What the well dressed tree is wearing this year.

A procession of girls moves jauntily down Oxford Street. Each girl carries an identical Gap carrier bag and wears brightly coloured skinny trousers. The legwear ranges through many colours and materials – there are 23 different types in the shop.

It took me a while to realise it was an advertising event. Initially I just assumed that ‘Jeggings’ had really taken London by storm, either that or Mayor Boris had passed a new bye-law banning big trousers.

How tempting was it to join that line? So called ‘modelling’ is one of the strongest determinants of human behaviour. But by the time I had got into those trousers the line would have reached Tottenham Court Road and disappeared.

Some animals are hard-wired to behave exactly the same as their neighbour, making possible formations like shoals of fish and flocks of starlings. Someone explained to me that starlings and fish do not need to be particularly clever to pull off this trick. All they need is the instruction ‘do the same as the one next to you’.

Humans like to create this effect too, in Busby Berkely movies for instance or the Red Arrows air display team.

We are used to seeing similarly clad people in other contexts, such as children in school uniform and North Koreans in boiler suits. We like to be wearing the right things.

A demonstration of modelling behaviour is one of many attractions to be found in the local shopping centre. Since social services closed all the day care facilities, shopping malls and libraries are the best places to hang out to keep warm.

Compared with the library, the shopping centre is quieter and more studious in atmosphere. Also there are more books to read.

This part is vital – before you visit the shopping centre – establish the goal. On this occasion the target is: 1.To experience the sensation of being out of place; 2. Not to respond to this sensation by buying something.

For your day out, start by re-framing the shopping centre as a kind of art gallery.

All the familiar shops / exhibits are there (not you Woolworths). There are lots of things you can do free: try out the mattresses in John Lewis, try on lots of jeggings, use the computers in PC world to look up reviews on the same model you are trying, so you can spurn the attentions of the salesperson, use the cameras to take pictures of other people testing cameras on you, try on tester perfumes and marvel at their interesting names.

Or go into Superdrug, and ask for a super drug, such as beta interferon. Ask why they call themselves Superdrug when the best drug they have is ibuprofen.

My hypothesis is that shopping behaviour is a sublimated form of hunting, or at least gathering. The important thing to remember is that all the fun is in the hunt, and once the quarry is cornered then the fun is over. It is all about the expectation of reward – pulling the trigger on a purchase is entirely unnecessary.

Buying something is like coming home from a day’s fishing with a small trout you could have bought in Morrison’s for £3. The trout’s dead eyes communicate to you: So what?

You should have thrown it back in.

Things are not always what they seem, and shopping malls allegedly have a purpose beyond amusement or art.

Shopping malls are meant to part people with their money, rather than act as a recreational facility for escaped psychiatrists. The architects and designers have put in some subtle influences to work on your mind.

One of these is the so-called ‘Gruen Transfer’. This is a place, within the centre, that is designed to disorientate people, by using a combination of unusual shapes and textures and lighting, often accompanied by Muzak.

Apparently the effect is similar to a unit of alcohol or other anxiolytic. People slow down through the Transfer, and co-incidentally this is where the higher priced items are located.

I am not convinced that there is a strong evidence base for the Gruen Transfer, or other devices perpetrated by the advertising industry. Certain low budget shops seem to generate the same emotional disruption.

The oddly named B and M store, sometimes sub-headed ‘Bargain Madness’ can induce such profound despair that it could probably be used as a testing lab for possible new antidepressant compounds. Here the store has been less discreet about its use of disorientation – the clue perhaps is in the word ‘madness’.

Agoraphobics, who tend to have panic attacks in shops, seem to dislike places where there is no clear sightline to the exit. The entrapment induces a sense of doom. Though Morrison’s have an excellent range of vegetables, the way they are laid out can set a person on edge.

Individually, fruit and veg items are not threatening, but when they gang up like this, piled high on all sides, it creates a kind of jungle effect reminiscent of Apocalypse Now.

Another piece of (probably bogus) psychology I have read, relating to supermarkets, is that people have an ‘innate tendency’ to gravitate anti – clockwise. This led to supermarkets placing their main entrances on the right hand side of the shop.

If it was on the left, people would just drift further leftwards into the vegetables section and beach themselves in the courgettes.

Staff would come out to spin customers into the next section, like fairground attendants on a waltzer.

I wonder if it is different in the southern hemisphere, or for the left handed?

It is perhaps a little frightening to think that someone has manipulated the environment in such a way that you have unwittingly bought yourself an expensive, weirdly named perfume.

I am not just referring to ‘Obsession’. What about ‘Hypnotic Poison’, ‘Crazy in Love’ and ‘Thallium’? The internet tells me there is a perfume called M-75, which is the name of the rocket Hamas fires into Israel.

Perfumes, like the Gruen transfer, and the clockwise supermarket, are designed to create an altered state, but what exactly is the state of mind called? In the case of perfume, if it isn’t the name, it is probably solvent intoxication.

Or perhaps it is the feeling of being out of one’s element, or out of step with others. A warning that you are on unfamiliar territory.

Behaviourally, it is supposed to trigger a purchase decision.

The purchase decision is a learned behaviour that creates comfort, possibly by stimulating the ‘anticipation of reward’ section of the mind. The unsettled feeling is briefly quelled, only to be replaced by regret that you have suddenly become poorer and the shop richer.

How comforting is it to be in a herd of people all dressed appropriately and behaving in the same way? Enough people must love formations of soldiers to make it worthwhile dressing thousands of people this way and arranging them in large city parks. Everyone seemed to love the Olympic opening ceremonies.

Lots of people like to be in queues, and will probably join the end of any queue if they find one. If other people are after something, instinct says there is probably something there to have.

There is often not much to be found at the end of a motorway queue, which is formed by the pulsatile dynamics of traffic flow rather than obstacles, but the queuing instinct has evolved over the lengthy period of human history before tarmac and has not yet abated.

The instinct to behave like the person to the left of you is deeply rooted and possibly imprinted at an early age. Experiencing the feeling of being in the wrong place or in the wrong outfit is deeply discomforting.

Many people hate the moment in a restaurant when they have to set out to find the toilets. The fear is not that they will never find the toilet, but rather they will make them-self look foolish to others by dithering round the restaurant.

That is why I think it is a very tall order for CBT to try and get people to fight the idea that it matters a lot what other people think of you.

In the golden era of CBT, pioneers tried to attack this set of cognitions using grand behavioural tasks.

Albert Ellis, pioneer of CBT and our hero, in his list of the top 12 Irrational Ideas, included this as number one:

‘the idea that it is a dire necessity for an adult human being to be loved or approved by virtually every significant other person in his community’

Loved? Maybe not. Approved? Maybe not? But thought to be wearing the wrong trousers? I’m afraid it’s a deal breaker.

Maybe it shouldn’t matter. Maybe not as much. Certainly try and test how much it matters. Certainly try and get it back into proportion.

But it just does.

That leaves us with a burning question. If it is so important to blend in with everyone, why do certain people do everything they can to attract attention to themselves? For instance by dying their hair a florescent colour?

This is perhaps the exception that proves the rule, since these people are relatively few in number, especially in professional groups like accountants or dentists.

Several answers to this – you choose the one you like best:

So that they are visible in traffic?

Reaction to feeling left out or insecure?

Mating ritual?

Group or gang identity?

Genuine lack of insight about how they look?

They are doing a CBT assignment to reduce the irrational cognition that it matters what people think about them?