I Took an IQ Test to Find Out What it Actually Measures

- In popular culture, the term IQ is everywhere. - Do IQ

test

s do that? - You probably need 120 IQ points. - I don't know

what

my IQ is. - And the IQ. - Intelligence quotient. - Intelligence quotient. - Individual with low IQ. - People who brag about their IQ are losers. -When people say IQ,

what

they mean is intelligence, an objective and rigorous measure of intellectual ability. But does it really work? Well, in this video I want to know: where does IQ come from? What does it really measure? What can it predict about your life? And I guess, what's my IQ?

I had never taken an official IQ

test

before. Honestly, I don't think he's very smart. I've always considered my IQ to be maybe a little above average. - Exothermic or endothermic? - I feel like that should be exothermic. - Good job, scientist. - There are many IQ tests online, but I am very skeptical about their accuracy. Still, I thought some of them might be good practice for reality. Tomorrow I'll take a real IQ test. Before I do that, I want to try to improve my score, so I'll try to do a bunch of practice tests. I think this test can be trained.

But tomorrow we will see if that is true or not. The idea of ​​intelligence testing dates back hundreds of years, but the first concrete breakthrough came in 1904. English psychologist Charles Spearman was studying students' grades in different subjects and wondered how their performance in a subject would relate to each other. , like English, with its performance. in another, like Mathematics. One option would be that the better a student did in math, the worse he would do in English, perhaps because he spent more time on his math work and therefore had less time to spend on English. Therefore, performance in different subjects would be negatively correlated.

Another option was that performance in one subject had no relationship to performance in another. After all, different subjects require different skill sets, so perhaps grades aren't fully correlated. The third option was that the better a student did in math, the better they would do in English. In other words, their grades would be positively correlated. A correlation coefficient can vary from negative to positive. A negative correlation coefficient indicates a perfect negative correlation, meaning that an increase in one variable corresponds to a precise and predictable decrease in the other variable. Similarly, a positive correlation indicates a perfect positive correlation.

A correlation of zero indicates that there is no relationship between the two variables. And any value between zero and one indicates a positive correlation, but the data has some random scatter. The square of the correlation coefficient indicates the amount of variation in one variable that can be explained by the variation in the other variable. For example, if the correlation coefficient is 0.5, then 25% of the variation in one variable can be explained by the other. When Spearman analyzed his data, he found a clear positive correlation. Students who performed better in mathematics also tended to perform better in English, and the correlation coefficient was 0.64.

But math and English were not the only subjects the students studied. They also

took

Classics and French. And when Spearman looked at the correlations between all of these themes, he found the same pattern. Students who did well in one subject tended to do well in all of them. So how is this observation explained? Well, Spearman proposed that every person has some level of general intelligence, what he called the g factor. This construct was intended to capture how quickly students could learn new material, recognize patterns, and think critically regardless of the topic, which explains why students' scores across subjects are correlated.

Those with high g score well in all subjects and those with low g score low in all subjects. Spearman published his

find

ings in an article titled "General Intelligence" Objectively Determined and Measured. But the correlations were not perfect. So, in addition to the g-factor, Spearman proposed subject-specific factors, or s-factors. A student's performance in mathematics, for example, would depend on his general intelligence plus his subject-specific factor for mathematics. Subject-specific factors could increase or decrease performance in that particular subject. Spearman believed that specific factors could be trained but general intelligence was fixed. That's why he wanted to

find

a way to reliably measure general intelligence.

Around the same time, in France, Alfred Binet was tasked with finding out which children needed the most help in school. Together with Theodore Simon, he developed the Benet-Simon test. Students were asked to name what was missing from the drawing, define abstract terms, and repeat sentences. And there was also the question of whose face is prettier. There were 30 tasks in total. His performance was compared with that of other students of different ages to assign them a mental age. For example, if a student performed as well as the average eight years old, her mental age would be eight.

This mental age was then divided by his actual age and multiplied by a hundred to arrive at the so-called IQ, and IQ was born. Therefore, the Binet-Simon test was the first IQ test in the world. Goddard translated it into English and brought it to the US. At Stanford, Lewis Terman standardized it using a large American sample and, with some modifications, it became the Stanford-Binet test, and for decades it was the most widely used test in the United States. State. But this was just the beginning. Many other IQ tests were developed and they all had the same goal of measuring the g factor.

The way they did it was by testing many different mental abilities, including memory, verbal, spatial and numerical skills. Each of these areas could have a specific thematic twist. But by averaging them all together, the idea was that the subject-specific effects would cancel out, leaving a decent approximation of g. Of course, there would always be some error. But that's why psychologists designed IQ tests with more than seven to 10 sections with distinct tasks to try to minimize subject-specific distortions. All the different IQ tests differed in the number of questions and their difficulty. So, to standardize the scoring system, each test was administered to a large sample of the population.

The raw scores were normalized, usually the mean was one hundred and the standard deviation was 15, and this is how it is still done to this day. This is known as IQ and is intended to be a measure of an individual's g-factor compared to the rest of the population. According to the scale, 68% of people have an IQ between 85 and 115. Only about 2% score above 130 or below 70. (calm music) 11 lions, four cats and seven crows have a total of... Oh, boy. While studying for my IQ test, I practiced all the different types of questions that appear on modern tests. One section will almost certainly be on vocabulary.

They give you a word like optimistic, and you have to choose which of the multiple choice options has the most similar meaning. Is he gloomy, stupid, recalcitrant, optimistic or reflective? You may also be asked to choose a word with the opposite meaning. So what is the opposite of insightful? Is he cunning, servile, boring, fanciful or shrewd? Another section tests your ability to detect patterns with numbers. So choose the number that best completes the pattern. 3, 5, 8, 12. What comes next? I was originally looking for complicated patterns, but as I became more familiar with online tests, I found that the patterns were usually pretty simple.

A good technique is to find the difference between adjacent terms. So in this case, the first two terms are separated by two, the next by three, and then by four. So the next logical term should be five more than 12, so 17. The answer is C. Sometimes numbers grow quickly, as in the sequence three, 15, 60, 180. What comes next? In cases like this, I look at the relationship between one number and the previous one. In this case, the second number is five times the first. The next number is four times as large and the next is three times as large.

So the answer should be twice the fourth term, which is 360, answer B. One of the most well-known types of IQ test questions is Raven's Progressive Matrices. These involve a three-by-three grid with symbols in each of the cells, and you must select the ninth cell that follows the pattern. I found that most of these puzzles obey one of a few different logical rules. One is translational movement. Then the symbols move from one cell to the next in a predictable manner. The second is the rotation movement. One or more objects rotate from one cell to the next. The third has missing symbols, where in each row or column each symbol appears once.

So, to find out which symbols appear in the final cell, you just have to detect which ones are missing. And the fourth is the sum, where the first cell plus the second cell equals the third cell. In this case, the overlapping lines cancel out, but one line plus nothing equals one line. In most modern intelligence tests, all questions are answered under time pressure. You may only have 10-30 seconds per question. Okay, this morning I'm taking an official IQ test and I have to say I'm pretty nervous. I always want to do well in exams, it's something I pride myself on.

But at the same time, who knows how this is going to end. I'm not allowed to take you there, because obviously people don't want the questions to come to light, and they don't even want a video of what it looks like there. They are very strict about these things. So I'm going to go in, take the test, come out and tell you how it went. Wish me luck. The remarkable thing about IQ tests is that an hour or two of questions about vocabulary, numbers, and arbitrary shapes can predict many things about your life. For one thing, the higher your IQ, the bigger your brain is likely to be.

A large 2005 meta-analysis estimated a correlation of 0.33 between IQ and brain size. So a high IQ is literally a big brain. IQ also predicts school success. In 2007, Scottish psychiatrist Ian Deary measured the IQ of 13,000 11-year-old children. And five years later, when these students completed national school exams, Deary compared their test scores to their IQ. - Their performance on an IQ test when they were 11 was correlated with their performance five years later in GCSEs, around 0.8. That's an extremely high correlation. - It means that about two-thirds of the variation in national school test scores could be predicted by IQ tests taken five years earlier.

Now, the correlation coefficient in this study is at the upper end of the range of 0.2 to 0.8 found in similar studies. But research supports the claim that IQ is a good predictor of school success. It also predicts how much schooling a person will complete. Perhaps this shouldn't be so surprising since some school tests are essentially IQ tests. It has been argued that tests like the SAT, ACT, and GRE are basically IQ tests. They correlate with standard IQ tests at about 0.8. Now, on my SATs I got a score of 1330, which corresponds to an IQ of around 130. So it will be interesting to see if my official IQ score matches that, or if I was able to increase my score by getting familiar. with IQ style questions.

I don't know. But IQ also has predictive power outside of school. One of the strongest findings is that IQ can predict job success. - Particularly in technical or highly complex jobs. -How is work success measured? - You ask people's bosses to rate them. You ask what people's income is. Productivity is measured in the same way that economists use generated output. - Correlations typically range between 0.2 and 0.6, and the effect is more noticeable on more complex jobs, which makes sense. The oldesteffect is for military training. In fact, the US military will not accept anyone with an IQ below 80.

They also limit the number of recruits with an IQ between 81 and 92 to 20%. During the Vietnam War, to increase the number of applicants, they relaxed this last requirement. But what they found was that those who were below the threshold were 1.5 to three times more likely to fail recruit training, and required three to nine times more remedial training. Altogether, this added so much strain that the army functioned more efficiently without additional recruits. In total, 5,478 people recruited under this initiative died with a mortality rate three times higher than that of ordinary recruits. So the military reset its requirements, and today anyone with an IQ below 80, or about 30 million Americans, would be ineligible to join the military.

Even outside the military, IQ appears to influence lifespan. In a Scottish study, scientists discovered IQ tests in children when they were 11 years old. Now, 65 years later, they checked who in the sample was still alive at 76 years old. And they found that, on average, for every 15-point increase on the IQ test, there would be a 27% greater chance of still being alive at that age. 76. A large meta-analysis confirms that people with higher IQs have a lower risk of dying during the period investigated in each study. The last thing that IQ seems to predict is income. This study shows a clear trend for income to increase with IQ and found a correlation coefficient of 0.3.

But the variation is enormous. In fact, the top three earners in this study all had IQs below 100. A large meta-analysis of 31 studies found that the correlation between IQ and income was 0.21. That is significant but small. This means that only 4.4% of the variance in income is explained by IQ. Maybe one of the reasons we don't see as high a correlation for income is simply because economically, intelligence isn't necessarily as rewarded, in the sense that maybe there are jobs, like just doing a real estate type plan, maybe that doesn't require a lot of intelligence. At the same time, there are all these very smart people who may become college professors, but that doesn't necessarily pay them very well. - Yes. - Many people who have very high intelligence scores do not have the same interest in accumulating money. - The relationship with net worth is even weaker.

It hardly seems to correlate with IQ, even though people with higher IQs are supposedly smarter and, on average, make more money each year. But apparently this doesn't translate into saving or accumulating more wealth overall. But if IQ correlates with school performance, job performance, income, and longevity, why don't we hear more about it? Why aren't more people tested? I think it's because IQ has a dark history. When Henry Goddard brought the Binet test to the United States, its use and interpretation changed dramatically. In France, Binet believed that intelligence could be improved through education. He designed the tests so that struggling students could get more help catching up.

But in the United States, the modified test was administered to adults to classify them according to their intelligence. And researchers like Spearman believed that g was immutable, that whatever general intelligence you were born with you would retain for the rest of your life. And many thought that the g was inherited, transmitted from parents to children. Today we would say that it has a genetic basis. There is some evidence to support these claims. IQ seems fairly constant throughout life. - So they did tests when people were 11 years old. They found all that evidence in a filing cabinet and they followed those people and gave them the same test when they were 90 years old, much, much later. - Their scores 80 years apart correlated between 0.5 and 0.6.

There is also evidence of a genetic basis for IQ. - You discover, for example, that if you have two identical twins and you give them an IQ test, they have a very strong correlation. In reality, it's about the same as testing the same person a few weeks apart. -Henry Goddard used claims that intelligence was inherited and immutable to put IQ at the center of the American eugenics movement. Eugenicists wanted to prevent those with undesirable traits from having children. In many states, laws were passed to allow forced sterilization of people who did not meet a certain threshold on an IQ test.

The constitutionality of these laws was confirmed by the Supreme Court in 1927. - Even the words we now use as insults, moron, idiot, imbecile, were used as scientific terms. - In his opinion, Justice Oliver Wendell Holmes wrote: "It would be better for everyone if, instead of waiting to execute their degenerate children for crimes, or let them starve for their imbecility, society could prevent those who are manifestly unfit to continue with their lives. "Three generations of idiots are enough." In total, more than 60,000 people were forcibly sterilized as a result of these laws. In fact, they served as a model for Nazi Germany.

Hitler himself claimed to be inspired by American eugenicists. - They have been used for horrible things in the past. - At the Nuremberg trials after the war, some Nazis cited the US Supreme Court decision. Given this terrible history, I think it's understandable that many people today completely ignore IQ. When it comes to the science of intelligence, there are a number of things that those early researchers got wrong. One is that IQ is not entirely determined by genetics. Can you quantify the effects of genetics versus environment? - When you look at twin studies, on average, over a lifetime, heritability and environment are about 50/50. - It simply cannot, for ethical reasons, be estimated in humans with a reasonable degree of certainty or precision.

Given my reading of that literature, it's a pretty wide range, probably between 40% and 70%. - Well. And since education can improve IQ, it is not completely fixed throughout life. Furthermore, intelligence may not be a single construct as initially imagined. Today, scientists recognize two forms of intelligence, fluid and crystallized. Fluid intelligence is your ability to learn, process information, and solve novel problems. While crystallized intelligence implies the knowledge that you have accumulated throughout your life. Both types of intelligence increase during childhood, but fluid intelligence peaks in early adulthood and then declines. While crystallized intelligence remains more stable. But IQ has been further abused to promote the idea of ​​racial differences in intelligence.

For example, there is a gap between the average IQ of white and black Americans. Articles have also been published on the IQ of different nations of the world. Many of these nations are assumed to have an average IQ below 70. That is the threshold for intellectual disability. How could this be? The conclusion that some draw is that there are genetic differences between races or nations in intelligence. But I think it is a serious misrepresentation of the data. I would say the problem is that IQ tests don't necessarily measure what you think they're measuring. And the proof is that there is a representative sample of white Americans whose average IQ is 70.

Who are these people? Just ordinary Americans who lived about a hundred years ago. Researcher James Flynn studied average IQ test results over the past century, and from time to time the tests are updated and renormalized to keep their average at one hundred. Now, what Flynn noticed was that every time they were renormalized, the scores had to drop a little more, about two or three IQ points per decade. And if they didn't do this, what we would see is that the average IQ of the entire population would increase at a constant rate over the last 100 years, adding up to an increase of about 30 points.

This is known as the Flynn effect. - Were our immediate ancestors on the verge of mental retardation? Because 70 is normally the mental retardation score. Or are we on the verge of all of us being gifted? Because 130 is the cut-off line for giftedness. - Now, population genetics haven't really changed in a hundred years. So what caused the increase? Well, there is some debate about the true causes, but one of them is probably improving childhood nutrition and health. - You know, the height also increased during that period of time. The people got taller and taller and taller. - Another cause is better education. - There is a lot of evidence that school makes you smarter. - You become better at solving problems if you have more knowledge.

Because it's easier for you to make associations if you have more things to make them with. - A third proposed cause is a change in the types of work most people do, from primarily manual work a hundred years ago, to much more abstract thinking today. And that change may have made us better at answering the types of questions asked on IQ tests. Spin again. The thing is, IQ tests seem to objectively measure intelligence, but they don't. Even in the same country, separated only by time, cultural changes can affect average scores on IQ tests. So why shouldn't we expect cultural differences between groups to have the same effect at the same time?

Some tests even go so far as to be labeled as cultural fairs, meaning that the questions should be equally valid for all cultures. But the truth is that it is impossible to develop such a test. That works? - Not well. - No. I mean, that's just a title, right? That's just a marketing term. I don't think there is such a thing as a completely culture-free or culture-fair test. - Culture fair tests assess visual relationships, shapes, and geometric patterns, ignoring the fact that cultures differ, for example, in whether they have words for shapes or spatial relationships. These differences influence how people think about and use categories.

It is also debatable whether cultures without printed materials perceive them the same way we do. What cultural fair tests don't test is ethnobotanical knowledge, training dogs to hunt, or surviving alone in the rainforest. These forms of intelligence are arguably more important to survival than knowing, say, the next number in the sequence. But because they are less common in our culture and we don't have good ways to measure them, we consider IQ puzzles to be the definitive way to quantify intelligence. And the people who do these tests agree. There are strict requirements before a test validated for one population can be used with a very different population.

Even in the limited forms of intelligence that IQ attempts to assess, there are other factors besides g that affect final IQ, such as motivation. How much someone is incentivized to complete the test can have a marked impact on their test score. Many studies have attempted to pay subjects to complete an IQ test. In some studios, they are offered a little, say about a dollar. Other studios offer between $1 and $10. And the real high rollers offer more than $10. A large meta-analysis showed that motivating people in this way increased IQ. And the larger the dollar amount, the larger the average increase.

At the high end, IQ increased by up to 20 points. The effect is greatest for those with below-average IQ. So in addition to g, IQ tests also measure motivation. But the thing do not ends there. They spin. Training and counseling for an IQ test can increase scores by up to eight points. I just completed the test on some random prompt. (mumbles) I can barely talk after that. It seemed fair enough. There were many different sections. The mathematics section in particular,I feel like I killed her. Those questions were easy. I would say that having done the test, I feel like it should be trainable, like you should be able to train someone to do it well.

Test-taking strategy is also important. Some people are simply better than others at taking exams under time pressure. I think the hardest part of the test was the time limits. Looking for the patterns in a number of ways, I mean, it usually takes me a bit of time, so I feel like I didn't finish them. You have to know when to skip questions, how to eliminate clearly wrong answers, and when to guess. Anxiety also plays a role. Apparently, a small amount of anxiety is good, but after a certain point, it negatively affects performance. I guess the overall review is that I think I did well and I think the training really helped me a lot.

That's my prediction. Let's fast forward to the future and see how I

actually

did. I

actually

got my results from the author of the IQ test I

took

. - Those are three areas, three specific areas. - For the math one, for the numbers one, I think that's where I felt very comfortable, and I got there before the time was up and then I was able to go back and look at some things. - Yes. You blew the roof of the quantitative. In the quantitative, it was 143. While in the crystallized intelligence index, it was 132. The fluid intelligence index was 118. - Hmm. - Which is still a score higher than 88.5%. - Not bad.

But I guess it's interesting that that one is significantly lower. - And that's not an unusual difference. Around that concept of g, people have strengths and weaknesses. If we were to look at the best estimate of g for you in this test set. And it would be different if you did a different test. It was at 134, which is higher than 98.8% of the population. - Wow. - I hope you're not disappointed with any of that. - No. I wanted to do it right. I feel like my motivation was high, possibly higher than the average person. So what is IQ for? - My clinical practice now is forensic neuroscience and about 90% of my cases are death penalty cases.

One of the most common problems is what is known as the Atkins defense, named after the US Supreme Court case that eliminated the death penalty for people with intellectual disabilities. - Can't the criminal just pass the IQ test? Can't they just intentionally... No. answer all the questions wrong? - We would know. I mean, we included, just like in the test that you did, there are built-in disability

measures

. It is detected using various mathematical algorithms. We are over 95% accurate in detecting people trying to fake poor performance. - Oh, wow. - One thing we might be interested in doing is increasing people's cognitive ability early in life so that even if they suffer cognitive decline, it takes them longer to get to the point where they have some sort of real functional ability.

Everyday issues where they lose independence, whether it's managing their money or reading labels, whatever it is that people struggle with when they enter later stages of cognitive decline. If we could discover a way to permanently increase people's intelligence, it would be a great help. - Perhaps its best use is to identify people with strong intellectual abilities who otherwise would not have been able to demonstrate them. - Teachers would recommend that a child be placed in the gifted and talented program because they have generally observed that they do well in the classroom. But if you replace that with a standardized test, an IQ test, you find a higher proportion of poorer children and children from minority ethnic backgrounds in the gifted and talented program when you use an IQ test.

And the reason is that you are using an objective measure. You're not just trusting some professor's opinion. Getting into a good school was about who you knew, or who your parents knew, or how much money your parents had, not so much about how you were doing. The idea that one could try to develop an objective measure that would try to eliminate all of those social biases was clearly a well-intentioned idea. - IQ is something with which not only psychology, but the general public has a love-hate relationship. - Tell me about it. - Psychologists hate talking about intelligence and people's intelligence test scores and that sort of thing.

And some parents, when I included intelligence as part of a neuropsychological assessment of their child, said, "Well, yeah, I'd like to know their IQ, but you know, we don't know." I really care about that. What was it?" (both laughing) - And then I think there's also the IQ debate, the extremes on both sides, which I think doesn't help. There's the extreme of people saying this is the most important thing that exists, that people's IQ is a very important factor that we must know about them, and then we can classify them into particular schools, or particular forms of education or whatever.

That is an extreme and I think it is totally unproductive. .But there is another extreme. The other extreme is the kind of blank slate view, which is that these tests are completely useless, they don't tell us anything, that they are just a tool of racism and prejudice, etc. It's wrong. And there's a huge firestorm on both sides going on around it. And the people in the middle are just forgotten, people have more moderate opinions on these types of issues. So I would recommend that people look for more moderate opinions at the. regard. - I think the big mistake is thinking that IQ somehow determines someone's value.

What is much more important, in my opinion, is how you interact with and help the people around you. That's why I think Stephen Hawking said, "People who brag about their IQ are losers." While IQ tells us something, it doesn't tell us what our lives will be like. We have the ability to dramatically improve our results by developing knowledge and analytical skills. And if you're looking for a free and easy way to do it, you should check out the sponsor of this video, shiny.org. With Brilliant, you can master key concepts in everything from data science and math to programming and technology.

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