Racist theories of intelligence are propounded this week in a book likely to bring a recent American controversy across the Atlantic.
Edinburgh University psychologist Christopher Brand follows in the footsteps of The Bell Curve, a book by Richard Herrnstein and Charles Murray which caused a furore by linking race and intelligence.
Citing studies of adopted children and twins raised apart, Brand argues that differences in intellectual ability are the result of a fixed and hereditary general intelligence.
Genetic factors may account for up to 75 per cent of variation in intellectual ability and have an important bearing on academic ability as well as probable success in later life, he claims.
Brand endorses Herrnstein and Murray's racist view that Afro-Caribbeans are less intelligent than Asians and whites, and discusses the possibility of encouraging low-IQ teenagers to choose partners of higher IQ to raise the intelligence of the next generation. However, his views are likely to be rejected by academics and educationists who increasingly view such theories as unreliable or irrelevant.
Rejecting environmental explanations of IQ, Brand argues that general intelligence - or the "g factor" - has been denied by experts in Britain in the face of mounting empirical evidence, often for ideological reasons. A severe critic of comprehensive education, he defends Cyril Burt, the psychologist whose theories about inherited intelligence and testing lay behind the introduction of the 11-plus exam. Subsequent research has "entirely vindicated" Burt's conclusions, he says.
Brand, a former prison psychologist whose academic research has involved a particular measure of IQ known as inspection time testing, goes on to call for radical educational reform, including self-streaming, pupil empowerment and accelerated learning.
"Instead of state schools providing a cross between a child-minding service and a reformatory, children should be allowed, at any time of day, a choice of classes of varying difficulty levels . . . streamed children of all ability levels have been found to be happier and to reach higher levels of attainment. "
He adds: "The 25-year experiment with comprehensive schools in Britain has not even helped those who are so often put forward as the prime concern of the modern educator: children of working-class origins now provide a lower percentage of university students than they did in 1970.
"Without special provision for the bright that streaming makes, secondary-school performance becomes mainly a matter of persistence with babyish exercises that are only tolerable to middle-class students who have extremely middle-class aspirations."
To Brand's critics, however, his insistence that "instead of running from the realities of IQ, utopians will have to face the music" merely begs the question.
"I completely reject the idea of a fixed and hereditary general intelligence and I think the evidence rejects it," says Professor Michael Barber, of London University's Institute for Education.
"Adherence to the notion of general intelligence, which this country followed between the Thirties and the Sixties, was one of the most damaging educational follies of the century.
"There is a very strong argument for much more flexibility in ability groups for some young people, but you do not have to believe in inherited intelligence for that," said Professor Barber.
David Reynolds, professor of education at Newcastle University, queried the relevance of IQ studies. "Even if genetic factors are important, the cutting edge of the environment is still very strong," he said.
"The danger about all this is that between-individual differences dwarf between-race differences. You will still have people who are of high IQ and low IQ, and if that is the case, there are no practical implications for teachers. "
And the scientific evidence was questionable: adoption studies were often seen to be flawed by the narrowness of the social range used in any sample.
"I don't think people are fighting shy of the evidence - it is because we are asking very valid questions about it," he added.
The g-Factor: general intelligence and its implications, published by Wiley at Pounds 24.95 and Pounds 12.99