I’ve been reading about IQ testing and I’m curious about where it all started. Who actually came up with the concept of measuring intelligence with a number? Was it one person, or did multiple researchers contribute to developing what we now call IQ?
Also, was the original purpose the same as how we use IQ tests today, or has the intent changed over time? I’d love to know the history behind this.
The first modern intelligence test was created by French psychologist Alfred Binet in 1905, along with his colleague Theodore Simon. They were asked by the French government to identify students who needed extra educational support. The term “Intelligence Quotient” or “IQ” came later—German psychologist William Stern introduced it in 1912 as a way to express test scores. Lewis Terman at Stanford then adapted Binet’s test for American use, creating the Stanford-Binet test in 1916, which popularized IQ testing in the US.
Alfred Binet invented the first practical intelligence test in 1905, but he actually didn’t like the idea of reducing intelligence to a single number—he saw it as a tool to help struggling students, not to rank people. The “IQ” score itself was invented by William Stern a few years later. Interestingly, the original purpose was much more educational and supportive, but it got twisted over time into ranking and classification, which Binet himself warned against. The way we use IQ tests today is closer to what later American psychologists developed, not what Binet originally intended.
Alfred Binet created the first successful intelligence test in 1905, and he revised and expanded it in 1908 and 1911. His original intention was to identify children who were struggling in school (see an article about that history). Wilhelm Stern, a German psychologist, was the first to come up with the idea of an “intelligence quotient,” originally calculated with the formula (mental age / chronological age) x 100.
Since Binet’s time, IQ tests have been used for many purposes: determining mental competency in trials, employment hiring and promotion, inform clinical judgment, and more. Amazingly enough, still they are often used to identify children who struggle in school. So, the intent behind IQ testing has changed in the sense that we use it for more purposes, but we haven’t ever discarded Binet’s original goal.
Systems for evaluating mental abilities existed long before 1905. China’s imperial examination system, for instance, had been assessing cognitive skills for over a thousand years. While these weren’t IQ tests in the modern sense, they represented sophisticated attempts to measure intellectual capacity and predict performance. We have to acknowledge that cultures worldwide have long grappled with how to assess and classify human abilities. The real innovation of Binet was more into applying statistical methods and age-norming to create a specific type of psychometric instrument.
I also think we should not romanticize Binet’s intentions too much. When IQ tests reached America, mainstream psychologists like Henry Goddard and Lewis Terman immediately used them for eugenics. Goddard tested immigrants at Ellis Island to label certain groups as feebleminded, while Terman advocated preventing low-IQ individuals from reproducing.
@prettymarion960 The romanticization you mention often comes from ignoring the deep, embedded cultural biases in the tests themselves. Terman’s work, which led to the Stanford-Binet, standardized a test that implicitly privileged the knowledge and language of the dominant, middle-class white culture, virtually ensuring that immigrants and minorities would score lower and be labeled “feebleminded.” The test wasn’t just used for eugenics; it was structurally conducive to it