TedEd: The dark history of IQ tests

A TedEd by Stefan C. Dombrowski

The IQ test was first created in 1905 by psychologists Alfred Binet and Theodore Simon. They were using it to test struggling students in France and figure out which of them needed extra attention. In the late 19th century, scientists came up with the idea that cognitive skills reflected the general intelligence, or g factor. A series of tests were given to get a single score, which was based on the average scores of an age group. Questions were adjusted based on age as well. A person’s score divided by their age time 100 yielded IQ, or intelligence quotient. Simon and Binet used the tests to measure general intelligence. But as the definition of general intelligence was not strictly defined, many people used the tests in bad ways. During WWI, for example, IQ tests were used to separate new recruits and see who was eligible for officer training. Later, they were also used when people believed in eugenics (the belief that there were desirable traits in humans that should be cultivated). Because of the belief that intelligence and traits were also linked to race and passed down by heritage, researchers used the results from army tests to claim that certain races were less intelligent than others, leading to things like the Holocaust and forced sterilizations. The problem was that they failed to account for the fact that many who took the test had limited exposure to English, being recent immigrants. However, the civil rights movements led to opposition of discrimination based on IQ from both scientific and moral standpoints. For example, evidence of environmental impact was found. The tests were recalibrated over the centuries to account for new generations, but they scored far too high on old tests to simply account for it based on inherited traits. This is known as the Flynn Effect, and scientists concluded that it occurred from things like better education and nutrition. But IQ tests aren’t fully obsolete. They can still provide good estimates of reasoning and problem solving skills. But that isn’t the same as one’s potential.