Pure Pedantry

ResearchBlogging.orgRelated to the question of why there is a gap between the genders in math and the sciences is whether there are possible means of remedy. With respect to possible remedies it is often a good idea to look internationally at which countries don’t have this problem — to see what they are doing right.

Guiso et al. used data from the 2003 Programme for International Student Assessment (PISA) which surveyed 15-year-old students from 40 countries who took identical tests in mathematics and reading. They compared this data with measures of the gender equity in these countries.

One such measure is the GGI index from the 2007 Global Gender Gap report. The index includes measures comparing the economic participation, educational attainment, political representation and health between men and women.

The authors found a significant correlation between GGI and the disparity in math performance between boys and girls. This is depicted below. (Figure 1 in the paper)


The R^2 for the correlation between GGI and math performance is .32.

The authors correlated performance on math and reading tests with other indices for cultural attitudes towards to women using data from the World Values Survey and political empowerment of women using data from the World Economic Forum. Both these indices also showed significant positive correlations with reductions in the math disparity between men and women (R^2 = .23 and .21).

The authors also considered that the difference in math performance represent systematic differences in genetics between the countries surveyed — maybe women are better at math in Norway:

To verify that these results are not driven by biological differences across countries, we analyzed whether they persist in populations that have a similar or identical evolutionary history. To assess history, we used a genetic distance measure (14-17) based on the frequency of each allele across DNA polymorphisms.

According to this measure, there are 13 European countries with genetic distance equal to zero and 26 European countries with genetic distance less than 100 (table S5). When we restrict the regression of the table (above) to either one of these two groups, our findings are substantially unchanged (table S6).

(Someone who know more about this is going to have to say whether they did that properly. That part is straining the limits of my understanding.)

Interestingly, when the authors look at reading scores, there is also a positive correlation with gender equity — only this one in favor of the girls. They calculate that as equity increases this gap will likewise increase.

The authors acknowledge that there are observable differences between boys and girls that do not vanish with increasing equity. For example, the boys are on average better at math than they are at reading in all countries surveyed. Likewise, while the overall gap in math performance closes, differences in subfields of math (geometry vs. arithmetic) do not:

These results suggest that the gender gap in math, although it historically favors boys, disappears in more gender-equal societies. The same cannot be said for how boys score in mathematics compared with how boys score in readings. Boys’ scores are always higher in mathematics than in reading, and although the difference between boys’ math and boys’ reading scores varies across countries, it is not correlated with the GGI index or with any of the other three measures of gender equality (table S7A). Hence, in countries with a higher GGI index, girls close the gender gap by becoming better in both math and reading, not by closing the math gap alone. The gender gap in reading, which favors girls and is apparent in all countries, thus expands in more gender-equal societies. Similarly, although the gender gaps in all math subfields decrease in societies with more gender equality, the difference between the gender gap in geometry (where the boys’ advantage relative to the girls’ is the biggest) and arithmetic (where the boys’ advantage relative to the girls’ is the smallest) does not (table S7B).

This is a good piece of work that I think provides a good piece of evidence in explaining the disparity between men and women in math and science. Further, these results are very similar to a study that compared the performance of male and female chess players as a function of their representation in a particular zip code. The study found that in those zip codes where there was equal numbers of men and women their performance was equivalent. Equal representation does appear to improve girls’ performance.

I have argued before — so I won’t again — that innate differences between the genders are not sufficient to explain the disparity in representation in math and the sciences. Some people have been misinterpreting me when I say that. I am not saying that no innate differences exist on average between men and women. Any gender psychologist would take a great deal of issue with that statement. (And this study supports that notion because of the failure of the superior performance of girls in reading to disappear.) What I am saying is that these differences are not sufficient to explain the disparity in representation. I will even grant that they may be part of the issue (a sum of variances approach), but from what I have read of the data I am unconvinced that the effect is very large or primary — particularly in comparison to the cultural effect that this study shows.

(Please actually read the above cited post before commenting about your prejudices to the contrary. Furthermore, since I know someone will say it: the upper tail effect is not sufficient either as men and women in the sciences do not necessarily come from the upper tail in mathematical ability.)

Now I will grant that this is a correlation study. It does not speak to the issue of causation. There could be some other cultural factor that is confounding. It could be income or access to child care, or a million other things. Also, the correlation factors — while significant — are not overwhelming. There are no doubt other issues at play.

What I am arguing, however, is that this is another piece of evidence suggesting that the disparity between men and women in math and science is primarily cultural, not innate. How are differences in innate ability supposed to account for this data? Basically for the innate differences hypothesis to be true, you have to say that not only are women and men different, they are differently different in each of the studied countries. Is that statement accurate? Is the effect of prenatal hormones on brains different enough in France and Norway to explain this effect? Does the additional X-chromosome function sufficiently differently in various countries to explain changes in performance?

I for one don’t think so.

Guiso, L., Monte, F., Sapienza, P., Zingales, L. (2008). DIVERSITY: Culture, Gender, and Math. Science, 320(5880), 1164-1165. DOI: 10.1126/science.1154094


  1. #1 Danniel Soares
    June 4, 2008

    Still, we’ll not have to wait much longer for some sort of “pro-nature” to appear and make up some explanation why this must be either some sort of mistake, or that if you do this and that you can actually measure a natural-intrinsic-innate gap. This behavior keeps repeating generation after generation, test after test, whenever any sort of innate gap may be slightly conceivable. They’ve “always” found that “now” they’ve finally measured the “real” innate gap.

    Preempting from some sort of strawman, it’s not that I think that there would never be any sort of ability gap in any circumstance, that all people are equipotent because the brain is a magical organ or something. Individuals differ biologically, and there will be innate differences in their potentials, but the whole school of thought that tended to hurriedly conclude that the apparent talents or test results of people represent the fulfillment of their innate potentials has historically been foolish.

  2. #2 zy
    June 4, 2008

    Does the additional X-chromosome function sufficiently differently in various countries to explain changes in performance?

    Medical anthropology, while I haven’t read widely in the field, seems to suggest the answer can be Yes. I was particularly intrigued by studies of menopause and how it manifests in physically different ways in different countries. Societal expectations may explain most of it but nobody can rule out that the bio-chemistry and brain chemistry of a Japanese woman, for example, isn’t different from that of a Japanese-American. Is the very sparse occurence of hot flashes among women in Japan explainable in terms of cultural expectation or are there bio-chemical differences built up during their lifetime and in their particular nutritional, geochemical, and behavioral-chemical environment? Adapting the question for math ability, can we rule out dietary reasons for the gap in women’s math ability in Italy and France, for instance, compared to Poland and Portugal? Perhaps carbohydrate consumption patterns have long-term affects on brain development. Perhaps Nordic populations’ consumption of different fatty acids stimulates brain chemistry one way, and different U.S. consumption patterens another way.

    I’m of course quibbling with your wording, rather than the point you’re making. The lines of enquiry opened up by medical anthropology seem if anything to reinforce the primary role of culture. It is often forgotten that culture is physical as well as mental.

  3. #3 zy
    June 4, 2008

    Correction to 3rd sentence in my second paragraph: nobody has ruled out. Properly designed research potentially can or could rule out.

  4. #4 agnostic
    June 4, 2008

    So, girls may or may not be able to give the equation for the directrix of a parabola, and meanwhile boys can’t read. Honest question: do you think that boys score lower than girls on reading tests because of sexism, however covert, against boys? What’s good for the goose…

    Their “can’t be genetic” argument is bogus. “Genetic distance” refers to neutral loci, so they tell us nothing about any observable phenotype. For example, Australian Aborigines and sub-Saharan Africans are very distant in this neutral genetic space, but they look fairly similar in many ways.

    You see the converse too: Ashkenazi Jews resemble other Middle Eastern groups at neutral sites, but if any other Middle Eastern group living in the West is brainy and dogged enough to win Nobel Prizes, etc., at about 10 times the rate you’d expect by chance, it’s a well kept secret. The reason is that Ashkenazi Jews differ from other M.E. groups at loci that are involved in neuronal function, which likely makes them smarter.

    What the authors would have to do is look at loci involved in math ability (or IQ or something) and show how the frequency of math-promoting alleles across countries didn’t predict between-country variation in the math gender gap. An analogy would be looking at genes that protect against some infectious disease, and the prevalence of that disease.

    For example, when Africans were first brought to the US, they probably had the same frequency of the sickle-cell allele as Africans back home. However, malaria was a lot less prevalent among Af-Ams — not because of genetic differences, but because there were less anopheles mosquitoes.

    You didn’t explicitly make this point, but I sense lurking beneath the surface here the idea that sources of variation between countries tell us something about sources of variation within countries. Maybe women in one country are closer to men than in another due to sexism — but that doesn’t tell us why, even in the non-sexist country, women still don’t dominate in math and science.

    Take height: probably a fair chunk of variation between countries is due to poor nutrition, endemic disease, presence or absence of modern medicine, etc. But within the developed world, height differences are mostly due to genetic differences, since we all have decent nutrition, low disease burden, access to flu shots, etc.

  5. #5 agnostic
    June 4, 2008

    My honest question should read: do you believe that gender gap in reading, which is always larger than the math gap, even in more gender-equal countries, is due to sexism against boys?

    Simple transitivity seems to require it: if you think it causes the puny math gap, it ought to contribute as much to a much larger gap.

  6. #6 limes
    June 4, 2008

    agnostic, welcome to Patriarchy Hurts Men too!

    If reading is viewed as “girly”, as “unmasculine” (this is obvious in our culture – consider all the manly-man heroes marketed to boys. How many of them read/try to learn?) then many boys will NOT READ. Or they will NOT READ WELL.

  7. #7 Eileen
    June 4, 2008

    “Non-sexist country?”

    Ha hah haaaah.

  8. #8 clew
    June 4, 2008

    I think it’s obvious that sexism hurts boys too; and one of the subtle things about that is that it’s part of the patriarchy that a few boys grow up to be in charge, and a whole lot prowl around on the edge of the herd and get nothing. (I don’t know how to tell if this is part of sexism, as a kind of Just-So animal logic; or if it’s classism yoked into service.) And it’s not hard to guess, looking at two classrooms in my country, which category the boys are likely to fall into.

    The thing about -ism is that it doesn’t matter which group is better at something; the things the group on top is good at will be more respected and better paid.

  9. #9 Veltyen
    June 4, 2008

    There is here in Australia (and I would suspect throughout much of the English speaking world at the present time) a strong bias against male teachers. Specifically because of a pre-supposition that any male wanting to spend time with children is a paedophile. As the society becomes more equal this bias becomes stronger, as it would be derived that there are more qualified women for these positions.

    This is even stronger in what are considered effeminate areas, such as the social sciences including language teaching, and also stronger in primary school teaching.

    While I’m not sure of the research into the differences in outcomes by gender measured against the gender of teachers, I would suspect that this would lead to lower outcomes for male children in education. Learning in effect becomes perceived as “womens work”, and may end up being outright rejected by male children.

    As more educators end up being biased towards one gender that gender would perhaps end up with more successful outcomes from education. Hence a closed gap where there was a negative influence, and an increased gap where there wasn’t.

    It would be interesting to see any research into single gender (both students and staff) institutions and educational outcomes.

    Apologies for the compounded conjectures.

  10. #10 Dan Evans
    June 5, 2008

    La Griffe Du Lion proves that the innate differences in IQ between men and women can account for all the disparity in mathematical achievement. Although the male/female IQ difference is less than 2 points, this translates to a significant percentage on the right tail of the bell curve where an individual must be to perform well in the math and science fields.



  11. #11 Luna_the_cat
    June 5, 2008

    A few quick thoughts:

    There is a profound cultural difference between Jews and Arabs, even though there is a close ancestral link. And anyone who argues that culture has no real effect on approach to education and academic achievement in general, needs a fast, hard reality check applied upside the head.

    And, dear old La Griffe seems to start from the premise “Mathematics is a man’s game” and seeks justifications from there, even going back to the old hypotheticals about “man the hunter vs. woman the forager” leaving men with better “visuospatial proficiency” and thus…proficiency for maths. Most of his own maths, however, consist of a rehashing of the status quo in order to show that it is statistically inevitable that men dominate; he offers nothing above the level of unsubstantiated hypothesis for the reason for the existance of the status quo.

    Considering he also subscribes strongly to the idea that IQ is racial and genetic, and that white males are unsurprisingly top of the heap because they have far more top-flight performers; the fact that he blissfully ignores the fact that chemistry, biology and medicine were defended as the province of men with near-identical arguments, which has quuite rightly been discredited in the face of the number of women now in the field; and the toxicity of his smug assurance that the status quo is what it is because that is what it must be, along with the paucity of actual data dealing with instances where it, well, isn’t — just sayin’, perhaps you don’t want to go there.

    …As a semi-unrelated side note, @agnostic — considering the nature of your own blog, your “I’m not sexist, just asking an innocent question” pose here does not carry any credibility.

  12. #12 Tony Jeremiah
    June 5, 2008

    Is the effect of prenatal hormones on brains different enough in France and Norway to explain this effect? Does the additional X-chromosome function sufficiently differently in various countries to explain changes in performance?


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