IQ and gender

I’ve been reading up on IQ and gender on Wikipedia.

Pretty funny really. If you know a lot about IQ tests and life outcome, it’s not the work of Einstein to see how some of the Lynns of this world will read SAT scores and university IQ tests as proof that women have a lower IQ, as the male average on all of these is a bit higher than female. The reason for the higher score is…that most of the really low IQ people won’t be taking those test, and they are mostly men.

It’s very simple. The lower the IQ, the more likely you are to drop out of school and not get around to sitting an exam that you know you’ll fail abysmally. If your IQ is less than 70 there is a 55% chance that you’ll drop out of high school, at 80 to 70 it’s 35%, at IQs above 120 it’s statistically insignificant (just me then).

The majority people with learning difficulties are male (about twice the number of women). The distribution for male and female IQs are a little different, women are more average, more men at the extreme ranges. From looking at the intakes of gifted schools and Mensa membership, male geniuses seem to be about twice as common as female. It skews the numbers to make male IQ look higher if you test the group minus the lowest perfoming members. If you want to test a population to find the mean, you have to test all of them. Anyone who understands statistics even a bit can see the bias.

Also, the statistics showing men to have heavier brains always fail to account for body fat differences between men and women. This is pretty important, as fat doesn’t require brain power to control it, and your IQ won’t go down  just you gain forty pounds. Long term obesity does seem to have an effect an IQ, but not just simple weight gain. The rough figures are 15% body fat for men, and 25% body fat for women. Correct for that, and there doesn’t seem to be a difference in relative mass. 

(I had this idea about a year ago, as far as I know it was original. I just looked on Wikipedia for a link, and there was my idea in print! Wow, someones either copying me, or it’s so obvious someone else has figured it out. )

There’s the issue of men performing better on the general knowledge tests. Having done some general knowledge quizes  (on a winning family pub quiz team) I can tell you why. It’s because women aren’t, as a rule, that interested in things that don’t directly affect their lives. They are more interested about the people that affect their lives, and have a better memory for other’s personal information.

It’s really that simple. Ask average woman who the prime minister is and you’ve only got an outside chance that she’ll know. Ask her the date of her best friends mums birthday though, and you’ll probably get a correct answer. Who’s the Captain in Star Trek the next generation,? No idea. What are the neighbour’s names? She’ll know most of them right up to the end of the road. It’s not that they store less information, it’s just that the information is of a different type.

As to the tests themselves, there was at least one IQ test where women scored higher than men by a few points. I suppose it depends on what kind of intelligence you think is most relevant and predictive. Women seem to do better academically than SAT scores would predict, and this does suggest that maybe the SATs do have a slight male gender bias.