The Chemistry of Love

Take this all with a grain of salt, but a book being published next month by Current/Penguin, The Chemistry Between Us: Love, Sex and the Science of Attraction, argues that all the sexy, impatient, bored, jealous, secure feelings you think you have regarding love—about your boyfriend or husband, the hot guy in the office, your ex — are really neurological responses to the chemical cocktails that flow through your veins. You’re not making decisions or choices, not really. You’re following the requirements of biology, and then telling yourself a culturally acceptable fiction like “love at first sight,” or “just my type,” or “so glad I dumped that douchebag cheater.”

The authors, Larry Young and Brian Alexander, are a neuroscientist and a journalist, respectively. They’re particularly interested in the rest of the animal kingdom — species that haven’t developed stories by which we explain away our biological impulses. By describing experiments in which researchers masturbate female rats, stimulate the cevixes of ewes, and study the cheating behavior of otherwise monogamous voles and zebra finches, they trace the biological foundations of human bonding.

So as an end-of-summer public service, I thought I’d pass along three of Young and Alexander’s tips on love and marriage.

1. Don’t marry the guy you meet while you’re ovulating.

The fertile period woman’s cycle has demonstrable effects on her appearance and behavior. The timbre of her voice changes. She takes more care with her appearance. She becomes more flirtatious. Men notice: Studies have shown that strippers who are ovulating make more money than those who are not. A University of New Mexico psychologist found that ovulating strippers made $354 per five hour shift, as opposed to $264 for non-ovulating strippers. Menstruating strippers earned even less.

But women also make riskier decisions at the fertile time of the month. They’re likelier to hook up with a stranger, likelier to respond to the attentions of a “bad boy” type, likelier to rent a house, sight unseen. Heather Rupp is a neuroscientist whose experiments on ovulating women are chronicled in Chemistry. “The guy you are most likely to pick mid-cycle — he is not necessarily the guy who is going to raise your children,” she says. “The perfect guy is the guy you like across the entire cycle, and they are rare!”

2. Size matters.

Oxytocin is a hormone that triggers bonding, especially in women and especially between women and their babies. It is released through the stimulation of the cervix (which explains, partly, the bonding that occurs between mother and infant after labor). Scientists at the University of Cambridge found in the eighties that if they stimulated the cervixes of ewes (with a dildo!) who had not recently given birth, the ewes behaved maternally toward lambs that did not belong to them. They exhibited “the full complement of maternal behavior … after five minutes of vaginal-cervical stimulation,” the scientists wrote.

Thus Young believes that the human penis has a similar, evolutionary purpose: To massage his sex partner’s cervix and thus release in her maternal feelings for him: “Men are using their penises … to entice women to babysit them.”

3. Some men have a “bad boyfriend” gene.

Evolutionarily, women bond to nurture and men bond to protect. The hormone that activates the protect-and-guard impulse (the bonding impulse) in men is called vasopressin. A variant in a gene called RS3 AVPRIA reduces men’s receptivity to vasopressin. According to a Swedish study, the married men with this gene variation were likelier to have experienced a marital crisis in the past year, likelier to have talked about divorce than those without the variant. They were also likelier, overall, to be unmarried. “If you want a guy that’s bonded to you tightly, you want to make sure you’ve got a guy with the right variance,” says Alexander in a phone call. In the last chapter of the book, the authors imagine a world in which online personals contain genetic information as well as physical details and professional status. “In addition to bundling the familiar ‘tall, professional, SWM’ in personal ads, why wouldn’t men proclaim ‘AVPRIA RS3 neg.’ as yet another selling point? Men and women routinely demand body types in their personals. Why not toss in genetic types?”

Any book that declares that biology is destiny is going to piss off a lot of people. Feminists and liberals might hate it. So might conservatives —especially the part about how most homosexuals and transgendered peoples’ sexuality is developed in utero. “When you’re developing as a fetus, this stuff gets laid down and there’s no escaping it,” says Alexander. Then there’s the somewhat creepy, sci-fi idea that everything we feel to be human is instead pre-programmed into us by some sort of ancient code. Which makes Alexander’s final take on the research he describes somewhat surprising. He believes his book is important because it demonstrates just how necessary face-to-face interaction — including flirting, touching, spit-swapping, and sex — are to human flourishing. “Society is really built on human bonds, all sorts of bonds,” he says. “You get that when you meet somebody, shake hands, look them in the eye. It does not happen digitally. People can say, ‘I’m best buddies with somebody on Facebook.’ Bullshit, you’re not.”