Men and women are more alike than different -- that's been the consensus view for many years among the researchers who study personality differences between the sexes. But a new study claims this wisdom is wrong. By correcting for measurement errors, three researchers put forth a study that was published on Wednesday on the Public Library of Science website saying they've found that men and women feel and behave in markedly different ways. They're almost like "different species," Paul Irwing, one of the researchers, told The Huffington Post.
The research, conducted by Marco Del Giudice of Italy's University of Turin and Irwing and Tom Booth of the UK's University of Manchester, involved getting 10,000 Americans to take a questionnaire that measured 15 different personality traits. According to their analysis, men are far more dominant, reserved, utilitarian, vigilant, rule-conscious, and emotionally stable, while women are far more deferential, warm, trusting, sensitive, and emotionally "reactive." The two sexes were roughly the same when it came to perfectionism, liveliness, and abstract versus practical thinking.
"If you translate it into the simplest terms," said Irwing, "only 18 percent of men and women match in terms of personality profiles, and that's staggeringly different from the consensus view."
The consensus view, most persuasively set out in a 2005 study by Janet Shibley Hyde, a professor of psychology and women's studies at the University of Wisconsin, Madison, demonstrated through a meta-analysis of 46 other studies that men and women were actually very similar, not only in personality traits, but in other realms of supposed gender difference, like self-esteem, leadership, and math ability.
In the early 1970s, Hyde became one of the first researchers to focus on the psychology of women. "Before that, psychology had been a psychology of men," Hyde told The Huffington Post, and many theories had been developed based on entirely male samples. So she began to study women, and the differences between women and men, and was surprised at how small those differences turned out to be. "I mean, I was trying to study difference," Hyde said.
Hyde says the final figure Irwing, Del Giudice, and Booth came up with -- the "global sex difference" -- is "really uninterpretable, it doesn't mean anything."
In past studies on this topic, researchers would simply add up all the survey responses, according to Del Giudice. This led to imperfect results because of careless responses and misreadings. Through a sophisticated method called "structure equation modeling," the researchers claim they were able to remove this random error. When asked if he could translate this concept for a lay person, Irwing replied: "I teach courses on this and it takes me approximately 20 hours."
Past research also usually compared one variable at a time, Del Giudice said. He believes this method led to underestimations of the sex difference because when you actually combine all personality traits, with all their small discrepancies, the result is a much more significant difference. For example, if you were to examine the difference between men and women's body types using the traditional method, you would look at torso circumference and waist-hip ratios and torso-leg ratios, one by one. In Del Giudice's method, you would crunch all these figures into one much larger number. And that's what he did with personality.
"They kind of globbed together all these personality dimensions and said there was a big difference," Hyde said. "They're throwing together apples and oranges and dishwashers to get this thing in 15-dimensional space. We don't know what 15-dimensional space looks like."
But Del Giudice contends that his team didn't measure "a haphazard list of traits." Rather, they considered 15 facets that could offer a reasonably complete picture of a person's personality.
Irwing thinks that some researchers in the past may have been biased in their methods, in order to reduce any gender difference. "It's for totally laudable reasons," he said. "People are very concerned, or were very concerned, that women didn't get equal opportunities, and that there was a lot of bias in selection processes."
"People are afraid that studies like ours will turn the clock back," Irwing added.
Hyde is one of those people. "This huge difference is not only scientifically false," she said, "it has unfortunate consequences for places like the workplace and education and heterosexual romantic relationships."
But the authors stand by their results, and are currently drafting a lengthy response to Hyde's objections. "I think distorting science because of what you would like to believe, or because of what you think the political consequences are, is very dangerous," said Irwing.
The study doesn't speculate as to whether the alleged differences are due to nature or nurture, although Irwing points out the results are consistent with standard evolutionary theory. Even if these differences aren't indelibly printed in our genes, Hyde believes there's still cause for alarm.
If men and women have wildly different personalities, "then how can we do the same job men can, and deserve equal pay for equal work?" she asked. "A married couple have marital difficulties, and they go to the therapist, who says 'he's from Mars, you're from Venus, you'll never be able to communicate. It's hopeless.' If you have a gender similarities point of view, you just need to work on communicating."