Faced with an impossible case, the baffled police have sometimes slipped round to see a psychic. Now they have a new witchcraft to call on - forensic psychology. The disastrous outcome of the Rachel Nickell murder inquiry makes you nostalgic for trances and crystal balls. The late, lamented Doris Stokes would not have suggested entrapping Colin Stagg by feeding him pornographic fantasies. Psychology emerges severely damaged from this distasteful saga.
Yet, at British universities, it is as fashionable as sociology was in the 1960s. The students are flocking in. The numbers are up from 2,094 in 1986 to 5,774 in 1993. Do they hope to emulate Jodie Foster and Anthony Hopkins, working edgily together on psychological profiles? The cinema has long had a love affair with psychiatry and its everyday cousin, psychology. Before The Silence of the Lambs - the reductio ad absurdum - was Alfred Hitchcock's Marnie.
'You display a charm and grace,' I read yesterday, 'that endears you to others and helps you get what you want. Though creative, your inspirations are a little erratic and need backing up with common sense. . . Great progress can be made in your career but you should protect any gains by playing your cards close to your chest . . . Find quiet time for reflection and any tensions will pass.' Unfortunately, this was my horoscope, and I am no fan of astrology. But that little slice of character analysis could just as easily have been written up by a magazine psychologist. Instead of 'Horoscope', the headline would have been 'You and Your Personality'. Plausible substitutes for the signs of the zodiac would be needed.
Thus Charles Handy, the business guru, divides managers into four character types: Zeus individuals, who 'tend to think intuitively and in wholes' and 'look for power over people and events'; Apollo individuals, whose thoughts are 'logical, sequential, analytical' and who 'value order and predictability'; Athena individuals, who are 'problem solvers' and think, meritocratically, that success 'is desirable if it has been earned'; and lastly, Dionysus individuals, who 'like to be exceptions to all generalisations' and 'do not acknowledge the power of the organisation'. You pays your money and you takes your choice. Management writers are great purveyors of cut-price psychology. Ever since Freud turned poor Oedipus into his unpaid lab technician, classical mythology has been ransacked to add an aura of certainty. But, as with horoscopes, the character sketches are so loose they match almost anyone. They are like the average police photo-fit which, when the crime is eventually solved, amazes you in retrospect by its lack of detailed resemblance to the man or woman in the dock.
Ruth Rendell has tapped into a public passion for weirdo psychology. The Stagg investigation was Rendell played for real. The police were advised by the Nottingham psychologist, Paul Britton, who 'claimed, on the basis of his own experience, that he could determine the likely thoughts of a murderer he had not met, and that these were the same thoughts as those Stagg expressed when trying to impress a likely lonely hearts correspondent. If Mr Britton's views had survived in court, then the tendency would be to control what people think as well as what they do'. This outburst came from David Canter, professor of psychology at Liverpool University, due to appear for the defence. Psychiatrists' differences in the witness box have long given barristers and judges an excuse for schoolmasterly sarcasm. Psychologists are following in those shaky footsteps.
Professor Richard Gregory, of the University of Bristol, is one of the rare psychologists with a sense of self-deprecation, even humour. He has called psychology 'a very odd science' and 'a suspect Cinderella'. It often consists of innumerable disconnected insights, many of them based on laboratory work, rather than observation of the world we live in. Gregory has speculated that psychology might best be seen as the study of our internal fictions: 'we may indeed live more by fiction than by fact'. Everyone, on this view, would be the novelist or script-writer of their own lives. More mundane psychologists have not followed him on to this dangerous territory, as tempting as a will-o'-the-wisp. What sort of science would a science of fiction be? Psychiatry and psychology, between them, are often clutched at to explain the inexplicable - crystal balls that emit a scientific glow. One of the founder figures of social science in Britain, the late Barbara Wootton, gave early warning signals. 'We should recognise,' she wrote in 1967, 'that psychiatrists who occupy themselves with the rehabilitation of criminals, the promotion of industrial peace, or the selection of officers for the forces, are taking on roles which have nothing to do with the healing function traditionally associated with medicine.' She would be horrified by the increasing use of psychological testing to decide among candidates for all kinds of jobs, an American practice that has spread to Britain.
For a long time, it was confined to officer selection boards. But when the Army introduced it, they were at least choosing people for a very precise, rule-bound job. That might seem simple enough, a psychological doddle. But the odds are that it was psychological mumbo-jumbo. The criteria that military men tell their psychologists to look out for may reinforce failure, not success.
One of the undisputed psychological classics is Norman Dixon's On the Psychology of Military Incompetence, published in 1976. Dixon had served in the Royal Engineers. His coruscating analysis of the military mind sprang as much from his army experience as from his later academic training. He argues that the neurotic traits which drew men to the military life, and helped them rise, were the same characteristics that presaged ultimate disaster. His favourite example is Douglas Haig, the British commander-in-chief in France between 1915 and 1918, who presided unmoved over so many deaths but would no doubt have passed any conceivable entry test.
Reflecting on such men, Dixon writes: 'These traits - need for approval, fear of failure, being deaf to unpalatable information, and the rest - are probably accentuated by their larger responsibilities and the fact that there is now no longer anyone higher up to whom they might appeal.'
Before social work became obsessed with later fashions, like gender or race awareness, it was obsessed with a cheapskate version of psychoanalysis. Mothers sinking into a morass of family problems were blamed for their personal psychological shortcomings. Social workers babbled about ego and id, much as they might now babble about sexism or racism. Baroness Wootton advised them to master the ins and outs of the welfare system; make sure their 'clients' (itself a pseudo-psychiatric term) got every shred of help they were entitled to; and leave them to live their own lives. Her advice would still make a good poker-work motto for the wall of most local authority social services departments.
When genuine psychological insights occur, the tendency is to apply them headlong. For example, the so-called anti-psychiatrists, R D Laing, David Cooper and Thomas Szasz, rightly emphasised that the people trapped inside mental hospitals were as human as the rest of us. They precipitated huge reforms. But some of their specific diagnoses - most notoriously, that families somehow 'chose' children they would stigmatise as mad - were as cruel, in their way, as the doctrines they dislodged. And the anti-psychiatrists' suggestion that mental illness was a social invention, an artefact of perception, led to policies that threw hundreds of patients into seaside welfare hotels or on to the streets.
It is always enlightening to discover the houses architects live in (as opposed to the ones they design for others). It is just as enlightening to learn what sort of home life psychiatrists lead. In the new biography of Laing by his son, we read of violence, alcoholism and despair. Unfortunately, we never find these things out at the time.
The growth industry of counselling claims a basis in psychology, though it usually seems more like a variant on the commonsense fact that, at desperate moments, everyone needs someone to talk to. Much psychology gets close to either the obvious or the commonsensical, like Desmond Morris on a bad day. The sharp eye of the intelligent observer can take you almost as far. Michael Korda, nephew of the film tycoon, wrote an amusing book called Power in the Office. In it he propounded the truth that, in any group of men, you can always tell who has the most power. He's the one with the shiniest shoes. Speaking as a man who, like the Chancellor of the Exchequer, always wears suede, I find this kind of witchcraft attractive.
John Major, as I noticed during a speech I saw him give last week, polishes hard. But perhaps (a psychologist writes) this is, deep down, a sign of inner uncertainty. Even, perhaps, a cry for help. Who can tell? And should we care?