Is Your Brain Male or Female?
Simon Baron-Cohen
The Guardian
April 17, 2003


What kind of brain do you have? There really are big differences between the male and female brain, says Simon Baron-Cohen.

My theory is that the female brain is predominantly hard-wired for empathy, and that the male brain is predominantly hard-wired for understanding and building systems. I call it the empathising-systemising (E-S) theory.

Empathising is the drive to identify another person's emotions and thoughts, and to respond to these with an appropriate emotion. The empathiser intuitively figures out how people are feeling, and how to treat people with care and sensitivity. Systemising is the drive to analyse and explore a system, to extract underlying rules that govern the behaviour of a system; and the drive to construct systems. The systemiser intuitively figures out how things work, or what the underlying rules are controlling a system. Systems can be as varied as a pond, a vehicle, a computer, a maths equation, or even an army unit. They all operate on inputs and deliver outputs, using rules.

According to this theory, a person (whether male or female) has a particular "brain type". There are three common brain types: for some individuals, empathising is stronger than systemising. This is called the female brain, or a brain of type E. For other individuals, systemising is stronger than empathising. This is called the male brain, or a brain of type S. Yet other individuals are equally strong in their systemising and empathising. This is called the "balanced brain", or a brain of type B.

A key feature of this theory is that your sex cannot tell you which type of brain you have. Not all men have the male brain, and not all women have the female brain. The central claim of this new theory is only that on average, more males than females have a brain of type S, and more females than males have a brain of type E.

And we all have anecdotal impressions about typical hobbies for men and women. Men are more likely to spend hours happily engaged in car maintenance, light aircraft piloting, sailing, mathematics, tweaking their sound systems, computer games and programming. Women are more likely to spend hours happily engaged in coffee mornings or pot-luck suppers, advising friends on relationship problems, or caring for friends, neighbours, or pets.

The evidence for a female advantage in empathising comes from many different directions. For example, studies show that when children play together with a little movie player that has only one eye-piece, boys tend to get more of their fair share of looking down the eye piece. They just shoulder the girls out of the way. Less empathy, more self-centred. Or if you leave out a bunch of those big plastic cars that kids can ride on, what you see is that more little boys play the "ramming" game. They deliberately drive the vehicle into another child. The little girls ride around more carefully, avoiding the other children more often. This suggests the girls are being more sensitive to others.

Baby girls, as young as 12 months old, respond more empathically to the distress of other people, showing greater concern through more sad looks, sympathetic vocalisations and comforting. This echoes what you find in adulthood: more women report frequently sharing the emotional distress of their friends. Women also spend more time comforting people.

Women are also more sensitive to facial expressions. They are better at decoding non-verbal communication, picking up subtle nuances from tone of voice or facial expression, or judging a person's character.

There is also a sex difference in aggression. Males tend to show far more "direct" aggression such as pushing, hitting and punching. Females tend to show more "indirect" (or "relational", covert) aggression. This includes gossip, exclusion, and bitchy remarks. It could be said that to punch someone in the face or to wound them physically requires an even lower level of empathy than a verbal snipe.

Boys are more interested in cars, trucks, planes, guns and swords, building blocks, constructional toys, and mechanical toys - systems. They seem to love putting things together, to build toy towers or towns or vehicles. Boys also enjoy playing with toys that have clear functions, buttons to press, things that will light up, or devices that will cause another object to move.

You see the same sort of pattern in the adult workplace. Some occupations are almost entirely male. Think of metal-working, weapon-making, crafting musical instruments, or the construction industries, such as boat-building. The focus of these occupations is on constructing systems. Professions such as maths, physics, and engineering, which require high sys temising, are also largely male-chosen disciplines.

We, of course, know that with time, culture and socialisation do play a role in determining a male brain (stronger interest in systems) or female brain (stronger interest in empathy). But biology also partly determines this.

Some of the most convincing evidence for biological causes comes from studies of the effects of hormones.

Our own study found that toddlers who had lower foetal testosterone had higher levels of eye contact. Presumably eye contact may have something to do with sociability and empathising. And a group of Canadian researchers found that the higher your prenatal testosterone the better you do on the mental rotation (systemising) test.

Some people may worry that this is suggesting one sex is better than the other, but a moment's reflection should allay this fear. The theory is saying that, on average, males and females differ in what they are drawn to and what they find easy, but that both sexes have their strengths and their weaknesses. Neither sex is superior overall.

Others may worry that a theory like this stereotypes the sexes. But we need to distinguish stereotyping from the study of sex differences. The study simply looks at males and females as two groups, and asks why on average, differences are seen. Stereotyping, on the other hand, is when a characteristic of a group is assumed to apply to an individual, and this is potentially discriminating and harmful.

(edited by David Van Alstyne)
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