At Madison Square Garden in midtown Manhattan last Sunday, Donald Trump characterized Vice President Kamala Harris, his opponent in the 2024 presidential race, as “a very low IQ individual.” At the same event, Tucker Carlson dismissed Harris as a “low IQ former California prosecutor.”
Trump’s and Carlson’s remarks tap into a broader discussion about whether intelligence is a critical factor for leadership. Both speakers implied that intelligence, as measured by IQ tests, is a necessary requirement for presidential competence.
Intelligence does, in fact, predict success across various life domains. In their 2021 book Noise: A Flaw in Human Judgment, Nobel laureate Daniel Kahneman and his coauthors point out that “Intelligence is correlated with good performance in virtually all domains . . . general mental ability predicts occupational level attained and performance within one’s chosen occupation and does so better than any other ability, trait, or disposition” and that intelligence “remains by far the best single predictor of important outcomes.”
The psychologist Paul Bloom, responding to claims that IQ tests don’t predict anything important, writes, “That’s absolutely true—so long as you don’t think grades, jobs, money, health, or longevity are important . . . intelligence test scores are highly correlated with just about every outcome human beings care about.”
In a Slate article titled “Yes, IQ Really Matters,” psychology professors David Z. Hambrick and Christopher Chabris note that “general mental ability—the psychological trait that IQ scores reflect—is the single best predictor of job training success . . . it’s more predictive than interests, personality, reference checks, and interview performance.” Given everything that social scientists have learned about IQ, it is reasonable to make it a factor in decisions such as whom to hire or admit to a particular college or university. They go on to note that “disregarding IQ is harmful both to individuals and to society.”
Indeed, how smart you are affects how likely you are to stay alive. If you have an IQ even 15 points higher than the average when you’re 11 years old, you’ll have a 21 percent higher chance of surviving into your seventies.
Intelligence doesn’t just predict academic success, earnings, or lifespan, though. Consider a study about tank gunners. You might not think a standardized intelligence test score would have a statistical relationship with the ability to shoot straight. But the data show it does. Replacing a gunner who scores around the 20th percentile with one who scores around the 55th percentile improves the likelihood of hitting a target by 34 percent.
To understand the value of intelligence, it’s helpful to define it. The psychologist Arthur Jensen provided a nuanced definition: “Assimilation of experience (i.e., learning) into cognitive structures which organize what has been learned in ways that subsequently permit quick and adequate retrieval and broad transfer of the learning in new relevant situations. Stated in simplest terms . . . the process of understanding what one has learned. It is ‘getting the idea,’ ‘catching on,’ having the ‘Aha!’ experience that may accompany or follow experiencing or learning something, and the relating of new learning to past learning and vice versa.”
Leading researchers in the field of intelligence released a paper years ago with their own definition: “Intelligence is a very general mental capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experience. It is not merely book-learning, a narrow academic skill, or test-taking smarts. Rather, it reflects a broader and deeper capability for comprehending our surroundings, ‘catching on,’ ‘making sense’ of things, or ‘figuring out’ what to do.”
Intelligence, then, encompasses how quickly and efficiently you can draw from your existing base of knowledge, grasp novel information, integrate that novel information into your existing knowledge base, and implement what you have learned to achieve your goals.
Indeed, in her 2023 book Eve: How the Female Body Drove 200 Million Years of Human Evolution, Cat Bohannon points out that “Smart brains are ones that can quickly assess problems and find creative solutions. Smart brains are good at remembering things and using those memories where appropriate. They’re good at learning rule sets, understanding symbolism, tracking patterns . . . That’s what IQ tests are for . . . how well and how quickly your brain can learn new things and solve problems.”
The importance of IQ has even made its way into classic fictional stories. In Kurt Vonnegut’s short story “Harrison Bergeron,” the handicapper general forces everyone with a high IQ to wear an earpiece that loudly buzzes every 20 seconds to interrupt sustained thinking. This is designed to bring them down to the intelligence of the average citizen.
Intelligence is a strong predicter of socioeconomic status as well as leadership attainment. People generally grant smart people a high level of status. And they prefer individuals in high positions to be smart. The second strongest predicter of socioeconomic success, after intelligence, is the personality trait conscientiousness, sometimes called “grit.” This trait encompasses the propensity to be orderly, persistent, and hardworking. Emotional intelligence also correlates with some measures of life success, but emotional intelligence, in psychometric terms, is merely a re-description of a combination of IQ and personality.
While emotional intelligence (sometimes called “EQ”) has received attention, Wharton organizational psychologist Adam Grant has pointed out that when it comes to predicting work performance among hundreds of salespeople, “Cognitive ability was more than five times more powerful than emotional intelligence. . . . When Daniel Goleman popularized emotional intelligence, he argued that ‘it can matter more than IQ.’ But every study comparing the two has shown the opposite.”
This correlation between intelligence, hard work, and accomplishment serves society well. An environment in which intelligence and industriousness did not pay off would be undesirable. A society where factors other than being smart and industrious reliably led to success is not a society most people would want to live in. This was apparent during the Cold War when individuals in Communist societies were far more likely to flee to capitalist ones than vice versa.
If you want a functional society, it’s wise to screen for people good at absorbing and synthesizing information and place them into positions where they hold influence and power. Of course, intelligence does not guarantee that a person will be ethical or competent at their specific job. But intelligence is, generally speaking, necessary if not sufficient for someone to be effective in a high-stakes position. Intelligence on its own is not enough to make someone a wise and effective leader, but meeting a minimal threshold is a suitable requirement.
Can you have too much intelligence? For professions that require technical skills, more intelligence is typically better. For leadership, though, too much smarts can backfire, as followers will feel unable to relate to you.
All else being equal, people report that they find leaders (and, interestingly, romantic partners) to be most attractive at about the 90th percentile of intelligence, which is around 120 IQ. People want leaders and romantic partners who are smart. But not too smart.
The psychologist Dean Keith Simonton has found that beyond the 90th percentile of intelligence, “more intellectual power detracts from influence. Beyond an IQ of 156, you would not do any better than if you had an IQ of 103 . . . There is a negative relationship between intellectual brilliance and how many electoral votes are cast.” Simonton goes on to suggest that, “Possibly, a person can be too bright to be president.”
Typically, leaders have an IQ between 1 and 1.5 standard deviations above their followers. The average IQ of U.S. citizens is 100. This suggests that presidents tend to have scores around 115–123, consistent with the idea that 120 IQ is the sweet spot.
Intelligence becomes less socially attractive at very elevated levels. Simonton suggests that a person has leadership appeal if he or she is able to understand ideas from highly intelligent people and can also effectively communicate with ordinary people.
Unlike with height, where the taller candidate typically prevails in presidential elections, the reverse may be true with intelligence. Very intelligent individuals often have difficulty relating to the thought patterns and concerns of most people. By the time you achieve the nomination of a major political party, you have already proven that you are smarter than average. But with two smart people, the one who is better able to relate to ordinary people has the advantage.
This explains why exceptional intelligence can be isolating, particularly for young people. Leta Hollingworth, a pioneer in the study of intellectually gifted children, shared an example in a 1926 study. One of her subjects, a nine-year-old boy with an IQ above 145, was an outcast among his peers. He regularly used words like “capitulate,” “reciprocal,” and “naivete.” He was later placed in a class of gifted children. Suddenly, he emerged as the class leader because his classmates understood what he was saying and could appreciate his brilliance.
When bright youngsters face the possibility of social isolation, they often adapt by finding ways to fit in. They might immerse themselves in solitary pursuits—studying complex subjects or reading poetry alone in their rooms. Over time, many learn to adjust: a boy might start talking about sports with classmates, and a girl might avoid using vocabulary that sets her apart. This effort often brings unexpected benefits, as these children come to see that their peers are more insightful and engaging than they initially assumed. Ultimately, the need to make this adjustment cultivates flexibility, maturity, and resilience. For these young individuals, the choice is often simple: either learn to fit in or risk being an outcast. The same lesson holds for those who seek leadership positions—you must learn to relate to and connect with those whom you wish to lead.
Donald Trump excels at this, whereas Kamala Harris continues to come up short. Her social ineptitude was on display at her recent Michigan rally, where she interrupted her supporters’ chants of support for her by instructing them to shout their own names instead, leading to a moment of awkward silence.
Interestingly, in terms of education and affluence, a mismatch exists between the candidates and their constituents. As the Democrats have increasingly become the party of the college-educated and affluent, they are led by Harris and Tim Walz, both of whom attended less selective schools and are less financially successful than their rivals, Trump and J. D. Vance. Nevertheless, Trump and Vance have been better than their competitors at exhibiting charisma and relatability.
If Trump is correct that Harris is “a low IQ individual,” he may be inadvertently highlighting one of her few strengths in the upcoming election. It’s not her lack of intelligence that is holding her back—it’s her inability to relate to ordinary people.
Photos: Anna Moneymaker/Getty Images (left) / EVELYN HOCKSTEIN/POOL/AFP via Getty Images (right)