Toward a cultural explanation of the math gap

August 13, 2010

Ok, so, we’ve arrived at the end of our Lise Eliot series. It’s time for the math gap.

Recall this, from my John Tierney post:

The Duke researchers — Jonathan Wai, Megan Cacchio, Martha Putallaz and Matthew C. Makel — focused on the extreme right tail of the distribution curve: people ranking in the top 0.01 percent of the general population, which for a seventh grader means scoring above 700 on the SAT math test. In the early 1980s, there were 13 boys for every girl in that group, but by 1991 the gender gap had narrowed to four to one, presumably because of sociocultural factors like encouragement and instruction in math offered to girls.

Since then, however, the math gender gap hasn’t narrowed, despite the continuing programs to encourage girls. The Duke researchers report that there are still four boys for every girl at the extreme right tail of the scores for the SAT math test. The boy-girl ratio has also remained fairly constant, at about three to one, at the right tail of the ACT tests of both math and science reasoning. Among the 19 students who got a perfect score on the ACT science test in the past two decades, 18 were boys.

Meanwhile, the seventh-grade girls outnumbered the boys at the right tail of tests measuring verbal reasoning and writing ability. The Duke researchers report in Intelligence, “Our data clearly show that there are sex differences in cognitive abilities in the extreme right tail, with some favoring males and some favoring females.”

The really weird thing about such arguments is how the people advancing them (usually white men) seem loathe to acknowledge that we could still be living in a sexist society. When Larry Summers made his comment about the possibility of men being innately more gifted at math than women, here’s what Steven Pinker told the Boston Globe:

Pinker said one explanation for this finding [that more men than women get the lowest and highest scores in IQ and math tests] may lie in a tenet of evolutionary biology, which holds that organisms try to maximize the survival of their genes in future generations. According to this theory, because men can have many more offspring than women, nature takes more risks with the genes that parents pass on to their boys. One result is that men are more likely than women to end up at the extremes of intelligence.

First, it’s just a weird argument to make, given how little we know about the biological basis of most higher mental functions, not to mention the evolutionary origins thereof. And second, has Pinker ever heard of stereotype threat? Thank God the Globe writer had:

[T]here are other possible explanations for this finding, ranging from test bias to a well-documented “stereotype threat” – a feeling of discomfort when women fear that they may fulfill a negative stereotype about their group.

Women’s math scores are also known to fall when the proportion of men in the room increases, a further indication that test scores are an imperfect measure of ability.

Pinker devotes six pages to the concept of stereotype in The Blank Slate, where we learn that categorization is — you’ll never believe this — biological! And just as would we expect from a biological capacity evolved to help us make important decisions in the wild:

People’s stereotypes are generally consistent with the statistics, and in many cases their bias is to underestimate the real differences between sexes or ethnic groups. (204; emphasis his)

He does allow some “important exceptions”:

Stereotypes can be downright inaccurate when a person has few or no firsthand encounters with the stereotyped group, or belongs to a group that is overtly hostile to the one being judged. (204-205)

Hmm, we have firsthand knowledge of men and women, right?

What are the implications of the fact that many stereotypes are statistically accurate? One is that contemporary scientific research on sex differences cannot be dismissed just because some of the findings are consistent with traditional stereotypes of men and women. Some parts of those stereotypes may be false, but the mere fact that they are stereotypes does not prove that they are false in every respect. (205)

Please don’t misunderstand him, though:

The partial accuracy of many stereotypes does no, of course, mean that racism, sexism, and ethnic prejudice are acceptable. (205)

Quite a ringing indictment of our racist, sexist society. Say, isn’t homophobia kind of like overt hostility to women? So, wouldn’t that mean we can’t trust our stereotypes about women?

I’m just sayin’.

Ok, so let’s see if Lise Eliot can straighten us out. As in our previous installments, she has her eye primarily on childhood development:

If girls have the advantage in verbal skills, boys have it in the spatial domain — the ability to visualize and manipulate objects and trajectories in time and three-dimensional space. Sex differences in spatial skills are among the largest of the cognitive gaps. The average man can perform mental rotation — that is, he can imagine how a complex object would look when turned around — better than up to 80 percent of women.

In 2008 two research groups reported a sex difference in mental rotation in babies as young as three months of age, and other evidence suggests that this skill is influenced by prenatal testosterone. Yet the actual size of the skill gap is much smaller in children than in adults: among four-year-olds, the average boy outperforms just 60 percent of girls. So it seems likely that the skill improves in boys thanks to the wide range of visuospatial interests — targeting, building, throwing and navigating through innumerable driving and shooting games — that they pursue far more than girls. In support of this idea, neurobiologist Karin Kucian and her colleagues at University Children’s Hospital in Zurich reported in a 2007 study that boys’ and girls’ brains display similar MRI patterns of neural activity while performing a mental rotation task that, as a 2005 study by the same researchers revealed, evokes different responses in the brains of adult men and women. So it appears that boys’ and girls’ brains diverge in spatial processing as they grow and practice different skills.

Ok, it’s a hand wavy argument, and God knows what to make of MRI studies, but it’s more culturally grounded than the evolutionary stuff.

The spatial skills gap, which Eliot sees as largely cultural, is critical to her overall argument:

Spatial skills are important for success in several areas of science and higher math, including calculus, trigonometry, physics and engineering. Research by educational psychologist Beth Casey of Boston College shows that the spatial skill gap between boys and girls largely accounts for the consistent male advantage on the math SAT exam, an obvious hurdle for admission to engineering and other technical degree programs.

I’ve started digging into Casey’s studies. I’ll let you know what I find out.

Here’s Eliot’s policy recommendation, as it were:

As important as they are, spatial skills are not something we deliberately teach in school. But many studies have shown they can improve with training, including playing video games! If boys naturally get more such practice in their extracurricular pursuits, girls may benefit from greater exposure to three-dimensional puzzles, fast-paced driving and targeting games, and sports such as baseball, softball and tennis.

In other words, the best experiment you could do on sex differences would be to treat boys and girls alike and see what happens. Who knows. We might even like it.

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2 Responses to “Toward a cultural explanation of the math gap”


  1. […] Toward a cultural explanation of the math gap […]


  2. […] toward postmodernism, I’ve come down hard on the side of culture over biology in the case of sex differences, in particular, and honestly, I am not in full enough command of the empirical details to be making […]


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