Sex and smarts: The sequel

Posted: Friday, September 29, 2006 4:33 PM by Alan Boyle

Three weeks ago, we took a look at research from University of Western Ontario psychologist J. Philippe Rushton - reporting that 17- to 18-year-old men had an advantage of several IQ points over women, based on an analysis of SAT scores. Virtually everything about the politically incorrect study could spark a controversy: How do you define "g," the measure of general intelligence that Rushton looked for within the SAT tests? Are g scores, or even IQ scores, a valid measure of intelligence? Are there statistical or societal factors that could distort the scientific results? And the questions go on and on....

Anyway, Rushton sent along an e-mail today that could shed more light, as well as heat, on the issue of gender and intelligence. The tone of the correspondence is a bit academic, but feel free to digest it and add your comments:

"What a difference a day makes. Just 24 hours ago, I was telling a newspaper reporter that my confidence in the finding that men average higher IQ scores than women would be greatly enhanced if new studies could be found in support. These new studies, from other than the 'usual suspects,' are now to hand.

"The finding of a male IQ advantage of 3.6 points on g from the SAT by Jackson and Rushton (2006), as earlier of 4 to 8 points by Richard Lynn, Paul Irwing, and Helmuth Nyborg, is validated by reaction time (RT) measures. The effect size of 0.24 favoring males found by Jackson and Rushton is matched by simple and choice reaction time (SRT and CRT) effect sizes of from 0.17 to 0.40.

"RT tasks are so easy that 9- to 12-year-old children can perform them in less than one second. Children with higher IQ scores perform faster than children with lower scores, because RT measures the efficiency of the brain’s capacity to process information, which is the same ability measured by intelligence tests. SRT correlates with IQ about 0.20, while CRT correlates about 0.40 - in aggregate, RTs can correlate 0.70 with IQ (Jensen, 2006).

"In a meta-analysis of 72 effect sizes derived from 21 studies (N = 15,003) of SRT over a 73-year period, Silverman (2006) found both secular trends and an effect size favoring men of 0.17. Several small sample studies have also found that men average faster on CRT, such as the Bonn Longitudinal Study of Aging (Mathey, 1976; reviewed in Deary & Der, 2005).

"The most definitive evidence comes from two recent population representative studies by Deary and Der, carried out to examine aging effects.

"In the first, Deary and Der (2005) tested [more than] 500 16-, 36-, and 56-year-olds from the West of Scotland. Participants were retested eight years later, at which time they also took the g-loaded Paced Auditory Serial Addition Test (PASAT). Individual differences on the RT measures were stable over the 8-year period (r ~ 0.50), correlated with the PASAT scores (mean r ~ 0.25), and declined with age (CRT from age 20; SRT from age 50). Importantly, men scored higher on PASAT (d ~ 0.20) and averaged faster on RT, especially on one of the CRT measures (d ~ 0.40).

"In the second study, Der and Deary (2006) reanalyzed data for 7,130 adults in the UK’s Health and Lifestyle Survey. Again they found CRT declined from age 20, SRT from age 50, and men consistently averaged faster.

"In conclusion, uncertainty over whether males really do average higher in general mental ability, a finding that has been missed for nearly 100 years, is considerably reduced."

References

Deary, I. J., & Der, G. (2005). Reaction time, age, and cognitive ability: Longitudinal findings from age 16 to 63 years in representative population samples. Aging, Neuropsychology, and Cognition, 12, 187-215.

Der, G., & Deary I. J. (2006) Age and sex differences in reaction time in adulthood: Results from the United Kingdom Health and Lifestyle Survey. Psychology and Aging, 21, 62-73.

Jackson, D. N., & Rushton, J. P. (2006). Males have greater g: Sex differences in general mental ability from 100,000 17- to 18-year-olds on the Scholastic Assessment Test. Intelligence, 34, 479-486.

Jensen, A. R. (2006). Clocking the mind: Mental chronometry and individual differences. Oxford: Elsevier.

Silverman, I. W. (2006). Sex differences in simple visual reaction times: A historical meta-analysis. Sex Roles, 54, 57-68.

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Comments

To borrow from an old sci-fi story by Poul Anderson, IQ tests are biased towards "Western" civilization - a Kalahari bushman (or woman, for that matter) would laugh if they knew the tests omitted water-finding ability. What is presented as a means of measuring intelligence works within very narrow constructs. I'd ask my Ph.D. psychologist wife for her feedback, but she laughs nearly as hard as I do at the absurdity and cultural biases built into these things.

Rick Dawson (Sent Saturday, September 30, 2006 1:40 AM)

Rick: We must test intelligence as relevant to our culture. You wouldn't consider asking a large group of techies intelligence-based questions on the subtleties of water-finding and wilderness survival skills, would you? Hardly. You'd ask them questions relevant to their culture (read, "Western IQ tests"), or you'd end up with results that were disproportionately low. Neither would you ask those Bushmen questions relating to American high-school math. One cannot adequately test the ability of individuals to obtain, retain, and utilize knowledge if one uses information that nobody in the test group has been exposed to. As far as gender bias is concerned, I challenge you to bring forth any evidence of such. No, the fact that men are performing better does not signify bias. It merely signifies better performance by men.

L J, Cincinnati, Ohio (Sent Saturday, September 30, 2006 12:26 PM)

What is really missing is intuition. Now my wife new what our children really wanted, were I never had a clue. Women are more aware of their surroundings and how it relates to the issues at hand. Another was her ability to know what was ailing our children before the doctors could diagnous the ailment without a test. As Rick noted, these test do not show how that IQ is applied to every day life. Notice that some high IQ males use the word uh and ah between words. That shows the inability to proccess their thoughts and require time to think about the next word to reach the point of their and lack the ability to talk and think at the same time, -chew gum and rub their head at the same time-.

Walt tortorici, Morgan Hill, Calif. (Sent Saturday, September 30, 2006 2:22 PM)

Of course men are better at single-minded tasks, but watch their scores plummet once you add a few more tasks into the mix.

Adam, Brisbane, Australia (Sent Saturday, September 30, 2006 6:58 PM)

Measure any one thing in a large group of objects and you will get a bell shaped curve. IQ: Bell curve: low IQ, some to the left, a few brain dead to the left of left. Hi IQ: some to the right, Superstars,a few to the right of right. The rest of us more or less in the center. You can shift the bell curve a little to the right or left depending on what and how you measure but, if you are measuring humans, it is the individuals to the "right of right" who make the difference (male,female, black, white or green) not the curve average, which is just statistican's fun.

Jim Cooper, Sierra Vista, AZ (Sent Sunday, October 01, 2006 8:58 PM)

Alan, it's a mistake for you to promote Rushton's work to a popular audience with simply a reference to its "political incorrectness" as a marker of how controversial this man and his work are. It isn't simply "politically incorrect:" Many serious people view his research and theories as quackery. Even a quick perusal of his web site shows it to contain many, many strange things.

Larry Birnbaum (Sent Monday, October 02, 2006 12:02 AM)

I just have to wonder... who cares? It seems the study has little purpose other than to stir up controversy. Even if we presuppose that it's entirely accurate, it doesn't really give you policy prescriptions -- knowing that men, in aggregate, are 3.6 IQ points higher than women, in aggregate, tells you absolutely nothing about the relative intelligence of any particular man or woman. About all it tells you is that if you find a very, very small income discrepancy in men and women, then it's probably not due to discrimination, but due to a very, very small IQ discrepancy. Except that even this is worthless, because there's a very large income discrepancy caused by much larger factors (e.g. differences in education, the fact that many more women leave work for years or decades to raise children than man do.) He says he doesn't want controversy, but frankly, I don't see what else he's contributed.

Grant, Redmond, WA (Sent Monday, October 02, 2006 12:07 AM)

Wow. Paragons of scientific thought we have here. A PhD in Psychology doesn't necessarily relate to expertise in the intelligence controversy - awareness of it, yes: expertise, no. PhDs are not omniscient. Actually, intelligence tests are designed (obviously not perfectly) to test abilities that are present across cultures - i.e. mental rotation, short-term memory capacity, working memory, etc. The fact the tests are designed primarily by WASPs is pertinent, but not necessarily fatal. Intuition? Einstein also believed in intuition. Perhaps intuition is simply the ability to perceive and synthesize subtle cues (actually a measure in classical IQ testing). And perhaps your wife's experience with her child gives here a significant advantage in determining what is wrong with them/what they want. Would you not say that it's significantly easier to make those determinations for someone you know well than for someone you don't?? Finally, EVERYONE's performance parabolically falls off when performing multiple tasks. Period. The ability to perform more than one demanding task at a time is small in humans. In fact, even performing multiple simple tasks sees dramatic rises in time to complete and error rates. For both men and women. Perhaps a confound may reside in the socialization that boys and girls receive. Let's face it: male and female children are not taught the same behaviors. They are treated differently in school such that boys are reinforced more for being competitive, answering questions, and generally being "smart". While women face stigma where intelligent women are not desireable, while being taught to be more timid and tractable. But no. This is not a confound to the research cited above. There are periods during which an animal (yes, this means people, too) must receive the proper stimulation or their ability to perform in specific areas is permanently reduced. They're called Critical Periods, and they exist for cognitive and sensory capacities.

Jacob, Fargo ND (Sent Monday, October 02, 2006 10:20 AM)

Equating speed to answer with intelligence is a pretty poor measure. So, if I randomly select solutions very fast, I am smarter than another person making the same randomly selected solutions at a slow speed? The study is flawed in conception. And, there is no mention about the error in these measurements. A 3 to 4 point difference seems to be so small that no conclusions can be reasonably made. If 3 to 4 points is significant, then maybe the test is too short.

Steve, Las Cruces NM (Sent Monday, October 02, 2006 1:19 PM)

I think something being overlooked is interest. Regardless of weather it's a man or woman, people are always able to interpret information faster if there interested in the subject. Our brains are wired for certain tasks, some meaningful some not. My sister could easily process any number of relationships and information regarding pop culture icons, where as if i was tested, I'd probly be designated as mentaly handicapped. Inteligence to me has always seemed to be more of an application based idea. The better you can apply the information at hand the "smarter" youd be, culturally and sexually biased tests, do nothing to show any level of intelligence other then information regurgatation. In college I can clearly remember the studants who got straight a's were deemed "highly" intelligent, but wouldn't be able to think there way out of a paper bag. Intelligence is more related to creativity, then to actual knowledge retention or how fast you can solve a 9 piece puzzle. My IQ was tested at 147, but I've never been able to spell. Not mind you, because im not intelligent, but because i dont care about the difference between their, there, and they're. I am more inclined to the duality of standing waves.

Ken Concord, California (Sent Monday, October 02, 2006 7:53 PM)

How come no one is concerned about the finding that cognitive abilities drop off with age? I mean, I’m getting older so doesn’t this finding also mean that the measures must be flawed? Or how about the finding that there are any individual differences at all, for surely we were all created equal, right? If the research does not conclude with results that meet our expectations, or if it suggests that there is some difference between groups of people, then certainly it must be flawed! After all, all the great research confirms things we already know, and if not, then certainly there is a problem with the research.

Sean, Jamestown, NY (Sent Monday, October 02, 2006 8:01 PM)

I have bi-polar disorder, and this makes me *faster* than other people. Consequently, I learn faster, talk faster, and am able to take tests -- such as the SAT -- faster than other people. I had only 2 mistakes on my SAT and I took a timed on-line IQ test and got some ridiculous number that must be too high. Being female, I also have an advantage over men regarding multi-tasking, so I can do better when distracted. If speed equals intelignece, why are fast people who have bi-polar considered having a "disorder" instead of normal people being considered having a "disorder"? One reason is that being fast isn't always good! From studying Artificial Inteligence (I programmed parts of a neural network in college), I can also tell you that when you make a computer learn "faster", it does not make it learn *better*. The learning curve is shaped like a "U" with the correct answer the lowest point on the "U". Lets say this "U" is 10 inches high. There is a formula, which i forgot, that determines how we and A.I. learn, but the basic idea is that you start at a random point and you get closer to the bottom point/correct answer by increments. If you start at a random point and learn by small increments (say .1 inch) toward the lowest point it will take longer but you will get closer to the correct answer than a fast person, like me, who will always bounce around a significant distance away from the lowest point because the learning increment is too large (say 5 inches). If you learn by going down 5 inch down the curve, you will bounce around the bottom by an average of 2.5 inch away, but if you learn by .1 inches, it will take longer but you will get closer to the bottom. And if you learn TOO fast, such as (distance to botton times three), you get further and further away from the lowest point instead of closer. People not familiar with Artificial Intelligence of similar theories or learning just have to take this on faith or research them themselves. BTW, intuition is part of neural-networks, just random connections going together. Neural networks are made of nodes and connections. Men have more grey matter (nodes) and women have more white matter (connections between nodes). This is a biological fact that was determined by looking at brains. I forgot how looked at it and when. Women's having less grey matter and more white matter means that in a woman's brain, everything is literally connected to everything else, and this makes creativity easier. Women complain that men keep things "compartmentalized". This is because they naturally lack connections in their brains. I do find that men are only able to think in streight lines, as soon as you take a detour to tie in some other fact or idea into your first idea, a man's brain over-flows and he stops listening. the man thinks that women ramble, but only because his own brain is too limited to follow down all the side-roads and see the big picture. Saying men are smarter is like saying "men are better drivers". As far as turning the wheel ang hitting the break goes, men ARE better drivers. And yet, with all of those driving advantages, men get into many more accidents than women do! Hmmm -- which one is smarter now?

Corwyn Green, Stamford, Ct (Sent Monday, October 02, 2006 10:27 PM)

It's quite simple, really - men get into many more accidents than women because of the many hazards created by women swerving on and off the "side-roads" across the highways.

Dan Rooney, Houston, TX (Sent Tuesday, October 03, 2006 8:01 AM)

What sort of uproar would there be if it was proven that women exhibited a 3-4 IQ point advantage? Probably not much of one. Where's the uproar when socio-economic studies are showing that women are graduating in increasing numbers, with higher degrees (no problem here, mind you) and the number of men graduating is *falling*? Where's the concern? Oh, it's ok, because the big bad brutish men are "getting theirs!" Please, come off it, all of you, and take this for what it is: it shows that, in a very *particular* situation, men exhibit a slight tendency to score "better" than their female counterparts. There are complementary *particular* situations that women will be guaranteed to hold, with an iron grip, an advantage in. What really is illustrated here, in particular with all the comments many of you are indignantly typing in, is an overall psychosis that cannot get over the fact that men and women are different, and necessarily so. The state of denial that everyone is in, that gender comparisons of capability must always show as either neutral or in favor of women, else it's completely fallacious, is rather sickening. Get over yourselves, women, and men: stop being so apologetic, already. You are ALL "better" at something or other, men AND women!

Michael Jaars, Atlanta, Ga (Sent Tuesday, October 03, 2006 8:59 AM)

I'm dumb, I admit it. I have been diagnosed with adult ADD....whatever. Did anyone see the Titans/Cowboys game? Go Cowboys! But oh yea, umm, uh, back to what I was saying, I'm dumb. Bad short-term memory(?), but I have a have an IQ around 150. Someone tell me what's up with that! I'm a musician, a good one, but tell me to divide 450 by 45 and I'll have to think for a while.......10! But ask me about physics or history and I can spit out some crazy stuff instantly, but i have a GED, yet I'm smarter than most of the people who graduated at my highschool. How 'bout them Cowboys!? Yea, you get the picture, intelligence is hard to figure out. Those genius scientists can't give me a clear definition of a planet, I can't count to 100 without skipping a few numbers. I think it's not what you know, it's how you use it.

James S., Springfield, TN (Sent Tuesday, October 03, 2006 11:33 AM)

I NEVER CONNECTED FAST REACTIONS WITH A "FAST" MIND. IT IS A REASONABLE CONCLUSION. I ALWAYS KNEW I WAS INTELLIGENT AND HAD SUPER FAST REACTIONS - NOW I BELIEVE THEY ARE RELATED. I CAN RECALL NO ONE I EVER KNEW WHO HAD FAST REACTIONS THAT DID NOT HAVE A BETTER THAN AVERAGE MIND.

LARRY G DUNCAN (Sent Thursday, October 05, 2006 2:36 PM)

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