The Brain in Love: New Study Discovers Why Love May Bowl Us Over

Love leaves a chemical imprint on the brain that is fueled by dopamine—even the thought of the one we love ignites the ‘feel good’ hormone.

Scientists have shown in a new study that love actually leaves a 'mark' on the brain. Jacob Lund/Shutterstock

We all know how good it feels to be in love, and findings from a new study may be able to tell us why.

Neuroscientists from CU Boulder found that the brain produces more dopamine—the hormone that makes us feel desire and pleasure—when we crave or spend time with the one we love.

It turns out that just the thought of being with our partner causes dopamine to flood the brain’s reward center, motivating us to seek them out to keep that connection strong. By contrast, the study suggests only a trickle of dopamine is released when thinking about an acquaintance or coworker.

The research suggests that our mates create a “chemical imprint” in our brains and that when those romantic relationships end, the imprint begins to fade.

The study, published in the journal Current Biology, used prairie voles for their experiments because they are part of a small minority of animals (3–5 percent of mammals) that create monogamous lifelong bonds.

These tiny creatures—akin to overly fluffy brown mice—are similar to humans in their behavior, engaging in long-term relationships, sharing the responsibilities of raising offspring, living together, and experiencing loss when they lose their spouse.

“What we have found, essentially, is a biological signature of desire that helps us explain why we want to be with some people more than other people,” Zoe Donaldson, senior author and associate professor of behavioral neuroscience at CU Boulder said in a press release.

The research team sought to gain a deeper understanding of romantic relationships and their effect on the brain, and what happens when those relationships come to an end. The study discovered, for the first time, that dopamine plays a crucial role in maintaining those relationships and keeping the fires of love burning.

“This research suggests that certain people leave a unique chemical imprint on our brain that drives us to maintain these bonds over time,” Ms. Donaldson said.

The Science of Love and Attachment

Scientists have studied human relationships and the nature of love and attachment for decades, and research has shown that there are specific regions of the brain and neural circuitry that are associated with our feelings of love, attachment, and desire.

Helen Fisher has a doctorate in physical and biological anthropology and is an author and expert on human relationships. She says that certain brain chemicals are associated with our feelings of love.

“The oxytocin and vasopressin system are now linked with feelings of calm and attachment,” she said in an interview about the science of attachment in relationships for Big Think.

Oxytocin is both a neurotransmitter and a hormone and plays a vital role in childbirth, breastfeeding, and bonding—from mothers bonding with their newborn babies, to how we bond with romantic partners—and even friends. Because oxytocin is so instrumental in creating intimate bonds, it is often called “the love hormone.”

Vasopressin, also known as “antidiuretic hormone,” is a hormone with a variety of bodily functions, including regulating kidney function and blood pressure. It also influences social behavior—especially bonding between couples.

Ms. Fisher and her colleagues have conducted brain scans on people in the various stages of relationships—from being in love to post-breakup.

She found that for those who were newly (and madly) in love, the dopamine system in the brain lit up, but for those who had been in love a bit longer, there was new activity in brain regions linked with attachment.

“Basically, when you fall madly in love with somebody ... that brain system can be triggered instantly. But the feelings of attachment grow—they grow as you learn about the person,” Ms. Fisher said.

The Dopamine Drive to Reunite

The vole researchers wanted to know what happened in the brain when the moles were separated from their partners and trying to get back to them.

With neuroimaging technology, they could watch, in real-time, the region of the brain called the nucleus accumbens—which, in humans, is a region of the brain responsible for seeking out things that are gratifying or pleasurable. Previous neuroimaging studies in humans have shown that this area of the brain is activated when we hold hands with our partner.

In one experiment, a vole had to push a lever to open the door to a room to get to her partner, in another, she had to climb over a barrier to be reunited. As the voles worked to overcome obstacles to get to their mates, sensors detected a dopamine surge, lighting up the scientist’s equipment like a Christmas tree.

By contrast, the light dimmed when a random or unknown vole was on the other side of the barrier.

“This suggests that not only is dopamine really important for motivating us to seek out our partner, but there’s actually more dopamine coursing through our reward center when we are with our partner than when we are with a stranger,” first-author Anne Pierce, a graduate student who worked on the study in Ms. Donaldson’s lab noted in the press release.

Hope for Grieving Hearts

Although the study authors emphasize that more research is needed to know how well their findings on voles translate to humans, they say their work could eventually be used to help people who have difficulty making connections with others or for those who struggle with sadness—a condition called prolonged grief disorder, which is “characterized by intense and persistent grief that causes problems and interferes with daily life,” according to the American Psychiatric Association.

“The hope is that by understanding what healthy bonds look like within the brain, we can begin to identify new therapies to help the many people with mental illnesses that affect their social world,” Ms. Donaldson said.