In Spike Jonze’s 2013 film Her, a man falls in love with his computer operating system, known as Samantha. The software has a beautiful feminine voice and a great sense of humor. Over time, the man experiences the same desire, romance, and attachment as he might with any other person — even though he can’t see, touch, or look into the eyes of the woman he imagines. And his heartbreak in the end is no less real.
The film raises the question: Is the experience of love all in our heads?
The answer, as for most philosophical quandaries, is yes and no. While there may come a day when we can program our perfect mates via an operating system, research suggests that our urge to find love is less an intellectual pursuit than a basic animal instinct.
Biological anthropologist Helen Fisher, PhD, is a Rutgers University professor and author of several books, including Why We Love: The Nature and Chemistry of Romantic Love. In one of her best-known studies, Fisher and her team put a group of smitten humans through a functional magnetic resonance imaging (fMRI) machine to collect data on the brain in love. They observed which areas of the brain were using the most oxygen and glucose, a clue to the most active regions.
The results, published in the Journal of Comparative Neurology in 2005, suggest that thoughts of one’s beloved activate the right ventral tegmental area and right caudate nucleus — two suspected hot spots for the creation and distribution of dopamine, a neurotransmitter associated with desire, motivation, and reward.
This fueled Fisher’s hunch that romantic love is — as the legendary rock band Boston sang — more than a feeling.
“You can be sad or happy and not do anything about it,” says Fisher, noting that emotions don’t necessarily motivate behavior. But romantic desire, with its link to craving, obsession, and total focus on the love object, definitely does.
“I’m just confirming what Romeo and Juliet could have told us centuries ago, and what poets have known forever: What people will do for romantic love is astonishing.”
Just as Romeo and Juliet didn’t need a lab report to confirm they were in the throes of passion, a neurochemical analysis can’t tell us how or whom to love — or how to make it last. What the research can offer, though, is an unprecedented understanding of the brain in love and the role of the brilliant constellation of hormones that drives thoughts, feelings, and, sometimes, inexplicable behavior.
Built for Love
Our drive for love evolved millions of years ago, according to Fisher, “to focus our energies on an individual with whom to start the mating process.”
Love involves three distinct stages: lust, attraction, and attachment. Each uses different pathways in the brain and is powered by a different combination of neurochemicals. (For more on how these chemicals operate, see “The Chemistry of Love,” below.)
Lust is relatively indiscriminate. As a neurochemical experience, it simply seeds a broad interest in finding a mate. Researchers believe it evolved to increase the pool of prospective partners; an overly picky species doesn’t fare well.
When you do eventually set your sights on a particular someone, you enter the attraction stage, and your energies become focused on that person.
Fisher observed that lovers are not just single-minded about the object of their love; they’re obsessed. She suspected that the obsessive nature of love was due not only to a spike in the neurotransmitters dopamine and norepinephrine, but also to a corresponding drop in serotonin. This meant that those in full swoon shared something in common with those suffering from obsessive-compulsive disorder, who also tend to run low on serotonin.
Fisher found support for this theory in 1999: An Italian research team learned that of 60 study participants, those with a full-on case of love sickness had significantly lower levels of serotonin compared with the control group.
This chemical roller coaster may help explain why the initial stages of love are so fun, so exciting, and, ultimately, so exhausting. And why it’s so appealing when attachment, also known as companionate love, takes over — when you decide to shack up, share chores, give foot rubs, and tolerate each other’s reality TV shows for as long as you both shall live (or not).
As far as the survival of the species is concerned, the attachment drive appears designed to keep couples together at least long enough to bear and raise a child.
While a securely attached relationship is often seen as the jackpot of the dating lottery, the attached often long to return to the lust and attraction phases. Although the attachment provides a much-needed sense of security and comfort, many at this stage mourn the feeling that the thrill is gone.
Researchers believe there’s a good reason the thrill passes: The state of love-stricken obsession is metabolically taxing. The brain’s no dummy, and it conserves energy wherever it can.
“When your brain has made a new thing procedural, it can free up all that energy for other things,” says Kayt Sukel, a science journalist and author of This Is Your Brain on Sex. In other words, when the brain downshifts from the excitement of new love, it enables you to think about finding food again.
Still, there’s more at play than hormones and neurotransmitters. The human brain also responds to its environment in unique ways.
“We aren’t prairie voles,” Sukel insists, referring to the monogamous rodent. “We have these giant frontal lobes that control for culture, morals, and judgments that affect our decision making.”
Any human behavior, Sukel points out, is a complex and unique dance of biology and environment.
Esther Perel, couples therapist and author of the best-selling book Mating in Captivity, maintains that the excitement of unfamiliarity, for example, is more cultural than biological.
In her view, the radical social and economic changes of the 20th century have conspired to create an ideology of love that expects romantic partnerships to satisfy every need.
“Never before have we expected so much from marriage,” she says. “We still want everything the original family was meant to provide, such as security and children, but we also want our partner to love us, desire us, be interested in us, be our best friend and confidante, and passionate lover to boot. We expect one person to give us everything an entire village used to provide. That’s a tall order for a party of two.”
Love Outside the Lab
What science can teach us is that some of what we feel when we’re in love is surprisingly universal — and maybe not even personal.
For Perel, the neuroscientific description of love is more useful as metaphor than answer key.
“I listen to the research, I follow it, but I don’t like to talk about love as dopamine, oxytocin, norepinephrine,” she says. Perel is more interested in the art of love than the science. And frankly, so are most of us.
Perel has spent three decades listening to people talk about love — and, if they’re on her therapy couch, their struggles with it. She’s heard a lot about the anger, fear, and despair people feel when love isn’t what it used to be. Nonetheless, the counterintuitive advice Perel offers couples to help keep love alive is based on scientific insights about the brain in love.
For her, the key to reviving romance in a long-term relationship isn’t necessarily to bring one’s partner closer but to let love breathe. Desire, Perel says, needs air. Romance is more exciting when we let our partners become a little unfamiliar to us again.
When couples feel love growing stale, Perel suggests exploring ways of being in partnership that allow more space for people to flourish as individuals. This paradoxical advice can help couples to recover some of what was so exciting about those early stages. Namely, mystery.
Sukel concurs. “What you can’t do is look at studies and figure out how to keep someone faithful or how to make love stay,” she says. What you can do is fire up the neurochemicals associated with lust and attraction by doing new things together and independently, which can effectively make you feel like a new person, and to see a new person in the one you love.
Novel experiences trigger the production of dopamine, the neurotransmitter responsible for feelings of pleasure and motivation. So make a point of seeking out fresh experiences and perspectives, both together and apart.
Regardless of what studies come out next, says Sukel, science will never be able to give us all the answers: “There’s still plenty of mystery to go around.”
It seems that many researchers agree that a certain amount of mystery is not only fascinating, it’s vital to keeping a relationship vibrant.
In the end, the degree of romance and excitement in your relationship may be determined by the degree of uncertainty you can bear.
While some thrive on closeness and intimacy, Perel notes, others feel smothered by it. “You need to create an environment in which both familiarity and surprise can thrive.”
Playfulness. Novelty. Anticipation. Curiosity. “These are the erotic ingredients,” says Perel. “They’re what make desire sustainable.”
In the end, it seems to be what we don’t know, not just about the brain, but about each other, that has the power to transform and sustain long-term love. So don’t fight the enigma. Enjoy it.
The Chemistry of Love
Love happens in three stages, according to love researchers: lust, attraction, and attachment. Each stage has its own signature cocktail of hormones and neurotransmitters.(Neurotransmitters fly from synapse to synapse in the brain, while hormones flow through the bloodstream. Some neurochemicals, such as oxytocin and vasopressin, can actually do both.) If you’re crushing hard on someone new or enjoying the comfort of a long-term partner, you’re feeling the effects of some chemical combination right now.
Powered mainly by the hormone testosterone, this stage is responsible for your get-dressed-go-out urge. It evolved to help motivate humans to seek sexual union with any appropriate partner.
The mark of someone in full swoon is not unlike someone suffering from obsessive-compulsive disorder. Distracted by thoughts of the love object and checking the phone every other second, the person newly in love is unable to focus on anything else. This mayhem involves the following neurotransmitters:
Dopamine: The Buzz
Once you’ve zeroed in on an appealing person, dopamine takes over. It helps you feel focused, motivated, and energized. Because this neurotransmitter is associated with learning and reward, you study the object of your love like the best book you’ve ever read.
A dopamine blast can feel intensely pleasurable — or not. It’s like a strong cup of coffee: delicious, but with side effects that can include sleeplessness, loss of appetite, heart palpitations, breathlessness, and even fear.
Norepinephrine: The Jitters
This neurotransmitter also fosters energy and focus. It’s responsible for the physical sensations of desire and attraction, like dry mouth, sweaty palms, and weak knees.
Serotonin: The Cool Factor
If dopamine and norepinephrine are the brain’s accelerators, serotonin is the brake. It has a calming, cooling influence on the mind. Some research has found that, unsurprisingly, serotonin drops during the initial stages of romantic love. A dip in serotonin may contribute to the obsessive nature of early love and your restless, distracted thinking.
Obsessive love (usually) gives way to a mellower kind of bonding and attachment. Here are the chemicals involved in the postjitter stage:
Oxytocin and Vasopressin: The Cuddle Chemicals
These twin neuropeptides are released by the hypothalamus. They’re associated with the desire to be close and connected. Oxytocin is stimulated by physical touch, including nursing: It helps mothers bond with their newborn infants.
While oxytocin promotes bonding, vasopressin stimulates the protective impulse. It raises parents’ hackles in defense of their children, and causes lovers to feel defensive when someone else is flirting with their dates.