WaPo spouts some hooey about sex differences

Conventional wisdom + bigger microphone = excellent journalism!

High fives all-around for Charlotte Allen who repackages conventional wisdom about sex differences to a degree rarely attained by print journalists.

My favorite part:

Depressing as it is, several of the supposed misogynist myths about female inferiority have been proven true. Women really are worse drivers than men, for example. A study published in 1998 by the Johns Hopkins schools of medicine and public health revealed that women clocked 5.7 auto accidents per million miles driven, in contrast to men's 5.1, even though men drive about 74 percent more miles a year than women. The only good news was that women tended to take fewer driving risks than men, so their crashes were only a third as likely to be fatal. Those statistics were reinforced by a study released by the University of London in January showing that women and gay men perform more poorly than heterosexual men at tasks involving navigation and spatial awareness, both crucial to good driving.

The theory that women are the dumber sex -- or at least the sex that gets into more car accidents -- is amply supported by neurological and standardized-testing evidence. Men's and women's brains not only look different, but men's brains are bigger than women's (even adjusting for men's generally bigger body size). The important difference is in the parietal cortex, which is associated with space perception. Visuospatial skills, the capacity to rotate three-dimensional objects in the mind, at which men tend to excel over women, are in turn related to a capacity for abstract thinking and reasoning, the grounding for mathematics, science and philosophy. While the two sexes seem to have the same IQ on average (although even here, at least one recent study gives males a slight edge), there are proportionally more men than women at the extremes of very, very smart and very, very stupid. (Emphasis mine.)

First, with respect to driving, those statistics may be true, but they ignore a variety of confounds that could shape the data. For example, maybe women are more likely to drive with other people in the car -- particularly with children. Maybe women are less likely to commute (most accidents as I understand it happen close to your home).

Second, driving is not a straight-out spatial task, but even if it was there is no evidence that women perform worse on spatial tasks in general. The data suggests that on average women perform spatial tasks differently than men (although there is a great deal of overlap in the distributions of that trait). For example, in spatial navigation, women are more likely to use landmarks than men. However, this trait does not generalize into a deficit in spatial ability relative to men, and it certainly does not generalize to a general deficit in mathematical ability.

Third, the sentence that "women are the dumber sex" is just ridiculous. In what way does car accidents prove that?

Fourth, the notion that brain size is correlated with intelligence or mental ability was abandoned by serious neuroscientists long ago. (In no small part because that view is closely associated with the eugenics movement. For more information read, this book by Stephen Jay Gould.) For example, fetal hydrocephalics may be born with markedly reduce brain sizes. (Hydrocephaly is a disorder where the cerebrospinal fluid builds up and puts pressure on the brain.) Though there is a great deal of variation in outcome -- usually related to how early the condition is corrected by putting in a shunt -- many individuals with hydrocephaly go on to have normal IQ. In addition, numerous species have a larger brain size in relation to total size than humans -- such as whales. Should we be attributing higher intelligence to them? The association between the brain size and function can sometimes be viable when you are talking about a brain region, but systematic differences in IQ are not related to total brain size.

Fifth, I have discussed extensively before all this business about differences in psychological ability -- particularly in math -- between men and women. (See here, here, here, and here.)

The take homes from those discussions are as follows:

  • Elaborate surveys of the psychological differences between men and women show that they differ most widely with respect to aggression and sexuality. They do not differ widely -- i.e. the distribution of traits with respect to men and women overlap considerably -- with respect mathematical ability or visuospatial skills. The data suggests that women and men are overwhelmingly more psychologically similar on average than they are different. There are much more intra-gender differences than there are inter-gender differences.
  • For the math story, there are a variety of confounds that affect the result including handedness and sexual orientation.
  • The data with respect to variance in ability is mixed. In some cases, you find equal variance; in some cases men have more. However, the notion that an "upper tail effect" can account for this discrepancy in participation of women in math assumes two things. 1) That there is a unitary ability -- a mathematical "right stuff" -- for which men have higher variance. 2) That having this right stuff makes you more successful. I discuss in detail why these assumptions aren't true here.
  • There is no evidence to suggest that these difference in mathematical ability are innate. Differences between men and women change over the course of development, and women placed in the appropriate educational milieu can reach parity.

It never ceases to astonish me how myths of this nature of bandied about so easily; however, one could respond to this criticism that "this is a fluff piece and that no one takes it seriously." Well, that is probably true. However, if Ms. Allen intended for this to be a fluff piece, she needs to keep her aspirations toward scientific discussion out of it.

It is corrosive to public's understanding of fact to have demonstrable falsehoods repackaged as a genuine scientific discussion. If Ms. Allen would like to have a discussion on the intellectual level of The View so be it, but don't try and cite data while you do it.

Categories

More like this

I was at a wedding this weekend, and I was getting in one of those conversations that drunk people get into at weddings: what are the gender differences in cognition? OK, so maybe you don't get into conversations like this with people you don't know well, but I do. Anyway, it got me thinking…
When Lawrence Summers suggested that the reason there aren't more women in the top academic positions in math and science is that they don't have the aptitude for it, a firestorm was created that may have cost him his job as president of Harvard University. Sometimes lost in the hullabaloo…
Okay, I know I promised the next entry would be devoted to Temple Grandin's views on language -- a subject well worth exploring -- but I've found myself distracted by some of my other reading this week. (So much to read, so little time.) Be assured, we'll delve into "Grandin on Language" at a later…
Yesterday, we discussed sex differences at the highest levels of achievement and found that there are some significant differences between males and females. But despite these observations, it's still unclear why the disparity exists, and what can or should be done about it. Sex differences in…

...women clocked 5.7 auto accidents per million miles driven, in contrast to men's 5.1, even though men drive about 74 percent more miles a year than women.

Well, I guess that shows that Ms. Allen doesn't understand basic descriptive statistics and what the phrase "per million miles driven" means.

Here's a random anecdote: The only accident my wife has had was in a grocery store parking lot, when she and someone on the other side of the lane were both backing out at the same time. I'm not familiar with the study Ms. Allen quotes, but I'd be willing to wager that the reason women have a slightly higher accident rate and lower fatality rate is because they do a higher proportion of their driving in settings where low-speed accidents are prevalent.

women clocked 5.7 auto accidents per million miles driven, in contrast to men's 5.1, even though men drive about 74 percent more miles a year than women.

Since these statistics are normalized for distance driven, the mention of men driving longer distances is irrelevant. Allen seems to think this makes the difference even more significant, however, as in "Wow, men drive more but get into even fewer accidents."

I want to question the meaning and the statistical validity of your statement: "most accidents as I understand it happen close to your home".
Does anyone know of documentation for this assertion? What is meant by "close"? What is the ratio of miles-driven close to home to miles-driven not-close to home? I would guess that most miles driven are "close to home" because a lot of driving is done for short trips - to the grocery store, to the dry cleaners, to school, etc. And such trips are on busy urban streets, while miles driven not-close to home are on highways with divided lanes, less stopping and starting, less cross traffic, etc. Any comments?

Yep, out of necessity, *any* short trips will increase the relative probability that any particular accident will occur close to home.

By Baba Ghanoush (not verified) on 03 Mar 2008 #permalink

Plus, of course, the idea that women are worse drivers is contradicted by the fact that they pay lower insurance premiums - to the point where some of my friends actually paid less if they added their girlfriends to the insurance.

@Jefrir: The difference is likely to be partly due to the extent of damages. AS explained above, women tend to get in more fender-benders and fewer fatal accidents.

The one age/gender category where really bad accidents are most likely to occur is in males 16-25 years. This is probably the mahor reason for the discrepancy.

Another thing to be considered is that if males do 74 percent of the driving, they have more practice and have encountered more dangerous situations, so therefore, the accident rate probably should be slightly lower.

By natural cynic (not verified) on 03 Mar 2008 #permalink

Jake,

I have no problem with your points #1-3. There's a great deal of literature out there that directly contradicts point #4. Haier, among others, has done some good work on this. A couple of starting points: 1, 2 (apologies for linking to press releases- I don't have uni access at the moment).

Neither of those studies found that men are smarter than women because they have larger brains-- and I assume the researchers would be the first to reject that inference and conclusion-- but I think you go too far by explicitly dismissing all brain size-IQ correlation. Haier has found that the size of certain regions correlate much more strongly with IQ than others, but the base brain size-IQ correlation is between .20 and .40, depending on the study and whether head size is used as a proxy, or if brain size is measured via MRI/CAT. Miller and Penke's 2007 MRI meta-analysis found r=.431.

I also feel you ignore Allen's point about more males than females at both edges of the bell curve.

Inflammatory, confused(!), and sometimes simply false hooey, yes. But seeded with some interesting facts: I don't think all of the things Allen brings up should be, or can be, categorically dismissed.

Wrong about almost everything you wrote. Serious neuroscientists are very interested in the link between brain size and IQ (really, the size of particular parts).

http://en.wikipedia.org/wiki/Neuroscience_and_intelligence

Males have higher spatial ability by about 0.6 to 0.7 SD (see Jensen's *The g Factor*). You're just focusing on "different ways of navigating," but spatial ability is a cognitive skill that has many highly correlated components.

Using a tail-effects argument about math representation does not require a unitary "math ability." That's wrong. The distribution of eminence is known to be log-normal -- has known to be this way for at least 50 years, maybe more. True for all arts and sciences. The standard explanation of a log-normal distribution is that several variables are involved, and that their values are *multiplied* rather than added.

So, males may have "small" advantages on, say, 5 traits (spatial skill, desire to sit still, desire to work with things over people, etc). But these advantages are compounded because of multiplying, like interest, and so widen the gap more than if we were adding the advantages together.

Observation for the day: conditioning on reading the phrase "demonstrable falsehood" in a piece of writing, the probability that the writing is anything other than obfuscation is negligible.

agnostic, the Wikipedia citation is not impressive. It presents a total of 3 studies reporting an association between brain size and IQ, and does not mention the long standing move away in nearly all neuroscience and psychological science from directly connecting overall brain size to IQ.

Honestly, 'g' tells us nothing about people and their potential for success on an individual level. It's little more than a bunch of test items that have been chosen because they correlate well together.

Just look up stereotype threat. Saying "there are no gender differences on this test" to participants before they take a math test causes men and women to perform equally well on it. Not saying those words will cause the typical result of men doing better than women. The change is mostly in women's performance between the two conditions (as the "threat" is removed for them) but the change also happens for men -- their confidence is removed. I hope this allows people to realize that stereotype threat is a constant issue for women in many careers, particularly math and science. If only we could remove the threat from these careers.

By Katherine (not verified) on 04 Mar 2008 #permalink