What psychologists term the "availability error" is prominent in so many different forms throughout our mental life that it's debatable whether this constitutes a form of delusion at all. Still, some examples are so egregious that unpicking them may help us in the general direction of better mental hygiene.
A few weeks ago a serviceably pretty young woman went to a big ugly house to meet a handsome man who happens to be the president of America, and his mildly steatopygic wife. For the occasion, the young woman slipped on a fairly nondescript dress. In due course, when photographs of this prettyish woman wearing said dress appeared in the papers, there was a frenzy as thousands upon thousands of crazed punters attempted to log on to the website of the British high-street label Reiss to buy it.
Put simply, the availability error consists in judging by the first thing that comes to mind; in this case, we can summarise the thought processes of the wannabe Reiss-buyers thus: Kate Middleton is wearing that dress and looks good, therefore if I put on that dress I will look good as well. We could elaborate, because undoubtedly there is a further murkier tier to such unreasoning: Kate is wearing that dress, therefore, if I wear that dress, one day I will be queen of England (as well as Scotland, Northern Ireland, Wales, Bongo-Bongo Land, etc), hobnob with the Obamas, wear diamonds the size of pigeons' eggs - and so on.
A variation of the availability error that I've discussed in this column before, in connection with my propensity - or otherwise - for urinating into the Dyson Airblade hand dryer, is the halo effect. The halo effect implies that if one person has a single, very obvious, characteristic, the rest of his or her attributes are invariably perceived in the light of it. This is why - despite all evidence to the contrary - good-looking people are often viewed as sagacious, amusing, possessed of phenomenal ball control, and so forth.
Ms Middleton is no film-star beauty, nor has she ever done anything in her short life worthy of note save part her thighs for the heir to the throne, then marry him. Be that as it may; paradoxically, her approachable, girl-next-door vibe becomes incorporated into her halo, so that potential dress-buyers formulate syllogisms of this sort: "All girl-next-door types wear mid-range fashion labels, Kate Middleton is wearing a mid-range fashion label, therefore Kate Middleton is a girl next door." This conclusion won't necessarily sell that many £175 Shola dresses (the Reiss design that Middleton wore to meet the Obamas), but it will, of course, sell the object - the Windsors - to their subjects, at a time when the populace might well resent the spectacle of hereditary multibillionaires lording it over them without even minimal concessions to such coalition virtues as choice and fairness.
The use of the availability error and the halo effect by advertisers is nothing new - when I was a kid, there was a scare to the effect that big corporations were pushing their product by inserting subliminal imagery into feature films. The rumour was that, for a split second during some parched scene of Lawrence of Arabia or another, an ice-cold can of Coca-Cola was flashed up on screen, ensuring that, come the intermission (remember them?) everyone would rush to the foyer and begin guzzling down the sinister sarsaparilla.
In fact, most advertisers have no need for such subterfuge - they can openly supply the imagery and we will subliminally influence ourselves. Thus shampoos provoke orgasms, mobile phones collapse cities like packs of cards and cars . . . Well, cars morph into just about everything imaginable and then chomp up the road. Do I believe that there is something intrinsically wrong with this? Yes, I think there may be.
Take Chinese Elvis. He runs a not terribly successful restaurant on the Old Kent Road, and once or twice during the evening's sittings he emerges from the kitchen dressed as the King to sing "Suspicious Minds" or "Heartbreak Hotel". He doesn't look a bit like Elvis, and he certainly doesn't sound like him, but such is the potency of the late rock monarch's halo effect that, even years after his death, it can still garrotte the unsuspecting.
In fairness to Chinese Elvis, he's only helping to sell his food - which isn't too bad - but it remains a bizarre aspect of contemporary commerce that stuff can now be sold not only by the famous, but also by their impersonators - and how mad is that? l