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There is little doubt that men and women's brains are not the same, but is that helpful in making decisions about people? Not usually, because all brains are different and no two brains are exactly alike––as far as science knows.
There are a staggering number of connections and chemical interactions in the brain. It is made up of 100 million cells and a quadrillion synaptic connections (a message linking one part of the brain with another part of the brain). But even more limiting is the fact that the brain is trying to study itself, and all of us—scientists and non-scientists—have biases that have developed out of our experiences. These experiences influence how we interpret scientific findings.
If we ask the casual observer on the street, we find that most people believe that genders differ in their behavior and emotions, and of course, these differences go back to the brain. Standup comedians love the humor involved in pointing out these differences. Some joke that men compartmentalize their thoughts and have one box for each subject, such as wife, children, car, and sex. And the boxes must never touch each other.
Another much talked about difference is navigation. People have observed that most men don't ask for directions while women do, and that women navigate by relying on maps or local signposts such as “take a right after the McDonald's,” while men claim to have big maps in their heads.
One popular explanation for these supposed brain differences is the division of labor experienced by our hunter-gatherer ancestors. Men needed to range widely in order to trap and kill animals and would run through the bush triangulating their position relative to fast-moving prey. They also had to react quickly, perhaps impulsively, to defend against attack. This might explain why more males suffer from attention deficit disorder.
Women, on the other hand, cultivated food and learned to verbally communicate with others to fend off male aggression, sexual and otherwise. But those supporting the equality of male and female brains are suspicious of these historical reports or believe they’re not relevant today. After all, common sense told us the earth was flat and the sun rotated around our planet.
If there are real differences, they should show up in studies of animals—and they do. This is not the place to examine individual studies, but Robert Sapolsky has done us a favor by reviewing some of the research. I refer the reader to pages 213 to 220 of Sapolsky’s book, Behave.
Here is a quick review: In guinea pigs, male aggression is due to prenatal masculinization of the brain. Also, male primates are more aggressive than female primates, while female primates are more affiliative and more involved in social grooming and interacting with infants. Male adult rhesus monkeys are far more interested in playing with masculine human toys, i.e. wheeled toys, than feminine ones, i.e. stuffed animals, and females slightly prefer feminine toys.
Of course, hormonal differences affect the brain. Males are more rough-and-tumble even when testosterone levels are suppressed at birth. When pregnant monkeys are treated with testosterone their female offspring are more rough-and-tumble and aggressive than those not treated.
Sapolsky’s reporting shows that it's also possible to look at humans because of CAH, which is Congenital Adrenal Hyperplasia, a condition where the adrenal glands produce testosterone. CAH girls are more rough-and-tumble, play with masculine toys, and show less tenderness. CAH males are more aggressive, have better math scores, and are more assertive. They also suffer from a higher percentage of attention deficit disorder and autism.
An inverse of CAH is AIS, Androgen Insensitivity Syndrome, which results in insensitivity to testosterone. Women with AIS have lower rates of autism, are more anorexic, and have less athletic ability.
But those who do not support gender differences point out that the brain allows for plasticity, and some changes in the brain can take place based upon the environment and perhaps the culture in general. According to Sapolsky’s review, maternal malnutrition impairs the fetal brain. Maternal stress leads to more substance abuse, poor diet, blood pressure, and poor immune defenses. And good rat mothering can even alter gene regulation in their offspring.
A recent study by Joel Daphna of Tel Aviv University, published in Trends in Cognitive Sciences and Philosophical Transactions of the Royal Society, says the real question is exactly how different behaviors emerge. On average, men and women do differ with respect to some brain and behavior changes, but these differences are found in large numbers and cannot be relied upon to predict individual behavior or attitudes.
So where does all this leave us? I draw two conclusions. One is that there are differences between the genders, but when it comes to individual assessment one needs to look at behavior rather than theorizing about gender. This reliance on studying behavior is why the field of psychology has made progress over the past 40 years. The study of behavior is much more reliable and achievable than theorizing about what goes on inside a person’s brain.
My second conclusion has to do with arrogance. We still have a lot to learn about the brain. I’m reminded of a 3-year-old at the beach filling her pail with water in an effort to diminish the size of the ocean, or to discover what is lurking at the bottom of the sea. We now have exploratory submarines and underwater research gear, but I believe we should be careful about inferences about the brain and gender, although findings to date have been interesting.
Would I ever use perceptions about gender, based on research and experience, in decision making? I would have to conjure up an artificial situation such as being assigned to select 1000 individuals for hand-to-hand military combat and the choice would be 1000 randomly-selected males or 1000 randomly-selected females. Based upon what I think I know, I would be foolish not to choose the males. While all the females could be better than all of the males at lugging 50 pound backpacks up steep mountain trails and engaging in guerrilla warfare, I think this is doubtful. However, there is no doubt that some number of females would do better than some of the males.
When evaluating people in the real world, on an individual basis, for occupations such as childcare or military combat, the best predictors of future behavior are past behavior, motivation, and rigorous evaluation––not gender.
