Peter Sedgwick

Class, race and ‘intelligence’

(15 August 1970)

From Socialist Worker, 15 August 1970.
Transcribed by Ted Crawford.
Marked up by Einde O’Callaghan for the Marxists’ Internet Archive.

ARTHUR JENSEN, the American psychologist responsible for a controversial statement on the role of heredity in intelligence, has faced withering criticism from his critics both in the United States and England.

Writing in the Harvard Educational Review last year, Jensen tried to demonstrate:

First, that differences in IQ score between whites and Negroes were mostly attributable to inferior genetic endowment among blacks.

Second, that education for the disadvantaged social group should not take the form of a cultural ‘enrichment programme’ designed for the hopeless task of boosting low IQs, but should instead concentrate on rote-learning of concrete concepts, in which black children could expect to do relatively well.

The response of Jensen’s critics has ranged from complex exercises in statistical disproof to the cry ‘Fire Jensen’. White racist groups in the United States and the National Front in Britain have been quick to vulgarise his ideas as part of their campaign against equal opportunity in education.

Jensen dissociates himself from his racist supporters and affirms that science should be able to ask any questions, irrespective of the political construction that may be placed upon them:

Much of the opposition to Jensen has, indeed, been fairly irrational. Some of the critics are content to state that ‘intelligence test’ scores don’t measure human potential at all adequately (which ignores the fact that substantial score differences have been found in different social groups, and need explaining).

Others have implied that genetic influences have little or no bearing on human nervous structure. Human beings may be born with different sex glands, bone structures, skin composition, and even temperamental tendencies, it seems but their brains are identical at birth.

Interesting work

There is a genuine scientific argument about the role of heredity in determining human intellectual capacities, but it is not Jensen’s.

Much interesting work, for example, has been conducted on the development of identical twins separated in early childhood. It is generally found that these resemble one another in IQ and in temperament, for example, far more than they do in their expressed political attitudes.

It has been known for many years that the IQs of fostered or adopted children are more similar to those of their natural parents than they are to those of their substitute parents. It would be completely irrational and mystical to demand that this sort of research should not be conducted or published.

After all, even if heredity were found to produce inequalities in educational attainment, there is no reason why suitable corrective measures should not be introduced to reduce or even abolish these genetic disadvantages.

Where, however, differences in performance are ascribed to heredity, the comparison should be made between groups of subjects who are not greatly unequal in their cultural endowment. Jensen has deliberately focussed, to prove his hereditarian case, on two social groups, American whites and blacks – separated by an immense cultural gulf originating in two centuries of exploitation and discrimination.

Of course people who are educationally and socially deprived will be worse performers on educational tests (including IQ tests) than subjects who are relatively privileged. The only surprising fact about white-Negro IQ differences in the United States is that they are as small as they are: somewhere around 15 points, or around 11 if some of the cruder social-economic differences are balanced out.

Considering that a gain of about 8 points of IQ can be made in children simply by feeding vitamin and mineral supplements to their mothers while they are still pregnant there is little that is sensational in Jensen’s findings.

Some of his data, indeed, suggest precisely the opposite conclusions to those he favours. Take a look at the following table, which shows for one sample, the relative proportions of children with an IQ below 75 (which is well within the special school ‘educationally subnormal’ classification in British terms), for whites and blacks, with social class separately tabled.

Social-economic status



1 (High)












5 (Lowest)



Jensen interprets this table as strong evidence in favour of the racial determination of IQ. Yet, bearing in mind that the sampling error will be more serious in the small numbers of subjects identified in the higher social groups, the class-gradient is much more striking.

Jensen has, in fact, produced what amounts to horrifying evidence of the effects of whole generations of systematic terror directed against black Americans by the social system which oppresses them. There can be no ‘control groups’ of whites with which the majority of the Negro population can be compared. For whites (even poor whites) lack anything like the same subordinate status which imprisons blacks from childhood onwards.

On this point, one of Jensen’s Negro opponents has said all that needs saying: ‘Blacks will accept nothing as proof or evidence – except complete equal opportunity.’

Peter Sedgwick


Last updated on 25.11.2004