In The Mismeasure of Man, Stephen Jay Gould, prominent American paleontologist, evolutionary biologist, and historian of science exposes the myths behind standardized testing of human intelligence and the latent racism of its application.

Gould begins his study with a narrative history of the Western European and American search for proof of the hereditarian nature of mental prowess, particularly in the United States. Gould uses American icons such as Thomas Jefferson and Abraham Lincoln to illustrate how pervasive this belief was, even among those we venerate as enlightened.

Moving into the science of racial superiority, Gould then identifies a series of attempts by nineteenth century scientists to correlate physical features with levels of intellect, including phrenology, crainometry, and morphology. Despite the sometimes disingenuous attempts by practitioners of these pseudo-sciences to make the connection, all fell short of any definitive, quantifiable relationship.

This changed with the advent of intelligence testing, first developed by French psychologist Alfred Binet. Binet created a system of testing that combined multiple activities that could measure general ability without being dependent on the products of formalized schooling. It was Binet’s belief that this type of testing was only useful in the very narrow circumstance of identifying students who had fallen behind their peers. He insisted that the test was invalid for differentiating between individuals testing normal or above.

Regardless, psychologists in the United States quickly adapted Binet’s test as a general intelligence test (and renamed it the Intelligence Quotient, or IQ), assigned numeric values to the scores and placed them on a linear scale. The low end of the scale had specific classifications such as idiot, imbecile and moron. Someone testing just below normal might be psychologically labeled as a “high-grade moron”. A strong underlying component of this testing was the belief that intelligence was an inherited trait, and was largely immutable.

Twisting Darwin’s evolutionary theories, scientists proposed that there was a specific gene for intellect, that population distinctions were the visible effect of genetic variance (Social Darwinism) and that by Mendelian selective breeding societies could eliminate the recessive genes for innate stupidity. The forced sterilization of poorly testing subjects was often proposed, and in some states became public policy.

For Americans, much of this enthusiasm for testing supported deeply ingrained racial biases, and it is no surprise that the hierarchy of American society was reflected in the results. After the U.S. Army allowed its inductees to be tested en masse, testers had over 1.7 million subjects that could be ranked by ethnicity, and based on this data, Congress passed (and President Coolidge signed) the Immigration Restriction Act of 1924, which severely curtailed immigration from Southern and Eastern Europe, the homelands of groups that tested low. Interestingly, in England, testers were more interested in establishing that class was a result of biology, rather than race, the object being to show that aristocracy deserved its place at the top and common laborers rightly belonged at the bottom.

A more insidious and long-term impact of this process is the deeply held conviction by many that it is useless to attempt to raise the prospects of the disadvantaged, as they are in their socio-economic situations as a result of their natural state, and that general intelligence is largely fixed from birth anyway. It may be thought: Why waste time and resources on the genetically hopeless? Better to invest in the bright and capable who will be a benefit to society.

Gould argues that there is no such thing as “intelligence” per se, only those qualities which we perceive as evidences of intellect and which are highly subjective and almost entirely defined by culture. He claims that as testing becomes less specific to a particular subject and more general, its value declines proportionately. Gould also decries the cynical, dismissive attitude that hereditarianism has on disadvantaged youth, in essence condemning countless millions to educational inferiority, crushing both hope and potential in a large segment of society.

 Much of the popularity of these ideas dissipated after the Second World War, as the Holocaust appeared as a warning to civilization about the potential for barbarity when hereditarian principles become a matter of state policy. This is not to say, however, that we are free of it entirely. Some academics still search for evidence of genetic superiority, and books such as The Bell Curve (1994), persist in making the argument. The SAT and ACT tests remain, with colleges differentiating between equally bright students who may be separated by a few points, and MENSA claims exclusive membership for 100,000 people with IQs in the top 2% of the population.