IQ has long been an official marker of intelligence in the public eye. The government uses it to determine what jobs people qualify for in the military, it is used to evaluate job applicants and friends take tests to see who is actually smarter. Many people take for granted that IQ is the perfect tool to measure exactly how smart a person is, but the unfortunate reality is that IQ’s use is complicated at best. In addition, it has a questionable past that can make its continued use problematic.
At its inception, the IQ test was not all bad. A British scientist named Charles Spearman was studying schoolchildren. He noticed that people doing well in one subject tended to do well in all subjects. This doesn’t sound like a remarkable finding, but it became the basis for the idea of what he called the “G Factor.” He supposed that there was some base level of intelligence that a person has that is unchangeable. Combined with what he called the “S Factor,” a person’s subject-specific aptitude for something, he suggested you could accurately measure intelligence. He created a test across several subjects and averaged the scores between them to try and correct for the “S factor” and determine someone’s general intelligence. This became our modern-day IQ or Intelligence Quotient Test. It is calculated by seeing how your score compares to the average score of different age groups, then divided by your expected score. The average would be 100, and 68% percent of the population would score within 15% of that score.
At a base level, the IQ test does a great job of what it sets out to measure. It is really good at analyzing how good someone is at different reasoning tasks, and there have been some proven positive correlations between IQ scores and average yearly salary, success in school, highest level of education, SAT/ACT scores, and even brain size. On those fronts, IQ is a decent measure. But the problem with the IQ score comes when anything else is assumed. The only thing that the test proves is how good someone is at a certain set of culturally agreed upon reasoning skills, and the history of this test proves that it has been hugely problematic.
For one, IQ was the basis of the Eugenics movement in the latter part of the 19th century. People with a low IQ were determined to be useless to society, and thus they should not be allowed to reproduce, especially targeting people of color (due to slavery’s abolishment not even 50 years ago) as they didn’t score as high as other races. This, combined with the Eugenics movement, created the idea that people of color are not as smart as white people and therefore should be sterilized. In the US, during this period, over 60,000 people in states like Virginia were forcefully sterilized because they were deemed, by an IQ test, to be unfit to have children. This choice was not only enforced at the state level but when appealed, upheld by the Supreme Court in 1927. This decision was so influential that Adolf Hitler said that he was inspired by the American Eugenics movement. After WWII, many of the German soldiers on trial even quoted the Supreme Court.
Besides the history, there are also problems with the test itself. For one, studying for the IQ test can yield around a ten-point increase, your level of motivation can change it by up to 20 points, your level of anxiety can affect the results by five points and the culture you come from can have a huge effect on your score. So, for example, if someone who would have scored around a 70, which is generally the line where someone is considered intellectually disabled, studied well, was highly motivated, was just around the right level of anxious, and grew up in America, they could score as high as a 100, which would be considered an average score. Conversely, someone who may have scored a 100, under the right conditions, could score as high as 130, which is generally the line for ‘geniuses.’ While this doesn’t prove that the test is useless, it does prove that it is highly fallible. The cultural assumptions that people make about IQ are generally not correct. Another example of this is that every decade, the test results are renormalized to 100 because people have tended to score higher over the past 100 years, at a rate of about 5 points per decade. This means that people who were average then would score around 70 today. And someone like Albert Einstein, who famously had an IQ score of 160, would have a 130 today which is not nearly as rare. So if Albert Einstein isn’t a super genius, what’s the point?
