As an European, I did never have any IQ test, nor I know anybody who (to my knowledge) was ever administered an IQ test. I looked at some fac-simile IQ tests on the internet, expecially Raven's matrices.

When I began to read online blogs from the United States, I started to see references to the concept of IQ. I am very confused by the fact that the IQ score seems to be treated as a stable, intrinsic charachteristic of an individual (like the height or the visual acuity). 

When you costantly practice some task, you usually become better at that task. I imagine that there exists a finite number of ideas required to solve Raven matrices: even when someone invents new Raven matrices for making new IQ tests, he will do so by remixing the ideas used for previous Raven matrices, because -as Cardano said- "there is practically no new idea which one may bring forward"

The IQ score is the result of an exam, much like school grades. But it is generally understood that school grades are influenced by how much effort you put in the preparation for the exam, by how much your family cares for your grades, and so on. I expect school grades to be fairly correlated to income, or to other mesures of "success".

In a hypothetical society in which all children had to learn chess, and being bad at chess was regarded as a shame, I guess that the ELO chess ratings of 17 year olds would be highly correlated with later achievements.  Are IQ tests the only exception to the rule that your grade in an exam is influenced by how much you prepare for that exam? Is there a sense in which IQ is a more "intrinsic" quantity than, for example, the AP exam score, or the ELO chess rating?


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Short answer, yes you can get better at IQ tests by learning the common patterns and practicing the tests. Some people do so, and reach very high IQ scores. But there is essentially no reward for doing this, and thus almost no one bothers to do it. In the absence of practice, IQ is an empirically relatively stable metric which correlates with a number of other empirical outcomes, about as well as anything in the social sciences ever does.

But there is essentially no reward for doing this



Things people want are are not gated by certified IQ scores. Think of jobs, sexual partners, popularity, etc.  Except in extraordinary circumstances there's just no incentive to do better on IQ tests for any reason other than just being smarter.

For the purpose of bragging rights, its easier to just lie about your score than it is "cheat" by prepping for the test.

In the U.S., things people want are no longer gated by IQ scores because the Supreme Court has ruled that doing so violates the Civil Rights Act (Griggs V. Duke Power []).  Prior to 1971 IQ scores were commonly used in hiring decisions; my mother got the highest score her employer had ever seen and was fast-tracked to management.

I heard at local Mensa that there is a guy who keeps coming to take the IQ test every year, and every year he fails to pass the Mensa limit. And he's been doing this at least for a decade.

For me, it is difficult to imagine, because Raven's matrices (the IQ test my local Mensa usually uses) is like the same two or three patterns over and over again. How could anyone take the test twice without noticing this? And if you notice the pattern, then you should get at least 80% of questions right very easily, which probably should be enough to pass the Mensa limit... (read more)

Agreed. I am pretty sure practise can increase IQ scores, but people don't do it.

Well, IQ tests used to be common in assessment centers. I haven't heard about this being still used but if so studying for the test would make sense.

Maybe I am in the minority, but I think that I in my teenage years I would definetely have studied for an IQ test if I had had to take one. 

Let us say that only 1% of people are like me, and the other 99% does not care. With your premises, that 1% would get a very high IQ. This is still a lot of people; is it possible that they are the majority of the people with high IQ? Or do you think that most of the people with IQ > 130 are "natural" (in the sense that scored high without solved made similar exercises before)?

2Teerth Aloke2y
While I would tilt towards the 'natural' option, this question is worthy of some research.
This isn't a case where we need more research.  This is a case where we have over a century of credible data(1) and the strongest theoretical constructs in psychology or any other social science.  We just ignore the answers we have because nobody likes them.  We'd rather believe that effort matters more than genetics. (1) The US military in WWI and WWII tested tens of millions of men from broad swaths of society.  

I love the social sciences, but they tend to tell you more about the people studying them then they do about the actual subjects they study. I'm a believer that much of the data in the Social Sciences would benefit from reexamination using recalibrated metrics, as the political shifts in the world of the last 50 years have caused seismic shifts in the ways data is collected, organized, and interpreted. I've got some ideas of major areas of the Social Sciences which need to be reconsidered, as they have significantly impacted legislation in ways that have c... (read more)

Technically yes. You could increase your score on IQ tests by practicing them. But there is no point to doing so.

Your general intelligence (also known as -factor) matters. IQ is a good metric for general intelligence. IQ is such a good metric for general intelligence that it is often used as shorthand for -factor. IQ matters because it is a measurement of your general intelligence (-factor). You could increase your score on IQ tests by practicing them but that won't increase your general intelligence. It would just cheat the metric. We treat IQ as a stable, intrinsic characteristic because general intelligence is a stable, intrinsic characteristic.

Thank you for your answer, however, the question is not if it is worthy, or useful to practice for IQ test; the question is if it can be done (and, secondarily, how many people do it). 

Usually, the ranking of abilities for a task are well correlated with the amount of practice. There is the rare child prodigy who beats the chess grandmaster, but usually all the people who can beat a chess grandmaster have practiced a lot of chess.

Is IQ special in this respect? Is the majority of people who is extremely good at IQ tests just "naturally" extremely good ... (read more)

Short answer: it's not preparation.  Sure, if you study the answer key of a test, you'll get a better score on that test.  However, there's no known method (including practice) that increases the cognitive ability (Spearman's g factor) that IQ tests measure.  Some IQ tests [] have no behavioral component at all; they just scan your brain and calculate your IQ.   For a solid primer on IQ, I recommend Intelligence: Knowns and Unknowns [].  It's a consensus report of a task force of the American Psychological Association, so it's as credible as anything. Personally, I took an IQ test for toddlers when I was about 3 (my neighbor was a psych grad student who wanted to practice giving the test and my mom wanted a short break from having a toddler). I got a 168 (the limit), surprising my neighbor quite a bit.  I had done about as much test prep as the typical toddler (none, unless Sesame Street counts).  I haven't taken an IQ test since then, but my life experience since then indicates that the test was qualitatively accurate. Some people are naturally good at IQ tests and some people are naturally bad at them, and there's not much a person can do to change their scores (aside from brain damage, of course).  The people who are good at IQ tests have an advantage in any situation where absorbing, remembering, manipulating, and applying information is useful, which is a lot of situations.  The people who aren't have a disadvantage in those situations, and (with our current technology) we have no way to help them.
Thank you, I will look at the paper.
Enjoy.  Keep in mind that it was written 25 years ago.  The findings still hold up, but the paper's forward-looking statements ("this might get better") didn't pan out.

Also, too, one of things g-factor is good for is the ability to learn, and especially the ability to apply previous experience to novel situations. So, the very ability of someone to get better at IQ tests (which when done well are not rote memorization exercises) indicates that there is some "there" there.

I agree that different peoples have different learning curve.  I wonder if perhaps a more appropriate test of "general intelligence" (+ motivation/grit) would be assessing how much you are able to improve in a task, given 1 month to practice. Probably it is hard to make this work, because you could cheat in the first test doing it terribly on purpose.
Maybe if you have to pass a certain level to start, and then you have a bunch of different kinds of things to learn, but each person gets to specialize in what they do/like best so the test covers both breadth and depth of learning. It would probably take a few years, but the administrator could provide some sort of general certificate of intelligence+grit that potential employers and spouses could check without having to administer the test themselves?

Small quibble - general intelligence varies by age, and IQ tests are age-adjusted.  But that's a small clarification of your basic claim, which is supported by the data as I understand it.

You should distinguish between "intelligence as a trait of the brain which we are trying to measure" and "the result of using a specific IQ test". Learning the IQ test is like standing on tiptoes when someone measures your height... yes, you will get a higher result, but you didn't actually grow up, you just cheated the test. You can cheat the IQ test and get a higher score e.g. by learning the right answers, but that doesn't increase your intelligence as such.

(And by the way, please do not take online IQ tests, ever. They are practically all scams. Especially those that say they are endorsed by <whatever organization>; they are not.)

Intelligence is not the same as knowledge or skill. As you get older, you naturally get more knowledge, and you get more skills. And the IQ tests adjust for this; they are calibrated for each age group separately, so a 10 years old would get higher IQ than a 20 years old if both answer correctly 15 out of 20 questions.

In practice, IQ is measured by test (because, how else would you measure it?), and you can cheat by specifically preparing for the test. That increases your test score, but not the underlying intelligence. For example, imagine that someone spends years practicing for one IQ test, and then is unexpectedly given a completely different IQ test. This would probably result in their "true IQ" being revealed.

Shortly, you should imagine intelligence as something like "ability to solve new problems". Of course, there is the technical problem that whenever someone designs a test that measures this ability, people can take the test repeatedly or find the questions and answers online, and then the problems are no longer "new" for them. Yes, this is a problem of tests. It does not make the underlying concept of "ability to solve new problems" invalid.

Raven's matrices are only one example of an IQ test. Performance across a wide range of domains, from pattern recognition to sensory discrimination to knowledge to reaction time is correlated. This widespread pattern of correlations is likely due to the performance on these many domains sharing causes, with the broadly shared causes being called g.

Since g affects your performance on tests, IQ tests to an extent measure g. However, as you point out, you can often just practice a test to become better. This practice will only make you better at that specific test, though; training your pattern recognition skill with matrices will not make you better at distinguishing the weights and colors of objects using your senses. That is, practice doesn't change your g, but instead improves the test-specific skills called s.

Your IQ score is a combination of g and s factors (and other factors too). And it doesn't even exist unless you take an IQ test. So it can't be a stable innate characteristic of an individual. But g - that is, whatever underlies performance across wildly different tests - must exist independently of the tests, as a characteristic of the individual, and empirically it appears reasonably stable in adulthood, and highly genetic.

Roughly speaking, the IQ score measures one's ability to recognize patterns, so it isn't a direct measurement of intelligence per se, but of an ability that correlates strongly with several other abilities that people associate with the much fuzzier concept of intelligence.

If you practice for IQ tests, you're going to become better at detecting the specific kinds of patterns used in IQ tests, but then your IQ score will correlate less with your general pattern-recognition ability, and in turn with those other traits, so at some point your score will stop reflecting your general intelligence.

To increase your intelligence as a whole you'd have to become better at recognizing more and more complex patterns in general, and not only for when you're focusing on problems, but on the automatic, as a passive ability. That would require quite a lot of cerebral plasticity, which is something adults almost universally lack.

Now, having a great pattern recognition, and by extension a high IQ score, by itself, doesn't suffice to say someone is actually intelligent in a broad sense, because when one is very good at detecting very hard-to-perceive patterns (hard to perceive for the majority), they also become very good at detecting patterns that aren't there at all. For example, conspiracy theorists -- the kind who creates conspiracy theories, not mere followers -- are usually very high IQ individuals whose pattern-recognition went in quite wrong directions. Hence, a high IQ is, at best, a very raw measure of one's cognitive potential, more than one's cognitive execution. This one does require training to be turned into something actually able to accomplish great things.

Be as it may, there have been some studies on what does increase the average IQ scores for populations at large. The main factor, above everything else, is better nutrition during infancy. That helps the brain to develop without hindrances, resulting in most of those children, when they grow, being able to recognize much more patterns than peers of theirs who were malnourished in their first years. That one factor cannot be compensated for later in life. And on top of that, access to excellent education in a stable environment during one's formative years also helps with a few extra points.

Finally, it should be noted that the effects of IQ scores are better understood (because easier to study) for lower IQs than for higher IQs. For lower IQs there are lots of correlations with anti-social behavior, criminality, impulsiveness, mental illnesses etc. For higher IQs there are correlations with mathematical prowess and having better incomes, probably because we live in a society that values professions requiring pattern recognition (engineering, law, finance, programming, anything requiring complex strategizing etc.), but not much beyond that.

Thank you for your answer!

If you practice for IQ tests, you're going to become better at detecting the specific kinds of patterns used in IQ tests, but then your IQ score will correlate less with your general pattern-recognition ability, and in turn with those other traits, so at some point your score will stop reflecting your general intelligence. [...]

Are you sure of this? Maybe the sort of people who are motivated to get an high score in a IQ test are the same sort of people who are motivated to get good grades in the college, who work harder to advance... (read more)

A and B are only different if "motivation" is not an innate factor. But what else would it be? Is it even an actual thing, or just a name for a phenomenon, masquerading as an explanation of the phenomenon?
(A) and (B) make different predictions. If (B) is true, people with high IQ will not be particularly good at a new task when they try it for the first time - but then they would improve by application. If (A) is true, people with high IQ will be immediately good at new cognitive tasks (or, at least, much better than people with low IQ).
This is essentially proposing a correlation between intelligence and conscientiousness. But from my reading they appear to be mostly uncorrelated.
Yes. It measures an intrinsic ability, not a learned skill. I'll make an analogy: Suppose there was an "athletic ability" measurement score calibrated so that it can gauge, via a set of physical tests, the athletic potential of individuals. It's devised so that a population with no specific training can take it, and the result correlates with, for example, how fast a person will be able to run if they dedicate themselves to short range training full time. This limit, notice, is genetic. Your genes determine the structure and interconnection of your skeleton, muscles, nerves etc. and how well they all respond to diet, training regimen, stimulants, and other external factors. Hence, every person will have a range of running speed that goes from their speed when running without any specific training, let's call this speed A, all the way up to their maximum genetically determined potential, let's call this speed B. The "athletic ability" scoring then, taking into account several factors tested, including your current, untrained running speed, will give you a number that, when you look at a table constructed after test with thousands of other individuals, show that your maximum speed, if you dedicate yourself completely to developing your running potential, will be B. Now, suppose an individual, for some reason, trains day and night at short range running before taking the "athletic ability" test. Maybe they're a teen with parents who insist they excel at the test due to, let's say, the potential to get tuition fee reductions in college. Or maybe they have a parent who's an running champion and they want to impress them, be up to their standards, or whatever. They thus decide to look at how the test is applied, does everything to nail it, and so, when the day comes, they take the test -- in which, among other things, they run at their current speed P --, and as a result obtain a much higher score than they would have gotten otherwise. According this score, when they
Here you are supposing that everyone does the same amount of preparation; otherwise, recalibrating the score would not be enough. I think that this is the main point: does everyone prepare the same amount for IQ tests?
AFAIK, most don't prepare at all since there isn't much at stake. Very few companies hire based on high IQ, when they do it's usually because the problems the employee will have to deal with are highly mathematical and/or logical in nature and a person with a low (real) IQ would do really poorly in that, and in any case they still require candidates to have specific skills, which are more determinant than the IQ. And when such companies do take IQ in consideration, they usually do so not by requiring an official score, but by making candidates go through aptitude tests and puzzles, then checking how they scored in those. Very few go for a fully certified score, and when they do, they have requirements such that they may well also require a full personality evaluation, meaning a full Big 5 assessment. On the flip side, there are jobs that have a maximum IQ score requirement, and don't hire people above that, the reasoning being that anyone with an IQ higher than that would get utterly bored at that job and leave it on the first opportunity, thus wasting the company's time and training investment. So they provide a test and if you get too good a score on it you're let go. Hence, if one were to try gaming the score, one would either end up in a job with such extreme mathematical and logical thinking requirements they would end up constantly mentally exhausted and leave, unable to cope with spending so much mental energy (and this is measurable, brain scans of high IQ individuals show their brains do very energy expenditure when dealing with complex tasks that, for average IQ individuals, cause their brains to flare up in a storm of long, constant, intense activity). Or, on the other extreme, would put them in a job with such low requirements for their abilities that it'd make them feel miserable until they in fact jumped ship for something more stimulating. Now, one important thing to keep in mind is that IQ scores aren't absolute values, they're relative values ba
The shape is perceptibly different from a Gaussian (at least in the distributions that I found googling "empirical distribution of IQ" and similar keywords). This is not surprising, because almost nothing in Nature is an ideal Gaussian.
Not really. Currently IQ distribution is defined as a Gaussian, so if tests are made correctly and the proper transformation is applied the shape of the curve, for a large enough population, will literally be a Gaussian "by definition". Check this answer on Stack Exchange for details and references: * Wood [], Why are IQ test results normally distributed?, URL (version: 2019-12-23) [] Now, evidently, for smaller sub-samples of the population the shape will vary.
It's designed to be a normal distribution, but actual implementations don't work out exactly that way.  For starters, the distribution is skewed rightward because brain damage is a thing and brain augmentation isn't (yet).
I would avoid athletic metaphors for IQ.  People naturally tend to assume brains work like muscles.  Muscles get stronger with exercise.  Brains do not get smarter with "exercise" (study/puzzles/classes/etc).  The data is clear - it just doesn't work that way.

A lot of actor's have children that grow up to be actors because they hung out with actors growing up. A lot of politicians have children who grow up to be politicians because they hung out with politicians growing up. A lot of ex-convicts have children that grow up to be ex-convicts because they hung out with ex-convicts growing up. Access to resources, or lack of them, seem to have a huge impact on human potential. I often wonder how many of our characteristics are truly innate, and not just learned or trained. Nature or Nurture? An argument for nature undercuts the idea that education and good opportunities should be made available to everyone. 

In the case of IQ this has been well established. There's some variance due to nurture, but the bulk of it is nature. For example, very young children adopted by high IQ couples, and raised with a focus on intellectual matters, still demonstrate an IQ much closer to that of their lower-IQ biological mother than to that of their adoptive parents. This isn't to say that being raised by high IQ parents has no consequences. These children learn several personal and cultural skills in an environment that nurtures their abilities, and therefore manage to, for example, obtain a bachelor's degree with a much higher likelihood than average for for their origin groups, meaning their Big 5 "Conscientiousness" trait did grow remarkably. In terms of their raw IQ, though, other than the increase due to better nutrition, no, nurture has no effect, unfortunately. Not really. And "is" doesn't determine an "ought". It can easily be argued, to the contrary, that precisely because low IQ individuals need more institutional support compared to high IQ individuals, they should receive a much better tailored education and much better vocational opportunities, as high IQ individuals are much more likely to solve what they need solved on their own without, or with bare minimum, external aid.
And "is" doesn't determine an "ought". That's not entirely true.  Whether or not something "is" known to work or to fail often determines whether you "ought" to do it. The IQ research cuts against the grain of our culture's belief in equality and hard work, so nobody really likes it and even mentioning IQ in many contexts is socially dangerous.  However, the IQ research is generally considered to be the strongest and most conclusive body of evidence in the social sciences.  Trying to equalize the effects of IQ using education doesn't work [].
Not at all. Knowing that doing X causes Y only informs that if you want result Y, the way to achieve that is by doing X. It doesn't tell you whether Y is desirable or not. Hence, if a society wants maximum productive efficiency, and allocating more resources to their most intelligent members is the most effective way to achieve that, then yes, allocating more resources for them, and less for less gifted individuals, is the way to go. On the flip side, if a society wants, let's say, to maximize equality of outcomes among its members, then they'll completely ignore that means, and look for the method that will provide that outcome. The decision about the "ought", then, is what truly determines which "is" will be chosen, not the other way around.
That's true, but in the actual case society(1) wants to maximize equality of outcomes among its members, and we've spent decades looking for a method that will provide that outcome, and nothing we've come up with works(2).  You might think we "ought" to be doing that, but the judgement is now between "we should continue to pursue this value, knowing that it's never worked before and we have no reason to believe that it will start working any time soon" and "we should pursue other values that seem to be achievable" - which is a very different judgement. (1) or the segment thereof that controls education policy (2) There are a lot of marginal claims of questionable statistical and practical significance that never seem to scale up, but "nothing works" [] is a reasonable summary.

There are three components:

  1. Practice with the test improves scores, but only to a point
  2. Working on brain improving activities, especially age 0-3, and 3-25, but somewhat at any point will make your brain work better
  3. There is a huge genetic component to people's maximum possible score, after 1 & 2, as well as their baseline score before 1 & 2, and how well #2 works.

Interesting, can you direct me to some scientific papers which prove conclusions (1) and (3)?

(I already believe (2))

Sadly, I can only share the synthesized results of years of reading - I don't keep track of where my ideas come from (though I do try to avoid known-bad sources) #1 is seen with SAT scores - taking the test a second time / taking a prep course improves the median student's score by ~10 percentage points. I (and others) attribute this to improvements in the "IQ test taking ability" portion of the SAT, not the "have memorized vocabulary and rules of math" portion. #3 is clearly seen in results from twin studies, adoption studies, and just looking at the world (ie we see a wider range in "ability to do things we would predict high IQ people to be better at" among people with similar childhoods than we do among people with dis-similar childhoods in extended families.
1Phil Scadden2y
Just stick "heritability of intelligence" in I have only had experience of intelligence tests on 4-6 six year olds. Quite a few dimensions to the test - but nothing that would have been practiced at home. A very limited sample, but the resultant ranking fitted my pre-determinations in terms of general problem solving abilities.

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