Stock questions
Bernard Dixon
There was some sound commonsense, amid the bitterness and the science, in London last week when the Institute of Biology held a two-day symposium on the touchy topic of 'Racial Variations in Man.' Most of it came from the only lady speaker, Dr Barbara Tizard, who calmly but thoroughly exposed the defects and ambiguities of the evidence on both sides of the debate about the role of heredity in determining Intelligence. Neither lobby, she showed, commands anything like sufficient understanding out of which to make scientific or political capital. Perhaps, indeed, they never will. The problem may be as complex as that. It may even prove to be a phantom problem — one that disappears the more searching light is cast upon it.
The debate is already absurdly polarised as far as observers are concerned. Privately at least, both sides concede that all human characteristics, intellectual and physical, have a genetic basis, but that from the moment of conception we also interact continuously with our environment. Instead, therefore,of asking whether intelligence is innate or determined by environment, the argument ranges over the degree to which intellectual differences between individuals, social groups, and 'races' can be attributed to external or genetic factors.
The main plank of Dr Tizard's paper was a rigorous analysis of all the evidence so far, particularly that adduced by Professor Arthur Jensen and his followers to support his argument for the overwhelming influence of genetic factors on IQ. In rill cases, Dr Tizard showed, an environmental explanation accorded equally as well with the evidence as did the genetic case.
Take, for example, the question of adoption. It has been argued that the IQs of adopted children separated from their mothers at birth correlate more closely with those of their biological mothers than with their adoptive mothers. But as Dr' Tizard points out, one cannot draw any conclusions from such evidence unless the children were placed in their new homes at an age old enough to allow prior assessment of their intellectual status (tests in infancy have little predictive value), and the children would have to be moved from an 'average to an 'above average' environment. Recent research by Dr Tizard which came near to satisfying these conditions has, in fact, supported the environmental case. She compared three groups of four-and-ahalf-year-old children, black and Nirhite, all of whom had been placed before the age of four months in institutions which were "in many respects of high quality." At an average age of just over three years, one group of children had been adopted into white middleclass families, and a second group had been restored to their mothers in working-class homes. The third group remained in the institutions. The result was that the mean IQ of the children restored to their mothers was 100, while that of the institutional children was 105, and that of the adopted children was 115 — significantly higher than for the other groups. Within each group there was no significant difference between the IQs of black and white children.
But Dr Tizard does not suggest that her researches — or those of other scientists working in the same area — are in any way conclusive. She concludes merely that in almost all cases alternative explanations are possible. To pretend otherwise is unjustified: "The emphasis which one gives to different studies and the conclusions which one draws from them are more a reflection of one's own views about society than of some inexorable truth."
Given this state of ignorance, Dr Tizard rightly argues, Jensen's thesis is politically offensive "because, whatever the motivation of the author, it serves as a respectable academic rationale for racist policies." Not only that, it is educationally irrelevant — because, whatever the truth of the matter, teachers and educationalists can only work on the environment. They cannot — not yet at least — alter your genes or mine,
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