On “Wide hats and Narrow minds“, the eminent professor Broca, the most re-known academician of medical field at that time, concluded his long lasting debate against the anatomist Gratiolet with these triumphal words ” In general, the brain is lager in men than in women, in eminent men than in men of mediocre talent, in superior races than in inferior races. Other things equal, there is a remarkable relationship between the development of intelligence and the volume of the brain

In the prelude to Middlemarch, George Eliot lamented the unfulfilled lives of talented women:

Some have felt that these blundering lives are due to inconvenient indefiniteness with which the Suprem Power has fashioned the natures of women: if there were one level of feminine incompetence as strict as the ability to count three and no more, the social lot of women might be treated with scientific certitude

Eliot goes on to discount the idea of innate limitation, but while she wrote in 1872, the leaders of European anthropometry were trying to measure “with scientific certitude” the inferiority of women. Anthropometry, or measurement of human body, is not so fashionable a field these days, but it dominated the human sciences for much of the nineteenth century and remained popular until intelligence testing replaced skull measurement as a favored device for making invidious comparisons among races, classes and sexes. Craniometry, or measurement of the skull, commanded the most attention and respect. Its unquestioned leader, Paul Broca (1824-1880), professor of clinical surgery at the Faculty of Medicine in Paris, gathered a school of disciples and imitators around himself. Their work, so meticulous and apparently irrefutable, exerted great influence and won high esteem as a jewel of nineteenth-century science.

Broca’s work seemed particularly invulnerable to refutation. Had he not measured with most scrupulous care and accuracy? But science is an inferential exercise, not a catalog of facts. Numbers, by themselves, specify nothing. All depends upon what you do with them. Broca depicted himself as an apostle of objectivity, a man who bowed before facts and cast aside superstition and sentimentality. He declared “there is no faith, however respectable, no interest, however legitimate, which must not accommodate itself to the progress of human knowledge and bend before truth

Women, like it or not, had smaller brains than men and, therefore, could not equal them in intelligence. This fact, Broca argued, may reinforce a common prejudice in male society, but it is also a scientific truth. L. Manouvrier, a black sheep in Broca’s fold, rejected the inferiority of women and wrote with feeling about the burden imposed upon them by Broca’s numbers:

Women diplayed their talents and their diplomas. They also invoked philosophical authorities. By they were opposed by numbers unknown to Condorcet or to John Stuart Mill. These numbers fell upon poor women like a sledge hammer, and they were accompanied  by commentaries and sarcasms more ferocious than the most misogynist imprecations of certain church fathers. The theologians had asked if women had a soul. Several centuries later, some scientists were ready to refuse them a human intelligence

The most extensive data of Broca came from autopsies performed personally in four Parisian hospitals. For 292 male brains, he calculated an average weight of 1325 grams. For 140 female brains he calculated an average of 1144 grams. There was a difference of 14 percent. Broca understood, of course, that part of this difference could attributed to greater height of males. Yet he made no attempt to measure the effect of size alone and stated that anyhow it cannot account for the entire difference because we know, a priori, that women are not as intelligent as men:

We might ask if the smaller size of the female brain depends exclusively upon the smaller size of their body. Tiedemann has proposed this explanation. But we must not forget that women are, on the average, a little less intelligent than men, a difference which we should not exaggerate but which is, nonetheless, real. We are therefore permitted to suppose that the relatively small size of the female brain depends in part upon her physical inferiority and part upon her intellectual inferiority

In 1873 he year after George Eliot published  Middlemarch, Broca measured the cranial capacity of prehistoric skulls from l’Homme Mort cave. Here he found a difference of only 99.5 cubic centimeters between males and females, while modern populations range from 129.5 to 220.7 cubic centimeters. Topinard, Broca’s chief disciple, explained the increasing discrepancy through time as a result of differing evolutionary pressures upon dominant men and passive women:

The man who fights for two or more in the struggle for existence, who has all the responsibility and the cares of tomorrow, who is constantly active in combating the environment and human rivals, needs more brain than the women he must protect and nourish, the sedentary woman, lacking any interior occupations, whose role is to raise children, love, and be passive

in 1879, Gustave Le Bon, chief misogynist of Broca’s school, used these data to publish on the most respected anthropological journal what must be the most vicious attack upon women in modern scientific literature (no one can top Aristotle):

In the most intelligent races, as among the Parisians, there are a large number of women whose brains are closer in size to those of gorillas than to the most developed male brains. This inferiority is so obvious that no one can contest it for a moment; only its degree is worth discussion. All psychologists who have studied the intelligence of women, as well as poets and novelists, recognize today that they represent the most inferior forms of human evolution and that they are closer to children and savages than to an adult, civilized man. They excel in fickleness, inconstancy, absence of thought and logic, and incapacity to reason. Without doubt there exist some distinguished women, very superior to the average man, but they are as exceptional as the birth of any monstrosity, as, for example, of a gorilla with two heads; consequently, we may neglect them entirely“.

Le Bon was, therefore, horrified by the proposal of some American reformers to grant women higher education on the same basis as men:

A desire to give them the same education and, as a consequence, to propose the same goals for them, is dangerous chimera….The day when, misunderstanding the inferior occupations which nature has given her, women leave the home and take part in our battles, on this day a social revolution will begin and everything that maintain the sacred ties of the family will disappear

Re-exmaning the Broca’s data – the basis for all this derivative pronouncement – we can find his numbers sound but his interpretation ill-founded, to say the least. The data supporting his claim for increased difference through time can be easily dismissed. Broca based his contention on the samples from L’Homme Mort cave alone – only seven male and six female skulls in all: so little data for ranging any conclusion.

In 1888, Topinard published Broca’s more extensive data on the Parisian hospitals. Since Broca recorded height and age as well brain size, we may use modern statistics to remove their effect. Brain weight decrease with age and Broca’s women were, on average, considerably older then his men. Brain wight increases with height, and his men were in average half a foot taller than his women. Using multiple regression analysis I corrected the data for height and age. Doing so, the different in weight among the women and the men went down from 181 grams to 113 grams.

I do not know what to make of this remaining difference because I cannot access other factors known to influence brain size in major way. Cause of death for example has an important influence on brain weight: for example men killed in accident would have brains weighing in average 60 grams more than men dying of infectious diseases. There are 100 grams of difference of brain weight among people died owing to degenerative arteriosclerosis and people died by violence or accident. And many Broca’s subjects were very elderly women (we may assume that some of them suffered of degenerative disease).

The scientist Manouvrier found a correlation among brain weight and muscular mass. And when he corrected the data for that (being men more muscular than women in average), women actually came out slightly ahed of men in brain size.

To appreciate the social role of Boca and his school, we must recognize that his statements about the brains of women do not reflect an isolated prejudice toward a single disadvantaged group. They must we weighted in the context of a general theory that supported contemporary social distinctions as biologically ordained. Women, blacks and poor people suffered the same disparagement.

As one of Broca’s disciples wrote in 1881:

Men of black races have a brain scarcely heavier than that of white women“.

 

Sources 

From “The Panda’s Thumb” by Stephen Jay Gould (W.W. Northon & Company,)