Some time ago, my children and I did some questions similar to IQ tests online. Unexpectedly, these problems seemed to be easy for my sister. She answers questions very quickly and with very high accuracy. Considering some of her previous performances, such as having a poor academic attitude but excellent grades, and being quiet but having one of the best writing skills in the grade, this contradiction is puzzling. We consulted with the school psychologist about testing for Asperger’s syndrome, and my friend suggested we give her an IQ test.
The Origins of IQ Testing
The IQ test really took shape in 1904, when the British psychologist Charles Spearman studied students’ performance in different subjects, trying to find whether there was a correlation between these subjects.
He found that students who performed well in one subject tended to perform well in all subjects, and therefore proposed that everyone has a certain degree of “G factor”, that is, general intelligence, believing that this relatively fixed intelligence reflects The speed of learning new knowledge, cognitive models, and critical thinking also explain why students’ scores in various subjects show a certain correlation.
However, the correlation is not absolute. Factors such as personal interest, teacher’s teaching, and effort will have a certain impact. Spearman calls these potential variable errors “S factors.”
Based on this, he conceived a method to measure “inherent intelligence”, to weaken the influence of the S factor through a series of diverse questions, to reflect a person’s objective intelligence level as truly as possible. This is the IQ test. His underlying goal is to identify children with high IQs from lower socioeconomic groups and provide them with better educational opportunities.
Soon after, the world’s first IQ test, the “Benet-Simon Test”, came out in France and was quickly introduced to Stanford, becoming the most widely used IQ testing tool in the United States in the following decades. IQ tests measure the G factor by assessing an individual’s performance in multiple mental abilities such as memory, language ability, spatial ability and numerical skills.
To standardize scoring, the test is administered across a wide range of people, and the results are presented as a mean of 100 and a standard deviation of 15. For example, a high school graduate with an IQ of 105 would score one-third of a standard deviation above the mean.
This measurement is still used today, with 68% of the population having an IQ score between 85 and 115, meaning that a score of 115 is higher than 84% of the population.
Today, the highest IQ score is four standard deviations from the mean, or 160; the lowest is 40. Once outside this range, the accuracy of the test is affected, so those claiming IQ scores of 190 or 250 are fiction.
In fact, only about 2% of the population has IQ scores above 130 or below 70.
What Exactly Can IQ Predict?
Psychologists generally agree that the G factor, the core of intelligence, is a relatively stable attribute, which means that a person’s intelligence level will hardly change much throughout his life. Therefore, they believe that many people will be surprised that a test of one or two hours focusing on numbers, graphics, and vocabulary questions can predict many possibilities in a person’s life.
First, the higher the IQ, the more likely the brain will be. A large analysis in 2005 showed a correlation coefficient of 0.33 between IQ and brain size.
IQ also predicts academic achievement. In 2007, Scottish psychiatrist Ian Deary measured the IQs of tens of thousands of 11-year-old children. Five years later, Derie compared their national secondary school examination results with their IQs and found that there was a significant difference between the two. The correlation is as high as 0.8. This extremely high correlation suggests that children’s IQ test scores when they enter school predict how they will do when they graduate and even how far they will go academically.
IQ also predicts job performance, especially in high-complexity occupations. For example, in military training, those with IQs below 80 will not be accepted into the U.S. military, and the number of recruits with IQs between 81 and 92 is limited to 20%. During the Vietnam War, to expand the supply of troops, the US military relaxed this standard but found that recruits who were below the threshold were 1.5 to 3 times more likely to fail in training than the normal standard, and required 3 to 9 times of remedial training. Ultimately, the added stress and costs of this approach make the military more efficient at operating without these extra recruits. As a result, the military reinstated conscription standards.
In addition, IQ can predict health and longevity. In one study, scientists followed 11-year-old children who took IQ tests 65 years later and found that, on average, every 15-point increase in IQ test increases the likelihood of surviving to age 76 by 27%.
Surprisingly, however, the correlation between IQ and income is not as high as one might think. A large sample study showed that the correlation coefficient between IQ and income is only 0.21, which means that IQ can only explain 4.4% of the income difference, and the top three highest-paid people in the study all have IQs of less than 100 points. This suggests that, from an economic perspective, high-income professions do not necessarily require the highest levels of intelligence. At the same time, many people with high IQ scores are not interested in accumulating wealth.
A Dark History That Inspires Prejudice
Since its birth, IQ testing has fallen into a dark history of causing bias. Initially, in France, the “Benet-Simon Test” was designed to help low-achieving students. However, when the concept reached the United States, things changed. Researchers like Spearman insist that the G factor is fixed and that a person’s lifetime intelligence level is determined at birth.
Many people believe that intelligence is inherited. For example, the correlation of scores over 80 years between a test given to 11-year-old children and the same test taken when they were 90 years old was 0.6, which seems to indicate that IQ is heritable and unchangeable.
Thus, IQ testing became a piece of evidence for eugenics. Eugenicists sought to prevent those with undesirable genetic traits from reproducing, and many states passed laws allowing forced sterilization of people whose IQ test scores did not reach a certain threshold, a practice that was even recognized as such by the U.S. Supreme Court in 1917. As a result, more than 60,000 people were forcibly sterilized as a result of these laws.
Even darker, these measures provided a model for Nazi Germany. Hitler himself claimed that he was inspired by eugenics.
In addition, IQ tests have been misused to promote ideas about racial differences. For example, differences in average IQ between blacks and whites in the United States have been observed, and studies have been published on average IQs in various countries around the world. Such conclusions promote racial discrimination.
For another example, Jews have contributed many geniuses to the world. Their average IQ is about 110-115, which is nearly one standard deviation higher than the average.
However, scientists now realize again that these data were misleading.
In fact, IQ is not completely fixed. Education improves IQ, and the average IQ of the entire population has increased at a steady rate over the past 100 years. Therefore, the differences in IQ between different races and countries may be the result of the influence of development stage, diet and nutrition, and cultural education.
Just like height, while it may be relatively constant for an individual over a lifetime, the average height of a group can change over time and external conditions, such as diet. The tallest Dutchman in the world today was the shortest in Europe 160 years ago.
And, taking an IQ test with training and coaching can improve scores by as much as eight points, especially in the math section.
Are IQ Tests Valuable?
The topic of IQ testing has aroused complex emotional responses in the psychology community and even the public, with love and hate intertwined. Due to the complex and dark history behind it, many people are critical of IQ testing, arguing that it has lost its validity and is even viewed as a product of racial bias.
However, many psychologists have come out to speak out about the importance of IQ testing, emphasizing that the value of IQ cannot be ignored just because it may cause racial controversy. Differences in IQ are a reality that cannot be ignored and are an important window for understanding a person’s abilities.
For example, psychologist Jordan Peterson, a professor at Harvard University, pointed out that the study of IQ has become a mature field in psychology since the 1920s. The psychologists who developed the IQ tests were among the first to adopt statistical techniques, which have become a standard tool for psychologists to verify and test hypotheses. He emphasized: “If we deny IQ research, then the conclusions of all other branches of psychology can be discarded. Because IQ research defines intelligence in a more rigorous and precise way than almost any other psychological research, and It can predict a person’s life trajectory to a certain extent.”
Jordan Peterson raised a question: “A person is born in a family with more than 95% of the population’s wealth, or a person is born in a family with an IQ higher than 95% of the population. By the age of 40, in which case will the person develop better? Okay?” His answer was the latter.
The impact of IQ is far-reaching and cannot be ignored. Peterson also mentioned: “In the era of artificial intelligence, people with the highest IQs are pushing the boundaries of technology, which to some extent increases the gap between them and ordinary people. IQ is largely about thinking and reaction speed, and in the rapidly changing field of artificial intelligence, people with high IQs are more likely to get the upper hand.”
For example, OpenAI CEO Sam Altman’s IQ is estimated to be 170, according to DgFresh. This means that his intelligence level exceeds 99.9998% of the population.
Peterson said: “We must face the fact that in modern society, people with an IQ below 85 are almost unable to do any job, and this group of people accounts for 15%. Can we really choose to turn a blind eye? This is A social issue with wide-reaching consequences.”
Self-Fulfilling Prophecy
IQ tests may contribute to a “self-fulfilling prophecy,” especially if we or others change our attitudes and expectations about our children as a result of the test results. If children are told that they have high IQs, they may receive more attention and higher expectations. Such treatment may positively or negatively affect their behavior and performance; conversely, if children are considered to have lower IQs than expected, children may accept it. Lower expectations, thereby limiting one’s potential. Therefore, we should treat IQ tests with caution and focus on developing a child’s strengths and interests regardless of the test results. Creating a supportive and encouraging environment can effectively reduce the risk of a self-fulfilling prophecy.
Of course, for those gifted children with truly high IQs, it is undoubtedly beneficial to take IQ tests to obtain a more matching education.
To be clear, IQ is not the same as intelligence. A higher IQ does not mean a person is better. It is a complete mistake to view IQ as a measure of personal worth or as a tool for bias. As Stephen Hawking said: “Anyone who brags about his or her IQ is a loser!”
