“You cannot rank intelligence – with all its components of motivation, mental arousal and emotion – as if it were a unilinear attribute.” Even the man who has worked out the questions for Saturday’s programme, a psychologist from Queen’s University, Belfast, admits he has never taken the test himself.The BBC’s “mass experiment” will not only produce misleading results, but may also depress or even alarm some participants, while encouraging the mentally vulnerable to believe that they are brainier than they are. “The whole idea is a hangover from the 1930s,” according to Professor Steven Rose. Educational “specialists”, consulted by anxious middle-class parents concerned about their children’s performance at school, will continue to use them as a guide to the most appropriate school for a child, and even to whether thoughts of a university education should be abandoned as being over-ambitious.Yet many of those who make a study of intelligence dismiss tests of this kind as reductive and inaccurate. As an adult, he lived a disastrous and miserable life and, having worked in a series of lowly clerical jobs, died destitute and unemployed.It will be said that Test the Nation is little more than a harmless parlour game, but IQ tests are already used widely as a test of intelligence, and the endorsement by the BBC will provide them with added authority. “The whole foundation on which my life was construed fell down,” he wrote later. “I seemed to have nothing left to live for.”The world’s greatest child prodigy, William James Siddis, understood Russian, French, German and English at five and, by eight, had not only passed into Harvard Medical School but had invented a new system of logarithms.

Any useful form of brightness involves imagination, wit, the ability to understand and appreciate light and shade and nuance – in other words, the very qualities which, if deployed in IQ tests, will have you down among the dead men at the bottom of the class.The novelist Flannery O’Connor once said that there is a grain of stupidity that writers of fiction cannot do without, and the briefest glance at the history of those with famously high IQs suggests that the same grain is useful for all of us. As a quiz, it makes Lily Savage’s Blanket Blank look serious-minded. As a survey, it is a joke in poor taste.IQ tests are a hopeless guide to true intelligence. Three hundred people will be in the studio to answer a series of questions – putting shapes in order, spotting the odd one out and so on.

Meanwhile the sad saps who accept the BBC’s urgings to participate on-line will be told that, not only are they assessing their own brainpower, but they will be helping provide a “snapshot of the nation’s intelligence”.Of all the stunts perpetrated by the new, ratings-crazed BBC, this is the silliest and most harmful. There is to be a one-off special, which will be presented by the BBC’s resident Madam Whiplash, Anne Robinson. Do not, on any account, go near your TV set.
Of course, you would probably avoid it anyway. Saturday night has become established as the moment when television programme-makers set out to prove how debased and vulgar their medium has become, filling up hour after hour with lowest-common-denominator entertainments presented by grinning speakerines and C-list celebs. Enjoy yourself in some traditional and, if possible, mindless way. If you must stay in, invite friends around for an evening of booze, food and chat, or settle down with a good book Do not, on any account, go near your TV set

A word of advice: go out on Saturday night.