Why do so many scientific studies highlight gender differences?


When science journalist Angela Saini was on book tour, a man approached her from the audience. He stuck his face right up in hers and backed her body into a corner. All this to spit out: “Women just aren't as good at science as men are. They've been shown to be less intelligent.” Saini listed names of celebrated female scientists and cited a few studies, but he wouldn’t budge. "In the end," she admits, "I gave up. There was nothing I could say for him to think of me as his equal."

Earlier this year, Saini published the book that man should have been reading instead of denigrating women in STEM. It's called Inferior: How Science Got Women Wrong, and the New Research That's Rewriting the Story

Inferior is "a set of scientific arguments...to reinforce that equality isn’t just a political ideal but every woman’s natural, biological right," Saini writes in her introduction. Through 100+ years of biology, anthropology, and neuroscience research, she illustrates that many studies on hard-wired gender differences have been debunked, exaggerated, or misinterpreted by the press. Few of these studies have been successfully replicated. Female scientists have even conducted research with different results, only to find their male counterparts were unwilling to acknowledge them. Scientific journals looking for cutting-edge research don't showcase the majority of gender difference experiments, which reveal that there aren't many differences at all -- at least not statistically significant ones.

Worst of all, these dubious "facts" are perpetuating myths on gender that still haunt women today. Over the next three Sundays, I’ll be sharing three scientific studies that Saini dissects in Inferior. I hope these give you counterarguments whenever somebody tries to tell you how your female brain works. 

Simon Baron-Cohen & "Systematizing-Empathizing" Brains

Remember Larry Summers, the former president of Harvard who insisted women's brains are worse at grappling with STEM subjects? The study used to defend his remarks was an experiment done on infants, testing the hypothesis that girls are born as empathizers and boys are born as systematizers. Simon Baron-Cohen, a psychologist and neuroscientist at Cambridge University, led the charge.

The study was run on over 100 babies around 2 days old. These newborns were supposed to represent “nature untainted by nurture,” Saini writes, their brain in its most natural state before gendered socialization. What comprised the experiment?

“Every baby was shown a face, which happened to be [graduate student] Connellan’s own, and a mechanical mobile made from a picture of Connellan’s face. They then measured how long every child looked at each one, if they looked at all. This long-established experimental method in baby research is known as “preferential looking.” More socially inclined babies, the researchers hypothesized, would prefer to stare at the face, while more mechanically inclined babies might choose to look at the mobile.”

When the results were published, they caused a shock wave:

“A large proportion of babies showed no preference for the face or the mobile. But around 40 percent of the baby boys preferred to look at the mobile, compared to a quarter who preferred the face. Meanwhile, around 36 percent of the baby girls preferred the face, while only 17 percent preferred the mobile. It certainly wasn’t the case that every boy was different from every girl, but, in research terms, the difference was statistically significant, enough for the scientific community to take notice. In the published paper, Jennifer Connellan, Simon Baron-Cohen, and their colleagues argued that this was overwhelming evidence that boys are born with a stronger interest in mechanical objects, while girls tend to have naturally better social skills and more emotional sensitivity. 'Here we demonstrate beyond reasonable doubt that these differences are, in part, biological in origin,' they wrote.”

Today, the Baron-Cohen study is a go-to for academics looking to prove sex differences. Saini notes that the results have been cited “at least three hundred times in other research papers, as well as in books about pregnancy and childhood.” Aside from being used to defend Larry Summers, they've also been conjured by Harvard’s Steven Pinker and LSE’s Helena Cronin “to argue that innate differences between the sexes exist.” The experiment also became a major factor in Baron-Cohen publishing his broader "empathizer-systematizer" theory. “Its basic message,” Saini writes, “is that the “female” brain is hardwired for empathy, while the “male” brain is built for analyzing and building systems, like cars and computers.” Baron-Cohen's reasoning is that male fetuses are exposed to more testosterone in the womb, which he links to systemizing behavior. Girl babies, with their lack of testosterone, are left behind. 

Suffice it to say that there are problems with the Baron-Cohen experiment. Since its findings were published in 2000, other scientists have not only discovered multiple errors in the experiment design, but have failed to replicate the results. They’ve even conducted new experiments with results contradicting Baron-Cohen’s conclusions. Here are the specifics:

1. the researcher knew the gender of many infants she tested.

The researcher who completed the study was Jennifer Connellan, Baron-Cohen’s 22-year-old graduate student. It turns out she knew the gender of many of the infants she tested. Psychologists say that this error introduces bias into the experiment and “makes it hard to take the results seriously”:

"New York psychologists Alison Nash and Giordana Grossi dissected the experiment in forensic detail and catalogued a string of problems, big and small…Their most damning criticism was that Connellan knew the sex of at least some of the babies she was testing. This could have caused any number of subtle biases. For instance, consciously or not, she may have moved her head to make the girls look at her longer, Nash and Grossi pointed out. The need to avoid this sort of problem is exactly why scientists are advised to carry out these studies blind, without knowing the sex of their subjects."

Today, Connellan even admits these shortcomings and likens the experiment design to a “science fair project.” She paid the price when it came time to defend her work for her doctorate, failing the first round before eventually succeeding with a new panel. When she spoke to Saini for Inferior, she attributed the design flaws to her lack of experience at the time.

2. children don't show toy preferences until around twelve months. when they do, it's not linked to testosterone.

The results of Baron-Cohen’s study have never been replicated, which is a flag that the findings are still unreliable. As psychology professor Melissa Hines tells Saini, “A lot of research findings never get replicated and probably are false...It’s just the way science works. You can’t study the whole world, so you have to take a sample, and your sample may or may not be representative.”

That’s why Hines has stress-tested many of her own experiments on babies’ and toddlers’ toy preferences. She’s conducted several studies that have convinced her that gendered toy preferences don’t even surface until around twelve months. Though it’s true, according to her experiments, that boys are more likely to choose toy trucks and girls dolls, she has found nothing linking these choices to hard-wired brain differences or the presence of testosterone. According to Hines, “sex difference in empathizing and systemizing is about half a standard deviation.” Saini explains that’s like saying the average heights of women and men differ by one inch. For comparison, our heights actually differ on average by 5.5 inches. Half of a standard deviation is pretty small.

Feel free to use these points in your next debate with a hard-core “Men are from Mars, Women are from Venus,” believer. Or you can send along this link to Inferior and save yourself the trouble. 


Books Mentioned