Geneticists and the biology of race crossing

Writing in Science in 1973, Will Provine argues (pdf):

Geneticists in England and the United States clearly reversed their published remarks on the effects of race crossing between 1930 and 1950. [. . .] The entire reversal occurred in the light of little new compelling data from studies of actual human race crosses.

Provine also displays the following bit of prescience:

Geneticists' ideas about the related question of hereditary mental differences between races is perhaps undergoing a similar development to that seen earlier in their ideas about race crossing. [. . .] It will be interesting to see if during the next several decades geneticists will argue, on the basis of little additional evidence, that hereditary mental differences between races do not exist.

More excerpts below (continue reading).

[Provine WB. Geneticists and the biology of race crossing. Science. 1973 Nov 23;182(114):790-6.]

Beween 1860 and 1900 Europeans and Americans felt a new urgency about race problems. The Civil War and the freeing of slaves in the United States stimulated a huge outpouring of books and pamphlets about race, in Europe as well as America. Europeans divided up the entire continent of Africa and carved out spheres of imperialistic activity throughout the world, dramatically increasing their contacts with other races. Race-related social problems grew accordingly.

Most whites from Europe and the United States believed these problems resulted from the mental inferiority of nonwhite races. Nineteenth-century biologists concurred. They believed that races of man differed in hereditary physical and mental characteristics, and viewed crossing between distant races with suspicion or outright antagonism (2). Specifically, they argued that Negroes were, on an average, mentally inferior to European whites. In 1869 Francis Galton provided a simple quantitative model for the distribution of intelligence within and between populations (3). He theorized that the intelligence of Negroes was, on an average, two grades below that of Englishmen, while the intelligence of the "Athenian race" of the Fifth Century B.C. was two grades above that of Englishmen. One of Galton's grades corresponds to approximately ten points on current IQ distributions. [. . .]

Galton's analysis of racial differences indicated that an intellectually superior race should not breed with an inferior race because a small reduction in average intelligence caused a much greater reduction in the proportion of individuals in the highest grades of intelligence. And, he said, "We know how intimately the course of events is dependent upon the thoughts of a few illustrious men" (3, p. 343). [. . .]

Early Influence of Mendelism on Ideas of Race Crossing

[. . .] Davenport believed that the moral for human races was clear. Each race had, through a long process of natural selection, developed genetic traits that were harmoniously adjusted both with each other and the environment. When two races differing by a number of characters interbred, some new combinations of characters were formed in the hybrids. Mendelian segregation would produce many more new combinations in subsequent offspring of the hybrids. Davenport thought many of these new combinations would be disharmonious, although some would be beneficial. For example, he said that a large, tall race might breed with a small, short one to yield, in the second generation, some offspring with "large frames and inadequate viscera" or "children of short stature with too large circulatory apparatus." Another example was the overcrowding or wide spacing of teeth probably caused by the "union of a large-jawed, large-toothed race and a small-jawed, small-toothed race." Nor were disharmonious combinations confined to physical characters. "One often sees in mulattos an ambition and push combined with intellectual inadequacy which makes the unhappy hybrid dissatisfied with his lot and a nuisance to others." In short, "miscegenation commonly spells disharmony--disharmony of physical, mental and temperamental qualities and this means also disharmony with environment. A hybridized people are a badly put together people and a dissatisfied, restless, ineffective people" (7, pp. 366- 367). [. . .]

Davenport carefully avoided condemnation of entire races as inferior. Others had no such hesitancy. In 1918 two young geneticists, Paul Popenoe and Roswell H. Johnson, wrote Applied Eugenics (8), the most widely used textbook on this subject for more than 15 years. In a chapter entitled "The color line," they suggested that racial antipathy was a biological mechanism to protect races from miscegenation. They also argued that Negroes were inferior to whites. Their evidence was that Negroes had made no original contributions to world civilization; they had never risen much above barbarism in Africa; they did no better when transplanted to Haiti; and they failed to achieve white standards in America. Negroes scored significantly worse than whites on the new IQ tests. [. . .] Popenoe and Johnson concluded that "the Negro race differs greatly from the white race, mentally as well as physically, and that in many respects it may be said to be inferior, when tested by the requirements of modern civilization and progress, with particular reference to North America." Regarding race crossing between Negroes and whites, they concluded that "in general the white race loses and the Negro gains from miscegenation." Consequently, they felt that they "must unhesitatingly condemn miscegenation" (8, pp. 291-292). They recommended legislation to prohibit intermarriage and all sexual intercourse between the two races. Applied Eugenics sold well. I can find no evidence that geneticists disapproved of the chapter on race.

Edward Murray East of Harvard's Bussey Institution elaborated the arguments on race mixture advanced by Davenport and Popenoe and Johnson. [. . .] East cited two genetic objections to wide human race crosses, as between Negroes and whites. First, Mendelian segregation would "break apart those compatible physical and mental qualities which have established a smoothly operating whole in each race by hundreds of generations of natural selection." Second, it was "an unnecessary accompaniment to humane treatment, an illogical extension of altruisnm . . to seek to elevate the black race at the cost of lowering the white" because "in reality the negro is inferior to the white. This is not hypothesis or supposition, it is a crude statement of actual fact" (9, pp. 253-254). [. . .]

Harmonic and Disharmonic Race Crossings

[. . .] Castle argued, disharmonies in race crossing were not to be expected. [. . .] Castle freely admitted, however, that African blacks had less native intelligence than whites. that mulattos were intermediate in intelligence, and that race crossing might legitimately be opposed for social reasons.

From Condemnation to Agnosticism

[. . .] Recognizing the German threat to personal liberty and to the world, some geneticists and anthropologists published popular books and articles debunking Nazi propaganda. We Europeans (35), published in 1936 by Julian Huxley and A. C. Haddon, and Heredity and Politics (36), published in 1938 by J. B. S. Haldane, were perhaps the two most significant examples. Both Huxley and Haldane attacked Nazi race doctrines with vigor, but they stopped short of denying hereditary mental differences or condoning all racial intermingling. [. . .]

From Agnosticism to Certitude

During and shortly after World War II, biologists and anthropologists published many books attacking Nazi race theories and racism in general. Most of these books exhibited a further change in attitude. They declared that race crossing was sometimes biologically favorable, but never detrimental. The new orthodoxy was well represented in 1946 by Leslie C. Dunn and Theodosius Dobzhansky in their little book Heredity, Race, and Society (38). [. . .]

To the public this statement by Dunn and Dobzhansky represented a significant change of view from that expressed by Haldane and Huxley in 1938. Race crossing now appeared to involve no biological danger. But the scientific evidence on race crossing had not changed significantly between 1938 and 1946. There simply was not a decisive study on race crossing during that time. [. . .]

The Unesco Statement on Race

An examination of the 1951 Statement on Race by the United Nations Educational, Scientific, and Cultural Organization (Unesco) indicates clearly that the view of Dunn and Dobzhansky on race crossing was widespread among geneticists by that time. But before turning to the Unesco statement, I should emphasize that many geneticists were reluctant to formulate or sign such a statement before the war. For example, Franz Boas wrote to Raymond Pearl in October 1935, requesting him to formulate a statement on race. It was hoped that the statement, to be signed by prominent anthropologists and biologists and then circulated around the world, would counteract Nazi propaganda on race. [Pearl refused.]

[. . .] The statement's assertion that race mixture was harmless received very little criticism, however. Only A. H. Sturtevant questioned the validity of the assertion. [. . .] It is true that in the next 2 years Gates and C. D. Darlington publicly criticized the statement's position on race crossing; both were dismissed as radical hereditarians by most human geneticists in the United States and England. Thus the 1951 Unesco statement marks a clear point at which the public attitude of geneticists on the issue of race crossing had reached the current dominant view: that race crossing is at worst harmless. [I've posted before on Ashley Montagu and the UNESCO statement on race.]

Summary and Conclusions

Geneticists in England and the United States clearly reversed their published remarks on the effects of race crossing between 1930 and 1950. The reversal occurred in two steps. First came the change in the 1930's from a condemnation of wide race crosses to an agnostic view. The second change, from the agnostic view to the belief that wide race crosses were at worst biologically harmless, took place during and shortly after World War II.

The entire reversal occurred in the light of little new compelling data from studies of actual human race crosses. The lack of new data is unsurprising. Few geneticists wished to initiate experiments that took three human generations to complete. And controlled race crosses are hard to arrange, even with government grants. What might be more surprising was the willingness of geneticists to make such positive statements about race crossing when they had so little reliable genetic evidence.

I interviewed or wrote to ten prominent geneticists who worked on human genetics between 1930 and 1950. Not one believed that new evidence on race crossing was the primary reason why geneticists changed their minds about the effects of race crossing. One plausible explanation, that the rise of "population thinking" (44) caused geneticists to change their minds, does not fit the evidence. Castle was no more of a "population" thinker than East, yet they differed radically in their conclusions about race crossing. What, then, did cause geneticists to change their minds?

Most important was the revulsion of educated people in the United States and England to Nazi race doctrines and their use in justifying extermination of Jews. Few geneticists wanted to argue, as had the Nazis, that biology showed race crossing was harmful. Instead, having witnessed the horrible toll, geneticists naturally wanted to argue that biology showed race crossing was at worst harmless. No racist nation could misuse that conclusion. And geneticists did revise their biology to fit their feelings of revulsion.

Geneticists' ideas about the related question of hereditary mental differences between races is perhaps undergoing a similar development to that seen earlier in their ideas about race crossing. In 1951, judging from the response to the Unesco second statement on race and comments in genetics literature, most geneticists agreed with Muller that races probably differed in significant average mental traits. By 1969, when Arthur Jensen advocated this view in his controversial article (45), most geneticists who spoke publicly on the issue had adopted an agnostic position. Knowledge of hereditary racial differences in IQ had scarcely changed since 1951, but society had changed considerably in racial attitudes. It will be interesting to see if during the next several decades geneticists will argue, on the basis of little additional evidence, that hereditary mental differences between races do not exist.

I am not condemning geneticists because social and political factors have influenced their scientific conclusions about race crossing and race differences. It is necessary and natural that changing social attitudes will influence areas of biology where little is known and the conclusions are possibly socially explosive. The real danger is not that biology changes with society, but that the public expects biology to provide the objective truth apart from social influences. Geneticists and the public should realize that the science of genetics is often closely intertwined with social attitudes and political considerations.