It’s Official – Men are Smarter than Women

In this article, Professor Richard Lynn explains that science shows, test after test, that men are smarter than women. And he’s no dummy himself. He’s a Professor who’s spent the majority of his career studying intelligence – specifically differences in intelligence between the sexes. And he’s a skeptic. A skeptic of the glass ceiling, that is. He claims it’s not an invisible ceiling that’s responsible for the disproportionate percentage of men in executive-level jobs or upper-level math and science careers. It’s the fact that men outnumber women 8 to 1 at the genius level. He even explains how this happened using evolutionary psychology.

Professor Lynn is aware that his point of view is bound to be unpopular, and isn’t politically correct. But he claims loyalty to the data, and will not be deterred by social pressures. He fully expects a backlash from angry feminists and the PC police.

But what if his critics aren’t just angry feminists?

In this post, I’m going to examine his two chief claims:

(1) That men of average intelligence score 5 points higher on IQ tests than women of average intelligence
(2) That men outnumber women 8 to 1 at the genius level

I’m not going to touch the evolutionary psychology because it’s not germane to his argument, and because I view evolutionary psychology as a bunch of speculative bs rationalizations anyway.

First, some confessions on my part. I get him to an extent. I don’t think it’s a crazy idea that men and women might have different strengths, weaknesses, and interests. (He acknowledges, for example, that women outperform men at verbal reasoning and languages). And based on that belief, I don’t think all organizations or careers should be 50/50 men and women.

I’m probably the only one of the Skepchicks that thinks there are probably more men than women at TAM because more men are attracted to the idea of TAM. I think organizations naturally attract the people most interested in them, and as long as there’s no outright exclusion of a certain faction, it’s best to let the membership assemble organically. Any outside force is artificial – whether it’s exclusion by the group or activism to cultivate a certain faction of membership. I suppose an argument could be made that this sort of activism is necessary to offset the negative cultural influences that (purportedly) cause the demographic disparity, but my personal preference is to allow organizations to develop organically without force from either side.

And I’m a big fan of letting the data speak for themselves whether I like the results or not. For example, I took the GMAT a few years ago and looked up every possible score comparison to see where I stood. One of the comparisons I researched was score by demographic, and I found that white males scored highest, then white females, then ethnic minorities. To some people, even saying (or typing) that result is insulting. Not to me. It’s just a statistic, and there are lots of explanations for the differences, many of which don’t involve insulting the intelligence of a particular demographic.

So going into his article, I’m ready to accept the data whether I like them or not. Sure, tests can be culturally biased, but I’ll take test scores over speculative apologies explaining low scores any day. But there were no test data in the article to accept – the reader is left to look them up for him or her self.

Since my degrees are in business, I consulted an expert in the field who practiced psychology for over 30 years. Not the touchy-feely, blame your parents for everything psychology – but the kind that involves collecting and interpreting data. He studied psychometrics, and spent his entire career administering IQ tests to gifted and learning disabled kids in the public school system. He’s familiar with all of the major tests, their pros, cons, flaws, and biases. He’s worked with every demographic. And he also happens to be my dad. Here’s what he told me:

I suspect this article is intended for an uninformed audience.

Not uninformed as in stupid, but uninformed as in an audience of non-specialists who wouldn’t know how the IQ test is engineered or how different populations score on the instruments. So he filled me in.

When IQ tests are engineered, they are put together item by item, category by category. Each potential item is tested to see how different populations score on it. If it is a highly biased item it is discarded. Items that may have a slight bias are counterbalanced with items that compensate for it. The end result is a test that is not biased overall.

So…IQ tests are deliberately designed to eliminate disparities between demographics. Any questions that test with a statistically significant difference are discarded so that the score variation can only be attributed to differences in individual intelligence. The creators of the tests don’t allow questions in which one demographic scores significantly higher or lower than another. If women consistently scored lower than men on a particular test, that test would be unmarketable because its results would be viewed as biased and invalid.

That said, several studies have shown normalized results of the WAIS (Wechsler Adult Intelligence Scale) that show a 3-5 point difference in the overall IQ of men vs. women. The consistency and credibility of these results have been discussed and criticized by the scientific community. A detailed and highly technical criticism of these results can be found here.

Do these studies “prove” that men are smarter than women? Absolutely not. At best, they open the door for some controversy. But did Professor Lynn call his article “Studies Start Controversy that Men are Smarter than Women”? No.

Controversy does not a scientific conclusion make. To unequivocally state that science has proven men to be smarter than women is just plain false.

But what happens when we look at the upper end of the bell curve? Professor Lynn claims that men outnumber women 8 to 1 at the genius level. And that certainly would explain the disproportionate number of men in upper level careers. If it were true.

Here are my source’s thoughts on this:

The norm sample of an IQ test is designed to be comprised of individuals that collectively are the same as the general population. Therefore, it has about the same proportion of geniuses that the general population does – and that isn’t very many. With such a small sample size, trying to answer questions about this group specifically, such as – are there more men than women in it, is just guessing. Also, items intended to discriminate a 140 IQ from a 150 IQ are extremely few (if any). So what would you be basing your conclusion on? Maybe two test questions? The tests just weren’t designed to answer those kinds of questions. I think the most responsible approach to assessing this question is to look at how norm groups have tended to score on IQ tests rather than to latch on to one particular test.

And what test did the Professor use to come to this radical conclusion? The Raven’s Progressive Matrices test. This is a nonverbal test in which the subject is shown figures that logically form some sort of pattern, and he or she is asked to identify that pattern. This is considered a valid and well-established test, but it covers only a very narrow window of mental abilities. It is by no stretch considered ideal or equivalent to the more standard IQ tests (Wechsler, Binet, Woodcock- Johnson). Here’s the test manufacturer’s description:

Raven’s Progressive Matrices provide a trusted, nonverbal assessment of intelligence. Because these scales minimize the impact of language skills and cultural bias, they are particularly well-suited to measuring the intelligence of individuals with reading problems or hearing impairment, as well as those whose native language is not English.

Minimizes the impact of language skills.

Wait, at what skills did Professor Lynn concede that women are better than men? Oh yeah, verbal reasoning and languages!

So, just to recap, Professor Lynn says:

– Women and men have different strengths and weaknesses
– Two of the chief strengths of women are verbal reasoning and languages
– Men outnumber women at the genius level by 8 to 1 based on the Raven’s Progressive Matrices Test, a test that minimizes the measurement of language skills

That’s just disingenuous. I suspect even he knows better.

So, where does that leave us in regard to the original question – are men smarter than women? Pretty much nowhere. Counter intuitively, the IQ test is a poor tool for determining the smarter sex because valid tests so carefully avoid any questions that demonstrate demographic bias. And because the test doesn’t evaluate large numbers of individuals at IQs above 145, the questions about this population can’t be definitively answered. Professor Lynn may or may not be wrong about men being smarter than women, but he is wrong to say that it’s been scientifically proven with IQ tests.

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  1. More men are attracted to TAM? What about how more women are economically disadvantaged and can’t take work off for/afford to attend TAM?

  2. Great post, Stacey.

    I think its very important to note that what IQ tests primarily measure is proficiency at taking IQ tests. After that, there’s plenty of controversy and always has been. There’s just no way to know how the tests correspond with ‘intelligence’ because none of the other ways of measuring it don’t correlate well with IQ (success in career, for instance).

    I suppose we could cut out the middleman and just define intelligence as ‘proficiency at the kinds of tasks IQ tests measure,’ but I’m pretty sure most people don’t want that kind of circularity.

  3. @TheNerd: Believe me, I’m well aware that I’m in the minority on that issue, especially on this site.

    @jblumenfeld: Actually, IQ tests are used to predict educational achievement, job performance, and income, but the other factors that influence those results (interpersonal skills, diligence, etc.) make it difficult to use the IQ score alone to predict overall success.

  4. @Stacey: “Actually, IQ tests are used to predict educational achievement, job performance, and income, but the other factors that influence those results (interpersonal skills, diligence, etc.) make it difficult to use the IQ score only to predict overall success.”

    I agree with @jblumenfeld. The only thing these tests can directly measure is performance on these tests. If they are attempting to measure other things like future success and they don’t do it well then this only reinforces the point.

  5. @davew: Yes, IQ can’t be used by itself to predict sucess, but I don’t like to throw the baby out with the bath water. It’s a piece of the puzzle, just like the other factors.

  6. Oh yeah, well, if we ain’t the smarter ones, how is it that we get to look at boobies and you all only get to look at hairy backs?

    (Lesbians may be the smartest people in the world)

  7. Stacey:

    Wonderful, well-thought out, beautifully written article.

    I am a woman with a “genius” IQ. That and $3.50 gets me a cup of coffee at Starbucks…which makes the Starbucks founders SIGNIFICANTLY more intelligent than myself. ;)

  8. Okay, on a more serious note…

    Professor Lynn may study intelligence, but I do wonder how much sociology he’s studied.

    Every job I’ve ever had, I just do what I do and do it brilliantly. It takes at least a year for the managers – male or female – to look past my gender. Much like Stacey, I have no problem with letting the data speak for itself, but studies like this that have logical flaws just contribute to the sociology of intelligence. The glass ceiling exists – I’ve bumped my head against it once or twice. It was when I switched to a more “feminine” version of IT (i.e. – usability and accessibility, the former having elements of psychology, the latter being a “do-good” kind of speciality, apparently), that that ceiling cracked a bit and people took me more seriously. That I’m very good at both fields because I actually have the programming chops doesn’t seem to matter to many.

    Lies, damned lies, and statistics.

  9. @slxpluvs:

    I’m being sarcastic. Let’s make that clear right now.

    It comes from my mother – she and my uncle (her favorite brother), also have Genius IQ’s. They are fond of saying “We’re FUCKIN’ GENIUSES!”, in the most sarcastic tone they can muster.

    In my family, being smart is the norm. Most of us have had the IQ tests and most of us are geniuses – if not, it’s a scant point or two away. We were never allowed to let our heads get big over it – smart or not, you are still a person in society and being smart doesn’t excuse you from being a polite, decent person. Hence my Starbucks comment.

  10. Great article, well thought-out and well written.

    I lean more towards @Stacey than @davew and @jblumenfeld on the idea that there is some validity to be found in these tests. For example, as poor a predictor of overall intelligence that the SAT is, it does do a remarkably good job at predicting how well a student will do in college.

    I also think that there is a huge problem in that the definition of “intelligent” is woefully imprecise, in that there are no hard and fast criteria by which we can say that this person is intelligent while this other person isn’t. You can have a genius-level IQ and be saddled with extreme laziness, or be prone to poor life decisions. I would wager that the best we can do is have a smattering of tests that measure (for better or worse) one or more aspects of what we can call intelligence, and each such test can give us a view towards one small part of the overall puzzle. I don’t believe it’s even possible to come up with anything better than this “bunch of pinholes” view.

    Finally, an observation of mine from a previous career: I spent eleven years teaching collegiate mathematics, and had thousands of students over that time. There did tend to be a much greater percentage of males taking the higher-level courses, but that’s another topic; what I think is pertinent is that, at all levels, females on the whole performed exactly as well as males: they were just as likely to be at the top of the class, and at the bottom, for example. And statistically speaking, the distributions of male grades versus female grades were statistically identical, with almost perfectly matching distribution curves. Yet another piece of the overall puzzle.

  11. @Chasmosaur: This is interesting to me because, as someone pointed out in the comments of the Professor’s article, I would think biology would have a bigger impact on IQ than sex. A genius man is going to pass his intelligence on to his daughters, not just his sons…no?

  12. I think the previous post regarding “boy toys vs girl toys” might factor into any observed disparity as well.

    One small issue: “I view evolutionary psychology as a bunch of speculative bs rationalizations anyway.” The idea that (some of) our behaviours are the result of evolution seems logical. That said, huge castles of speculation are built up on that simple and logical premise, and people use it to prove what ever it is they want to be true (but evo-psy is not unique in that regard).

  13. @Quaap: Yeah, I think you and I are on the same page. My statement was probably a bit too strong. It’s just one of my biggest pet peeves when people use evolutionary psychology to sound intelligent while they explain why they’re a jerk. And the very fact that evo-psy tries to explain the “why” rubs me the wrong way. “Why” is speculative, not testable, and there are a million ways to rationalize anything.

  14. @Stacey: But you seem to be taking a very, very, very simplistic view of the whole thing, and not taking anything else except “they just aren’t interested” into account.

    I suppose an argument could be made that this sort of activism is necessary to offset the negative cultural influences that (purportedly) cause the demographic disparity

    These things are very real and they matter. You can’t just ignore them, shrug, and go, “Oh, well, that’s how it is! We’ll just let it be.”

    Also, “purportedly” seems really disingenuous, especially when you remember how much of a stronghold religion has on women, and also the fact that many women in our country don’t have access to such basic things as birth control, or that their right to choose is severely limited, and that they are expected to be the ones to raise any children they may have, while men aren’t.

    It’s hard for women to go to fun conferences when they have kids and a house to take care of.

  15. One of the findings – the 8 to 1 ratio of geniuses – doesn’t really support the conclusion. There could be a similar 8 to 1 ratio of male idiots; i.e., the mean could be the same, with men having a higher standard deviation (possible rationale: men are indeed a bit more sensitive to the quality of their single X chromosome, in women 2 X chromosomes average out). That would give disproportionate ratios of men BOTH at the top and the bottom.

    By the way, while test designers DO try to eliminate questions that highly favor a specific demographic, I’d love to see one that actually achieved the balance your father indicated – as far as I know, IQ tests have been quite biased as race is concerned, see

  16. @Stacey: Well, you can — I’m not saying that you need to fight the good fight. But it seems ridiculous to me to not at least recognize that the problems exist. You’re shrugging them off and come really close to saying they don’t exist at all.

  17. “He fully expects a backlash from angry feminists and the PC police.”

    He also fully poisoned the well. Of course women and men aren’t going to be exactly the same at everything, but he can’t dismiss legitimate criticism and discussion on the basis of “backlash”.

  18. @jensfiederer:

    One of the findings – the 8 to 1 ratio of geniuses – doesn’t really support the conclusion. There could be a similar 8 to 1 ratio of male idiots; i.e., the mean could be the same, with men having a higher standard deviation (possible rationale: men are indeed a bit more sensitive to the quality of their single X chromosome, in women 2 X chromosomes average out). That would give disproportionate ratios of men BOTH at the top and the bottom.

    That’s exactly what Professor Lynn claims – that there are more genius men and more stupid men. And that somehow it all shakes out that, on average, men are 5 points smarter than women.

    It’s really important to look at his two claims separately, though, because there’s tons of evidence about average IQ levels and very little about genius IQs. So, whether the average number of genuis vs. stupid men doesn’t affect the average IQ score of men, has nothing to do with whether there are more men than women at the genius level.

    Also, there is some controversy over racially biased scores. My dad and I spoke about this briefly, but I didn’t feel it was essential to Professor’s argument about sex. Here’s what my dad had to say about race:

    Different racial groups have typically shown some differences in overall scores although test manufacturers do their best to minimize these differences because their tests are routinely accused of being racially biased. This can become a complicated debate but this has not been true concerning men versus women.

  19. I find it interesting that, according to the article, there are more dumb men too. I’d like to see the median IQ versus the mean to see if it’s just a small % of really high IQ guys throwing off the simple average.

    Also, I don’t agree that the difference in science professors could be attributed to IQ differences. I don’t think you need to be a high IQ genius to be a science professor.

  20. @jensfiederer: I too am skeptical that one can remove bias from these tests. I mean, one can remove questions from the test that seem that test in demographically biased ways, but isn’t that process itself limited by degrees of subjectivity? (e.g., How do they define the demographic group? By race? Gender? Socioeconomic status? Or by a combination?)

    To me, the calculus of intelligence (the precise role of genetics, culture, education, sex, etc.) appears to be too complex for our current scientific knowledge to make declarations as to whether men or women, as a gender, are inherently more “intelligent.”

    If I were to speculate, however, I would guess that the differences in intelligence between individual human beings attributable to non-sex factors are large enough to render any difference based on gender irrelevant … as in not particularly useful, except to provoke people in a publication, that is. But as someone said above, that and $3.50 will get me a Starbucks coffee – with one shot.

  21. @marilove: Yeah, that’s probably fair criticism. I guess the number of possible reasons that less women might be attending TAM is overwhelming to me. I wouldn’t know where to begin the fight, or know that I was fighting the actual force causing the shortage. So, beyond being involved and positive myself, I don’t have much to add.

  22. @Kimbo Jones: Hey, we agree! I felt that his article set up any opponents to be dismissed as “angry feminists”, which is part of why I was so careful to focus solely on the data and methods of interpretation.

  23. Why would it matter even if men *were* smarter than women? In any real world situation — choosing a partner, hiring an employee, etc. — we judge *individuals* on their character, intelligence, etc. Sure there are sexists out there, but they are going to be sexist whether or not they have evidence that there’s a minuscule 3 or 5 point difference in intelligence between the sexes.

  24. While I don’t think that it’s not worth studying, I have to say that I have always been incredibly skeptical (more so than usual) of any intelligence studies.

    I honestly think that this subject is as complex as, say, weather prediction but without the understanding of they underlying physics. I’m not yet convinced that we have a strong enough understanding of societal, environmental, and genetic influences, nor yet of even the underlying biology of brain mechanics to draw any meaningful conclusions.

    At best I see this kind of research as very preliminary, and any conclusions as highly suspect. I suspect that any information gleaned may be used as foundations for future useful work, but in itself not terribly trustworthy.

    Of course, I’m speaking as a lay-person who is merely somewhat scientifically literate, and whose only formal scientific training is a Linguistics degree (which has similar fuzzy areas) from 20 years ago. My opinion is likely formed from inadequate knowledge, however that merely means that I need far more information before I could be convinced of the significance of this study. As I said, I am skeptical.

  25. I think it’s really hard to any specifics to TAM attendance. The conference is less than 1500 people, and we know there are plenty of women and men able to attend the conference if so interested.

    I’ve always had a suspicion that for the first few years of the conference, that knowledge of the conference was a little clicquey, and 99.5% of the people you’d ask on the street had no idea what it was.

  26. Great post and great discussion.

    Personally, I think the most practical use of IQ measures is this: If someone reports their numerical IQ value to you in conversation, you can assume they’re not worth your time. If you want to be seen as intelligent, behave intelligently.

  27. @BigMKNows: I think that’s a really great point regarding the Professor’s claim about the 5 point difference in average intelligence. Even though a 5 point difference in a large sample is statistically significant, on an individual basis a 3-5 point difference would have no practical consequence.

    His more inflammatory claim is that men outnumber women significantly at the genius level, which in his opinion, proves there’s no glass ceiling – just less really smart women.

  28. @Stacey:

    That’s exactly what Professor Lynn claims – that there are more genius men and more stupid men.

    I haven’t read his work, but you took issue only with the claim about the genius men, I wanted to mention the other tail. The quick Wikipedia consensus @ suggests having more genius/stupids among men is well supported (not the figure of 8x, but you can probably get any ratio you want by adjusting your cutoff point), but the difference in mean has little support – and as you pointed out, the specific tests Lynn chose seemed to reach at the desired conclusion.

    Of course, lately even some of the fairly well accepted differences have been questioned, like skill at chess:

  29. No offense was taken, because I don’t feel you meant any, but my hairs stand on end when people dismiss counseling psychology as “touchy-feely.”

    My soon to be wife (in a year), is a PhD student in counseling psychology. She is every bit as skeptical as just about anyone here (although she’s too busy to read the blog much so I give her the details ;)).
    Counseling Psychology can be full of quacks and new-agey bullshit, but there is a very large core of CPs who base their practice off of scientific studies and carefully follow the new data to better help their clients/patients. But dismissing emotions and their importance to CP is foolish. There is still a lot of research that needs to be done on emotions and how they affect people. So in a practical sense, conducing therapy is an art as well as a science. A good therapist will use a scientific basis to come up with a rational conceptualization of the case and use that to guide them when they help their client.

    While researchers like Stacy’s father are very important, so are the field workers who take their data and use it in real life. My fiancee for example, uses IQ tests and Strong Interest Inventory tests in both her research and her practice, as she is interested in vocational issues.

    Again, I don’t think any of this was meant to be insulting. I didn’t feel that vibe from this post (which was very good and well written @Stacey ). I just like to point out some of this when I can, because I feel that many skeptics don’t seem to respect the need for good counselors.


    PS. As I am a SysAdmin, I may have gotten some of the details incorrect. If I have I apologize, but my overall message is good I promise ;)

  30. @jensfiederer: Yeah, I pretty much agree with everything you said. I didn’t address his claim that there are more stupid men because he seemed to offer that as an olive branch, drawing no practical conclusions about it. He used the other “tail” to support his opinion that the glass ceiling doesn’t exist.

    And yes, he didn’t make up the statistics that he used – he just omitted the fact that he relied on a test that minimizes the impact of skills at which women have been shown to outperform men.

  31. @rubbsdecvik: I’ve been called out! And fairly!

    You’re absolutely right, and believe it or not, my step-mom is a counselor who is very good at her job, and who I have a lot of respect for.

    My defensiveness came from years of getting a negative reaction whenever I mention that both my parents are psychologists because (1) people often think psychology is bs, and (2) people may be intimidated by the idea of being analyzed themselves. And I’m especially defensive writing to an audience who so highly values scientific facts.

    Sorry! I do think there are both crackpots and professionals out there, for sure.

  32. @Stacey: No need to apologize! I know exactly why you felt you had to qualify what type of psychology you were talking about. I didn’t think you meant it as insulting. And I completely understand being defensive in advance.

    It’s just one of my personal crusades to help shed light on what psychology really is. To me it’s similar to medical doctors. There are plenty of “doctors” who will sell you quackery, but there are good ones too. When medicine was a fairly young field, there were more crackpots than professionals. Now that medicine is more mature, you see a lot more professionals out there than BSers. Psychology is still young so there are a lot of crackpots to deal with, but the number of professionals is growing.

    That said. Your article is very well written and interesting. Your ideas on IQ testing is very similar to Adrienne’s (my fiancée). She views it as a tool to find one piece of the puzzle, but it isn’t everything. She and I have had long discussions on the bias of IQ tests. I was someone who thought they had a strong racial bias. Adrienne has shown me that while that is still a possibility, its more likely that other factors play into certain demographics’ performances on IQ tests. Things such as stresses and environmental causes for disparity. IQ testing is still fairly new field too, and has a lot of work to do before we can truly understand what’s going on. Until then, I don’t put a lot of stock in the actual result of IQ tests. It’s just one piece of a very large puzzle.

    Thanks for the great article!

  33. @Stacey: And that’s totally fine. You can’t be expected to be involved in EVERYTHING. :) I think just being there means you’re involved, though, even if you don’t realize it.

    The issue is highly complex — there isn’t one reason that there aren’t more women in science, or attending TAM. However, some of them are glaringly obvious, like how hostile male-dominated environments can sometimes be for women, or the fact that women are still thought of as second-class citizens in a large part of the world and even in our own country – I mean, the fact that women can be arrested for having a miscarriage in one of our own states is a pretty good example of that. Also, something that has been brought up before, is the fact that TAM isn’t necessarily a family-friendly environment – what about single mothers? They can’t bring their kids, so they don’t attend.

  34. ““He fully expects a backlash from angry feminists and the PC police.” ”

    And this is why I dismiss him as a credable scientist in this study.

    “If you disagree it’s just cause you’re stupid and have preconceived notions” is NOT complimentary to the idea of peer review. If you go straight by the data there is no reason for you to attack your critics personally. Until it’s replicated by someone else I see no reason to bother with it now.

  35. I think his “skepticism” about the glass ceiling is poor reasoning, regardless of his conclusions about intelligence differences. It’s very naive to think that the people in the highest positions are there because they are most intelligent. I guess it’s the myth of meritocracy showing up again.

  36. Very good post Stacey!

    What seems to be missing in your assessment is that a domain of the Wechsler contains non verbal questions that are very similar to the Raven’s Progressive Matrices test. So to delineate between the two tests as different is not completely accurate and would lead me to see the Wechsler as much more accurate broad based test than just the Raven’s also. It also seems that another question needs to be asked regarding the definition of genius and if the questions become exponentially fewer in discriminating who is and is not, and to what degree one is a genius. Perhaps a better tool needs to be developed to asses those who initially test above the genius level.

    Also the history of IQ testing has enormous amounts of confirming reliable data that demonstrates the test is very accurate in predicting academic and employment success later in life. That to my knowledge is not in dispute. Social and relationship success is perhaps an area where some testing domain should be developed, except it would likely look more like a psychology assessment rather than an intelligence test.

    And for some historical perspective it should be noted that the initial development of the IQ test was done by academics at the request of the Army in the early 1900’s. The Army wanted a tool to screen soldiers to determine who would be able to complete and excel in artillery training where math, complex problem solving and decision making are important. They had a high wash out rate and were wasting money training men who could not complete the course. The test that was developed helped solve this problem quite well.

    Also I wonder if there’s been any study with other primates or species to see if there are gender intelligence and problem solving differences between the male and female. I’m having lunch with a psychologist today who is an expert in the IQ and statistical analysis area of psychology and I’ll ask him about this.

  37. @BigMKNows:

    Why would it matter even if men *were* smarter than women? In any real world situation — choosing a partner, hiring an employee, etc. — we judge *individuals* on their character, intelligence, etc.

    This sort of thing matters because statistical tests can be used as evidence of discrimination – as mentioned, for example, that “glass ceiling”.

    If we can show that there are very few really smart women, and there is a job out there that requires lots of smarts, and women are rarely hired for it, then we have an explanation that dismisses claims of discrimination.

    If qualified women are being held back because of their sex, there is going to be some outrage. If women just plain aren’t qualified, hey, that’s tough, quit bitching.

    There are so many factors here that I think it is challenging to establish the existence of a “glass ceiling” with pure statistics – or for that matter to deny it. Far more convincing to me are experiments where a resume with a male name attached gets more attention than that same resume with a female name – but it’s pretty hard to do a study that goes beyond the resume stage, since most people aren’t going to be fooled about sex at the interview stage.

  38. Two things I want to add.

    1) The Pygmalion effect. Women are told they’re not as smart, so they don’t score as high.

    2) About there being 8 times as many male geniuses as women, there are differences for how male and female intelligence are distributed. The average IQ for both sexes is the same, but men disproportionately fill out the extreme ends, while women are disproportionately in the center. So, sure, there are more men who are geniuses compared to women, but there are also more men who are mentally retarded compared to women. Just giving half of the statistic is dishonest.
    And, a cite

  39. @marilove:

    Thanks for bringing the so-called “feticide” laws to my attention. I did a double-take when I saw your comment about laws against miscarriage and had to Google it.

    … Now I’m pissed at the start of a otherwise nice weekend.

  40. Okay here’s what Robert Thorndike PhD had to say when I told him about Lynn’s conclusions over lunch. Robert said Lynn’s conclusions are flawed because he does not look at all available evidence and Lynn clearly does not appreciate what the full range of gender IQ results says about what is average and what the mean is. Robert said that when you look at the bell curve spread of male and female IQ’s they consistently have the same mean. In other words the average male and the average female based on IQ mean have the same intelligence.

    Robert also said that it is in fact true and consistently shown that while males do have a significantly higher number of representatives identified as genius it must be appreciated that when you look at the deviations from the mean males have more at the high end and a similar equally higher proportion, over females, in the lower range. So in the same way men are an 8 to 1 over representation in the genius side, they are also similarly over represented in the mentally retarded or very low intelligence side. To visualize this, think of the male bell curve as being lower in the middle than the female bell curve and a bit thicker at each end. Robert said that there are even some identified genetic reasons for this difference including Fragile X syndrome which only affects men. Robert’s conclusion was that while the ends of the spectrum may be different there is in fact no discernable difference based on the mean and average which is the best representation of real differences. (This is also mentioned by Vene in his post above.)

    And for what it’s worth Robert has a substantial established reputation in this field and is the author of one of the most used college psychometric statistic text books.

  41. Well here’s my thoughts on the topic. It is very clear that IQ is a good predictor of success at school. It is also reasonably good at predicting success at work and income, but you can see how those things go together-> good at school -> good at work -> higher income. So IQ and school success correlate really highly (correlation coefficient is 0.9) so usually you can predict how well someone will do at school if you know their IQ (obviously this is not going to work on every individual, it’s not your destiny set in stone, so yeah). Personally, I think this is a pointless endeavour, can’t you just predict school success bases on previous school success? But I digress.

    So IQ correlates with school success and you can predict school success with IQ. This means you can predict IQ based on school success. Right now, girls are doing better in school than boys are. Does this mean girls have on average higher IQ’s than boys? I don’t know, because this study didn’t factor age group which is pretty important because of The Flynn Effect.

    We know that the Flynn Effect is winding down in 1st world countries, but IQ continues to increase in other countries. Maybe the Flynn Effect will take a bit longer in females than males because males got a bit of a head start in terms of education?

    Anyway, to make claims that there isn’t a ‘glass ceiling’ is out of the scope of this study.

  42. @Advocatus Diaboli: “So IQ and school success correlate really highly (correlation coefficient is 0.9)”

    I was under the impression the coefficient was 0.5, therefore having a 25% predictive value.

    Do you have a source for your number?

  43. When did we decide that people in management positions were geniuses? I didn’t see any statistics on this. Perhaps I missed it.

    Based on purely anecdotal evidence, it seems to me that the people at top management levels are, to a high percentage, retards. Most of them also seem to be crooks and assholes. That’s just my impression; I didn’t do a study or nothin’.

  44. @Agranulocytosis:
    You know what? I was doing that based off memory, which is really sloppy and I apologise. I checked in my old psych text book to refresh my memory (Psychology by Western, Burton and Kowalski (2006)) and it actually said 0.6-0.7 which is still really high for psychology but not 0.9 (thank you for catching my error, which was sheer laziness on my part). I think I was thinking 0.9 because that’s the ‘magic number’ for reliable predictions we use in my data analysis class. Makes you think about the reliability of IQ predictions doesn’t it?

  45. @Stacey: i also come from a “family of geniuses”. it’s a big, giant, catholic family; there are 35 of us in my generation, on my mom’s side alone, and i’d say most of us, regardless of gender, are in the 140-160 range. most of my cousins are still working out their life paths, so i’m not really sure if there are any budding brilliant scientists among us; there’s a veterinarian, a theologian, and a couple of construction workers so far :p

    mostly it’s fun because we’re all a bunch of nerds. despite our differences (most of them are still devoutly catholic) we share an outcast sensibility and a twisted sense of humor.

  46. There’s another problem with this kind of study (I include “The Bell Curve” thesis as well) regardless of whether the study is properly done and the conclusions of valid. Basically, if you know before you start that your conclusion will be misinterprated and used for negative purposes, is it right to publish it?

    Most people have a lousy sense of statistics. If there are two bell curves, and one averages slightly higher than the other, then the chances that any random point on one curve is higher than any random point on the other curve is only negligibly above 50%. When it comes to things like upper body strength, guys probably realize that even though men on average are higher than women, that doesn’t mean I can win a fight against a female athlete. But when it comes to something nebulous like intelligence, it’s way too easily, consciously or unconsciously, to assume “I disagree with something she says, but I can rationalize this by assuming she’s stupid.”

  47. OK.

    Well, I administered IQ tests for the better part of a decade and I was responsible for knowing all the psychometric properties of each test I administered.

    I am NOT PC about data, and I am a feminist. But neither of those come into play when I say this is a crock of horseshit.

    This guy is defining intelligence as “Scores on an IQ test.” Now, while I’m aware that all kinds of fuzzy anti-science educational folks have sufficiently made such a statement almost meaningless with their special snowflake advocacy, I mean it as this: that’s a tautology.

    What’s intelligence? A score on an IQ test. What’s an IQ test? Something that scores intelligence.

    There is much debate as to whether there is such thing as a “G” factor…an overall intelligence. We each have strengths and weaknesses. Some argue that geniuses are simply those with excess memory capacity. Blah blah. The permutations are endless.

    So simply, as a doctoral level psychometrician I have no idea WTF he even thinks he means. Yes, it’s not “popular” to say this, but that isn’t his problem. His problem is what the vast majority of psychologists’ problem is — they get fixated on the tool and don’t sufficiently evaluate the concept.

  48. Meh. The standard deviation of a typical IQ test is about 15, so a difference of 5 in the mean, even if statistically significant, means almost nothing when it comes to the next person who walks through the door.

    Secondly, integrate the tails of any two distributions with even a slightly different mean and you can make the ratio look as impressive as you like just by choosing your ‘genius’ cut-off judiciously.

    So until someone shows a difference of a standard deviation or more – which I doubt will ever happen – big yawn.

  49. Great blog; very reasonable. I have contributed one article to this topic and I do think Lynn is right in his summary of the data, but I hate evo psych explanations as they are “just so” and don’t seem falsifiable.

    It seems more likely than not that a small sex difference exists– whether it’s caused by brain size or hormones, I dunno.

    Some comments on your counters:

    It’s bizarre to look for sex differences on a test made to have none. I think the potential solution is to use elementary cognitive tasks as g estimates and then see whether the sexes vary. At least in my one study on this, they do (by about 3-5 IQ points– linked below).

    Sex and age are the only demographics corrected for. Typically sex-biased items are discarded and older test takers get points for being old. There is no correction for race differences (no one’s figured out how to do this correction while still measuring g).

    The reason it’s ok to throw out sex biased items is a principle called the indifference of the indicator. All mental test items measure g to some degree or another. It doesn’t matter what the content is (vocabulary, block design, judging line lengths), it just matters that the items are good measures of g. So, one can toss a specific sex biased item (say requiring verbal fluency which favors females) but still have plenty of other items left over to create a g-loaded, sex-neutral test.

    For a couple reasons, I think your expert’s wrong on the difficulty comments. The Wonderlic, for example, has been taken by something like 130 million people. That’s enough to get good data on really hard items.

    Also, the Ravens has a version for people of superior intelligence. It probably is the ideal test to look for sex differences if indeed there are sex differences. I remember spending 45 minutes trying to deduce the answer to one of the harder problems in the exam (some people not me can solve it in 30 seconds (anecdote). The Ravens probably can distinguish 140 from 150.

    Also, in general, the Raven’s is probably the purest measure of g. It is not measuring some narrow cognitive skill– in fact, it’s the exact opposite.

    No one is suppressing female superiority in the academic literature. There are specific cognitive abilities that show large differences favoring females. Anything sensory or perceptual shows moderate to large female advantages (except night vision). These are well-replicated / well-known effects.

    If indeed a small mean IQ difference exists between groups, then it follows that at some extreme cut point there will be 8:1 over-representation.


  50. Also, aggregating a small individual difference (3 IQ points) to a larger group (male and female scientists) produces very large differences in outcomes.

    As one example, the correlation between IQ and teenage pregnancy rates (using individuals) is a mere -.19. Only 4% of the variance explained. Yawn/who cares.

    Aggregating to the 50 US states, the correlation becomes -.71!

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