This Is Your Brain … On Love

(Editor’s note: This article from a past issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)

Love is the Drug

Faith in love is a little like faith in God: extremely important to our lives, yet rarely examined. Perhaps we don’t really want something that we cherish to be dissected on a lab table. Love is one of those things that seem enhanced by a little mystery.

But scientists know better than anyone that behind every mystery lies another, deeper mystery. In 1996, biological anthropologist Dr. Helen Fisher decided to attempt to answer the age-old question, What is love? So she put up flyers around the campus of SUNY Stony Brook querying, “HAVE YOU JUST FALLEN MADLY IN LOVE?” and the campus lovebirds flocked to her.

Reflecting on her motives in her book “Why We Love,” Fisher wrote, “If I could establish which regions of the brain become active while one is feeling romantic rapture, that might confirm which primary chemicals are involved. Perhaps these data would help explain the evolutionary roots of romantic love, why we choose one person rather than another, even how people can find and sustain this glorious passion.”

Fisher and her colleagues Arthur Aron and Lucy Brown used an fMRI machine, which records blood flow to different parts of the brain, to study their young lovers — collecting 144 scans of each subject as they gazed at photos of their beaus, performed a dull counting exercise, and looked at photos of a neutral acquaintance. They then examined the areas of the brain receiving the most blood during each action — indicative of heightened activity. When contemplating their beloved, subjects showed increased activity in two regions of the brain, the ventral tegmental area and the caudate nucleus, a large C-shaped region near the center of the brain. The caudate nucleus sits smack-dab in what is sometimes referred to as our “reptilian brain” — the oldest part of the brain, in evolutionary terms. “The more passionate they were,” wrote Fisher, “the more active their caudate was.”

The caudate controls bodily movement. What wasn’t well known at the time of the study is that it is also important to the brain’s reward system, generating arousal, pleasure and desire. The ventral tegmental area also plays a central part. When in love, it releases both the hormone norepinephrine, which increases your heartbeat, and focuses your attention and dopamine, which activates the brain’s pleasure systems. Fisher had suspected dopamine was a key player all along. Euphoria? Check. Sleeplessness? Check. Loss of appetite? Check. Increased energy? Check. As Fisher later told a CNN reporter, “Exactly the same system becomes active as when you take cocaine. You can feel intense elation when you’re in love.” Dopamine brings addiction as well as pleasure. Lovers crave more of it, and that makes them want to be together all the time. Robert Palmer had it right when he sang, “You might as well face it, you’re addicted to love.”

The revelation Fisher and her colleagues had after analyzing the data might surprise you even now: Love is not merely an emotion. As Fisher’s colleague Arthur Aron had suspected, it is a motivation system. Motivation systems are our basic drives, compelling us to find things like water, food, and safe places to sleep. In other words, the neural systems that support our romantic notions are goal-oriented, pushing us to find a mate and produce offspring. When we find that person, we experience the reward: not just dopamine, but emotions like elation and hope, and possibly offspring.

Another thing Fisher found was that new lovers experience a drop in serotonin levels of about 40 percent. Another segment of the population with low serotonin levels are OCD sufferers. Is it any wonder we obsess on the objects of our affection? Fisher’s research indicates new lovers think about the other person 95 percent of the time.

Over the past decade, Fisher has performed several more studies on the topic. In “Why We Love,” she outlines three distinct systems for love in the brain: lust (craving sexual gratification), attraction (the intense, dopamine-fueled early love), and attachment (long-term love). Lust, Fisher insist, is the weakest of the three drives, pointing out that people don’t commit suicide over thwarted sex.

Love at First Sight

Science suggests attraction happens in a fraction of a second. “By the time you think, She’s really attractive, your body has already had a response,” says Andrew Trees, author of “Decoding Love.” When you see a good-looking face — typically a symmetrical one, indicating good genes — it activates your nucleus accumbens (a pleasure center) and orbitofrontal cortex, important for decision-making, pleasure, and reward. Meanwhile, unconsciously, your olfactory system is taking in that person’s scent and determining if one is a good genetic match (See: Pharmaceuticals Aren’t Suitable).

If you’re already excited, you’re more likely to find a stranger attractive. In a now-classic experiment, men forced to cross a narrow bridge over a deep ravine rated a woman working for the study as more attractive than a control group did. Excitement triggers dopamine, adrenaline, and testosterone — all key players in the game of love. “The arousal of fear gets confused with the arousal of desire,” says Trees. “The brain is complicated, and a little messy at times. There’s not a clear compartment that is love, with nothing else touching it — it’s interlocked with all these other things.”

Many social theorists believe that love is a cultural construct: a pervasive belief that becomes a self-fulfilling prophecy. But whatever label you put on it, scientists have found the same chemistry and brain patterns in lovers from all cultures, all over the world. However, love is different from lust. It only takes a fraction of a second to have a sexual response to a stimulus, characterized by increased activity in the hypothalamus and amygdala. (Australian scientists found the bigger the amygdala, the more lustful a man can be — proving once and for all that size does matter.) People in love, however, have a distinctly different response pattern. “We now have physiological data that suggests there are different brain systems for sex and love,” Fisher told CNN.

The most important thing, says Trees, is to trust your instincts. Research shows that too much analysis can make you go against what your body chemistry is telling you. “Trust your gut and don’t talk about it too much,” he advises. “Our mind is really good at giving us reasons, but they’re just what we can articulate, not what’s actually going on. Studies show that our friends do a better job of predicting if our relationships will last than we do.”

True Love

In his book, Trees urges readers not to fall into the trap of looking for the “one” true love who will change our lives forever. “There are different kinds of love,” he explains. “I think we are in love with the chemical side of love: the overwhelming feelings when the brain releases chemicals that are like cocaine and amphetamines, when you feel fantastic. That exists, but it’s only short-term. So I’m always a little leery of people who see this initial onrush of feelings as a sign. I think that’s why love so often fails — because we want it to be that chemical high all the time. We’re addicted to one kind of love. But you don’t get 60 years of the endorphin rush.”

Up until very recently, scientists agreed, ascribing passion an average half-life of 15 months. Otherwise, as Fisher once opined, “We would all die of sexual exhaustion.” Most frame it in evolutionary terms: Gaga young lovers might do anything for each other in the short term, but long-term survival requires clear-headed thinking. After mating and conceiving, it’s time to think about food and shelter again. “You want the chemical charge to last long enough that the couple stays together until the child is old enough that it can survive if the couple breaks apart,” says Trees. Researchers studying the chemistry of love used to believe limerance, the elevated dopamine levels we associate with passionate love, began to decline within six months and dissipated within 10 years.

But a study published by Dr. Arthur Aron suggests there are rare couples who retain the passion of early love throughout their relationships. Aron performed fMRI scans on couples who had been together for over 20 years. While most did not display that tell-tale rush of dopamine when they were presented with a photo of their beloved, about one in 10 of them did. Aron named these couples “swans,” after the animals that mate for life. While he doesn’t claim to know all their secrets, he did find some features that their relationships shared. Swans engage in new activities together. They minimize stress. And perhaps most importantly, they keep the fires of love burning by stoking them with regular sex, which releases the feel-good neurotransmitter oxytocin and strengthens their bond. “More sex with your partner is always a good thing,” agrees Trees. “The research about sex is all good news. It keeps couples together and is good for your health — it’s fantastic!”

(Editor’s note: This article from a past issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)

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