Trumpian “Common Sense” and the History of IQ Tests

In the eighth essay of the Legacies of Eugenics series, Pepper Stetler explores the troubling history of IQ tests and special education.

By Pepper StetlerMay 8, 2025

• Science & Technology

• History

• Politics

This is the eighth installment in the Legacies of Eugenics series, which features essays by leading thinkers devoted to exploring the history of eugenics and the ways it shapes our present. The series is organized by Osagie K. Obasogie in collaboration with the Los Angeles Review of Books, and supported by the Center for Genetics and Society, the Othering & Belonging Institute, and Berkeley Public Health.

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AT A PRESS CONFERENCE on January 30, 2025, the morning after a tragic midair collision in Washington, DC, between a military helicopter and an American Airlines plane, President Donald Trump rationalized the crash by invoking the Federal Aviation Administration’s attempts to diversify its workforce. “The FAA is actively recruiting workers who suffer severe intellectual disabilities, psychiatric problems, and other mental and physical conditions under a diversity and inclusion hiring initiative spelled out on the agency’s website.” Citing no evidence that diversity programs had anything to do with the accident, which killed 67 people, his point—presumably—was to show that disability and competence do not mix. Those unable to discern the categorical difference between the two lacked what he labeled as “common sense.”

Trump was tacitly invoking the logic of eugenics by foregrounding what he saw as a clear-cut divide between “the highest level of genius” and “severe intellectual disability,” which mapped for him onto the divide between valuable workers and disposable and dangerous ones. His insults exploit the clarity—a false clarity, I argue—of the type of human intellectual categorization implicated in IQ tests. In Trump’s world, a high IQ score serves as shorthand for wealth, success, and power; “high IQ” and “low IQ” are his preferred ways of describing his respective allies and enemies. Starting in the first half of the 20th century, IQ tests fueled a high-stakes system of classification that informed who was deemed to deserve educational and professional opportunities. It is a history worth exploring because of how it persists in the “common sense” of our time, our current president, and his administration.

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Nowhere has the logic of IQ tests had more influence than in the field of educational psychology and in the American school system. Access to educational opportunity has been a boon in many respects, but it has also naturalized socioeconomic inequality, in part because decisions about access exploit the comparative logic at the heart of IQ tests. In its earliest forms in the years around 1905, the French psychologist Alfred Binet used a series of tests to define what a child should be able to do at a particular age. The first test consisted of a series of 30 short tasks—related to expectations for comprehension, reasoning, and memory—that were sequenced according to their difficulty. A child proceeded through the exam until she could no longer complete the tasks. The age associated with the last task she could perform was her assigned mental age. To be sure, IQ scores are now calculated in a more complex way, but their meaning still emerges through a logic of comparison. Plotted on a bell curve, “the intellectually disabled” and “the gifted” are, through the logic of a graph, shown to be objectively different from the great swathe of “normal” people in between.

But over time, what constitutes a “gifted” as opposed to a “normal” or “intellectually disabled” student has fluctuated, revealing the historical and social contingency of such categories. For example, in 1959, former president of Harvard University James Bryant Conant proposed moving the cutoff for labeling a student as gifted to an IQ score of 130, 10 points lower than what psychologist Lewis Terman had established 30 years earlier. Suddenly—due to the act of moving a line on a graph—there were a great many more “gifted” students. This shift dramatizes the arbitrary nature of matching score to label. Why not 125 or 135 instead? The stakes are even higher on the other side of the bell curve: people with an IQ score of 72, for example, might be denied the support and services that accompany a diagnosis of “intellectually disabled” if the cutoff is 70. Or, alternatively, they might escape forced sterilization if they happened to live in Oregon before 1981. (Oregon was the last state to uphold the practice.) The story of eugenics, IQ tests, and education is, then, about who gets the best opportunities and who gets discriminated against, all in the name of commensuration.

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“Whatever exists at all exists in some amount. To know it thoroughly involves knowing its quantity as well as its quality,” Edward Thorndike, the founder of educational psychology, wrote in 1918. Thorndike believed intelligence to be a biological attribute and advocated for the wide use of IQ tests to quantify it. But even he admitted it was an inordinately tricky entity to measure. Unlike the measurement of density, velocity, or temperature, there is no known unit of intelligence. It therefore must be expressed through “relative size in terms of arbitrarily chosen units and reference points. This is the case, for example, with the most commonly used measurement in psychology and education, that due to applying the Binet-Simon tests.”

No one in the 20th century sought to overcome these limitations with more enthusiasm than Henry Goddard. A schoolteacher and principal for six years before receiving his PhD in psychology, he became in 1906 the director of research at the Training School in Vineland, New Jersey, where he began setting up a scientific laboratory. The school, which was founded in 1887 by Reverend S. Olin Garrison, housed 230 students, who had been labeled as “feebleminded,” in small cottages set in bucolic farmland. With Goddard’s arrival, what had been a charitable endeavor became a scientific institution devoted to measuring their intelligence.

That the thing called intelligence lacked a quantifiable unit was of little consequence to Goddard. By establishing his own system of classification, he was able to mask any uncertainty about what Binet’s test was actually measuring. Until then, the diagnosis of feeblemindedness had been based on appearance, symptoms, and the intuition of a physician. This meant that the same patient could be described as an “idiot” by one physician and as an “imbecile” by another. After giving Binet’s test to children at Vineland, Goddard proposed that “idiot” should now be used categorically to describe those who had no higher intelligence than a two-year-old. Those with the mental age of three to seven years would be called imbeciles. For a third classification, which was supposed to capture those with a mental age from eight to 12, Goddard proposed a new term, “moron.” This last group concerned Goddard the most. These children could—alarmingly, in his mind—slip through the cracks and pass for normal. “Our public school systems are full of them,” Goddard lamented, “and yet superintendents and boards of education are struggling to make normal people out of them.”

Goddard quickly expanded his work, publishing a study of the IQ tests of 2,000 public school children in 1911. Concluding that a whopping 18 percent were feebleminded, he set the stage for the segregated special education classrooms that endured for most of the 20th century. “Educationally the conclusion is forced upon us that it is very unfair to the normal child to keep these children in the same class with him,” he argued. “They should be segregated and given a special teacher who understands their case and is allowed to train them as their mental condition will permit.” Developed in response to a host of factors—new compulsory education laws, new sciences like educational psychology, child development, and statistics—and against the backdrop of an exploding population of immigrants, special education was in large part the product of growing anxieties about what it meant to be a “normal” American.

It didn’t seem to matter to teachers, school administrators, and educational psychologists that Goddard had identified a suspiciously large percentage of students as feebleminded. The risk of not following the directive of this new scientific tool was deemed far too great to ignore. In part, this was because feeblemindedness was not only a diagnosis of so-called low intelligence but also intimately intertwined with immorality and poverty, and as such, the 18 percent in schools threatened the larger body politic. The feebleminded, according to Goddard, “should not […] be turned out into the community” due to the likelihood of their becoming paupers or criminals, and thus blights upon the nation. “Society is facing a tremendous problem in this high grade feeble-minded child,” Goddard warned in a 1910 op-ed. “[A]t present the public school is the only agency that can grapple with it and bring a measure of relief.” Relief, that is, to those who saw American society as in need of genetic purification.

Approaching the issue through the lens proffered by the new science of heredity, Goddard decided that feeblemindedness was a disease curable only through sterilization. The logic here was straightforward: “The feeble-mindedness that is due to heredity can only be prevented by preventing the birth of such children,” he declared. If a procreative “accident” does occur, backwardness must then be detected in a timely manner through “the Binet test” so that the child can be expeditiously placed in the “proper environment”—namely, an institution for the feebleminded. There was one glaring problem with this solution, however: its price tag. With so many feebleminded children purportedly in need of institutionalization, Goddard’s proposed intervention was prohibitively expensive for federal and state governments to fund. The special education classroom—as opposed to immediate institutionalization—became a cost-savvy second-best option. What might it look like? “Every state institution for the feeble-minded should,” Goddard advised in 1910, “be a model school for observation by prospective teachers of special classes.” It should look and function like Vineland and other such institutions, in other words. His aim was now to convince teachers and school administrators that IQ tests were to their advantage. Happily, the Binet test was, he assured them, fairly accurate even in the hands of inexperienced test administrators. While more nuance would admittedly require a trained expert like a psychologist, “any person with good judgment can give the test and get results of immediate use and value.”

Goddard’s favorite part of Binet’s test was the form board, a simple and engaging activity that endures as a children’s toy today. A child is given a wooden board with 10 shapes carved into its surface. As the child works to fit each block into its corresponding shape on the board, an examiner keeps time and notes when the child struggles to match each block to the right shape. Developed in the 19th century by the psychologist Édouard Séguin, the form board test was indispensable precisely because it could be employed by teachers. Goddard wrote that “no other test […] shows us so much about a child’s condition in so short a time.” The results were consistent, he said, with more complicated exercises administered by experts. The data followed a near perfect bell curve, which in the minds of Goddard and his peers was a sign of its accuracy as a measure of intelligence. Surely, it had captured an essential truth. Public schools did indeed welcome the form board test and Binet’s intelligence test more generally.

One factor accounting for their near-immediate adoption of the tests may have been changing demographics and, concomitantly, transformations in public education and the perceived need to sort the wheat from the chaff in a such a large quantity of students. Before the turn of the century, school attendance had been sporadic and contingent on the needs of families during planting and harvesting seasons. By 1918, however, all states had school attendance laws mandating that every child receive an education. This strained the system, as it were, and elicited plenty of objections. Surely the law didn’t mean all children, said observers like Dr. Leta Hollingworth, Thorndike’s colleague at Columbia’s Teachers College, who argued that the inclusivity of such laws was actually pernicious: it required teachers to waste their time on pupils who could not learn and thus would not benefit from instruction. In her own analysis of the country’s turn toward compulsory education, Hollingworth described the tension between efforts to achieve civic equality through education and more elite ideas of citizenship as grossly discordant. “Thus the subnormal child and the school were forced into a reluctant mutual recognition of each other,” she lamented in her 1920 book The Psychology of Subnormal Children. Hollingworth’s disdain was directed at immigrants as much as the feebleminded.

In the lingo of the then-emerging science of statistics, Hollingworth writes that “‘an education’ meant that which constituted the curriculum for the great average.” An education, this phrase seemed to suggest, assumes a homogeneous group of students who embody that average. Therefore, the main job of special education was to absolve general education from dealing with the left side of the bell curve. “Misfits,” according to Hollingsworth, were concentrated there, in that graphic terrain, and categorically unable to assimilate. While special education teachers might be praised for their sacrifice in dealing with such children, the sacrifice was, then, not for the benefit of the students they were teaching. Rather, it was for policing the boundary between feebleminded and normal to make sure that segregated classrooms and their students remained out of sight.

It wasn’t long before schools began experimenting with organizing classrooms according to students’ mental—rather than chronological—ages. In June 1917, the Los Angeles City School District conducted an “intelligence survey” and devised a “plan of segregation,” which involved collecting school records, health information, testimony of teachers, and the results of Binet IQ tests. Students who were judged to be behind grade level were assigned to “adjustment rooms.” Students who could not be adjusted were demoted to “development rooms,” which served as a kind of purgatory after “everything that modern education can do for a child is done.” In 1920, two researchers found that more than a quarter of students at the Northwood School of Columbus, Ohio, were in higher grades than where they belonged according to their mental age. So, in February 1921, at the beginning of the second semester, 41 pupils repeated the fall semester. Six students were demoted half a grade and one was demoted a whole year. Forty-seven pupils whose test scores were on the other side of the bell curve were given an extra promotion of a half grade, and 22 skipped an entire year. According to the researchers, the new classification of pupils according to mental age worked well. The Columbus school was “in a very good section of the city,” and therefore the results were unsurprising, they noted. “There is evidently large wastage of good mental material—a wastage such as we always find in schools made up of children of good mental ability.” In this way, statistics and assessment seamlessly infiltrated education, and in this new regime, what mattered was how young minds performed on tests.

The classification of students according to “mental age” in Los Angeles and Columbus represents one of the earliest examples of “tracking,” a practice that then thrived for most of the 20th century. Its success was predicated on the public’s trust in IQ tests as objective measurements that made statistically legible where each student belonged in the American public school system. In 1954, more than 75 million standardized tests were being taken by 25 million students in order to evaluate their abilities and sort them accordingly. As Jeannie Oakes points out in her 1985 book Keeping Track: How Schools Structure Inequality, IQ testing gave tracking the illusion of a meritocratic justification. “Science” was invoked to “prove” students with higher IQs deserved a better education. But faith in the science of testing required the public to ignore questions that plagued the test from the start: What is intelligence? What does an IQ test actually measure? Fomenting anxieties about national identity—and national prowess in the Cold War—served to divert attention from these fundamental questions. Tracking also functioned under the assumption—although rarely stated as explicitly as Goddard had done—that students with the lowest test scores should learn their place early. It solidified the dog-eat-dog, competitive values of the American education system and of American capitalism more generally. To prioritize other values besides efficiency and productivity—such as collaboration, equal access to resources, and social-emotional development—would be a waste of “good mental ability.”

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In the 1960s and ’70s, the Civil Rights and disability rights movements compelled some special educators and scholars to voice their unease with the eugenicist undertones of this system. “Much of our past and present practices are morally and educationally wrong,” Lloyd Dunn, a prominent scholar at the George Peabody College for Teachers in Nashville, Tennessee, admitted in 1968. Addressing the persistence and excesses of the practice of segregating students with low IQs, Dunn wrote that “this expensive proliferation of self-contained special schools and classes raises serious educational and civil rights issues which must be squarely faced.” Special education implies the need for isolation to foster better learning outcomes—and yet, as he and others noted, research shows that access to general education curricula and classrooms improves the academic progress of students with disabilities. In fact, scholars have argued that segregated classrooms persist not because of good educational outcomes (which are far from the case) but because they are validated through entrenched practices of teacher certification and local school districts. Their persistence is, then, more about habit, limiting the rights of some groups, and the challenges of change than about effectiveness.

“The Six-Hour Retarded Child,” a report issued by the President’s Committee on Mental Retardation in 1969, called out the toxic outcomes of tracking students based on IQ scores. “We now have what may be called a 6-hour retarded child,” the report states, “retarded from 9 to 3, five days a week, solely on the basis of an IQ score, without regard to his adaptive behavior, which may be exceptionally adaptive to the situation and community in which he lives.” The report echoed Thorndike’s admission decades before—that intelligence was a slippery unit of measurement and the categories promised by commensuration were anything but set in stone. What should students be called, it asked, who were “retarded” and yet perfectly functional in ways not captured by quantitative measurement? Should we call them “functionally retarded,” the study asks, as a way to distinguish them from the “organically retarded”? The difficulties with labels disclosed a larger systemic flaw, which had plagued intelligence testing for more than 50 years: the educational system was quick to label, but what those labels actually meant was anything but straightforward.

By the 1970s, some researchers were beginning to wonder whether all forms of tracking were inherently unequal. Studies began to show the degree to which inferior tracks presented fewer postgraduation options than advanced ones and that teachers in these tracks set inordinately low expectations for their students. Most of us who have gone through the American public school system can look back on our own experiences and recall the self-fulfilling predictions as well as moral judgments engrained in tracking. Students in high-achieving courses are touted for their potential and morality. Students in low-achieving groups are known for sinister behavior and troublemaking, as Goddard established decades earlier. These assumptions become our “common sense.” But the passage of time reveals them to be not entirely predictive. Consider one of the most famous longitudinal studies of the correlation between IQ and life success: in 1921, Lewis Terman identified 1,521 children (“Terman’s termites,” as they were nicknamed) who scored over 135 on the Stanford Binet intelligence test. The children were studied over the course of the next 80 years. Some took up professions such as law or medicine, but plenty of others became sales clerks or technicians, pursuits deemed “far below their intellectual potential.” Ultimately, the study seemed to show that the path from potential to its fulfillment was far from guaranteed. Other nonquantifiable factors clearly mattered too.

In 1972, Elliot Richardson, the US secretary of health, education, and welfare, called for a systematic review of the classification and labeling of “exceptional children” on the left side of the curve. “The inappropriate labeling of children as delinquent, retarded, hyperkinetic, mentally ill, emotionally disturbed, and other classifications has serious consequences for the child,” Nicholas Hobbs admitted in a multivolume response to Richardson’s request. Children “may be stigmatized by labels that make them easy to count but difficult to help, and all too frequently the labels lead nowhere or to treatments that compound the problem.” Hobbs comes close to denouncing the education system’s dependence on intelligence tests. “[T]he routine use of such tests as the sole determinant of intelligence, as the primary basis for school placement, and as the justification for permanently labeling a child as mentally retarded is at best questionable, and at worst indefensible.” The dangerous decision to provide teachers with an excuse not to educate a child to their best ability could impact “serious matters” including “involuntary hospitalization, sterilization, the right to marry and have children, and the determination of incompetence.” These downstream “determinations [are] often made in court, and those decisions are often informed by IQ testing and the labels resulting from it.”

Hobbs’s report acknowledged the tangled ambivalence of a society dependent on such labels. “Children may be assigned to inferior educational programs, deprived of their liberty through commitment to an institution, or even sterilized,” he found. Yet the world was already made in ways that were difficult to undo. While classification and labeling may be harmful, the answer, according to Hobbs, was by no means to stop doing it. “[I]mproved classification could increase their chances of getting needed services,” he claimed. “Classification and labeling are essential to human communication and problem solving.” The solution, according to Hobbs and many bureaucrats still today, is to double down, create more categories, and establish more ways of measuring children. The No Child Left Behind Act of 2001 is one example of such a strategy. In the views of many of its critics, it succeeded, but only by reducing the entire endeavor of learning to what can be measured on a standardized test. In 1962, most students took three to five standardized tests per year; in 2014, one study found that some 11th graders spent up to 15 percent of the school year taking standardized assessments. Illogically, we have tried to solve the problem of testing with more tests, which has led to a narrowing of what has counted as learning and what the outcomes of learning must look like.

More testing has not led to better education and individualized care. Also troubling is the fact that access to resources and support is still based on the very system of classification that once facilitated horrific treatment and segregation. Untangling the helpful from the harmful outcomes of such a system is difficult. My daughter, who has Down syndrome, is required to take an IQ test to access the support she needs to succeed in school. While her peers certainly take lots of tests, the stakes aren’t nearly as high for them as for her. Administrators might look to her test scores as evidence that she no longer belongs in a regular classroom. Later in life, bureaucrats might look at her IQ score to determine whether she qualifies for Medicaid or other social services and supports. The IQ test links her to a system of support, but it might also betray her at any moment.

With tracking comes assumptions about which students ought to be exposed to certain educational material. The “life skills class,” as it is called, is a euphemism for segregated special education classrooms. Rather than being exposed to academic subjects that might impact and shape their worldview (for example, the history of the disability rights movement), students in these classes face different, usually watered-down, opportunities that do little to increase their sense of agency in the world or afford them the satisfaction of thinking deeply about things that matter to them. States have developed alternative curricula, which, according to various studies, school districts then seize on as a rationale for segregated classrooms, often starting in kindergarten. Once a student can only access this alternative curriculum, they are no longer in a position to return to a “normal” track, and earning the requirements of a high school diploma becomes a bridge too far. This raises the question: does segregation prepare students for an inevitable future, or is it a self-fulfilling prophecy condemning them to isolation from “normative” peers?

Tracking is not inherently unjust. Nor is special education. One could imagine a system in which students are tracked by professional or academic interests. And, in turn, special education is a vital service that—in the best of circumstances—allows students to access support they need while also participating in mainstream educational environments in meaningful ways. But placements are not usually left to students or families to decide.

Decades of studies have concluded that students with disabilities benefit socially and academically from inclusive classroom experiences. Students without disabilities benefit too. Both groups experience improved peer relationships, become more open to new learning environments, and are more accepting of differences. They have access to different, perhaps more expansive, kinds of knowledge. Working and learning alongside students with diverse abilities becomes “normal” for them. These benefits are difficult to measure quantitatively, and metrics are what Americans want—which means that high-achieving US students are now narrowly funneled toward STEM-oriented “success” that shows up well on a test. As we are discovering, rocketing levels of anxiety among students is one salient downside of this fixation. Our sense of achievement, spawned and shaped by our culture of testing, does not, it would seem, lead to a better world—and may be psychologically damaging too.

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How does Trump perpetuate the faulty logic of IQ tests and tracking? By suggesting that people with disabilities do not belong in the workforce. Despite his claims, however, they may be highly qualified for jobs at the FAA, or any other part of our society, thanks in large part to the education now legally guaranteed to them. November 29, 2025, marks the 50th anniversary of the Education for All Handicapped Children Act, which is now known as the Individuals with Disabilities Education Act (IDEA). The legislation was supposed to ensure that students with disabilities participate as fully as possible in the general education curriculum.

And yet, despite numerous court rulings and decades of research affirming that an inclusive classroom is the best place to educate all students, schools still typically segregate students with intellectual disabilities. In the 2022–23 school year, 7.5 million public school students (about 15 percent) were served by IDEA. But less than 18 percent of students with intellectual disabilities have access to general education settings for more than 80 percent of the school day, and this statistic has been stagnant for the past 25 years. The overrepresentation of minority students in special education persists. A 2016 study showed that Black students are 40 percent more likely to be labeled with a learning or intellectual disability than all other students.

Rather than addressing these challenges, Trump has promised to dismantle the Department of Education. When Secretary of Education Linda McMahon was asked on March 7, 2025, what she would say to parents concerned about the lack of oversight if the department is eliminated, she responded, “We will see scores go up.” And so the blind faith in what test scores mean continues. Health and Human Services Secretary Robert F. Kennedy Jr. recently commented that people with autism will “never hold a job. They’ll never play baseball. They’ll never write a poem.” We are, in short, witnessing a horrific return to a eugenicist “common sense” even though history shows us that the way test scores register intelligence is far from objective science, and that competence is not biologically ingrained in white, able-bodied men, as the Trump administration—atavistically—would like us to think.

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Featured image: G. E. Shuttleworth, “Form-Board,” from Mentally-Deficient Children: Their Treatment and Training, 1922, is in the public domain.