In part one of a three part series, Andy Bodle discusses the central differences in the chemistry and physicality of men and women.
“Wake up. Men and women are different!”
Right. This is a touchy subject, so I’d like to make it clear from the offset that I’m not trying to be confrontational, or controversial. I’m simply stating an opinion, based on the facts I have access to. If anyone has any better facts (or interpretations), feel free to make them known. My mind is open.
Some of the most ferocious opposition to evolutionary psychology is almost ideological in nature. Some people react with shock—fury, even—that anyone could contemplate the idea, central to evolutionary psychology, that there might be differences between men and women. (It was because of this attitude that virtually no research was carried out in this area for around 30 years.)
There are people who believe that men and women are the same. I’d like to examine that assertion in detail, over the course of three posts.
Humans, as I have explained before, are animals. Here are some pictures of some other animals:
“Hold, sir!” you cry. “There’s only one fish in that picture!” Actually, there are two—the female is the big thing; the male is the little lump protruding from her belly. In many species of anglerfish, the male is essentially a parasite: it latches on to a female, then fuses with her permanently, becoming totally dependent on her for food (in return for which it provides sperm. Nice deal if you can get it).
Clearly, nature doesn’t give two f*cks about fairness.
This phenomenon, whereby there are consistent, observable differences between the sexes, is called sexual dimorphism, and it is widespread in nature. It occurs in ducks and deer, sheep and cows, chickens and spiders, lions and elephant seals, peacocks and seahorses, and in some of our closest relatives (orangutans and gorillas).
True, there are many species in which it is virtually impossible to tell the sexes apart, either by their appearance or their behaviour. But I hope you can see that there’s no empirical reason why sexual dimorphism couldn’t be found in humans too.
So how do male and female humans measure up? There’s the small matter of the sexual apparatus, of course. But here are a few other points of divergence:
- Men are, on average, five inches taller and 15% heavier than women
- Men have denser bones and thicker skulls, while women have wider pelvises
- Adult males have more body hair and larger larynxes
- Men are more prone to conditions such as schizophrenia, haemophilia and baldness (and more prone to illness generally)
- Women are more likely to suffer from lupus and osteoporosis
- Men produce twice as much saliva as women
- Women tend to live longer than men
- Men have greater upper body strength
- Women have a more highly developed sense of smell and touch
In the grand scheme of things, these are all fairly minor differences. And such is the variation across the species that you can’t make any safe predictions about any two individuals; there are plenty of women, for example, who are taller than a lot of men.
Perhaps the more important question is: what about our brains? Are we wired differently?
Well, men’s brains are, on average, 10% larger than women’s. But that’s not to say, as was once thought, that men are more intelligent. Brain size is not a particularly good indicator of brain power (if it were, whales and elephants, not humans, would be the masters of the world). A better indicator is body mass to brain ratio, and by that measure, there’s nothing between us.
There are some structural differences. The hippocampus, a part of the brain associated with memory function, tends to be larger in women, while the amygdala, involved in emotional processing, is usually larger in men.
As well as running around in slightly different makes of car, we also have different oil in our engines. Men typically have seven to eight times more of the hormone testosterone in their system, for example, than women, and women produce more oxytocin than men. The jury’s still out on exactly what these chemicals do—the effects vary with context—but they are undoubtedly important: simply injecting them into people (of either sex) can have dramatic results. Higher levels of testosterone are associated with more aggression, more risk-taking, and enhanced spatial ability, and oxytocin seems to have positive effects on fidelity and generosity (to people you know/care about), and negative effects on vigour, memory and vigilance.
So how does all this translate into differences in ability, in thought and deed? If our bodies are designed differently, that suggests we’re designed to perform different tasks. Could it be that women are adjustable spanners, and men monkey wrenches?
I’m afraid I’m going to do some maths on you now. Sorry, but it’s pretty simple, and if you can get your head round it, it sums up the situation quite well.
This is a bell curve: a simple graph, with the x-axis (the horizontal one) representing the “score” for a particular characteristic (it could be anything, but let’s say, for argument’s sake, it’s laziness), and the y-axis (the vertical one) representing the number of people who have that score. So here, a very few people are not lazy at all; a larger number are slightly lazy; most people are fairly lazy; then the curve slopes down again, so as the score goes up, the number of people registering it comes down, until you have the tiny number of individuals who are total layabouts. Typically, because of the wonderful variety of life, most human abilities are described by some sort of bell curve.
Now it just so happens that, on most measures, from intelligence to ability at chess and fondness for cheese, the male and female bell curves look like this:
(Please ignore the text—it was the only half-decent image I could find.)
The curve is flatter and wider for men and taller and narrower for women. To look at it another way, there are more “outliers”—people at the extreme ends of the scale; you might call them “freaks”—among men than among women. So while there are a small number of men who record exceptionally high scores, there are an equal number who score lower than everyone else. But the key point is that the curves for both sexes peak at the same point – which means that *the overall average for both is the same*.
It’s true that for some attributes, the curves’ mid-points don’t line up exactly: on tests of spatial ability, for example, the average male score tends to be slightly higher, and on verbal ability, the girls have the edge. But the differences are slight, and may be, to a greater or lesser extent, attributable to cultural factors. There’s a lot of interesting research going on right now, for example, into stereotype threat. Either way, even if the differences are hardwired, they’re hardly a big deal; as with the physical differences, the variation between any two men is generally greater than the variation between one man and one woman. There’s no fundamental reason why things should have turned out this way; it just neatly happens to be so. There’s nothing stopping any one woman becoming a brilliant engineer, just as there’s nothing stopping any one man being a fantastic nurse. Even if the differences were more pronounced, dissimilarity is not the same thing as inequality. There’s huge variation across all the men in the world, and they’re equal in the eyes of the law.
But there is one particular area where the differences are huge, consequential, perhaps even insurmountable. And since I’ve blathered on for too long already, I’ll get to that in the next post.
This post originally appeared at Womanology.