It happens like this: You and your husband come home from a long day at work. You're both tired and stressed. You want to talk about a confrontation you had with your boss and a project that's giving you trouble. They want to lie on the couch and channel-surf. If you can convince them to listen to you, they promptly tell you what you should have done about the boss blowup. The whole thing turns into an argument, and instead of talking it out with you, they storms off.
At least some part of this argument should sound familiar to many women. We're constantly asking ourselves what's going on in that man's head:
"Why doesn't he ever seem to listen?"
"Why doesn't he remember things I've told him?"
"Why doesn't he notice how messy the house is?"
"What is it with him and that remote control, anyway?"
Turns out they're not just being stubborn, and it's not just how they were raised. According to family therapist Michael Gurian, author of the new book What Could He Be Thinking?, male and female brains are wired differently long before birth. The surge of hormones --testosterone for men, estrogen for women (although we each get some of both hormones) -- that floods our developing fetal brains leads to marked differences in brain development and neural connections.
Brain imaging technologies such as magnetic resonance imaging (MRI) and positron emission tomography (PET) scans demonstrate these differences, says Gurian, who has relied on the work of a variety of neuroscientists and biologists in writing What Could He Be Thinking? These scans can show how and where the brain functions during activities. The typically "male" brain, for example, devotes much more brain area to spatial skills -- things like mechanical design, manipulation of physical objects, and abstraction. With so much brain area devoted to spatials, male brains usually have less area for word use and word production.
There are a number of other differences, and some of them aren't just structural, but chemical. The male brain usually produces less of two powerful chemicals, serotonin and oxytocin, than the female brain does. Serotonin tends to calm us down, while oxytocin may be related to bonding behaviors.
Picturing the Brain
PET scans provide a dynamic, "living color" illustration of male-female brain differences. "If you line up PET scans of 50 male brains and 50 female brains, you'll see more colors lighting up in the female brain because there's about 15% more blood flow, on average, in the female brain," says Gurian. If you show those 100 men and women a picture of someone looking sad, he says, you'll notice that less of the male brain lights up as the men try to figure out the emotion involved. "There's less involvement of the emotive centers and less going on in the hippocampus, where memory storage is."
On the other hand, if the same 100 men and women were asked to do a math or science problem, the PET scan would show, on average, that women used more of their brain to get the answer than the men did. "The male brain tends to be more efficient to lateralize and compartmentalize, which has the advantage of making him more task-focused. The female brain has more [nerve] connections and constantly cross-signals and takes in more, so it tends to see and feel more than the male brain," Gurian says.
And new research from UCLA scientists suggests that male-female brain differences may be genetically hard-wired in place from the very beginning, even before the flood of hormones occurs during fetal development. Studying the brains of male and female mice, researchers found 18 genes produced at higher levels in male brains while 36 genes were produced at higher levels in female brains. "This provides evidence that there are differences in gene expression in male and female brains, before any influence of hormones," says Eric Vilain, MD, assistant professor of human genetics and urology at the David Geffen School of Medicine at UCLA and a pediatrician at UCLA's Mattel Children's Hospital. "It's possible that these genetic differences may influence the development of differences in male and female brain structures, independently of hormonal action."
Why Won't They Talk?
So why don't they want to talk? "Males, first of all, don't take in as much of the conversation as women do," Gurian says. "Because we have more cortical areas devoted to spatial mechanicals and fewer verbal centers, we're not getting as much of it, and in general, men will want to end conversations more quickly than women."
When he sprawls on the couch with the remote at the end of the day, a guy may not be deliberately ignoring their wife or girlfriend. The male brain rejuvenates differently than the female brain does, Gurian says. "Using brain scans, University of Pennsylvania neuroscientist Ruben Gur found that the male brain goes to a rest state to rejuvenate much more than the female brain does. To build brain cells and restore himself, a man needs to 'zone out,'" Gurian says. That's why he channel-surfs or stares at the computer.
But the female brain, thanks to all that oxytocin, wants to bond at the end of the day in order to rejuvenate. "She wants to talk, using all those verbal centers, and she wants to get close to him," Gurian says. But the timing's all off. "If the wife takes a break and vents first to someone else -- a friend on the phone, perhaps -- and lets her husband rejuvenate during that zone-out period, he'll be much more prepared to listen later on, during dinner, for example. It's all about timing."
Of course, male-female brain differentiation isn't black and white. We all know men who are better at talking and expressing their feelings than their wives are, and women who can fix a flat while their husband is still on the phone to AAA but would rather get root canal than talk about their feelings. "I'm arguing that there is a broad brain spectrum, and we're all along the continuum," he says. "There isn't just one kind of male and one kind of female."
Gurian has also dubbed some people, both men and women, "bridge brains" -- people whose brain wiring crosses sexes and fits in as much with the predicted behavior of the opposite sex as with their own. "Nature has always liked the exception as much as the rule," he says.
And he's not arguing that men can point to brain research and say, "Great! Now I have an excuse not to talk, to channel-surf all the time, and forget our anniversary."
"Males and females both have to do their part. Men do need to listen to their spouses," Gurian says. "But what I'm suggesting is the natural rhythm is awry right now. If men and women could both understand better how their brains work differently, they could use these natural rhythms to relate better."
