people who can't quite bother to read Smith will come as well in a kind of cinematic Cliffs-notes attempt to learn about Smith without actually reading anything. That may be one explanation, a sense that biopics are to some extent pre-sold - but that's a reason for commissioning the film, made at the executive level. The reasons for creating the story in the first place are likely to be less commercial.

Another cynical possibility is that, while the screenwriters know it's a load of nonsense, they know the majority of filmgoers probably won't. Based on the success of some of these movies, some people think it's just romantic, rather than sentimental and by implication pretty insulting to the talent of these impressive individuals. In that scenario, the actual stuff that got written just forms a pretty background, much like the costumes in Merchant Ivory films, sweetening the atmosphere without actually having to come from a rigorous brain.

But added to that, there's a very definite dodge in such scripts: a certain amount of the writing has already been done for you, by a better writer. Want a really good line? A touching scene? A meaningful moment? Read through the oeuvre of the biopic's subject. There's bound to be something there, and you can then either quote it directly or pastiche it, and in so doing, imply that Smith, the writer, drew inspiration for that scene from real life - so it wasn't you copying Smith; in effect, you thought of it first. Or at least, real life did, and in this film version, you're the one who says what real life is. It's one of the few situations where out-and-out copying works in your favour: rather than saying, 'Ahh, he just ripped that scene off from Smith, how stupid,' the audience will be saying, 'Why, that scene was just like a scene in Smith - how clever!'.

That's so sneaky it's practically a confidence trick. The screenwriter hasn't actually written a better script than the plagiarist in terms of what they created themselves, but they've found a way to semi-appropriate really good writing, and get some of the credit reflected back on them. There are many ways to cheat in writing, and that one is really dirty.

Literary appropriation is an old trick, and this is not the only way it works - larding your work with references is another. But really, it's all a con. Don't believe it! J. Smith wrote the stuff first! Keep your money! Give it to me instead!

That concludes this public service message.

Incidentally, if you want to watch a good biopic about a writer, watch The Passion of Ayn Rand. Despite the hagiographic ring the title has to it, it's a thoughtful, critical look at the personality of Rand and the effect it had on those around her - which, according to the film, was pretty thoroughly negative, although Helen Mirren's regally pathetic performance as Rand is a beautifully judged portrait of a poisonous but still human personality. Rand explicitly linked her own personality and life with her work and philosophy, so it's unusually appropriate to make a film about her life, and it's a well-acted and well-directed reflection on the failings of the Rand following. (If anyone reading this is a Rand devotee and wants to write in declaring that it isn't completely accurate: yes, I know; it's a fictionalised interpretation. But it's a good one, and having read The Fountainhead and various commentaries on Rand, I find its interpretation intelligent.)