Andrew Trees explains that oxytocin creates a period of neuroplasticity that can help new lovers make a fresh start. “We are all carrying romantic baggage,” he says. “But if you have a powerful enough response to someone, you’ll be able to get rid of some of that mental baggage, wipe the brain clean and form new neural connections.”
An upbeat attitude also is also important. In his book, Trees discusses a study wherein people in happier marriages were more likely to rate an interaction with their spouse as “positive” even when it was rated “neutral” by impartial observers. “This builds up a reservoir of good will,” explains Trees, “because all of these day-to-day interactions are shifted into positive ground. There’s an advantage to being optimistic and putting a rosy glow on things.”
The brains of long-term lovers demonstrated more activity in the areas of the brain that create oxytocin and vasopressin than their newer counterparts. Oxytocin is sometimes called the “cuddle” chemical, and it is released by the brain during activities as diverse as orgasm, breastfeeding, massage, and acupuncture. Oxytocin suppresses the amygdala, which processes fear, helping to generate a feeling of intimacy, confidence, and trust. Normally promiscuous mice, when injected with a gene for oxytocin, become as monogamous as swans. Swiss researchers have demonstrated that oxytocin encourages positive behavior in couples, and reduces levels of the stress hormone cortisol. After the dopamine bloom of love wears off, high levels of oxytocin and vasopressin can remain, as passion mellows into contentment.
Mars and Venus
Perceived differences between the sexes have long been sources of humor, torture, and delight. Science is beginning to get to the bottom of some of these thorny issues, and while it may come as no surprise to some, there are fundamental cognitive differences between men and women when it comes to love and attraction.
Men
Testosterone is the rocket fuel of the male sex drive. It actually can suppress oxytocin and vasopressin, making a high-testosterone guy cuddle-resistant and less likely to settle down. Once a man does enter a relationship, his testosterone levels drop about 20 percent, according to researchers in Pisa, Italy. In fact, a team of Harvard University anthropologists found that testosterone drops if a man simply holds a baby—players beware. After their testosterone is under control, men can settle down to the joys of long-term commitment and child-rearing. While oxytocin has a greater effect on women, men seem to be more governed by the hormone vasopressin, which appears to make men more possessive of their mates. Swedish researchers have shown that men with a specific vasopressin gene-variation are more likely to have happy marriages.
Evolutionary theory suggests men are alert for visual indications of fertility. Men in love show more activity than women in the parietal region of the temporal lobe, where visual stimuli is processed, indicating that looks are important for men. Pornography activates the same region.
Women
“I’m not even sure that men and women fall in love in the same way at all,” says Trees. “Men are simple. But for women it’s a much more complicated mix. They’re better at processing emotions, remembering things and intuiting social encounters. Some scientists theorize that women have to be skeptical romantics because they carry the burden [raising a child] if it doesn’t work out.”
But while women may be more skeptical than men at first — in one study, 75 percent of men agreed to sex proposed by an attractive stranger, while no women did — once they fall, they fall harder. Women have more mirror neurons than men, causing them to be more empathetic and influenced by their partner’s mood. Estrogen increases sensitivity to oxytocin, encouraging women’s trust, affection, and loyalty to their partner. Women also demonstrate more activity in the hippocampus, suggesting they’re more likely to remember the details of a first date.
“They’ve done excellent studies that the kind of men that women find attractive can vary enormously,” says Trees. “If you are at peak fertility, you’re much more likely to be attracted to a high-testosterone alpha male. If you’re not at peak fertility, you’re more likely to be attracted to a guy who will commit, be a good provider and stay around.”
The Book of Love
So what are we to make of all this? Does our new understanding of love reduce it to a banal neurotransmitter cocktail? Not necessarily.
To say that our experience of love is just an interaction of chemicals in the brain is akin to declaring that the evening news is just a grid of tiny colored lights on a television screen, or that a book is nothing more than ink on paper. These mediums carry meaning not even hinted at in their physical qualities. The observable, neurological effects of love would be empty without the vastness of our subjective experience. To a person in the throes of love, the mechanics are irrelevant.
To accept any experience as merely chemical is to deny the confluence of factors that led the chemical to be released, and all the ramifications that may have. To say “war and peace” is just ink is to deny its sweeping narrative — and to dismiss love as neurotransmitters is to deny the narrative of your very life. As Andrew Trees told me, “You can’t let the science overwhelm your humanity.” Your chemical bliss, whether the first rush of dopamine or the comfortable embrace of oxytocin, has infinite depth. Neurotransmitters are merely the ink in which your epic story is being written.
Cupid’s Arrows: Your Handy Guide to Love’s Neurotransmitters
- Dopamine: Creates powerful feelings of euphoria. Addictive.
- Norepinephrine: Generates feelings of excitement; gets your heart racing and your palms sweating. Also released if chased by a bear.
- Serotonin: Falling in love causes a big drop in this neurotransmitter, encouraging obsessive behavior.
- Oxytocin: Released by the pituitary gland in moments of intimacy, this neurotransmitter makes you physically affectionate and trusting.
- Vasopressin: Inspires aggressive posturing, courtship, possessiveness, and commitment in males.
- Testosterone: Fuel for the sex drive, especially in men. Elevated testosterone can suppress oxytocin and vasopressin, making a man more likely to go on the prowl than settle down.
Pharmaceuticals Aren’t Suitable!
Romantic love isn’t all about the dopamine rush. It also involves a major drop in your serotonin levels — up to 40 percent. Guess who else has low serotonin? People with obsessive-compulsive disorder. See the connection? People in love think about their partner up to 95 percent of the time, according to Fisher’s study.
Antidepressants like Prozac and Zoloft increase the presence of serotonin. While it’s critical that serious depressives obtain treatment, these drugs can impede one’s love-life by preventing that (often agonizing) inability to think of anything but your crush. Patients on antidepressants might believe that they haven’t met the right person, when in fact they’ve corked up the brain’s ability to go gaga. In a speech to the APA, Fisher warned that prescription-happy doctors may be “inhibiting patients’ well-being and possibly their genetic future.” Antidepressants can also cause sexual dysfunction in men and inhibit orgasm in women.
But antidepressants aren’t the only drug would-be lovers need beware. Ironically, birth-control pills also throw a major monkey wrench into the gears of love, by causing infertility via tricking the body into thinking it’s already pregnant. Normally, humans are attracted to potential mates with immunity genes that differ from their own. If you love your lover’s smell, chances are it’s telling you that your offspring will have strong immunity due to your combined genetic codes. But guess whose body odor is pleasant to a pregnant woman? Family members, with genes similar to her own, who may help protect her baby. If you marry someone whose genes are too similar to yours, your children have weaker immunity and you’ll be more likely to cheat on your spouse. The trouble is, a woman on the pill may be attracted to a man with a similar genetic profile — but once she goes off the pill, she could find herself suddenly ambivalent, and more attracted to other men. “There should be a surgeon general’s warning on the birth-control box,” says Andrew Trees, author of “Decoding Love.” Bottom line: Women who meet their mates while on the pill should drop it before they get engaged.
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