gender
Rule #11
Male and female brains are different.
THE MAN WAS A hot dog. The woman was a bitch.
The results of the experiment could be summarized in those two sentences. Three researchers created a fictitious assistant vice president of an aircraft company. Four groups of experimental subjects, with equal numbers of men and women in each group, were asked to rate this fictional person’s job performance. Each group was given the vice president’s brief job description, but the first group also was told that the vice president was a man. They were asked to rate both the competence and the likability of the candidate. They gave a very flattering review, rating the man “very competent” and “likable.” The second group was told that the vice president was a woman. She was rated “likable” but “not very competent.” All other factors were equal. Only the perceived gender had changed.
The third group was told that the vice president was a male superstar, a stellar performer on the fast track at the company. The fourth group was told that the vice president was a female superstar, also on the express lane to the executive washroom. As before, the third group rated the man “very competent” and “likable.” The woman superstar also was rated “very competent.” But she was not rated “likable.” In fact, the group’s descriptions included words such as “hostile.” As I said, the man was a hot dog. The woman was a bitch.
The point is, gender biases hurt real people in real-world situations. As we hurtle headlong into the controversial world of brains and genders, keeping these social effects in mind is excruciatingly important. There is a great deal of confusion regarding the way men and women relate to each other, and even more about why. There is confusion about the terms as well, blurring the line between the concepts of “sex” and “gender.” Here, sex will generally refer to biology and anatomy. Gender will refer mostly to social expectations. Sex is set into the concrete of DNA. Gender is not. The differences between men’s and women’s brains start with how they got that way in the first place.
the x factor
How do we become male and female? The road to sex assignment starts out with all the enthusiasm sex usually stimulates. Four hundred million sperm fall all over themselves attempting to find one egg during intercourse. The task is not all that difficult. In the microscopic world of human fertilization, the egg is the size of the Death Star, and the sperm are the size of X-wing fighters. X is a good letter for this enterprise—the name of that very important chromosome that half of all sperm and all eggs carry. You recall chromosomes from biology class, those writhing strings of DNA packed into the nucleus that contain the information necessary to make you. It takes 46 of them to do it, which you can think of as 46 volumes in an encyclopedia. Twenty-three come from Mom, and 23 come from Dad. Two are sex chromosomes. At least one of those chromosomes has to be an X chromosome, or you will die.
If you get two X chromosomes, you go into the ladies locker room all your life; an X and Y puts you forever in the men’s. This sex assignment is controlled by the male. Henry VIII’s wives wish he’d known that. He executed one of them for being unable to produce a boy as heir to the throne, but he should have executed himself. The Y can be donated only by sperm (the egg never carries one), so the male determines the sex.
Gender differences can be divided into three areas: genetic, neuroanatomical, and behavioral. Scientists usually spend their whole careers exploring only one—each difference is like a separate island in a common research ocean. We’ll tour all three, starting with a molecular explanation of why Henry VIII owes Anne Boleyn a big fat apology.
One of the most interesting facts about the Y chromosome is that you don’t need most of it to make a male. All it takes to kick-start the male developmental program is a small snippet near the middle, carrying a gene called SRY. In our tour, we immediately notice Gene Island is dominated by a single scientist, David C. Page. He is the researcher who isolated SRY. Though in his 50s, Page looks to be about 28 years old. As director of the Whitehead Institute and a professor at MIT, he is a man of considerable intellect. He also is charming and has a refreshingly wicked sense of humor. Page is the world’s first molecular sex therapist. Or, better, sex broker. He discovered that you can destroy the SRY gene in a male embryo and get a female, or add SRY to a female embryo and turn her into a male (SR stands for “sex reversal”). Why can you do this? In a fact troubling to anybody who believes males are biologically hard-wired to dominate the planet, researchers discovered that the basic default setting of the mammalian embryo is to become female.
There is terrible inequality between the two chromosomes. The X chromosome does most of the heavy developmental lifting, while the little Y has been shedding its associated genes at a rate of about five every one million years, committing suicide in slow motion. It’s now down to less than 100 genes. By comparison, the X chromosome carries about 1,500 genes, all necessary participants in embryonic construction projects. These are not showing any signs of decay.
With only a single X chromosome, males need every X gene they can get. Females, however, have double the necessary amount. You can think of it like a cake recipe calling for only one cup of flour. If you decide to put in two, things will change in a most unpleasant fashion. The female embryo uses what may be the most time-honored weapon in the battle of the sexes to solve the problem of two X’s: She simply ignores one of them. This chromosomal silent treatment is known as X inactivation. One of the chromosomes is tagged with the molecular equivalent of a “Do Not Disturb” sign. Since there are two X’s from which to choose, Mom’s or Dad’s, researchers wanted to know who preferentially got the sign.
The answer was completely unexpected. There were no preferences. Some cells in the developing little girl embryo hung their sign around Mom’s X. Neighboring cells hung their sign around Dad’s. At this point in research, there doesn’t appear to be any rhyme or reason, and it is considered a random event. This means that cells in the female embryo are a complex mosaic of both active and inactive mom-and-pop X genes. Because males require all 1,500 X genes to survive, and they have only one X-chromosome, it would be stupid for them to hang up “Do Not Disturb” notes. They never do it. X inactivation does not occur in guys. And because males must get their X from Mom, all men are literally, with respect to their X chromosome, Momma’s Boys—unisexed. That’s very different from their sisters, who are more genetically complex. These bombshells describe our first truly genetic-based findings of potential gender differences.
We now know the function of many of the 1,500 genes that reside on the X chromosome. Swallow hard here. Many of those genes involve brain function. Many of them govern how we think. In 2005, the human genome was sequenced, and an unusually large percentage of the X chromosome genes were found to create proteins involved in brain manufacture. Some of these genes may be involved in establishing higher cognitive functions, from verbal skills and social behavior to certain types of intelligence. Researchers call the X chromosome a cognitive “hot spot.”
These findings represent one of the most important regions on Gene Island. But it is hardly the only important region, and not even the most important island.
is bigger better?
The purpose of genes is to create molecules that mediate the functions of the cells in which they reside. Collections of these cells create the neuroanatomy of the brain (which in turn creates our behavior). Leaving Gene Island, our next stop is Cell Island, a region where scientists investigate large structures in the brain, or neuroanatomy. Here, the real trick is finding structures that aren ’t affected by sex chromosome dosage.
Labs—headed by scientists of both sexes, I should perhaps point out—have found differences in the front and prefrontal cortex, areas of the brain that control much of our decision-making ability. This cortex is fatter, in certain parts, in women than in men. There are sex-based differences in the limbic system, which controls our emotional life and mediates some types of learning. Prominent differences lie in the amygdala, controlling not only the generation of emotions but also the ability to remember them. Running counter to current social prejudice, this region is much larger in men than it is in women. At rest, female amygdalas tend to talk mostly to the left hemisphere, while male amygdalas do most of their chatting with the right hemisphere. Brain cells communicate via biochemicals, and these have not escaped sex differences, either. The regulation of serotonin is particularly dramatic. Serotonin is key in regulating emotion and mood (Prozac works by altering the regulation of this neurotransmitter). Males can synthesize serotonin about 52 percent faster than females. Do these physical differences mean anything? In animals, the size of structures is thought to reflect their relative importance to survival. Human examples at first blush seem to follow a similar pattern. We already have noticed that violinists have bigger areas of the brain devoted to controlling their left hand than their right. But neuroscientists nearly come to blows over how structure relates to function. We don’t yet know whether differences in neurotransmitter distributions, or in the size of a brain region, mean anything substantial.
Such cautions have not stopped brain scientists from going after the question of behavior differences, and they won’t stop us, either. Fasten your seat belts and strap on the Kevlar, for we are about to land on the noisiest, most intellectually violent island on our imaginary itinerary: Behavior Island.
battle of the sexes
I didn’t really want to write about this. Characterizing gender-specific behaviors has a long and mostly troubled history. Even institutions holding our best minds aren’t immune. Larry Summers was Harvard ’s president, for Pete’s sake, when he attributed girls’ lower math and science scores to behavioral genetics, comments that cost him his job. And he is in exceptionally good intellectual company. Consider these three quotes:
“The female is an impotent male, incapable of making semen because of the coldness of her nature. We therefore should look upon the female state as if it were a deformity, though one that occurs in the ordinary course of nature.”
Aristotle (384–332 BC)
“Girls begin to talk and to stand on their feet sooner than boys because weeds always grow up more quickly than good crops.”
Martin Luther (1483–1546)
“If they can put a man on the moon ... why can ’t they put them all there?”
Jill (1985, graffiti on a bathroom wall, in response to Luther’s quote)
And so the weary battle of the sexes continues. Almost 2,400 years of history separate Aristotle from Jill, yet we seem to have barely moved. Invoking planet metaphors like Venus and Mars, some purport to expand perceived differences into prescriptions for relationships. And this is the most scientifically progressive era in human history.
Mostly, I think, it comes down to statistics.
There may very well be differences in the way men and women think about some things. But when people hear about measurable differences, they often think scientists are talking about individuals, such as themselves. That’s a big mistake. When scientists look for behavioral trends, they do not look at individuals. They look at populations. Statistics in these studies can never apply to individuals. Trends emerge, but there are variations within a population, often with significant overlaps between the genders. It is true that every time neuroscientist Flo Haseltine does an fMRI, she sees different parts of the brain light up depending upon whether she is viewing a man or a woman. Exactly how that relates to your behavior is a completely separate question.
first hints
What we do know about the biological roots of behavioral differences began with brain pathologies. Mental retardation is more common in males than in females in the general population. Many of these pathologies are caused by mutations in any one of 24 genes within the X chromosome. As you know, males have no backup X. If their X gets damaged, they have to live with the consequences. If a female’s X is damaged, she can often ignore the consequences. This represents to date one of the strongest pieces of evidence showing the involvement of X chromosomes in brain function and thus brain behavior.
Mental health professionals have known for years about sex-based differences in the type and severity of psychiatric disorders. Males are more severely afflicted by schizophrenia than females, for example. By more than 2 to 1, women are more likely to get depressed than men, a figure that shows up just after puberty and remains stable for the next 50 years. Males exhibit more antisocial behavior. Females have more anxiety. Most alcoholics and drug addicts are male. Most anorexics are female. Says Thomas Insel, from the National Institute of Mental Health, “It’s pretty difficult to find any single factor that’s more predictive for some of these disorders than gender.”
But what about normal behavior? The three research islands have very few bridges between them. There are bridge-construction projects, however, and we are going to talk about two of the best.
dealing with traumatic situations
It’s a horrible slideshow. In it, a little boy is run over by a car while walking with his parents. If you ever see that show, you will never forget it. But what if you could forget it? The brain’s amygdala aids in the creation of emotions and our ability to remember them. Suppose there was a magic elixir that could momentarily suppress it? Such an elixir does exist, and it was used to show that men and women process emotions differently.
You have probably heard the term left brain vs. right brain. You may have heard that this underscores creative vs. analytical people. That’s a folk tale, the equivalent of saying the left side of a luxury liner is responsible for keeping the ship afloat, and the right is responsible for making it move through the water. Both sides are involved in both processes. That doesn’t mean the hemispheres are equal, however. The right side of the brain tends to remember the gist of an experience, and the left brain tends to remember the details.
Researcher Larry Cahill eavesdropped on men’s and women’s brains under acute stress (he showed them slasher films), and what he found is this: Men handled the experience by firing up the amygdala in their brain’s right hemisphere. Their left was comparatively silent. Women handled the experience with the opposite hemisphere. They lit up their left amygdala, their right comparatively silent. If males are firing up the right hemisphere (the “gist dictator”), does that mean males remember more gist than detail of a given emotional experience related to stress? Do females remember more detail than gist of an emotional experience related to stress? Cahill decided to find out.
That magic elixir of forgetting, a drug called propranolol, normally is used to regulate blood pressure. As a beta-blocker, it also inhibits the biochemistry that usually would activate the amygdala during emotional experiences. The drug is being investigated as a potential treatment for combat-related disorders.
But Cahill gave it to his subjects before they watched a traumatic film. One week later, he tested their memories of it. Sure enough, the men lost the ability to recall the gist of the story, compared with men who didn’t take the drug. Women lost the ability to recall the details. One must be careful not to overinterpret these data. The results clearly define only emotional responses to stressful situations, not objective details and summaries. This is not a battle between the accountants and the visionaries.
Cahill’s results come on the heels of similar findings around the world. Other labs have extended his work, finding that women recall more emotional autobiographical events, more rapidly and with greater intensity, than men do. Women consistently report more vivid memories for emotionally important events such as a recent argument, a first date, or a vacation. Other studies show that, under stress, women tend to focus on nurturing their offspring, while men tend to withdraw. This tendency in females has sometimes been called “tend and befriend.” Its origins are unknown, and the reason comes straight from the mouth of Stephen Jay Gould: “It is logically, mathematically, and scientifically impossible to pull them apart.”
This quote reminds me of my two sons in a fight, but Gould is actually talking about the age-old nature vs. nurture argument.
verbal communication
Behaviorist Deborah Tannen has done some fascinating work in this area, studying gender differences in verbal capacity. The Cliff Notes version of Tannen’s and others’ findings over the past 30 years: “Women are better at it.” Though the specifics are often controversial, much of the empirical support comes from unusual quarters, including brain pathologies. We have known for years that language and reading disorders occur approximately twice as often in little boys as in little girls. Women also recover from stroke-induced verbal impairment better than men. Many researchers suspect that risk disparities like these hint at underlying differences in normal cognition. They often point to neuroanatomical data to explain the difference: Women tend to use both hemispheres when speaking and processing verbal information. Men primarily use one. Women tend to have thick cables connecting their two hemispheres. Men’s are thinner. It’s as though females have a backup system that is absent in males.
These clinical data have been used to support findings first noticed by educators. Girls seem verbally more sophisticated than little boys as they go through the school system. They are better at verbal memory tasks, verbal fluency tasks, and speed of articulation. When these little girls grow up, they are still champions at processing verbal information. Real as these data seem, however, almost none of them can be divorced from a social context. That’s why Gould’s comment is so helpful.
Tannen spent a long time observing and videotaping how little girls and little boys interact with each other. Her original question was to find out how boys and girls of different ages talked to their best friends, and if any detectable patterns emerged. If she found some, she wanted to know how stable they were. Would the patterns detected in childhood also show up in college students? The patterns she found were predictable and stable, independent of age and geography. The conversational styles we’ve developed as adults come directly from the same-sex interactions we solidified as children. Tannen’s findings center on three areas.
cementing relationships
When girl best friends communicate with each other, they lean in, maintain eye contact, and do a lot of talking. They use their sophisticated verbal talents to cement their relationships. Boys never do this. They rarely face each other directly, preferring either parallel or oblique angles. They make little eye contact, their gaze always casting about the room. They do not use verbal information to cement their relationships. Instead, commotion seems to be the central currency of a little boy’s social economy. Doing things physically together is the glue that holds their relationships intact.
My sons, Josh and Noah, have been playing a one-upmanship game since they were toddlers. A typical version might involve ball throwing. Josh would say, “I can throw this up to the ceiling,” and would promptly do so. Then they would laugh. Noah would respond by grabbing the ball, saying, “Oh yeah? I can throw this up to the sky,” and throwing the ball higher. This ratcheting, with laughter, would continue until they reached the “galaxy” or the big prize, “God.”
Tannen saw this consistent style everywhere she looked—except when observing little girls. The female version goes something like this. One sister says, “I can take this ball and throw it to the ceiling,” and she promptly does. She and her sibling both laugh. The other sister grabs the ball, throws it up to the ceiling, and says, “I can, too!” Then they talk about how cool it is that they can both throw the ball at the same height. This style persists into adulthood for both sexes. Tannen’s data, unfortunately, have been misinterpreted as “Boys always compete, and girls always cooperate.” As this example shows, however, boys are being extremely cooperative. They are simply doing it through competition, deploying their favorite strategy of physical activity.
negotiating status
By elementary school, boys finally start using their verbal skills for something: to negotiate their status in a large group. Tannen found that high-status males give orders to the rest of the group, verbally or even physically pushing the low-status boys around. The “leaders” maintain their fiefdoms not only by issuing orders but by making sure the orders are carried out. Other strong members try to challenge them, so the guys at the top learn quickly to deflect challenges. This is often done with words as well. The upshot is that the hierarchy is very evident with boys. And hard. The life of a low-status male is often miserable. Independent behavior, which is a characteristic of control at the top, tends to be highly prized.
Tannen found very different behaviors when observing little girls. There were both high-status and low-status females, as with the boys. But they used strikingly different strategies to generate and maintain their hierarchies. The girls spend a lot of time talking. This communication is so important that the type of talk determines the status of the relationship. To whom you tell your secrets determines “best friend” status. The more secrets revealed, the more likely the girls identify each other as close. Girls tend to de-emphasize the status between them in these situations. Using their sophisticated verbal ability, the girls tend not to give top-down imperial orders. If one of the girls tries issuing commands, the style is usually rejected: The girl is tagged as “bossy” and isolated socially. Not that decisions aren’t made. Various members of the group give suggestions, then discuss alternatives. Eventually, a consensus emerges.
The difference between the genders could be described as the addition of a single powerful word. Boys might say, “Do this.” Girls would say, “Let’s do this.
into adulthood
Tannen found that over time, these ways of using language became increasingly reinforced, which incited different social sensitivities in the two groups. Any boy who gave orders was a leader. Any girl who gave orders was bossy. By college age, most of these styles were deeply entrenched. And that’s when the problems became most noticeable, showing up at work and in marriage.
A 20-something newlywed was on a drive with her girlfriend, Emily. She became thirsty. “Emily, are you thirsty?” she asked. With lifelong experience at verbal negotiation, Emily knew what her friend wanted. “I don’t know. Are you thirsty?” she responded. There then ensued a small discussion about whether they were both thirsty enough to stop the car and get water.
A few days later, the woman was driving with her husband. “Are you thirsty?” she asked. “No, I’m not, he replied. They actually got into an argument that day. She was annoyed because she had wanted to stop; he was annoyed because she wasn’t direct. This type of conflict would become increasingly familiar as their marriage aged.
Such scenarios can play out in the work force just as easily. Women who exert “male” leadership styles are in danger of being perceived as bossy. Men who do the same thing are often praised as decisive. Tannen’s great contribution was to show that these stereotypes form very early in our social development, perhaps assisted by asymmetric verbal development. They transcend geography, age, and even time. Tannen, who was an English literature major, sees these tendencies in manuscripts that go back centuries.
nature or nurture?
Tannen’s findings are statistical patterns, not an all-or-none phenomenon. She has found that many factors affect our language patterns. Regional background, individual personality, profession, social class, age, ethnicity, and birth order all affect how we use language to negotiate our social ecologies. Boys and girls are treated differently socially the moment they are born, and they are often reared in societies filled with centuries of entrenched prejudice. It would be a miracle if we somehow transcended our experience and behaved in an egalitarian fashion.
Given the influence of culture on behavior, it is overly simplistic to invoke a purely biological explanation for Tannen’s observations. And, given the great influence of brain biology on behavior, it is also simplistic to invoke a purely social explanation. The real answer to the nature-or-nurture question is “We don’t know.” That can be frustrating to hear. Everybody wants to build bridges between these islands. Cahill, Tannen, and countless others are doing their best to provide us with the boards and nails. That’s not the same thing as saying the connections exist, however. Believing that there are strong associations between genes and cells and behaviors when there are none is not only wrong but dangerous. Just ask Larry Summers.
ideas
How can we use these data in the real world?
Get the facts straight on emotions
Dealing with the emotional lives of men and women is a big part of the job for teachers and business professionals. They need to know:
1) Emotions are useful. They make the brain pay attention.
2) Men and women process certain emotions differently.
3) The differences are a product of complex interactions between nature and nurture.
Try different gender arrangements in the classroom
My son’s third-grade teacher began seeing a stereotype that worsened as the year progressed. The girls were excelling in the language arts, and the boys were pulling ahead in math and science. This was only the third grade! The language-arts differences made some sense to her. But she knew there was no statistical support for the contention that men have a better aptitude for math and science than women. Why, for heaven’s sake, was she presiding over a stereotype?
The teacher guessed that part of the answer lay in the students social participation during class. When the teacher asked a question of the class, who answered first turned out to be unbelievably important. In the language arts, the girls invariably answered first. Other girls reacted with that participatory, “me too” instinct. The reaction on the part of the boys was hierarchical. The girls usually knew the answers, the boys usually did not, and the males responded by doing what low-status males tend to do: They withdrew. A performance gap quickly emerged. In math and science, boys and girls were equally likely to answer a question first. But the boys used their familiar “top each other” conversational styles when they participated, attempting to establish a hierarchy based on knowledge aptitude. This included drubbing anyone who didn’t make the top, including the girls. Bewildered, the girls began withdrawing from participating in the subjects. Once again, a performance gap emerged.
The teacher called a meeting of the girls and verified her observations. Then she asked for a consensus about what they should do. The girls decided that they wanted to learn math and science separately from the boys. Previously a strong advocate for mixed-gender classes, the teacher wondered aloud if that made any sense. Yet if the girls started losing the math-and-science battle in the third grade, the teacher reasoned they were not likely to excel in the coming years. She obliged. It took only two weeks to close the performance gap.
Can the teacher’s result be applied to classrooms all over the world? Actually, the experiment is not a result at all. It is a comment. This is not a battle that can be won by testing one classroom in a single school year. This is a battle properly fought by testing hundreds of classrooms and thousands of students from all walks of life, over a period of years.
Use gender teams in the workplace
One day, I spoke about gender with a group of executives-in-training at the Boeing Leadership Center in St. Louis. After showing some of Larry Cahill’s data about gist and detail, I said, “Sometimes women are accused of being more emotional than men, from the home to the workplace. I think that women might not be any more emotional than anyone else.” I explained that because women perceive their emotional landscape with more data points (that’s the detail) and see it in greater resolution, women may simply have more information to which they are capable of reacting. If men perceived the same number of data points, they might have the same number of reactions. Two women in the back began crying softly. After the lecture, I asked them about their reactions, fearing I may have offended them. What they said instead blew me away. “It was the first time in my professional life,” one of them said, “that I didn’t feel like I had to apologize for who I was.”
And that got me to thinking. In our evolutionary history, having a team that could simultaneously understand the gist and details of a given stressful situation helped us conquer the world. Why would the world of business be exempted from that advantage? Having an executive team or work group capable of simultaneously understanding both the emotional forests and the trees of a stressful project, such as a merger, might be a marriage made in business heaven. It could even affect the bottom line.
Companies often conduct management training with situation simulations. They could take a mixed-gendered team and a unisex team and have them go at a project together. Take another set of two teams, but first teach them about the known gender-based differences before taking on the same project. You have four potential outcomes. Would the mixed teams do better than the mono teams? Would the trained groups do better than the untrained groups? Would these results be stable in, say, six months? You might find that management teams with a gist/detail balance create the best shot for productivity. At the very least, this means that both men and women have an equal right to be at the decision-making table.
We could have environments where gender differences are both noted and celebrated, as opposed to ignored and marginalized. Had this been done earlier, we might have more women in science and engineering now. We might have shattered the archetypal glass ceiling and saved companies a lot of money. Heck, it may even have salvaged the Harvard president’s job.
Summary
Rule #11
Male and female brains are different.
• The X chromosome that males have one of and females have two of—though one acts as a backup—is a cognitive “hot spot,” carrying an unusually large percentage of genes involved in brain manufacture.
• Women are genetically more complex, because the active X chromosomes in their cells are a mix of Mom’s and Dad’s. Men’s X chromosomes all come from Mom, and their Y chromosome carries less than 100 genes, compared with about 1,500 for the X chromosome.
• Men’s and women’s brains are different structurally and biochemically—men have a bigger amygdala and produce serotonin faster, for example—but we don’t know if those differences have significance.
• Men and women respond differently to acute stress:
Women activate the left hemisphere’s amygdala and remember the emotional details. Men use the right amygdala and get the gist.
