27 Geniuses With The Highest IQs In History — And The Surprising True Stories Behind Them

Published June 27, 2023
Updated June 28, 2023

William James Sidis, Marilyn vos Savant, and Leonardo da Vinci have some of the highest IQs in history — but are they really the world's smartest people?

Over the years, intelligence quotient tests, or IQ tests, have been seen as a way to quantify a person’s brainpower. In general terms, the higher a person’s IQ, the more intelligent they are. Naturally, this has sparked conversations about who has the highest IQ in the world — and whether that individual should be considered the smartest person in the world.

Famed physicist Albert Einstein’s name often comes up in conversations like these. He had an estimated IQ of 160, but that is not the highest IQ ever recorded. In fact, there are several child prodigies who have scored higher than Einstein. And public figures like Marilyn vos Savant and Christopher Langan have also been hailed as the smartest people in the world.

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Of course, IQ tests do have limitations and many have questioned whether or not they should be used as a determination of a person's intellect. There is also a dark history behind some IQ tests, as they've been used in the past to discriminate against people belonging to certain racial and ethnic groups.

What's more, both the reliability and efficacy of IQ tests have frequently been called into question. Some experts have suggested that they may be less an indicator of intelligence and more an indicator of a person's motivational level, quality of schooling, health status, and other variables.

That said, it's fascinating to read the true stories behind the people with the highest IQs in the world. Learn about these individuals in the photo gallery above, then read more about the complicated history of IQ testing below.

The Creation Of The First IQ Test

In the late 1800s and the early 1900s, a great deal of interest was stirring in the scientific community regarding research on intelligence. Early works on the subject were published by Sir Francis Galton, the founder of differential psychology, who believed that intelligence was hereditary and could be determined by observing how a person performed sensorimotor tasks.

According to Verywell Mind, these tasks involve the human brain receiving a message, and then producing a response (like slowing down after you see someone in front of you slowing down). Galton, an English polymath, often used statistics while explaining how to measure a person's intelligence.

Highest IQ In The World

Public DomainAlfred Binet, the French psychologist who developed the first IQ test, known as the Binet-Simon Scale.

Around the turn of the century, a French lawyer-turned-psychologist by the name of Alfred Binet became fascinated by Galton's work. He too began research into the development of tests to measure intelligence, which were put to wide-scale use in 1904 when the French government enlisted Binet's help to try and determine which children would struggle the most in school.

Binet and his colleague Theodore Simon then created a test comprised of a series of questions focused on skills such as attention and problem-solving — not necessarily skills that were taught in classrooms, but skills that could possibly affect a child's ability to learn. This 30-question test became known as the Binet-Simon Scale, the first officially recognized IQ test.

The Evolution Of Testing Intelligence

Over time, the Binet-Simon Scale was improved upon — first by Stanford University psychologist Lewis Terman, who standardized the test and used two scales of measurement in his revision, rather than one, to provide more accurate results. He also translated the test into English in 1916.

A year later, psychologist Robert Yerkes developed two IQ tests for the U.S. Army, the Alpha and Beta tests. The Alpha test was a written exam, while the Beta test was made up of pictures for recruits who couldn't read or who weren't fluent in English. Both tests were designed to help the Army determine which recruits might be good fits for specific roles in the military.

Unfortunately, IQ tests like these were also used to screen immigrants entering the United States, which led government officials to impose discriminatory restrictions on groups who supposedly had "inferior" IQs.

David Wechsler

Public DomainPsychologist David Wechsler, who published a new intelligence test in 1955 called the Wechsler Adult Intelligence Scale.

Then, in 1955, American psychologist David Wechsler created a new intelligence test known as the Wechsler Adult Intelligence Scale (WAIS). Wechsler strongly believed that intelligence should be measured by comparing the scores of test takers within the same age group.

Several revisions were made to Wechsler's system, eventually evolving into the WAIS-IV, which is the modern standard for intelligence testing. Using this standard, the average score is fixed at 100, with two-thirds of test takers landing somewhere in the normal range of between 85 and 115.

Today, when we look at candidates for the highest IQ ever recorded, this is generally the scale that we're using (or an estimate that's based on this scale). In theory, the higher a person's score, the more intelligent they are — though this has also been called into question over the years.

Who Has The Highest IQ In The World?

Even with the standardization of IQ tests and the numerous revisions made to them over time, it's still not quite so simple to identify the highest IQ ever. There are, of course, people whose scores extend upwards into the high 100s and even into the 200s, but shockingly, some of the world's smartest people have much lower scores than you might expect.

Albert Einstein, for example, is widely regarded as one of the most brilliant minds in all of history, yet his IQ was only estimated to be around 160 — still well above the average, but not a forerunner for the highest IQ in the world. And Stephen Hawking's IQ has been estimated to be the same number.

You'd be hard pressed to find anyone arguing that Einstein and Hawking were unintelligent, of course, but from a purely statistical viewpoint, their estimated scores pale in comparison to the scores of William James Sidis and Marilyn vos Savant. Sidis was a child prodigy with an estimated IQ of anywhere between 250 and 300; Savant's IQ has been recorded as 228.

Smartest People In The World

Public DomainAlbert Einstein's IQ was never officially tested, but some sources have estimated his IQ to be around 160.

But IQ tests are not a perfect measure of intelligence. Critics have often called them "fundamentally flawed," and the discussion also raises the question of what, exactly, it means to be one of the world's smartest people.

Take Christopher Langan, for example. Langan's IQ falls somewhere between 195 and 210, leading some to call him the "smartest man in the world." However, Langan also happens to be a 9/11 truther and a believer in the white replacement theory who, in 2018, wrote a Facebook obituary for Koko the gorilla, then asserted that Western countries should admit gorillas as immigrants instead of Somalis, claiming that gorillas are more intelligent.

Because of this, some have called him "Alex Jones with a thesaurus."

Langan is an unusual example, but one that highlights the flaws of using IQ tests as a determiner of the smartest people in the world.

The "Fundamentally Flawed" Nature Of IQ Tests

As a report from The Independent explains, a 2012 study found that IQ tests fail to accurately represent the complex nature of human intellect.

"The results disprove once and for all the idea that a single measure of intelligence, such as IQ, is enough to capture all of the differences in cognitive ability that we see between people," said Roger Highfield, the director of external affairs at the Science Museum in London.

Researchers analyzed a sample of 46,000 individuals from around the world who filled out an online survey where they were asked to complete 12 mental tests to measure different aspects of their cognitive ability.

In the end, they determined that no single measure of intelligence could represent the variations seen among the three distinct components of cognitive ability: short-term memory, a verbal component, and reasoning.

"It has always seemed to be odd that we like to call the human brain the most complex known object in the Universe, yet many of us are still prepared to accept that we can measure brain function by doing a few so-called IQ tests," Highfield said. "For a century or more many people have thought that we can distinguish between people, or indeed populations, based on the idea of general intelligence which is often talked about in terms of a single number: IQ. We have shown here that's just wrong."

Does this mean IQ tests are completely useless? Not necessarily. But they shouldn't be used alone to determine the smartest people in the world.

After reading about some of the people with the highest IQs in the world, learn about these 15 interesting people that history forgot. Or, check out these photos of history's biggest musicians just before their rise to stardom.

Austin Harvey
A staff writer for All That's Interesting, Austin Harvey has also had work published with Discover Magazine, Giddy, and Lucid covering topics on mental health, sexual health, history, and sociology. He holds a Bachelor's degree from Point Park University.
Jaclyn Anglis
Jaclyn is the senior managing editor at All That's Interesting. She holds a Master's degree in journalism from the City University of New York and a Bachelor's degree in English writing and history (double major) from DePauw University. She is interested in American history, true crime, modern history, pop culture, and science.