The Female Brain (6 page)

Congenital adrenal hyperplasia causes fetuses to produce large amounts of testosterone, the sex and aggression hormone, from their adrenal glands starting at about eight weeks after conception—the very moment their brains begin to take shape into the male or female design. If we look at genetic females whose brains are exposed to surges of testosterone during this period, we see that these girls’ behavior and presumably brain structures are more similar to those of males than to those of females. I say “presumably” because a toddler’s brain isn’t so easy to study. Can you imagine a two-year-old sitting still for a couple of hours in an MRI scanner without being sedated? But we can deduce a lot from behavior.

The study of congenital adrenal hyperplasia provides evidence that testosterone erodes the normally robust brain structures in girls. At one year old, CAH girls make measurably less eye contact than other girls the same age. As these testosterone-exposed girls get older, they are far more inclined to scuffling, roughhousing, and fantasy play about monsters or action heroes than to pretending to take care of their dolls or dressing up in princess costumes. They also do better than other girls on spatial tests, scoring similarly to boys, while they do less well on tests that tap verbal behavior, empathy, nurturing, and intimacy—traits that are typically female. The implications are that the male and female brains’ wiring for social connection is significantly affected not just by genes but by the amount of testosterone that gets into the fetal brain. Lynn was relieved to have a scientific reason for some of her daughter’s behaviors, since no one had taken the time to explain to her what happens in the CAH brain.

G
ENDER
E
DUCATION

Nature certainly has the strongest hand in launching sex-specific behaviors, but experience, practice, and interaction with others can modify neurons and brain wiring. If you want to learn to play the piano, you must practice. Every time you practice, your brain assigns more neurons to that activity, until finally you have laid new circuits between these neurons so that, when you sit down at the bench, playing is second nature.

As parents, we naturally respond to our children’s preferences. We will repeat, sometimes ad nauseam, the activity—Mommy’s smile or the noisy whistle of a wooden train—that makes our little one giggle or grin. This repetition strengthens those neurons and circuits in the baby’s brain that process and respond to whatever initially captivated her or his attention. The cycle continues, and children thus learn the customs of their gender. Since a little girl responds so well to faces, chances are Mom and Dad will make a lot of faces and she’ll get even better at responding. She’ll be engaged in an activity that reinforces her face-studying skill, and her brain will assign more and more neurons to that activity. Gender education and biology collaborate to make us who we are.

Adult expectations for girls’ and boys’ behavior play an important role in shaping brain circuits, and Wendy could have blown it for her daughter Samantha if she had given in to her own preconceptions about girls being more fragile and less adventurous than boys. Wendy told me that the first time Samantha climbed the jungle gym ladder to go down the slide by herself, she immediately looked back at Wendy for permission. If she had sensed disapproval or fear in her mother’s facial expression, she probably would have stopped, climbed back down, and asked for her mother’s help—as would 90 percent of little girls. When Wendy’s son was that age, he would never have bothered checking for her reaction, not caring if Wendy disapproved of this step of independence. Samantha obviously felt ready to take this “big girl” leap, so Wendy managed to squelch her fear and give her daughter the approval she needed. She says she wishes she had had a camera to record the moment Samantha landed with a bump at the bottom. Her face lit up with a grin that expressed her pride and excitement, and she immediately ran over to her mother and gave her a big hug.

The brain’s first organizing principle is clearly genes plus hormones, but we can’t ignore the further sculpting of the brain that results from our interactions with other people and with our environment. A parent’s or caregiver’s tone of voice, touch, and words help organize an infant’s brain and influence a child’s version of reality.

Scientists still don’t know exactly how much reshaping can occur to the brain nature gave us. It runs against the grain of intuition, but some studies show that male and female brains may have different genetic susceptibility to environmental influences. Either way, we know enough to see that the fundamentally misconceived nature versus nurture debate should be abandoned: child development is inextricably both.

T
HE
B
OSSY
B
RAIN

If you’re the parent of a little girl, you know firsthand that she isn’t always as obedient and good as the culture would have us believe she should be. Many parents have had their expectations dashed when it came to their daughter getting what she wanted.

“Okay, Daddy, now the dollies are going to lunch, so we have to change their clothes,” Leila said to her father, Charles, who dutifully changed the outfits—into party clothes. “Daddy! No,” Leila screamed. “Not the party dress! The lunch outfits! And they don’t talk like that. You’re supposed to say what I told you to say. Now say it right.”

“All right, Leila. I’ll do it. But tell me, why do you like to play dolls with me instead of with Mommy?”

“Because, Daddy, you play the way I tell you to.” Charles was a little thrown by this response. And he and Cara were taken aback by Leila’s chutzpah.

Not all is perfectly calm during the juvenile pause. Little girls don’t usually exhibit aggression via rough-and-tumble play, wrestling, and punching the way little boys do. Girls may have, on average, better social skills, empathy, and emotional intelligence than boys—but don’t be fooled. This doesn’t mean that girls’ brains aren’t wired to use everything in their power to get what they want, and they can turn into little tyrants to accomplish their goals. What are those goals as dictated by the little girl’s brain? To forge connection, to create community, and to organize and orchestrate a girl’s world so that she’s at the center of it. This is where the female brain’s aggression plays out—it protects what’s important to it, which is always, inevitably, relationship. But aggression can push others away, and that would undermine the goal of the female brain. So a girl walks a fine line between making sure she’s at the center of her world of relationships and risking pushing those relationships away.

Remember the wardrobe sharing twins? When one asked the other to borrow the pink shirt in trade for the green, she set it up so that if the other sister said “no” she’d be considered mean. Instead of grabbing the shirt, she used her best skill set—language—to get what she wanted. She was counting on her sister’s not wanting to be seen as selfish, and indeed her sister gave up the pink shirt. She got what she wanted without sacrificing the relationship. This is aggression in pink. Aggression means survival for both sexes, and both sexes have brain circuits for it. It’s just more subtle in girls, perhaps reflecting their unique brain circuitry.

The social and scientific view of innate good behavior in girls is a misguided stereotype born out of the contrast with boys. In comparison, girls come out smelling like roses. Women don’t need to lay one another out, so of course they seem less aggressive than males. By all standards, men are on average twenty times more aggressive than women, something that a quick look around the prison system will confirm. I almost left aggression out of this book, after being lulled into a warm glow of communicative and social female brain circuits. I was nearly fooled by the female aversion to conflict into thinking that aggression simply wasn’t part of our makeup.

Cara and Charles didn’t know what to do about Leila’s bossiness. It didn’t end with telling her father how to play dolls. She screamed when her friend Susie painted a yellow clown instead of a blue one as she had ordered, and heaven forbid if a conversation at the dinner table didn’t include Leila. Her female brain was demanding that she be part of whatever communication or connection was taking place in her presence. Being left out was more than her girl circuits could bear. To her Stone Age brain—and face it, we’re all still cave people inside—being left out could mean death. I explained this to Cara and Charles, and they decided to wait out this phase instead of trying to change Leila’s behavior—within reason, of course.

I didn’t want to tell Cara and Charles that what Leila was putting them through was nothing. Her hormones were steady, they were at a low point, and her reality was fairly stable. When the hormones turn back on and the juvenile pause comes to an end, Cara and Charles won’t have just Leila’s bossy brain to deal with. Her risk-taking brain will have the stops pulled out. It will drive her to ignore her parents, entice a mate, leave home, and make something different out of herself. Teen girl reality will explode, and every trait established in the female brain during girlhood—communication, social connection, desire for approval, reading faces for cues as to what to think or feel—will intensify. This is the time when a girl becomes most communicative with her girlfriends and forms tightly knit social groups in order to feel safe and protected. But with this new estrogen-driven reality, aggression also plays a big role. The teen girl brain will make her feel powerful, always right, and blind to consequences. Without that drive, she’ll never be able to grow up, but getting through it, especially for the teen girl, isn’t easy. As she begins to experience her full “girl power,” which includes premenstrual syndrome, sexual competition, and controlling girl groups, her brain states can often make her reality, well, a little hellish.

TWO

Teen Girl Brain

D
RAMA, DRAMA, DRAMA.
That’s what’s happening in a teen girl’s life and a teen girl’s brain. “Mom, I so totally can’t go to school. I just found out Brian likes me and I have a huge zit and no concealer. OMG! How can you even think I’ll go?” “Homework? I told you I’m not doing any more until you promise to send me away to school. I can’t stand living with you for one more minute.” “No, I’m not done talking to Eve. It has
not
been two hours, and I’m not getting off the phone.” This is what you get if you have the modern version of the teen girl brain living in your house.

The teenage years are a turbulent time. The teen girl’s brain is sprouting, reorganizing and pruning neuronal circuits that drive the way she thinks, feels, and acts—and obsesses over her looks. Her brain is unfolding ancient instructions on how to be a woman. During puberty, a girl’s entire biological raison d’être is to become sexually desirable. She begins judging herself against her peers and media images of other attractive females. This brain state is created by the surge of new hormones on top of the ancient female genetic blueprint.

Attracting male attention is a newfound and exciting form of self-expression for my friend Shelly’s teenage daughters, and the high-octane estrogen coursing through their brain pathways fuels their obsession. The hormones that affect their responsivity to social stress are going sky high, which is where they get their off-the-wall ideas—and clothing choices—and why they are constantly staring at themselves in the mirror. They are almost exclusively interested in their appearance, specifically whether the boys who populate their real and fantasy worlds will find them attractive. Thank goodness, says Shelley, they have three bathrooms in their home, because her girls spend hours in front of the mirror, inspecting pores, plucking eyebrows, wishing the butts they see would shrink, their breasts grow larger and waists get smaller, all to attract boys. Girls would likely be doing some version of this whether the media were there to influence their self-image or not. Hormones would be driving their brains to develop these impulses even if they didn’t see skinny actresses and models on the cover of every magazine. They would be obsessing over whether or not boys thought they looked good because their hormones create the reality in their brains that being attractive to boys is the most important thing.

Their brains are hard at work rewiring themselves, and this is why conflicts will increase and become more intense as teen girls struggle for independence and identity. Who are they anyway? They are developing the parts of themselves that most make them women—their strength for communicating, forming social bonds, and nurturing those around them. If parents understand the biological changes happening in the teen girl brain circuits, they can support their daughters’ self-esteem and well-being during these rocky years.

R
IDING THE
E
STROGEN-
P
ROGESTERONE
W
AVES