The Male Brain (10 page)

She got so involved in the game that she didn't text Ryan to tell him where she was until his team was set up for the winning point. And then she excitedly sent him a text: "You're winning."

Ryan's heart sank. He couldn't help becoming furious as he
imagined Frank hitting on her
. He pushed the autodial button for Nicole's cell number. But the roar of the crowd that followed the final point of the game was so loud that she didn't hear her phone ring.

It was clear to Ryan that Frank was sneakily trying to lure Nicole away from him--
a tactic called mate-poaching
. Men who mate-poach consider it a double victory: They beat the guy and get the girl. This scenario is well documented in the animal kingdom, too. Groups of primates such as chimpanzees can live happily together until a female is in heat and ready to mate. At that point, the dominant males will become rivals and fight for her attention.

When Ryan finally got through to Nicole, she was at the victory celebration. After just a few sentences, Frank snatched Nicole's cell phone and gave Ryan the play-by-play of the winning points. And then he hung up--but not before covertly turning off Nicole's ringer.

Ryan tried Nicole several more times before going to bed, and every time he got her voice mail, he got more worked up. He was ready to rip Frank's throat out. He'd never experienced such jealousy and rage. As he tried to fall asleep, he couldn't get the image of Frank kissing Nicole--or worse--out of his mind.

Researchers have found that the fear of loss or rejection can
intensify our feelings of love
. Ryan's mating hormones, testosterone and vasopressin, were igniting the fear-of-rejection center in his amygdala and the mating area in the hypothalamus. His brain was putting him on red alert and driving his territoriality
and possessive mating instincts wild
. As Ryan was discovering, deeply passionate feelings can lead to enduring commitments. By the time his plane landed the next morning, all he cared about was making Nicole his. He knew his heart wouldn't stop racing until he popped the question. Ring or no ring, he couldn't wait. He asked her that night and she said yes. There was no doubt that Ryan's love and lust circuits were now in sync. What would keep them in sync? Sex.

AFTER A messy divorce, my patient Matt was finally getting on with his life, and I was glad to know he was feeling good about himself again. A handsome thirty-four-year-old lawyer, he had first come to see me a few years earlier when his wife filed for divorce. At that time, he was twenty pounds overweight, and his self-esteem was plummeting. But over the past two years, Matt had worked through most of his anger, gotten back into shape, and regained his self-confidence. He had even started dating again.

I've witnessed this "rebound transformation" in many men. After a brief hiatus, Matt's brain biology was once again driving him to seek sex and encouraging him to pursue a variety of partners. Researchers have reported that men want an average of fourteen sexual partners in their lifetime, while the women said they wanted an
average of one or two
. Researchers surmise that some of the disparity in these numbers can be chalked up to men's
interest in one-night stands
.

Given Matt's brain reality, I wasn't surprised to hear that speed dating had become his favorite way to meet women. As scientists know, a man's testosterone rises when he pursues attractive women. And when Matt walked into a room full of speed-dating women, it made his testosterone rise even further. Researchers in the Netherlands found it took only five minutes of casually interacting with attractive women for
men's testosterone levels to go up
.

Six feet tall with dark wavy hair and deep brown eyes, Matt never had trouble attracting women. But like most men, he frequently wished he didn't have to make the first move, and speed dating eliminated that hurdle. When I asked Matt how he could tell if he wanted to date a woman based on a six-minute speed-dating meeting, he shrugged and said, "I just know." He said he could tell if he was sexually attracted to a woman before she sat down at his table or uttered a single word. Researchers at the University of California found that it takes the male brain only one fifth of a second to classify a woman
as sexually hot--or not
. This verdict is made
long before
a man's conscious thought processes can even engage. And often it's the brain below his belt that knows first.

The penis has always occupied a larger-than-life place in the minds of both men and women. But when it comes to sex, size is less important than men think. What many women don't know is that men can feel just as self-conscious about their bodies and genitalia as women feel. Being seen naked by a new partner isn't much easier for some of them than it is for us. They worry about what we'll think of their bodies and can experience anxiety about the
way their penis is shaped
. And many men fear that their partners will find them too small and will be disappointed.

Even though most men say they wish they had a larger penis, 85 percent of women say they're
happy with their partner's size
. Women report being most turned on by other physical features, like his eyes, smile, jawline, and muscles. And when it comes to being selected as a long-term partner, studies show that men get more mileage out of improving their personality and their bank accounts than out of investing in penile enlargement. But regardless of what we women think, many men erroneously believe penis size
is their most important feature
.

The irony here is that most men have no reason to feel insecure about their penis size. The average penis is much
larger than it needs to be
. According to researchers in England, the average erect penis ranges
from 5.5 to 6.2 inches
. Compared with other male mammals, relative
to their females, it's supersize
.

All men know that the penis has a will of its own and can rise to attention without a single command from his brain. These reflexive erections are different from true sexual arousal because they come from unconscious signals from his spinal cord and brain, not from a
conscious desire to have sex
. The testosterone receptors that live on the nerve cells in a man's spinal cord, testicles, penis, and brain are what activate his entire sexual network. Women are surprised that the penis can operate on autopilot and even more surprised that men don't always know when they're getting an erection. The autopilot penis is part of a man's daily reality for most of his life, though it happens less as he gets older. We women often notice the rising tide before he does.

True arousal for men typically starts in the brain with erotic thoughts or images. That's all it takes for a man's brain to send signals down the spinal cord to the penis
to start an erection
. As long as men have an adequate supply of testosterone, seeing an erotic image will automatically activate their brain's sex circuits. And as Dr. Frank Beach, my neurobiology professor at UC-Berkeley, taught us, "The male brain's sexual-pursuit and arousal circuits must be primed for action by testosterone in
order for him to function
."

This hormone increases sexual interest and revs up the horsepower of his thrusting muscles and penis for high performance. So, prior to their forties, seeing is often all it takes for most
men to become fully erect
. After that age, the frequency of the instant hard-on is reduced, and men often need some physical stimulation to become erect enough for penetration. Because Matt was in his early thirties, the connection between his eyes and his penis was more than adequate.
If we could observe Matt's brain with a miniature PET scanner on his weekend date, we'd see how it was directing the show. When his date walked out of her apartment and he laid eyes on her curvy figure draped in a slinky red dress, we'd have seen his visual cortex send a message to his hypothalamus to start
the hormonal engines for erection
. One look at her long legs in high spike heels got his complete attention. Her full lips and the blush of her cheeks registered as signs of fertility in his brain. As she tossed back her shiny brown hair and gave him that come-hither smile, he knew she might be sexually interested. This would light up his anticipation-of-pleasure center, the NAc (nucleus accumbens), letting him know there was
hope of a sexual reward
.

Sexual arousal begins in the brain, but it is reinforced by physical contact. Once a man is aroused, a woman's simple touch can send sexual tremors through his brain and body down into his penis. Later that evening, when Matt's date began unzipping his jeans, our miniature camera in his brain would show his hypothalamus directing blood to rush into his penis. We'd see a jolt of activation lighting up his frontal lobe's
"pay total attention to this now" circuits
. Matt's brain and body were now on high alert for taking advantage of this sexual opportunity. The instant his date gave him the green light, he'd be ready to hit the accelerator and head for the promised land. He was relieved that it didn't take long. Soon,
she
was pushing her hips up against his. With our camera, we'd now see all his brain areas
not
needed for sex going dark and deactivating. Any and all distractions were being silenced as his brain sent out the message
Penetrate now!
The urgency quickly spread throughout his body as he sucked in a quick breath of air. Ready, get set, go, and with
one smooth thrust, he was inside
.

To heighten his sexual arousal Matt played erotic fantasies in his visual circuits. These sexual fantasies had always helped him maintain a firm erection whether during sex or masturbation. Like most sexually active men, Matt had amassed a sex-fantasy DVD library in his brain. In his case, it was an erotic fascination with breasts that did the trick. Matt wasn't consciously conjuring up these fantasies. They were playing out on their own internal circuits, building
sexual tension, arousal, and pleasure
. Visual stimulation--even in fantasy--is what turns a man on, makes his penis hard, and keeps it up.

According to sex researchers, men are not only more stirred by sexual visions than women are, but also want to be more sexually adventurous. In a large national study, Dr. Edward Laumann and his colleagues counted and categorized men's and women's sexual acts like vaginal sex, oral sex, and anal sex. They found that across the board, it was men, not women, who suggested broadening their sexual repertoire. For example, men reported wanting to have group sex thirteen times more than women reported wanting to have it,
and fellatio twice as often as women
.

Oral sex can be a source of conflict in many relationships. Sex researchers believe that men enjoy this sexual act for many reasons, but one of the biggest is heightened sensitivity: the tongue, lips, and fingers can stimulate and stretch a man's urethral opening, increasing sensitivity in a way that doesn't happen as much inside the vagina. Researchers at McGill University found that as a man becomes more and more sexually aroused, the tip area, the glans of his penis,
becomes less and less sensitive
. This may be Mother Nature's way of protecting a man
from pain during sexual intercourse
. So, if there are times when a man can't reach climax during intercourse, he often
can
orgasm with the extra stimulation of oral sex.

In order to reach orgasm, both men and women must first turn off a few parts of the brain--like the amygdala, the brain's danger and alert center--and the areas for self-consciousness and worrying--the anterior cingulate cortex, or ACC. Aside from that, for men, arousal and orgasm are relatively simple and mostly about hydraulics; they need blood to rush to one crucial appendage. But for women, to turn off the worrying part of her brain, the
neurochemical stars need to align
. It takes more for a woman to get in the mood, relax, and deactivate her amygdala. That's why many sex therapists say that for women, foreplay is everything that happens in the twenty-four hours preceding intercourse, while for men, it's what
happens three minutes before entry
. But once men and women reach orgasm, the differences are few. Researchers have studied men and women in a PET scanner while their partners were manually stimulating their
penis or clitoris to orgasm
. Although differences showed up between men and women while they were being stimulated, there were few, if any, discernible brain differences during orgasm itself.