The Science of Love

Originally published in Parade Magazine Feb. 12, 2012 .

The ancient Greeks called it “the madness of the gods”; the author Sherwood Anderson dubbed it “the divine ­accident of life.” But as it turns out, love is neither ­madness nor an accident. The more we understand how the brain works, the more it seems we are programmed for love, just as we’re programmed to eat and breathe. On this Valentine’s eve, discover how much we’ve learned about this crazy little thing called love.

The Power of Chemistry

It turns out that love truly is a chemical reaction. Researchers using MRIs to look at the brain activity of the smitten have found that an interplay of ­hormones and neurotransmitters create the state we call love. Four compounds—dopamine, norepinephrine, oxytocin, and serotonin—are likely to be particularly critical, says Helen Fisher, research professor of anthropology at Rutgers University and author of Why We Love: The Nature and Chemistry of Romantic Love. Although the way various chemicals interact in the brain is complex and still largely unknown, data suggests that each plays a different role.

Addicted to Love
Dopamine, a neuro­transmitter, makes you focus on the beloved—and desire more time with him or her. It is central to your brain’s reward ­circuitry: When you do something highly pleasurable, dopamine is released, effectively telling the brain, Do it one mo’ time. “If you have higher activity of ­dopamine in the brain, your susceptibility to falling in love may even go up,” Fisher says. “We’ve put over 50 people who were madly in love in the brain scanner [MRI], and one of the brain regions most activated is the area where dopamine is produced, the ventral tegmental area, or VTA.” Just about anything that gives you pleasure will elevate dopamine activity—from eating a box of chocolates to hitting a hole in one. Liquor both lowers inhibitions and may increase dopamine, which is why half the world’s relationships seem to start over a glass of wine. Novel experiences also raise dopamine activity, so if you want to up the chances of falling in love … well, having dinner with a new interest is great, but you might want to try skydiving, too.

Dopamine gets released when an addict uses drugs, which explains the feeling of being “addicted” to your partner when you’re falling in love. “Evolutionarily, one of dopamine’s purposes is to help us become attached to each other,” explains Larry Young, of the Center for Behavioral Neuro­science at Emory School of Medicine. In other words, when Bryan Ferry sang “Love Is the Drug,” he was more accurate than he knew. “There is a kind of addiction that occurs when we fall in love,” Young says.

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The Butterfly Effect
Norepinephrine, a stimulant closely related to dopamine, is most likely what gives you the energy for late-night sessions of staring into each other’s eyes. It can produce sleeplessness, elation, loss of appetite, butterflies in the stomach … in short, the whole megillah of nuttiness that comes with romantic love.

Obsessing, Much?
Serotonin, a neurochemical that creates feelings of calm, is present in lower levels in those experiencing the first blush of love. “This may go a long way toward explaining that state of anxiety and obsessive thinking that characterizes love in its initial phase,” Fisher says. There is unquestionably a relationship between love and emotions like anxiety and fear. In 2004, researchers from ­Italy’s University of Pisa released a study that measured hormonal activity in 24 young people who reported having recently fallen in love. The newly smitten had higher l­evels of the stress ­hormone cortisol than their workaday counterparts. The study also found that men in love had less testosterone than their single brethren; ­women in love, on the other hand, had more. This lends at least some biological credence to the popular idea that men in love are tamed and women in love are a little wilder and freer.

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The Urge to Merge
Oxytocin is what cements the trust and bond between two people. The neurochemical is released in both men and women when they have sex (women also get a dose when they give birth and breast-feed). It is, says Young, “the hormone of attachment and emotional empathy. Give a person intranasal oxytocin and they’ll look more deeply into the eyes of the person they’re with and report feeling a greater sense of trust.” Young has studied the effects of ­oxytocin on prairie voles. Here’s the thing about these voles: They aren’t players. They mate for life. Unless … “If you block their oxytocin receptors, they don’t become ­bonded to another partner,” he explains. “You can introduce two voles whose receptors are blocked and they can mate all night long, and the next day they don’t care.”

Scents and Sensibility

Fortunately for those of us who aren’t Julia Roberts or George Clooney, there is a wide range of tastes and preferences when it comes to appearance. But it seems that unconsciously there are certain characteristics we look for—qualities that, from an evolutionary point of view, bode well for our reproductive health. First and foremost is youth—particularly for men looking at women. No amount of diet, exercise, and Botox can deny that women’s eggs have a certain sell-by date. A study ­released last year tracked men’s eyes when looking at photos of women and found that their gaze lingered longer on waists and breasts, which may signal fertility, than on faces. Women tend to look for traditional signs of masculinity—distinctive cheekbones and a strong jaw.

Still, most of us have had that odd experience of meeting someone who is, objectively, very attractive—and yet we just don’t “feel it.” Sometimes we tell ourselves, “Oh, he didn’t smell right.” We usually don’t mean it literally—but a few scientists believe we may actually be onto something.

Love the Second Time Around

When we talk about “chemistry,” some theorize we’re talking about pheromones, the chemical messengers said to be exuded by the body to influence the behavior and mood of others. For decades, scientists have known that insects communicate their sexual receptivity to one another via pheromones. Termites, for example, use them to mark territory or lead members of their swarm to food.

The notion that humans also communicate ­subliminal messages with pheromones has long been suspected. Some studies have shown that during ovulation, women are more ­attentive to sexual messages from the outside world, dress more provocatively, and stare more at handsome men. This begs the question: Does a woman’s estrous ­cycle have a discernible effect on male behavior? Sure enough, in a study done by Saul Miller of the University of Kentucky and Jon ­Maner of Florida State University, men who interacted with ovulating women and then were asked to play blackjack were found to take more risks, in an attempt to make more money, than the men who’d interacted with non-ovulating women—meaning guys get all ­hunter-ish and daring in the presence of females who might be able to carry their seed into the next generation. Further, they found that men who smelled the T-shirts of ovulating ­women had greater levels of testosterone and were more likely to use ­sexual ­language than men who smelled the ­T-shirts of non-ovulating women. Nevertheless, ­pheromones ­remain controversial in the scientific community, with many doubting they play any kind of role. In his ­recent book The Great Pheromone Myth, ­Richard Doty, director of the Smell and Taste ­Center at the ­University of Pennsylvania, concludes that mammalian pheromones do not even exist. What it is about the scents of ovulating women that changes men’s behavior in the Miller-Maner studies is still ­unknown.

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Perhaps not surprisingly, taking birth control pills, which disrupt hormones, plays with these natural inclinations. According to a study at the University of Sheffield in England, women on the pill no longer experience a greater desire during ovulation for traditionally masculine men (good news for the Jonas brothers)—and, the study speculates, men no longer exhibit a higher or lower degree of interest for a ­woman on the pill based on her menstrual cycle.

Scent may even play a role in kissing. Though ­scientists aren’t sure ­exactly why people kiss, some postulate that it’s a reminder of the intimacy of early feeding experiences; others ­believe it’s a way of getting close enough to experience a ­potential ­partner’s smell.

Love That Lasts

Monogamy, while natural, is not always easy, for which there may be biological reasons. Both ­sexes have inherited the brain circuitry for deep attachment to a mate. But some scientists believe men are ­predisposed to procreate with as many ­females as possible, and women designed to land the best ­providers by any means necessary. If our ­libidos are giving us one message, our knowledge of medicine is giving us quite ­another. That’s because marriage, and its ­presumption of monogamy, may be the key to health. According to the CDC, the married are less likely to smoke or drink heavily than people who are single, divorced, or widowed. Other studies show they also have reduced levels of sexually transmitted ­diseases and lower rates of suicide. Want to live longer and happier (if chubbier—­married men tend to be heavier than single men)? If you like it, put a ring on it.

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Here’s some cheering news: Though everyone talks about how romance fades after the honeymoon, that isn’t ­necessarily true. Bianca Acevedo of Cornell Medical College and Arthur Aron of Stony Brook University compared the brain scans of couples who had just fallen in love with those of men and ­women who had been married an average of 21 years and said they were still intensely in love with their spouses. Those in long-term relationships were shown images of their partners, as well as of close friends and neutral acquaintances. Guess what? When subjects saw their beloved’s image, their dopamine-rich VTA lit up like a pinball machine.

“The brain scans were similar to those in the first blush of love, but there was a difference,” says Acevedo. Recall that the newly in love show low activity in the areas of the brain where serotonin is produced, which means ­anxiety and obsessive thinking. But those still ­romantically in love after many years show greater ­activation in serotonin and opiad-rich areas associated with ­elevated calmness and pleasure. “They’re in the ­secure phase of love,” ­Acevedo ­explains. “They still desire one another, they’re ­engaged, they experience the intensity—but not the ­anxiety.”

Let’s wish that kind of love to ­everyone who’s dear to us on this ­Valentine’s Day.

The Cure for a Broken Heart

A recent brain-scan study ­examined the ­newly dumped. When subjects stared at photos of the person who rejected them, their scans resembled those of people withdrawing from drugs. So how to ease the pain? “If someone is camping out in your head, treat it as an addiction,” Professor Helen Fisher says. “If you’re trying to give up alcohol, you don’t leave a bottle of vodka on your desk.”

1. CUT OFF COMMUNICATION
Place letters and pictures of your ex in a lockbox; take her number off your cell, her email address out of your contacts, and her IM name off your buddy list.

2. GET ACTIVE.
Exercise. By increasing the stores of dopamine in the brain, you drive up optimism and get ­renewed hope.

3. CALL THE SPA.
Get a massage and hug your friends. Both increase oxytocin levels.

4. TRY SOMETHING NEW.
Do novel things. “Whether it’s travel, new restaurants, new hobbies, or seeing people you haven’t seen in a while,” Fisher says, “novelty significantly elevates activity of ­dopamine in the brain.”

finis.

Special thanks to Lindsy Sell for the kitten picture, "Kitty Hearts".