Intelligence, genius and mental ability were a cluster of traits that received much attention in eugenics discourse. Intelligence was regarded as one of the good qualities superior men possessed, in turn beneficial for society as a whole. On the other hand, the socially problematic or unproductive were identified as being of inferior mental quality: “feeble-minded”. By and large, eugenicists thought that (1) intelligence was a unitary psychological trait that could be measured, being quantified as an intelligence quotient (IQ); (2) intelligence was paired with educational achievement, reputation, and economic success; (3) a certain degree of intelligence was necessary to act morally and to foresee the consequences of one’s actions. Despite the prominent role of intelligence in the history of eugenics, there is considerable lack of clarity in what this general mental ability was considered to be.

Galton and the link to eugenics
For most of the history of eugenics, “intelligence” was used synonymously with “general mental ability”. In 1914, Stern wrote that intelligence could also be teleologically defined: it is what allows one to adapt and deal affectively to new problems and situations (p. 3). Today it is still common to refer to intelligence in these terms.

Although success in the conventional sense (occurring at the social level) cannot be solely attributed (reduced) to underlying psychological attributes, Francis Galton (1922-1911), who coined the term “eugenics”, thought that intelligence was one of the great traits that superior man possessed and contributed most to their success. Reasoning that intelligence was normally distributed within populations and correlated with eminence, he hypothesized in Hereditary Genius (1869) that this trait was heritable. Galton also unsuccessfully attempted to measure intellectual capacity by correlation with sensory and physical capacity (e.g. reaction times, gripping strength -- see 1890).

At the beginning of the twentieth century, psychology was moving towards the standardization of classifications and measurements. Influenced by Galton, there were other attempts to quantify intelligence in the Unite States, such as those of James M. Cattell (1890) and Charles Spearman (1904). Eugenics became increasingly popular, and with it attributing society’s problems (e.g. crime, poverty or promiscuity) to those thought to be “mentally defective” or “feeble-minded”. In North America, “feeblemindedness” was being clinically diagnosed mainly on grounds of teachers’ and parents’ impressions of a person’s abilities. Because such diagnoses are subject to hidden interests and biases, and given that those thought feebleminded were often subject to negative eugenic policies, an independent measure of feeblemindedness was sought.

Testing, from France to North America
In France, Alfred Binet (1857-1911) and collaborator Theodore Simon were motivated to develop a tool to identify children in need of alternative education, independent of history or genealogy. In 1908 they presented a test to determine educational placement. The test consisted of tasks of increasing complexity thought to reveal children’s abilities at various ages. A child’s score, given as a “mental age”, corresponded to the average age of children getting that child’s raw score. Differently from Galton, they though intelligence was mutable by way of training, mostly not inherited, and that higher-level processes were more central to it than sensorimotor ones –although earlier intelligence testing could have been over these merely because assessments were already available (Mackintosh, 2011b p.4).

The same year, the Binet-Simon scale was translated into English by Henry H. Goddard (1866-1957), superintendent at the Vineland Training School for Feeble-minded Boys and Girls, in New Jersey. He proposed to use individuals’ test scores to identify the “feeble-minded”. In 1910, Goddard introduced a hierarchy of feeble-mindedness that became the standard nomenclature for decades. It included the grades of “idiot” (mental age of up to 3 in adults), “imbecile” (3-7), as well as the new grade “moron” (8-12) for those who were only mildly mentally defective, and could “dangerously” be mistaken for normal individuals. Goddard was a fervent advocate for institutionalization and family removal of the feeble-minded, as well as for mass testing in order to identify them in the general population.

In 1912, German-Jew psychologist William Stern (1871-1931) formulated a more intuitive way to present the results of the Binet-Simon test; the “Intelligence Quotient” (IQ) or ratio of the mental age to biological age multiplied by 100. In the US, many psychologists revised and expanded the Binet-Simon test. Lewis Terman’s (1877-1956) version, the Stanford-Binet test, became the most used. Terman’s public claims to mass administer the test in schools became a reality during the 1920s and 1930s in the US, being so used in interventionist programs and placements (Minton, 1998).

With the coming of World War I, Terman joined a committee of test developers chaired by Robert M. Yerkes (1876-1956), president of the American Psychological Association. This committee developed the Army Alpha and Beta tests administered to 1.75 million people, which determined the placements of army recruits. They hypothesized, in line with their commitment to the inherited mental superiority of whites and the upper class, that these populations will score higher on the tests. The results were congruent with this prediction; however, after the war the results were challenged and subject to much criticism for being biased. With some exceptions (e.g. following the publications of Arthur Jensen in 1969 and The Bell Curve in 1994) psychology has mainly kept away from such debates.

Uses and misuses of intelligence testing
Although rarely mentioned in legislation, intelligence testing had a prominent place in the debate around many eugenic measures, such as segregation and immigration restriction. During the first half of the twentieth century, it was commonplace to advocate for the segregation and compulsory sterilization of the “feeble-minded” in the name of reduction of delinquency, industrial inefficiency, poverty and prostitution. Residential schools and compulsory sterilization laws were introduced in numerous countries. By 1964, of the 60,000 people in the US who had been subject to compulsory sterilization, mental inferiority accounted for more than half of the victims (Mackintosh, 2011a p.23). Feeble-mindedness was a reason for sterilization in 31 out of 33 North American jurisdictions. In theory, eugenic boards relied on IQ testing as an independent tool for measuring intellectual capacity. In practice, however, IQ testing was missing in the diagnosis for about a third of the cases in British Columbia (Heeswijk 1994, Ch. 3) and in Alberta (Keith 2011), although the latter Eugenics Board approved 99% of its 4,785 cases with an average of 13 minutes per case. Today, psychometric tests are a common entry requirement for the police and military bodies, and sometimes are used for employee selection and educational placement in schools and universities. In the DSM V, IQ tests are among the diagnosis criteria for intellectual disability. In courts, they could be a valid factor to determine if the person is capable of informed consent or of parenting.

Conclusion
Historically, psychology’s notion of intelligence is entangled with that of eugenics. The idea that intelligence is a unitary graded psychological trait that can be quantified goes back to Galton, and the development and use of intelligence testing was popularized as a tool to implement eugenic measures. It is hard to deny that there was, and still is, a marked lack of agreement between psychologists on what intelligence is and what it involves: is it fixed or does it change over time? Is it a unitary entity or many? Is it mainly inherited or acquired? Is it connected closely to the peripheries of cognition or to its higher-order elements? Do tests measure functioning or ability? Can conclusions and comparisons be made from tests on groups, or their validity can only on an individual basis? However, the resulting unclarity about what intelligence is has not undermined our past or present practical reliance on intelligence measuring for classifying people.

-Aida Roige

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