By BOBBI CAROTHERS and HARRY REIS
Published: April 20, 2013
MEN and women are so different they might as well be from separate planets, so says the theory of the sexes famously explicated in John Gray’s 1992 best seller, “Men Are From Mars, Women Are From Venus.”
Indeed, sex differences are a perennially popular topic in behavioral science; since 2000, scientific journals have published more than 30,000 articles on them.
That men and women differ in certain respects is unassailable. Unfortunately, the continuing belief in “categorical differences” — men are aggressive, women are caring — reinforces traditional stereotypes by treating certain behaviors as immutable. And, it turns out, this belief is based on a scientifically indefensible model of human behavior.
As the psychologist Cordelia Fine explains in her book “Delusions of Gender,” the influence of one kind of categorical thinking, neurosexism — justifying differential treatment by citing differences in neural anatomy or function — spills over to educational and employment disparities, family relations and arguments about same-sex institutions.
Consider a marital spat in which she accuses him of being emotionally withdrawn while he indicts her for being demanding. In a gender-categorical world, the argument can quickly devolve to “You’re acting like a typical (man/woman)!” Asking a partner to change, in this binary world, is expecting him or her to go against the natural tendency of his or her category — a very tall order.
The alternative, a dimensional perspective, ascribes behavior to individuals, as one of their various personal qualities. It is much easier to imagine how change might take place.
But what of all those published studies, many of which claim to find differences between the sexes? In our research, published recently in The Journal of Personality and Social Psychology, we shed an empirical light on this question by using a method called taxometric analysis.
This method asks whether data from two groups are likely to be taxonic — a classification that distinguishes one group from another in a nonarbitrary, fundamental manner, called a “taxon” — or whether they are more likely to be dimensional, with individuals’ scores dispersed along a single continuum.
The existence of a taxon implies a fundamental distinction, akin to the difference between species. As the clinical psychologist Paul Meehl famously put it, “There are gophers, there are chipmunks, but there are no gophmunks.”
A dimensional model, in contrast, indicates that men and women come from the same general pool, differing relatively, trait by trait, much as any two individuals from the same group might differ.
We applied such techniques to the data from 13 studies, conducted earlier by other researchers. In each, significant differences had been found. We then looked more closely at these differences to ask whether they were more likely to be of degree (a dimension) or kind (a taxon).
The studies looked at diverse attributes, including sexual attitudes and behavior, desired mate characteristics, interest in and ease of learning science, and intimacy, empathy, social support and caregiving in relationships.
Across analyses spanning 122 attributes from more than 13,000 individuals, one conclusion stood out: instead of dividing into two groups, men and women overlapped considerably on attributes like the frequency of science-related activities, interest in casual sex, or the allure of a potential mate’s virginity.
Even stereotypical traits, like assertiveness or valuing close friendships, fell along a continuum. In other words, we found little or no evidence of categorical distinctions based on sex.
To some, this is no surprise; the psychologist Janet Hyde has argued repeatedly that men and women are far more similar than different. Yet to many others, the idea that men and women are fundamentally different beings persists. The Mars/Venus binary aside, it is all too easy to reify observed behavioral differences by associating them with the categories of the people doing the behaving, be it their sex, race or occupation.
It is important to keep in mind what we did not study. We looked only at psychological characteristics, qualities often associated with the behavior of women and men. We did not look at abilities or skills, and we did not directly observe behavior.
Just to be safe, we repeated our analyses on several dimensions where we did expect categorical differences: physical size, athletic ability and sex-stereotyped hobbies like playing video games and scrapbooking. On these we did find evidence for categories based on sex.
The Mars/Venus view describes a world that does not exist, at least here on earth. Our work shows that sex does not define qualitatively distinct categories of psychological characteristics. We need to look at individuals as individuals.
Bobbi Carothers is a senior data analyst at Washington University in St. Louis. Harry Reis is a professor of psychology at the University of Rochester.