The science of love

Biological love

Whether they’ve experienced it for themselves or not, most people know the reactions that come from the initial rush of falling in love – the racing heart, flushed skin and sweaty palms. But what is the scientific cause of these physical reactions?

Jen Uno, assistant professor of biology, says one source of this early giddiness comes from increased levels of dopamine, which research has shown to be a “pleasure chemical” and also is released in response to nicotine and cocaine.

Graphic by John David Parsons

“According to Helen Fisher at Rutgers University and other scientists, if you look at brain scans of people who have just fallen in love, areas in the brain linked with addiction and pleasure light up,” she says.

Early stages of love are also characterized by lower levels of the hormone serotonin, which can also be found in patients with obsessive-compulsive disorder.

“[This] may explain why people become obsessed with their lovers,” she adds.

As a result of the half-life of these chemicals, the physiologic response is relatively brief, Uno says, adding people can stimulate the release of more dopamine by thinking of the person or seeing a picture of a loved one. This is similar to the effect of drinking a coffee or soda with caffeine.

She says research by Larry Young, a neurobiologist at Emory University, has found that the molecules oxytocin and vasopressin are key to long-term mating habits.

“Oxytocin seems like the ideal love potion,” Uno says. “Young thinks that human love is set off by a long chain of events that begins during mother-child bonding due to the fact that oxytocin is stimulated and released during labor, delivery and nursing.”


Psychology of love

While the external reactions to love are apparent, there are also other psychological responses happening below the surface, in the crevices of the brain.

While Mark Prokosch, assistant professor of psychology, says love is difficult to operationally define, he views romantic love as a motivation system, a need that compels the lover to seek a mating partner and maintain a bond.

“As the song says, ‘Your love is my drug,’” he says. “This is quite literally the truth when we look at what the feeling of love does to our brains. Just like any emotion, love is our body’s adaptive response to the environment.”

When someone comes into contact with a loved one, the brain responds with increasing activity in certain areas, including the prefrontal cortex and the “reward” system, which can allow feelings of love, trust and attachment to be sustained over a long period of time.

Prokosch says human desire to find a lasting soul mate puts the species in the minority, with only three percent of mammals seeking long-term pair bonds.

“You wouldn’t expect to see love or attachment develop in species that aren’t social, don’t spend significant time raising their offspring and don’t seek partners to form bonds to work together,” he explains. “Finding that ‘one’ is a pretty significant task when you look at it from that perspective.”

By Caitlin O’Donnell ’13