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All That Matters
Intelligence: All That Matters by Stuart Ritchie
There is a strange disconnect between the scientific consensus and the public mind on intelligence testing. Just mention IQ testing in polite company, and you'll sternly be informed that IQ tests don't measure anything "real", and only reflect how good you are at doing IQ tests; that they ignore important traits like "emotional intelligence" and "multiple intelligences"; and that those who are interested in IQ testing must be elitists, or maybe something more sinister.Yet the scientific evidence is IQ tests are extraordinarily useful. IQ scores are related to a huge variety of important life outcomes like educational success, income, and even life expectancy, and biological studies have shown they are genetically influenced and linked to measures of the brain. Studies of intelligence and IQ are regularly published in the world's top scientific journals.This book will offer an entertaining introduction to the state of the art in intelligence and IQ, and will show how we have arrived at what we know from a century's research. It will engage head-on with many of the criticisms of IQ testing by describing the latest high-quality scientific research, but will not be a simple point-by-point it will make a positive case for IQ research, focusing on the potential benefits for society that a better understanding of intelligence can bring.
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First published June 18, 2015
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About the author
Stuart Ritchie
5 books71 followersStuart James Ritchie is a Scottish psychologist and science communicator known for his research in human intelligence. He has served as a lecturer at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London since the summer of 2018.
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March 27, 2017
Picture now, with me, a very-slightly-alternate universe.
In this other universe, most things are just as they are in ours. Humans themselves are no different. But the other universe differs from ours in one respect -- the way that its scientists conceive of physical fitness.
In our universe, we know -- in a casual, non-scientific (if not unscientific) way -- that there is such a thing as physical fitness. Some people are more fit than others. We recognize different levels of fitness, and refer to them in conversation. And we know that there is biology behind this notion. The body is a set of interconnected systems, and improvements in the functioning of one will often spill over into improvements in the functioning of the others. Thus, it makes some biological sense to speak of a person's "general" or "all-around" fitness, without getting into specifics like how much weight they can lift, how fast they can run and how far. But we know, too, that a full biological account would pull apart this general concept into distinct systems and performance measures, able to vary independently from one another: VO2max and vV02max, stroke volume and heart rate, myofibril growth and sarcoplasm growth, and so forth. Scientists, for their part, concern themselves almost wholly with these details; they do not deny that one could build a picture of "general fitness" by summing all the details together, but they have not built such a theory, and (I imagine) would not really see the use of building one.
In the other universe, scientific theory took a different course. In the early twentieth century -- when many of the biological details were, in fact, understood poorly or not at all -- physical performance was studied from a purely statistical perspective, by measuring it (how much can this person lift? how far can they run?) and computing distributions and correlations. The statisticians discovered something which was either remarkable or obvious, depending on how you looked at it -- perhaps both. They discovered that all measurements of physical performance were positively correlated in the population.
That is: suppose one takes a large number of people, sampled representatively from the population, and gives a battery of tests, measuring things like "how much can this person lift?" and "how far can they run?" Then, across the entire sample, being good at any one physical task will be associated with being good at all the others. Those who can lift more can, on average, can also run further, and run faster. Those with stronger arms have, on average, stronger legs. And so on, for every pair of tests you could conceive. Of course, there are individuals who are very good at some tests but very bad at others, but this "washes out" when one averages over the whole population, always leaving a positive correlation behind.
On one level, this is not surprising. It accords with our intuitive notion of "general fitness," for one thing. And it is not hard to imagine how these population-level trends might emerge from things we all know. Some people like exercise and some do not; some people have illnesses or jobs or lifestyles that bind them to a bed or chair all day, where all their systems atrophy simultaneously; some people play team sports, which tend to develop a number of (aerobic and anaerobic) capacities at once; and on and on.
The statisticians, however, saw this as a stunning scientific discovery. And not without reason. Intuition suggests that performance on physical tests would tend to correlate, but it was downright eerie how every single pair of tests correlated positively with one another. This result held up despite the heroic efforts, by some statisticians, to contrive tests which wouldn't correlate positively with all the others. And we must remember, too, that these statisticians were working before there was a detailed biological understanding of the body's various distinct systems. It was plausible at the time -- indeed, the result seemed to actively suggest -- that there might be a single biological thing, a sort of "fitness fluid" circulating in the body perhaps, which alone explained the correlations, and which would vindicate in a precise sense the conventional notion of "general fitness."
In any event, the alternate-universe statisticians began to speak of "general fitness" very seriously. They called it "f" for short, and defined it in terms of the positive correlations, in a way that was perfectly natural mathematically. Tests that correlated especially well with all the others were said to be especially good measures of "f." If one gave a person a whole battery of tests, one could estimate their "f" quite well. A suitably scaled version of "f" was dubbed the "FQ," or "Fitness Quotient"; you could be tested, and discover yours. (The population average was 100, by definition; professional athletes almost always exceeded 130.)
What's more, "f" could be correlated with all sorts of other things, too. It turns out that "f" was highly associated (in the population-wide-correlation sense) with success in many, perhaps all areas of life. One could come up with mundane explanations for this fact -- that various illnesses decreased "f" and also made it harder to succeed, that "f" correlated with height and lack of obesity and other things that made positive impressions in job interviews and the like, etc. -- but the fact remained.
This being the early 20th century, eugenicists were all over this stuff, and this gave Fitness Research (the study of "f") a stigma which it later could not shake. Prominent Fitness Researchers these days find this very frustrating. Their field has so much to offer, explains so much. They are not eugenicists, not now. They just have many amazing correlations to tell you about.
Meanwhile (still in the alternate universe), biology and physiology developed much as they did in our universe, and quite independently from the field of Fitness Research. As biology discovered the Krebs and Cori cycles, as physiology delved into the various ways the heart and muscles and nervous system adapted to exercise, the Fitness Researchers asked excitedly whether this or that molecule, this or that process, might be the biological substrate of "f," the key linking their field to these others. But it was never that simple. On the statistical level, there were the positive correlations, yielding the gloriously simple "f"; on the biological level, there were a mess of distinct but related processes, none of which looked like "f" when taken alone.
This, of course, does nothing to undermine the existence of the positive correlations. They remain untarnished, even in the year Alterna-2017. And the Fitness Researchers are frustrated that the public is so disdainful of their field. They can take a battery of tests and predict so much from it -- and people turn them away, saying that "general fitness" is a simplistic myth.
In a mood of outraged chutzpah, one Fitness Researcher decides to write a short book for a public audience, with the audacious title "Fitness: All That Matters" . . .
•
This has all been, obviously, a heavy-handed analogy for the history and content of intelligence research.
The cases of fitness and intelligence are admittedly distinct. I don't actually know that all fitness tests are positively correlated -- it just seems prima facie plausible. But the fact that all tests of intelligence are positively correlated is the entire basis for the field of intelligence research, for IQ and "g" (the equivalent of "f"). If we did find that all fitness tests were positively correlated -- and like I said, it wouldn't be too surprising -- then we could immediately construct an entire field of "fitness research" on the exact model of intelligence research, and it would look like the picture painted above. It may in fact be a historical accident that we have, in the real world, one of these fields and not the other.
Well, okay, there is another key difference, and it probably explains why we don't have "Fitness Research." Fitness is quite obviously trainable (although not always as trainable as we imagine -- cf. all of the "actually, losing weight long-term is almost impossible" studies, and the "aerobic exercise doesn't help you lose weight" ones). And it is plainly apparent that training one aspect of fitness does not magically improve all the others. If you go the gym and lift things with your arms, this will make your arms strong; it will not make your legs strong, or make you a fast runner. Because one can actually do such things -- many people do -- it is obvious from direct experience that "general fitness" is not a natural category, not a concept that maps naturally onto the way the body actually works. It is, at most, a useful statistical shorthand for the differences between bodies, in some zoomed-out, averaged sense.
Statistical shorthands can be quite useful indeed. They can sum up the variation in a population in a descriptive sense, and this can be essential for a clear understanding of the population, even if they have no relation to any of the individual-level physical mechanics, or only a cartoonish relation, not to be taken literally. (Cf. statistical mechanics in physics.) A variable called "general fitness" might well do a very good job of summing up how the population varies in its performance on physical tests. But it would not be much of a scientific discovery. The man on the street already knows about "general fitness," intuitively; and he also knows that there is more to the story than that. An account of human physical performance that only includes "f," the general factor, will say strictly less than what the man on the street knows. To insist that we throw away our intuition, and replace it with an "f"-only theory of fitness, is to move backwards.
Anyway, about the actual book: I read it months ago and don't remember very much about it. I remember that it did a decent job of arguing against some actual common misconceptions about intelligence research. But I also remember -- I was thinking about this as I read it -- that it said nothing at all that would not apply just as well to the hypothetical field of "Fitness Research" and its "f."
In this other universe, most things are just as they are in ours. Humans themselves are no different. But the other universe differs from ours in one respect -- the way that its scientists conceive of physical fitness.
In our universe, we know -- in a casual, non-scientific (if not unscientific) way -- that there is such a thing as physical fitness. Some people are more fit than others. We recognize different levels of fitness, and refer to them in conversation. And we know that there is biology behind this notion. The body is a set of interconnected systems, and improvements in the functioning of one will often spill over into improvements in the functioning of the others. Thus, it makes some biological sense to speak of a person's "general" or "all-around" fitness, without getting into specifics like how much weight they can lift, how fast they can run and how far. But we know, too, that a full biological account would pull apart this general concept into distinct systems and performance measures, able to vary independently from one another: VO2max and vV02max, stroke volume and heart rate, myofibril growth and sarcoplasm growth, and so forth. Scientists, for their part, concern themselves almost wholly with these details; they do not deny that one could build a picture of "general fitness" by summing all the details together, but they have not built such a theory, and (I imagine) would not really see the use of building one.
In the other universe, scientific theory took a different course. In the early twentieth century -- when many of the biological details were, in fact, understood poorly or not at all -- physical performance was studied from a purely statistical perspective, by measuring it (how much can this person lift? how far can they run?) and computing distributions and correlations. The statisticians discovered something which was either remarkable or obvious, depending on how you looked at it -- perhaps both. They discovered that all measurements of physical performance were positively correlated in the population.
That is: suppose one takes a large number of people, sampled representatively from the population, and gives a battery of tests, measuring things like "how much can this person lift?" and "how far can they run?" Then, across the entire sample, being good at any one physical task will be associated with being good at all the others. Those who can lift more can, on average, can also run further, and run faster. Those with stronger arms have, on average, stronger legs. And so on, for every pair of tests you could conceive. Of course, there are individuals who are very good at some tests but very bad at others, but this "washes out" when one averages over the whole population, always leaving a positive correlation behind.
On one level, this is not surprising. It accords with our intuitive notion of "general fitness," for one thing. And it is not hard to imagine how these population-level trends might emerge from things we all know. Some people like exercise and some do not; some people have illnesses or jobs or lifestyles that bind them to a bed or chair all day, where all their systems atrophy simultaneously; some people play team sports, which tend to develop a number of (aerobic and anaerobic) capacities at once; and on and on.
The statisticians, however, saw this as a stunning scientific discovery. And not without reason. Intuition suggests that performance on physical tests would tend to correlate, but it was downright eerie how every single pair of tests correlated positively with one another. This result held up despite the heroic efforts, by some statisticians, to contrive tests which wouldn't correlate positively with all the others. And we must remember, too, that these statisticians were working before there was a detailed biological understanding of the body's various distinct systems. It was plausible at the time -- indeed, the result seemed to actively suggest -- that there might be a single biological thing, a sort of "fitness fluid" circulating in the body perhaps, which alone explained the correlations, and which would vindicate in a precise sense the conventional notion of "general fitness."
In any event, the alternate-universe statisticians began to speak of "general fitness" very seriously. They called it "f" for short, and defined it in terms of the positive correlations, in a way that was perfectly natural mathematically. Tests that correlated especially well with all the others were said to be especially good measures of "f." If one gave a person a whole battery of tests, one could estimate their "f" quite well. A suitably scaled version of "f" was dubbed the "FQ," or "Fitness Quotient"; you could be tested, and discover yours. (The population average was 100, by definition; professional athletes almost always exceeded 130.)
What's more, "f" could be correlated with all sorts of other things, too. It turns out that "f" was highly associated (in the population-wide-correlation sense) with success in many, perhaps all areas of life. One could come up with mundane explanations for this fact -- that various illnesses decreased "f" and also made it harder to succeed, that "f" correlated with height and lack of obesity and other things that made positive impressions in job interviews and the like, etc. -- but the fact remained.
This being the early 20th century, eugenicists were all over this stuff, and this gave Fitness Research (the study of "f") a stigma which it later could not shake. Prominent Fitness Researchers these days find this very frustrating. Their field has so much to offer, explains so much. They are not eugenicists, not now. They just have many amazing correlations to tell you about.
Meanwhile (still in the alternate universe), biology and physiology developed much as they did in our universe, and quite independently from the field of Fitness Research. As biology discovered the Krebs and Cori cycles, as physiology delved into the various ways the heart and muscles and nervous system adapted to exercise, the Fitness Researchers asked excitedly whether this or that molecule, this or that process, might be the biological substrate of "f," the key linking their field to these others. But it was never that simple. On the statistical level, there were the positive correlations, yielding the gloriously simple "f"; on the biological level, there were a mess of distinct but related processes, none of which looked like "f" when taken alone.
This, of course, does nothing to undermine the existence of the positive correlations. They remain untarnished, even in the year Alterna-2017. And the Fitness Researchers are frustrated that the public is so disdainful of their field. They can take a battery of tests and predict so much from it -- and people turn them away, saying that "general fitness" is a simplistic myth.
In a mood of outraged chutzpah, one Fitness Researcher decides to write a short book for a public audience, with the audacious title "Fitness: All That Matters" . . .
•
This has all been, obviously, a heavy-handed analogy for the history and content of intelligence research.
The cases of fitness and intelligence are admittedly distinct. I don't actually know that all fitness tests are positively correlated -- it just seems prima facie plausible. But the fact that all tests of intelligence are positively correlated is the entire basis for the field of intelligence research, for IQ and "g" (the equivalent of "f"). If we did find that all fitness tests were positively correlated -- and like I said, it wouldn't be too surprising -- then we could immediately construct an entire field of "fitness research" on the exact model of intelligence research, and it would look like the picture painted above. It may in fact be a historical accident that we have, in the real world, one of these fields and not the other.
Well, okay, there is another key difference, and it probably explains why we don't have "Fitness Research." Fitness is quite obviously trainable (although not always as trainable as we imagine -- cf. all of the "actually, losing weight long-term is almost impossible" studies, and the "aerobic exercise doesn't help you lose weight" ones). And it is plainly apparent that training one aspect of fitness does not magically improve all the others. If you go the gym and lift things with your arms, this will make your arms strong; it will not make your legs strong, or make you a fast runner. Because one can actually do such things -- many people do -- it is obvious from direct experience that "general fitness" is not a natural category, not a concept that maps naturally onto the way the body actually works. It is, at most, a useful statistical shorthand for the differences between bodies, in some zoomed-out, averaged sense.
Statistical shorthands can be quite useful indeed. They can sum up the variation in a population in a descriptive sense, and this can be essential for a clear understanding of the population, even if they have no relation to any of the individual-level physical mechanics, or only a cartoonish relation, not to be taken literally. (Cf. statistical mechanics in physics.) A variable called "general fitness" might well do a very good job of summing up how the population varies in its performance on physical tests. But it would not be much of a scientific discovery. The man on the street already knows about "general fitness," intuitively; and he also knows that there is more to the story than that. An account of human physical performance that only includes "f," the general factor, will say strictly less than what the man on the street knows. To insist that we throw away our intuition, and replace it with an "f"-only theory of fitness, is to move backwards.
Anyway, about the actual book: I read it months ago and don't remember very much about it. I remember that it did a decent job of arguing against some actual common misconceptions about intelligence research. But I also remember -- I was thinking about this as I read it -- that it said nothing at all that would not apply just as well to the hypothetical field of "Fitness Research" and its "f."
August 4, 2016
The general verdict is that it is probably the best go to book for introducing someone to intelligence and related research now. It's somewhat better than Deary's similar, but somewhat dated (2001) book, and it's less technical than Gottfredson's great 1997 article, and much shorter than The Bell Curve, which is also notably dated by now.
Full review here: http://emilkirkegaard.dk/en/?p=6122
Full review here: http://emilkirkegaard.dk/en/?p=6122
July 13, 2020
Calm empirical overview. Incredibly clearly written, stopping short of off-puttingly plain.
Is the g theory of intelligence the most mature, replicated theory in psychology? 100 years old and ever-replicating; language- and culture-blind by now; at least somewhat predictive of some terminal values... What can compete? Operant conditioning, I guess.
This book is part of the "All that Matters" series - a coincidental subtitle which has no doubt enraged many people and caused him no end of grief.
I highly recommend his Twitter.
Is the g theory of intelligence the most mature, replicated theory in psychology? 100 years old and ever-replicating; language- and culture-blind by now; at least somewhat predictive of some terminal values... What can compete? Operant conditioning, I guess.
This book is part of the "All that Matters" series - a coincidental subtitle which has no doubt enraged many people and caused him no end of grief.
I highly recommend his Twitter.
April 11, 2020
Pro: Good and very compact overview of intelligence and what we know about it. It's very basic and only mentions the facts and sources. No long discussions or extra facts on all the different areas. All areas except race are covered. So it's a great introduction to intelligence that everyone should read. Even though it skips a whole area of the science.
Con: Not always interesting to read it but for the interesting knowledge in it. No personal stories about the author, no funny anecdotes or wordplays and no funny pictures. It describes the basics and feels like reading a Wikipedia article on intelligence. It feels longer than it actually is. A reedited version should try to illustrate all the points in colorful graphs and pictures. Words are often not enough to fully educate people.
The missing race discussion is a huge hole. He knows about the science in the area because several of the books he says are good reads on the subject are also about race... all good intelligence books are. But he says the area is too controversial and therefore we should avoid it or just call it controversial and not discuss it. I have seen this emotional argument in other books. Similarly in "Anthropology for Dummies" the author avoided the topic of sex differences because he claims it was too controversial a topic to write about - so he just avoided studying it altogether. I get where they come from. They could include the science on race and sex differences and then might be fired or lose some of their friends. Or maybe they just don't want novice readers talking about these things or even thinking about them? They might think that some topics are so controversial that laymen are not intelligent enough to handle them? It's understandable that they only want to write about the other less controversial topics. But it also leaves us with books that are informative but lacking. And as it is already not an engaging read I would not call it the definitive introduction to g factor. Read it anyway though. It's very informative.
Con: Not always interesting to read it but for the interesting knowledge in it. No personal stories about the author, no funny anecdotes or wordplays and no funny pictures. It describes the basics and feels like reading a Wikipedia article on intelligence. It feels longer than it actually is. A reedited version should try to illustrate all the points in colorful graphs and pictures. Words are often not enough to fully educate people.
The missing race discussion is a huge hole. He knows about the science in the area because several of the books he says are good reads on the subject are also about race... all good intelligence books are. But he says the area is too controversial and therefore we should avoid it or just call it controversial and not discuss it. I have seen this emotional argument in other books. Similarly in "Anthropology for Dummies" the author avoided the topic of sex differences because he claims it was too controversial a topic to write about - so he just avoided studying it altogether. I get where they come from. They could include the science on race and sex differences and then might be fired or lose some of their friends. Or maybe they just don't want novice readers talking about these things or even thinking about them? They might think that some topics are so controversial that laymen are not intelligent enough to handle them? It's understandable that they only want to write about the other less controversial topics. But it also leaves us with books that are informative but lacking. And as it is already not an engaging read I would not call it the definitive introduction to g factor. Read it anyway though. It's very informative.
May 13, 2022
This is a very clear, informative, and readable overview of the topic of IQ. Having already had a good familiarity with the data, I unfortunately learned very little new— If intelligence and its measurement is a subject you’ve never really delved into then I wouldn’t hesitate to recommend this book. If you’re already aware of the basics of what is currently known, though, maybe look elsewhere.
August 5, 2019
I am of a generation where skepticism over IQ was widespread. I don't know where it comes from exactly but I know that it is everywhere. Essentially I was raised with the idea that IQ had been "debunked". The reason I read this book is because I got into an argument with someone and afterwards I did some googling and saw that i appeared to be completely wrong. I saw an article by Ritchie about this topic and then found my way to this book.
So, first, about that subtitle: at no point does the book claim that intelligence is All That Matters so I sort of figured it's the name of the book series. But it doesn't appear to be. You can ignore the subtitle.
This book is a summary of the evidence for intelligence as a measurable fact of human existence (whether it be the IQ score or the "g-factor"). There appears to be an absolute ton of evidence and the book makes as compelling a case as it can that the evidence is there that IQ scores matter and that they genes play approximately 50% of the role in how smart anyone of us is. From the evidence Ritchie presents it seems this is correct (or as close to correct as we can currently be) and that the ideas that IQ "doesn't measure anything" or "measures privilege" or "only measures social" class (etc.) are nonsense.
But my biggest problem with this book is that it is (intended as) a cursory introduction t to the topic. Ritchie spends a couple sentences on what a psychological paper might spend its entirety on. I'm not saying I want to read every psychological paper on IQ in order to buy the argument, but rather that there is a happy medium between reading every paper and reading a 115 page summary (with huge font) and this isn't it. So many times I had questions about a particular study or claim or interpretation of a result but there was no space for it. I suspect Ritchie or his sources have the answers but they are not in this book.
The book does provide a ton of further reading suggestions, which is appreciated. But I wanted to read a more detailed book about the topic and did not realize I was getting a Teach Yourself summary this cursory. So while I want to recommend that all of us skeptics read up on this topic, I'm not sure this book is one I should recommend because it's so brief and lacks detail.
So, first, about that subtitle: at no point does the book claim that intelligence is All That Matters so I sort of figured it's the name of the book series. But it doesn't appear to be. You can ignore the subtitle.
This book is a summary of the evidence for intelligence as a measurable fact of human existence (whether it be the IQ score or the "g-factor"). There appears to be an absolute ton of evidence and the book makes as compelling a case as it can that the evidence is there that IQ scores matter and that they genes play approximately 50% of the role in how smart anyone of us is. From the evidence Ritchie presents it seems this is correct (or as close to correct as we can currently be) and that the ideas that IQ "doesn't measure anything" or "measures privilege" or "only measures social" class (etc.) are nonsense.
But my biggest problem with this book is that it is (intended as) a cursory introduction t to the topic. Ritchie spends a couple sentences on what a psychological paper might spend its entirety on. I'm not saying I want to read every psychological paper on IQ in order to buy the argument, but rather that there is a happy medium between reading every paper and reading a 115 page summary (with huge font) and this isn't it. So many times I had questions about a particular study or claim or interpretation of a result but there was no space for it. I suspect Ritchie or his sources have the answers but they are not in this book.
The book does provide a ton of further reading suggestions, which is appreciated. But I wanted to read a more detailed book about the topic and did not realize I was getting a Teach Yourself summary this cursory. So while I want to recommend that all of us skeptics read up on this topic, I'm not sure this book is one I should recommend because it's so brief and lacks detail.
July 6, 2020
Short and sweet, with an impressive collection of references at the end. There are very few surprises in this book, but it's well-written and it's a useful map which points in the right direction to learn more about any of the topics discussed.
I talk down a lot of books for being much longer than they needed to be so it's only fair that I mention this book is exactly as long as it needs to be, it's been shrunk down to a little nugget of knowledge you can read in an afternoon.
I talk down a lot of books for being much longer than they needed to be so it's only fair that I mention this book is exactly as long as it needs to be, it's been shrunk down to a little nugget of knowledge you can read in an afternoon.
April 9, 2018
Super short book about Intelligence and IQ tests, very well organized, well written. I’m not convinced it tells the whole story, but it seems like a good summary. I’d like to see a bigger more detailed version of the book, published by a mainstream publisher, so I could also read critical/thoughtful reviews.
July 20, 2022
La inteligencia es uno de los atributos que nos define como especie. Este es un libro pequeño, pero no dejes que eso te engañe: es fascinante y muy científico. Y quién mejor que Stuart Ritchie para hablar de la inteligencia de forma científica y escéptica.
Para mí, Ritchie es uno de los mejores pensadores científicos que existen, y aquí realiza una excelente investigación para explicar la inteligencia, la historia del campo para medir el coeficiente intelectual, sus formas de medirla y aumentarla, sus mitos, su biología y sus efectos ambientales, sus aplicaciones prácticas y mucho más. Hay muchos libros gigantescos que hablan de la inteligencia, y Stuart Ritchie te lo resume todo, lo más importante y necesario de conocer, en menos de 200 páginas. Es una gran introducción a la investigación sobre la inteligencia y el coeficiente intelectual, y por qué es importante.
Para mí, Ritchie es uno de los mejores pensadores científicos que existen, y aquí realiza una excelente investigación para explicar la inteligencia, la historia del campo para medir el coeficiente intelectual, sus formas de medirla y aumentarla, sus mitos, su biología y sus efectos ambientales, sus aplicaciones prácticas y mucho más. Hay muchos libros gigantescos que hablan de la inteligencia, y Stuart Ritchie te lo resume todo, lo más importante y necesario de conocer, en menos de 200 páginas. Es una gran introducción a la investigación sobre la inteligencia y el coeficiente intelectual, y por qué es importante.
July 2, 2017
A good short intro to research on intelligence and influence of various factors like genetics and education.
March 18, 2019
A bit too celebratory of social stratification based on innate qualities.
May 31, 2019
It's a quick, interesting read. I've found myself estimating the IQ of people around me since reading it; though I'm not sure that's necessarily good for me or my relationships. Nevertheless, it's fun, and I wouldn't be doing it if I hadn't read this book. Give it a go, it will only take an hour or two, and you'll probably come away knowing a thing or two.
September 25, 2022
Short and concise, useful overview of IQ and intelligence research.
May 8, 2024
Well written for the general audience. More facts not the answers. almost a decade now this was written.
December 29, 2020
A short primer on what IQ is, how it is measured, and its history. This a very nice, compact summary of the field circa 2015. It presents the ideas clearly and simply, with plenty of sources (including further books to read that are both skeptical and supportive of the idea of IQ). It covers what IQ is correlated with, by how much, and what this can mean (which also includes, why study IQ and intelligence at all?).
I thought the author did a good job of summarizing what we know carefully and explaining why some are skeptical of general intelligence. Very good for its length, with plenty of recommendations for further reading inside if you wish to go deeper.
I thought the author did a good job of summarizing what we know carefully and explaining why some are skeptical of general intelligence. Very good for its length, with plenty of recommendations for further reading inside if you wish to go deeper.
February 4, 2022
I don't usually write reviews but this book's title always seemed pretentious to me, which made me hold off on reading it for a long time. Now that I have finally read the book, I feel compelled to justify reading a book with such a pretentious sounding title.
Since I was concerned about the title of the book, I’m sure at least someone else out there is as well so let’s address that first:
It seems like "All That Matters" is a series of books, so I think "All That Matters" means "All the things that matter about Intelligence" rather than "Intelligence is the only thing that matters". This seems to fit with the content of the book as well, since Ritchie never says anything that suggests to me that he thinks Intelligence is all important.
On to the book:
Overall, I think the book was informative and interesting to read, the main weaknesses of the book seem due to the fact that the book is trying to summarize a complex and controversial topic in under 200 pages.
First, the good things:
I've generally been somewhat skeptical of the idea of IQ, but I also never knew much about IQ so it felt hard to justify the skepticism. Ritchie changed my opinion some on IQ: he addresses several criticisms of IQ that I've heard before and gives me the impression that IQ is probably a fairly reasonable proxy for intelligence.
He also did a good job at convincing me that IQ is worth paying attention to. Since IQ has so many correlates, it’s likely to be an informative metric in a variety of research. Whether you agree or disagree that it’s really measuring “intelligence” it seems like for a lot of research, you ignore IQ at your own peril.
I also appreciate that it didn’t feel like the book tries to hide the limitations of IQ. I like that Ritchie includes correlation coefficients rather than just saying “IQ is strongly associated with X” or “IQ is weakly associated with Y”. A lot of writing on IQ that I’ve seen isn’t specific about this kind of stuff and gives the impression that a whole lot of outcomes are strongly influenced by IQ. Being able to see the numbers makes it easy to see which factors are strongly influenced -- or maybe it’s better to say predicted -- by IQ vs the ones where IQ is unlikely to be a major factor. I think the book is not kind to IQ zealots in the blogosphere here. There are some things where IQ seems very important, but it seems like weak correlation is the rule rather than the exception.
There’s obviously a lot a correlation coefficient leaves out -- variance is a big one -- but the book also needs some balance of accessibility and rigor. r is a single number that’s fairly easy to understand so I think it made sense to include. It adds some rigor with minimal loss of accessibility.
On to the not as good things:
First, the book raises a lot of questions. This isn’t entirely bad, it’s nice when a book makes you think but it feels like several of them could have been answered and weren’t. When you consider what a controversial topic IQ is, I think the book would have benefited from being longer and more thorough.
A few things that come to mind are:
Ritchie talks about a Norwegian study on education improving IQ. The study takes advantage of a “natural experiment” where the Norwegian government added 2 more years of compulsory schooling but rolled it out at different rates, which allows researchers to compare different populations.
The problem here is that a lot of “natural experiment” studies really aren’t natural experiments. I won’t nitpick about this too much because you can’t expect a book to do a deep dive into every study’s methodology. I just wish he’d address obvious confounders:
This study stood out to me because I would expect roll out rates to be non-random. Specifically, I think urban areas would roll out at different rates than rural areas. Since knowledge work tends to be concentrated in cities, and knowledge workers tend to have higher IQs, I’d expect this to be a big confounder. Factor in that the study finds a big effect size and I get a little worried. I wish he would have gone into detail about how they addressed this particular challenge, if they addressed it at all.
Another point that Ritchie makes that I think deserves more detail is that it’s likely possible to game IQ tests but that the average person probably doesn’t which makes population level measurements relatively robust to gaming IQ tests.
Fair enough, but it’s easy to think of exceptions to this. For example, if comparing SAT scores to IQ scores, then gaming the system is probably the norm since the people who do best on the SAT tend to study for it, which means they’re actively studying vocabulary, which is tested in IQ tests.
In this case, you can easily get around this problem by IQ testing people long before they’re thinking about the SATs, but I imagine similar situations exist elsewhere. Goodhart’s Law seems to apply here: when a measure becomes a target, it ceases to be a good measure. If you find that IQ correlates with X, I think it’s important to ask “do I have reason to believe X makes people more likely to game IQ tests”. If people are just gaming the test, there’s probably not going to be much benefit associated with the increase in IQ that follows.
I also wanted to know more about is how g is calculated from the multiple tests. Ritchie mentions that each individual test may fail to measure intelligence reliably, but when combined they can reliably find g.
I suspect the reason for this is similar to how basic noise reduction works:
If you have some noisy signal, and you sample it many times you can separate the signal from the noise even when there is more noise than signal. This is because the signal won’t change much between samples while the noise will. Keep only what’s consistent and you can get the signal.
Importantly, this assumes the noise is random. I think the critique that “IQ might just measure X” is still valid if you expect many of the tests to be noisy in the same non-random way (particularly, in a way that’s influenced by X).
That said, most noise reduction algorithms are much more sophisticated than the one I described. It would be nice to know more specifically how g is calculated. But to be fair, this is undoubtedly outside of the scope of the book.
I’ll end the criticisms with a positive note, which is that the book at least ends with a good list of resources for further reading. As a short introduction to intelligence research it left me wanting a lot more depth. It’s nice Ritchie at least provides sources that give the reader that option.
Final verdict:
The book is short and informative. If you’re like me and were interested in the topic but put off by the title, I think it’s worth a read. If nothing else, it’s too short to waste much of your time.
Since I was concerned about the title of the book, I’m sure at least someone else out there is as well so let’s address that first:
It seems like "All That Matters" is a series of books, so I think "All That Matters" means "All the things that matter about Intelligence" rather than "Intelligence is the only thing that matters". This seems to fit with the content of the book as well, since Ritchie never says anything that suggests to me that he thinks Intelligence is all important.
On to the book:
Overall, I think the book was informative and interesting to read, the main weaknesses of the book seem due to the fact that the book is trying to summarize a complex and controversial topic in under 200 pages.
First, the good things:
I've generally been somewhat skeptical of the idea of IQ, but I also never knew much about IQ so it felt hard to justify the skepticism. Ritchie changed my opinion some on IQ: he addresses several criticisms of IQ that I've heard before and gives me the impression that IQ is probably a fairly reasonable proxy for intelligence.
He also did a good job at convincing me that IQ is worth paying attention to. Since IQ has so many correlates, it’s likely to be an informative metric in a variety of research. Whether you agree or disagree that it’s really measuring “intelligence” it seems like for a lot of research, you ignore IQ at your own peril.
I also appreciate that it didn’t feel like the book tries to hide the limitations of IQ. I like that Ritchie includes correlation coefficients rather than just saying “IQ is strongly associated with X” or “IQ is weakly associated with Y”. A lot of writing on IQ that I’ve seen isn’t specific about this kind of stuff and gives the impression that a whole lot of outcomes are strongly influenced by IQ. Being able to see the numbers makes it easy to see which factors are strongly influenced -- or maybe it’s better to say predicted -- by IQ vs the ones where IQ is unlikely to be a major factor. I think the book is not kind to IQ zealots in the blogosphere here. There are some things where IQ seems very important, but it seems like weak correlation is the rule rather than the exception.
There’s obviously a lot a correlation coefficient leaves out -- variance is a big one -- but the book also needs some balance of accessibility and rigor. r is a single number that’s fairly easy to understand so I think it made sense to include. It adds some rigor with minimal loss of accessibility.
On to the not as good things:
First, the book raises a lot of questions. This isn’t entirely bad, it’s nice when a book makes you think but it feels like several of them could have been answered and weren’t. When you consider what a controversial topic IQ is, I think the book would have benefited from being longer and more thorough.
A few things that come to mind are:
Ritchie talks about a Norwegian study on education improving IQ. The study takes advantage of a “natural experiment” where the Norwegian government added 2 more years of compulsory schooling but rolled it out at different rates, which allows researchers to compare different populations.
The problem here is that a lot of “natural experiment” studies really aren’t natural experiments. I won’t nitpick about this too much because you can’t expect a book to do a deep dive into every study’s methodology. I just wish he’d address obvious confounders:
This study stood out to me because I would expect roll out rates to be non-random. Specifically, I think urban areas would roll out at different rates than rural areas. Since knowledge work tends to be concentrated in cities, and knowledge workers tend to have higher IQs, I’d expect this to be a big confounder. Factor in that the study finds a big effect size and I get a little worried. I wish he would have gone into detail about how they addressed this particular challenge, if they addressed it at all.
Another point that Ritchie makes that I think deserves more detail is that it’s likely possible to game IQ tests but that the average person probably doesn’t which makes population level measurements relatively robust to gaming IQ tests.
Fair enough, but it’s easy to think of exceptions to this. For example, if comparing SAT scores to IQ scores, then gaming the system is probably the norm since the people who do best on the SAT tend to study for it, which means they’re actively studying vocabulary, which is tested in IQ tests.
In this case, you can easily get around this problem by IQ testing people long before they’re thinking about the SATs, but I imagine similar situations exist elsewhere. Goodhart’s Law seems to apply here: when a measure becomes a target, it ceases to be a good measure. If you find that IQ correlates with X, I think it’s important to ask “do I have reason to believe X makes people more likely to game IQ tests”. If people are just gaming the test, there’s probably not going to be much benefit associated with the increase in IQ that follows.
I also wanted to know more about is how g is calculated from the multiple tests. Ritchie mentions that each individual test may fail to measure intelligence reliably, but when combined they can reliably find g.
I suspect the reason for this is similar to how basic noise reduction works:
If you have some noisy signal, and you sample it many times you can separate the signal from the noise even when there is more noise than signal. This is because the signal won’t change much between samples while the noise will. Keep only what’s consistent and you can get the signal.
Importantly, this assumes the noise is random. I think the critique that “IQ might just measure X” is still valid if you expect many of the tests to be noisy in the same non-random way (particularly, in a way that’s influenced by X).
That said, most noise reduction algorithms are much more sophisticated than the one I described. It would be nice to know more specifically how g is calculated. But to be fair, this is undoubtedly outside of the scope of the book.
I’ll end the criticisms with a positive note, which is that the book at least ends with a good list of resources for further reading. As a short introduction to intelligence research it left me wanting a lot more depth. It’s nice Ritchie at least provides sources that give the reader that option.
Final verdict:
The book is short and informative. If you’re like me and were interested in the topic but put off by the title, I think it’s worth a read. If nothing else, it’s too short to waste much of your time.
January 28, 2019
This book is useful in clearing away misconceptions about intelligence research that have been popularized in Social Media and Liberal-leaning media outlets. One of the most shocking facts presented in this book is Howard Gardner's Multiple Intelligences has no basis in scientific research; at best, Musical Intelligence may be different from General Intelligence (G-Factor) but there are mixed results even there from the scientific studies. Studies on the so-called Multiple Intelligences has found no evidence that they're separate as Gardner claims them to be. The G-Factor generally shows that if you're good in one area, then you're good in others and you can improve your skills faster as a result. For instance, emotional intelligence falls into the category of IQ too and doesn't contradict the current psychological model of the five personalities. The only possible area where Gardner's theory might have merit is Musical Intelligence and the results for that are mixed from scientific research, so Gardner's claims there are also unlikely to have merit.
Ritchie explains in his book that there is a strong correlation between our genes and our IQ according to repeated scientific studies, there are two more important and crucial factors that should be mentioned; the most productive way to increase your IQ is to focus on living a healthy life because focusing on one's health helps improve our physical development especially before the age of 25, similar to research that shows malnutrition diminishes our brain development as children. Equally noteworthy is that our personal motivation plays a stronger factor in increasing and determining IQ than our genes which corroborates Angela Duckworth's book, Grit, where she explains how effort counts twice. Our genes play a factor, but they're not the sole or the most important factor. The scientific consensus shows that IQ can increase depending on our social environment and strikingly enough - absent any form of psychological, physical, or sexual abuse - parenting doesn't play a significant factor in influencing a child's IQ. Ritchie repeatedly clarifies that despite the genetic influence, studies show a stronger link with motivation and good health in determining our IQ. One sad fact from the scientific studies is that there is rabid cognitive decline for all human beings in our ability to learn and process new information quickly after the age of 25, so childhood development and motivation is especially important to increasing a person's IQ over a lifetime.
Ritchie goes on to dismiss the popularized book The Bell Curve by Charles Murray as there is a total lack of scientific research on the question of Race and IQ. Ritchie cautions making spurious generalizations due to the history of the eugenics movement; one such example of a genocide that I know of is the forcible sterilization of Native American women by several State governments within the US. All we can say at the moment is that we don't know enough about Race and IQ. Similarly, the IQ differences of men and women have no real scientific research to back them; at best, one country's analysis from the 1940s and it's impossible to determine what social factors could influence the results from back then. The research itself showed that men and women of a certain country were totally equal in intelligence with men having more spatial intelligence and women with more verbal intelligence as kids during the first study and as adults several years later. That isn't enough to make a determination or rule out social factors.
Apart from all of this, I feel he overstated his case. The G-Factor is but one of many competing factors in determining a person's success and he repeatedly admits that focusing on proper health, nutrition, and personal motivation completely trump genetics. Moreover, social background such as our economic status and the education of our community play an equally important factor as our genetic make-up in determining our IQ. I must emphasize that the genetic basis would be one's own family and especially if your sibling is an identical or fraternal twin as that has been the basis of most of the scientific research. If we eat healthy, exercise, and have a thirst for learning then we'll end-up on the higher end, but if not then we'll slide down to the lower-end or it won't see any measurable improvements that are different from our age bracket. He kept mentioning how IQ is downplayed. However, from the psychology books that I read, I never saw any of the authors outright dismiss the genetics of IQ, but instead emphasize that it is one of many factors as he does. I can only conjecture that this book is meant for Howard Gardner's fans, people who read only Social Media articles on IQ, and people obsessed with a slanted position on IQ - whether boasting of it or dismissing it.
Ritchie makes a joke based on his analysis; evidently, very intelligent people generally don't want to believe in IQ differences and prefer to argue that IQ is either biased or useless because it hurts their sense of pride in their accomplishments. After all, if you worked hard to get where you are, why would you want to hear that it was predetermined at birth based partly on your genes? Meanwhile, to Ritchie's amusement, the people with the lowest IQ are usually the ones obsessed over IQ differences and like to make vacuous generalizations on weak research that they misrepresent. I've seen such nonsense from the racist website, Alternative Hypothesis, where they linked an article about young black boys with severe cases of down syndrome and misrepresented the content that they linked to mean young black children in general.
Ritchie explains in his book that there is a strong correlation between our genes and our IQ according to repeated scientific studies, there are two more important and crucial factors that should be mentioned; the most productive way to increase your IQ is to focus on living a healthy life because focusing on one's health helps improve our physical development especially before the age of 25, similar to research that shows malnutrition diminishes our brain development as children. Equally noteworthy is that our personal motivation plays a stronger factor in increasing and determining IQ than our genes which corroborates Angela Duckworth's book, Grit, where she explains how effort counts twice. Our genes play a factor, but they're not the sole or the most important factor. The scientific consensus shows that IQ can increase depending on our social environment and strikingly enough - absent any form of psychological, physical, or sexual abuse - parenting doesn't play a significant factor in influencing a child's IQ. Ritchie repeatedly clarifies that despite the genetic influence, studies show a stronger link with motivation and good health in determining our IQ. One sad fact from the scientific studies is that there is rabid cognitive decline for all human beings in our ability to learn and process new information quickly after the age of 25, so childhood development and motivation is especially important to increasing a person's IQ over a lifetime.
Ritchie goes on to dismiss the popularized book The Bell Curve by Charles Murray as there is a total lack of scientific research on the question of Race and IQ. Ritchie cautions making spurious generalizations due to the history of the eugenics movement; one such example of a genocide that I know of is the forcible sterilization of Native American women by several State governments within the US. All we can say at the moment is that we don't know enough about Race and IQ. Similarly, the IQ differences of men and women have no real scientific research to back them; at best, one country's analysis from the 1940s and it's impossible to determine what social factors could influence the results from back then. The research itself showed that men and women of a certain country were totally equal in intelligence with men having more spatial intelligence and women with more verbal intelligence as kids during the first study and as adults several years later. That isn't enough to make a determination or rule out social factors.
Apart from all of this, I feel he overstated his case. The G-Factor is but one of many competing factors in determining a person's success and he repeatedly admits that focusing on proper health, nutrition, and personal motivation completely trump genetics. Moreover, social background such as our economic status and the education of our community play an equally important factor as our genetic make-up in determining our IQ. I must emphasize that the genetic basis would be one's own family and especially if your sibling is an identical or fraternal twin as that has been the basis of most of the scientific research. If we eat healthy, exercise, and have a thirst for learning then we'll end-up on the higher end, but if not then we'll slide down to the lower-end or it won't see any measurable improvements that are different from our age bracket. He kept mentioning how IQ is downplayed. However, from the psychology books that I read, I never saw any of the authors outright dismiss the genetics of IQ, but instead emphasize that it is one of many factors as he does. I can only conjecture that this book is meant for Howard Gardner's fans, people who read only Social Media articles on IQ, and people obsessed with a slanted position on IQ - whether boasting of it or dismissing it.
Ritchie makes a joke based on his analysis; evidently, very intelligent people generally don't want to believe in IQ differences and prefer to argue that IQ is either biased or useless because it hurts their sense of pride in their accomplishments. After all, if you worked hard to get where you are, why would you want to hear that it was predetermined at birth based partly on your genes? Meanwhile, to Ritchie's amusement, the people with the lowest IQ are usually the ones obsessed over IQ differences and like to make vacuous generalizations on weak research that they misrepresent. I've seen such nonsense from the racist website, Alternative Hypothesis, where they linked an article about young black boys with severe cases of down syndrome and misrepresented the content that they linked to mean young black children in general.
July 4, 2016
A short and lucid introduction to the science of intelligence and IQ. He sticks to the consensus views on the field, is very accessible, and has a nice section at the end detailing further sources of information, ranging from authors to books to papers, all neatly arranged in categories.
For anyone interested in the importance of IQ-- this is the best place to start. For anyone looking for more in-depth or obscure information on IQ, look elsewhere. This is an introduction, not a deep dive. He has a nice section on the health epidemiology of IQ, which some other intro's to IQ don't focus on quite as much.
For anyone interested in the importance of IQ-- this is the best place to start. For anyone looking for more in-depth or obscure information on IQ, look elsewhere. This is an introduction, not a deep dive. He has a nice section on the health epidemiology of IQ, which some other intro's to IQ don't focus on quite as much.
January 2, 2016
This is a really well written introduction to intelligence and IQ. Intelligently written, well structured and full of evidence-based information. What impressed me the most was the author's scientific approach to the evidence - particularly his treatment of uncertainty, which is sadly lacking in many such books. I also loved the "alternative" reading list at the end. Definitely recommended!
December 9, 2021
An excellent book. Recommend. Short, well-written, mostly non-technical, but very sober and reliable on the science.
Ritchie understandably skips over the scandal-prone area of intelligence differences between groups.
The section at the end recommended further resources and reading was helpful well organised.
Ritchie understandably skips over the scandal-prone area of intelligence differences between groups.
The section at the end recommended further resources and reading was helpful well organised.
February 9, 2016
An excellent introduction to intelligence, how it matters, and why various misconceptions are misconceptions. Studies & references galore.
May 28, 2016
Not my favourite book to say the least. There were too many facts and information that I got bored and it didn't help my position paper topic.
May 2, 2018
From reading Intelligence, subtitle All That Matters. Stuart Ritchie. McGraw-Hill, 2015. ISBN 9 781444 791877
In the 1960s, the Norwegian government (p 92) decided to add two extra years to the mandatory curriculum for all pupils.Two additional pieces of good luck allowed researches, who came on the scene much later, to turn this into a test of the effects of schooling on IQ.
First, the reform was implemented across the different parts of Norway in a staggered way – it happened in some areas years before it happened in others
Second, every male Norwegian sits an IQ test as part of their compulsory army service.
In 2012 the researchers were able to compare the later IQ scores of those who had been forced to stay in school for extra years with the scores of those who hadn’t (Brinch and Galloway, 2012).
1 Year Extra School, Increased IQ by 3.7 Points
They worked out that the extra schooling added 3.7 IQ points per year.
This confirmed the results of many other, previous studies that hadn’t used such elegant methods.
It's awesome that education can shift the entire distribution of IQs
It’s awesome that education can shift the entire distribution of IQs
Psychometricians, those that focus on measurement of intelligence via IQ, routinely adjust the mean of test scores to maintain the IQ average of 100, yet it remains true that the ability of people to solve intelligence questions continues to grow.
Other Noteworthy Points
Heritability (p 67). Fifty percent heritability doesn’t mean that 50% of an individual person’s intelligence is due to their DNA. It describes the reasons for variation among the people being studied.
Heritability doesn’t tell us anything about the average level of intelligence. Intelligence can be 50% heritable in a group where the average IQ is 85, 100, or 115, or an other number
‘Heritable’ doesn’t mean the same thing as ‘hereditary’. These words are often confused: a ‘hereditary’ trait is simply anything that’s passed on from parents to offspring, whereas ‘heritability’ is about the genetic variation in that trait.
Flynn Effect (p 94-99). IQs have been increasing about 3 points every decade since IQ testing began.
Ritchie mentions the interesting hypothesis that the cause may be cultural – we think more abstractly than our ancestors, not faster. Speculatively, we relate knowledge to how it is taught, not how it is experienced.
For example, a hundred years ago the answer of what do dogs and horses have in common was they are both are used to hunt (a relationship a person has seen). Now the answer is more likely they are both are mammals (a taught distinction).
In the 1960s, the Norwegian government (p 92) decided to add two extra years to the mandatory curriculum for all pupils.Two additional pieces of good luck allowed researches, who came on the scene much later, to turn this into a test of the effects of schooling on IQ.
First, the reform was implemented across the different parts of Norway in a staggered way – it happened in some areas years before it happened in others
Second, every male Norwegian sits an IQ test as part of their compulsory army service.
In 2012 the researchers were able to compare the later IQ scores of those who had been forced to stay in school for extra years with the scores of those who hadn’t (Brinch and Galloway, 2012).
1 Year Extra School, Increased IQ by 3.7 Points
They worked out that the extra schooling added 3.7 IQ points per year.
This confirmed the results of many other, previous studies that hadn’t used such elegant methods.
It's awesome that education can shift the entire distribution of IQs
It’s awesome that education can shift the entire distribution of IQs
Psychometricians, those that focus on measurement of intelligence via IQ, routinely adjust the mean of test scores to maintain the IQ average of 100, yet it remains true that the ability of people to solve intelligence questions continues to grow.
Other Noteworthy Points
Heritability (p 67). Fifty percent heritability doesn’t mean that 50% of an individual person’s intelligence is due to their DNA. It describes the reasons for variation among the people being studied.
Heritability doesn’t tell us anything about the average level of intelligence. Intelligence can be 50% heritable in a group where the average IQ is 85, 100, or 115, or an other number
‘Heritable’ doesn’t mean the same thing as ‘hereditary’. These words are often confused: a ‘hereditary’ trait is simply anything that’s passed on from parents to offspring, whereas ‘heritability’ is about the genetic variation in that trait.
Flynn Effect (p 94-99). IQs have been increasing about 3 points every decade since IQ testing began.
Ritchie mentions the interesting hypothesis that the cause may be cultural – we think more abstractly than our ancestors, not faster. Speculatively, we relate knowledge to how it is taught, not how it is experienced.
For example, a hundred years ago the answer of what do dogs and horses have in common was they are both are used to hunt (a relationship a person has seen). Now the answer is more likely they are both are mammals (a taught distinction).
January 24, 2021
Finally, a book which is written clearly and concisely. One of the biggest problems in science has been its communication to general public. This book does the job brilliantly. The question of IQ has often been derided. Of course, some people are smarter than others. It is just that you might not say that freely in polite company.
The book succinctly explains the current scientific knowledge regarding IQ. It accurately debunks myths like we have emotional intelligence, multiple intelligence. The book has plenty of scientific references and backs it up with some facts.
However, the book does not delve into many of the questions. For example, at some point in the book the author explains social class as a factor effecting intelligence. However, a more cross cultural understanding would better explain. He really tries though. I felt at some points the book just leaves the reader in hanging; craving for more knowledge.
Despite its shortcomings, the book is an excellent read if you are interested in learning about the current status of IQ research. There is so much we do not know. Further research on this should be encouraged.
The book succinctly explains the current scientific knowledge regarding IQ. It accurately debunks myths like we have emotional intelligence, multiple intelligence. The book has plenty of scientific references and backs it up with some facts.
However, the book does not delve into many of the questions. For example, at some point in the book the author explains social class as a factor effecting intelligence. However, a more cross cultural understanding would better explain. He really tries though. I felt at some points the book just leaves the reader in hanging; craving for more knowledge.
Despite its shortcomings, the book is an excellent read if you are interested in learning about the current status of IQ research. There is so much we do not know. Further research on this should be encouraged.
November 30, 2022
كتاب صغير وجميل وسلس وسهل بيقدم مقدمة صغيرة وملخص عن كل الي نعرفه لحد فتره قريبه عن موضوع الذكاء وحقيقي ممتع ولطيف هو ١٦٠ صفحة
اول شابتر بيعرف الذكاء ويعرف اختبار الذكاء وهو بيتكون من ايه وبيقيس ايه بالظبط
وبعدين في الفصل التاني بيتكلم عن ازاي بنختبر الذكاء ثم بيتكلم بعدها عن ليه الذكاء مهم في حياتنا ويشرح الارتباط الايجابي بين الذكاء والصحة وطول العمر والنجاح المهني والاجتماعي والمادي ثم بيتكلم عن تنمية الذكاء وبيقول انه المجتمعات ككل مستوى ذكائها بيرتفع بمرور الزمن وده بشكل اساسي بسبب التعليم الاجباري الي اتفرض على الدول النامية لكن للاسف لسه منعرفش ازاي يتم تنمية الذكاء على مستوى فردي ثم بعدها بيتكلم عن بيولوجيا الذكاء وازاي انه الذكاء تقريبا نص الاختلاف فيه بين البشر راجع لعوامل جينية وبيفند خرافات عن الذكاء وافكار مغلوطه تجاهه كتير اوي منتشرة كالنار وسط الناس وبعدين بيشرح ليه في جدال كتير بخصوص الذكاء وازاي انه يعني انه الموضوع محاط بأفكار مغلوطه كتير كتير اوي عنه وبيفندها.
كتاب صغير ولطيف وجميل وممتع واول مره احتك بسلسلة All that matters انا الي رشحلي الكتاب ده هو روبرت بلومين في كتابه المخطط الوراثي كيف يجعلنا ال DNA من نكون وحقيقي ترشيح موفق جدا.
الكتاب كذلك في نهايته مليان ترشيحات لمقالات وكتب ومواقع للتعمق في موضوع الذكاء.
اول شابتر بيعرف الذكاء ويعرف اختبار الذكاء وهو بيتكون من ايه وبيقيس ايه بالظبط
وبعدين في الفصل التاني بيتكلم عن ازاي بنختبر الذكاء ثم بيتكلم بعدها عن ليه الذكاء مهم في حياتنا ويشرح الارتباط الايجابي بين الذكاء والصحة وطول العمر والنجاح المهني والاجتماعي والمادي ثم بيتكلم عن تنمية الذكاء وبيقول انه المجتمعات ككل مستوى ذكائها بيرتفع بمرور الزمن وده بشكل اساسي بسبب التعليم الاجباري الي اتفرض على الدول النامية لكن للاسف لسه منعرفش ازاي يتم تنمية الذكاء على مستوى فردي ثم بعدها بيتكلم عن بيولوجيا الذكاء وازاي انه الذكاء تقريبا نص الاختلاف فيه بين البشر راجع لعوامل جينية وبيفند خرافات عن الذكاء وافكار مغلوطه تجاهه كتير اوي منتشرة كالنار وسط الناس وبعدين بيشرح ليه في جدال كتير بخصوص الذكاء وازاي انه يعني انه الموضوع محاط بأفكار مغلوطه كتير كتير اوي عنه وبيفندها.
كتاب صغير ولطيف وجميل وممتع واول مره احتك بسلسلة All that matters انا الي رشحلي الكتاب ده هو روبرت بلومين في كتابه المخطط الوراثي كيف يجعلنا ال DNA من نكون وحقيقي ترشيح موفق جدا.
الكتاب كذلك في نهايته مليان ترشيحات لمقالات وكتب ومواقع للتعمق في موضوع الذكاء.
August 23, 2020
Entre 4 y 5 estrellas (me es difícil ajustar la calificación a las restricciones de páginas de la serie)
Breve pero conciso.
Abarca la mayoría de los temas principales en el estudio de inteligencia humana, aunque en varios casos hubiera preferido un análisis más profundo (afortunadamente incluye al final una bien organizada lista de lectura posterior).
Aprovecha el formato digital mejor que la mayoría de los libros; está bien organizado internamente, y es visualmente agradable.
Me quedé con la duda sobre la continuación del efecto Flynn: a diferencia de lo que está en el libro, tenía entendido que en muchos paises desarrollados el efecto se había detenido o revertido.
También me sorprendió la mención de un aparentemente muy fuerte efecto causal de años de educación adicional sobre IQ.
Breve pero conciso.
Abarca la mayoría de los temas principales en el estudio de inteligencia humana, aunque en varios casos hubiera preferido un análisis más profundo (afortunadamente incluye al final una bien organizada lista de lectura posterior).
Aprovecha el formato digital mejor que la mayoría de los libros; está bien organizado internamente, y es visualmente agradable.
Me quedé con la duda sobre la continuación del efecto Flynn: a diferencia de lo que está en el libro, tenía entendido que en muchos paises desarrollados el efecto se había detenido o revertido.
También me sorprendió la mención de un aparentemente muy fuerte efecto causal de años de educación adicional sobre IQ.
March 18, 2021
This is a very short and simple introduction on Intelligence. Few of the findings presented in book confirm my own observation like general intelligence but many are quite eye opener like Emotional Intelligence, correlation with age, health etc and most importantly the malleability of Intelligence.
I would have appreciated this book more had I read it a decade earlier when I was of the 'opinion' that every one is born with same clean/blank slate and its only the environment and efforts that influence the intelligence. Of-course, I realized this much earlier that I couldn't be more wrong.
This book also inspired some hope that Intelligence is 'not' immutable - which was, ummm.. kind of my 'unacknowledged' belief :) Well, that's some hope!
PS: Author also included a section in the end containing references for books, research papers etc on the subject.
I would have appreciated this book more had I read it a decade earlier when I was of the 'opinion' that every one is born with same clean/blank slate and its only the environment and efforts that influence the intelligence. Of-course, I realized this much earlier that I couldn't be more wrong.
This book also inspired some hope that Intelligence is 'not' immutable - which was, ummm.. kind of my 'unacknowledged' belief :) Well, that's some hope!
PS: Author also included a section in the end containing references for books, research papers etc on the subject.
January 8, 2025
This is an extremely short and rather up to date book on intelligence research. Stuart Ritchie is a psychology researcher and wrote a work with little to no fat. I could talk about how annoying it is to read another introduction to figures like Galton, and Binet, and Spearman, and so on, but the point of this book is to offer an introduction to readers who want to see the lay of the land on intelligence research. This book provides that, almost impeccably. There is little to no fat, the points are made concisely and clearly. Ritchie doesn't obsess over the political and cultural controversies related to the field, he just states plainly what is supported by the research. The recommended sources in the back are excellent, and really turn this book into probably the best place to start reading about the field of intelligence research.
October 23, 2023
A very good introduction to the psychology of intelligence. IQ is always a difficult topic to talk about and Stuart does a great job of discussing it in a measured way.
Interesting that general intelligence as measured with IQ seems to be one of the most robust measures in psychology (in terms of how well replicated it has been). Discusses the importance of genetics and what environmental factors contribute (spoiler at the time of the book: genetic factors contribute substantially and direct parental environment surprisingly, not so much. Although some other environmental factors are important, though I suppose the field has made lots of progress since then).
Some depressing facts about the decline in IQs as we age and how difficult it seems to improve.
Interesting that general intelligence as measured with IQ seems to be one of the most robust measures in psychology (in terms of how well replicated it has been). Discusses the importance of genetics and what environmental factors contribute (spoiler at the time of the book: genetic factors contribute substantially and direct parental environment surprisingly, not so much. Although some other environmental factors are important, though I suppose the field has made lots of progress since then).
Some depressing facts about the decline in IQs as we age and how difficult it seems to improve.
December 1, 2025
Read the chapter titled “100 Ideas” to get a sense of the kinds of questions the book tackles. If it sparks your interest, this is the book for you.
That said, it falls short when it comes to complicated issues, e.g., how to actually interpret heritability (for example, what a value of 50% really means statistically). It also sidesteps highly contentious topics, such as group differences in intelligence by race or sex, though Ritchie does acknowledge the complexities without slipping into the denialism common among blank-slatist academics.
Overall, Ritchie succeeds in giving lay readers a clear, up-to-date overview of intelligence research from a pro-general-intelligence perspective. He includes plenty of pointers for further reading. A very solid introduction.
That said, it falls short when it comes to complicated issues, e.g., how to actually interpret heritability (for example, what a value of 50% really means statistically). It also sidesteps highly contentious topics, such as group differences in intelligence by race or sex, though Ritchie does acknowledge the complexities without slipping into the denialism common among blank-slatist academics.
Overall, Ritchie succeeds in giving lay readers a clear, up-to-date overview of intelligence research from a pro-general-intelligence perspective. He includes plenty of pointers for further reading. A very solid introduction.
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