Listen to this story as it was recorded for WKNC’s Eye on the Triangle:
It may start with an intriguing look. Or a kiss. Or a smell. Neurons fire and hormones secrete from the glands. It may seem like a primitive and crude description of what happens in our bodies, but even our higher emotions derive from a physiological pathway.
Love, despite its complex and enigmatic nature, has a natural origin. Without making an over generalization, love comes from basic instincts geared to furthering the species. However, regardless of this simple explanation, love tends to engross and confuse us.
Perhaps the cheesy pop songs had it right all along—love is a drug. Like getting a good grade on a test or shooting up heroin, romantic stimuli trigger the release of various hormones that give rise to the secretion of dopamine.
Dopamine is a neurotransmitter which aids in communication between nerve cells and is associated with a feel-good sensation. This, perhaps, is why romance feels tempting and fun.
In love, there are two primary stimuli that provoke the release of dopamine, Phenylethylamine and the more well-known oxytocin.
“You have two responses,” James Knopp, biochemistry professor, said. “You have a quick response, which some might call the lust response, from Phenylethylamine, called PEA.”
According to Knopp, the brain reacts to certain triggers, like body shape or smell, which generate PEA.
“You also get a norepinephrine response, which is like a fight-or-flight response, so that gives a traditional sweaty palms and heart rate, increased breathing,” Knopp said. “The feeling of ‘being in love.'”
The effects of PEA last between six months to three years, the necessary time for a couple to produce offspring. PEA may be responsible for titillating biological responses, but it’s not the deal maker for the deeper sense of love.
While PEA triggers the love-at-first-sight response, long-term romance occurs from a different protein called oxytocin. This hormone elicits the monogamous tendencies in humans.
Human subjects are hard to study and this limitation presents difficulties in research, since oxytocin affects few animals in the same way it does humans. However, mouse-like rodents called voles have the same response to the release of oxytocin.
There are two types of voles—prairie voles, which form monogamous bonds, and meadow voles, which are more sexually promiscuous.
“If you give a vole the option of huddling with its partner or with a stranger, they spend a lot of time cuddling with their partner,” John Godwin, an associate professor of zoology, said. “What’s really striking is the small genetic change between voles that are monogamous and voles that aren’t.”
Larry Young, a researcher at Emory University, discovered a molecular-biological technique to make the promiscuous voles respond to vasopressin, a chemical very similar to oxytocin.
“Through this technique, if you make the meadow voles’ brains responsive to the peptide [protein] in the dopamine pathway, then you can essentially make them more like the prairie vole, more monogamous,” Young said.
Just like voles, humans have a similar positive reinforcement effect due to oxytocin.
“This is the being in love over a longer period of time [response],” Knopp said. “If the oxytocin response doesn’t kick in after a while then usually a partnership will dissipate.”
Oxytocin is protein that originates from the pituitary gland, a region of the brain which is one of the most important hormonal gland in the body.
“A lot of things will initiate this, such as childbirth,” Knopp said. “Sexual activity will release this, in both men and women.”
Oxytocin elicits the feeling of deep attachment too. Biological anthropologist Helen Fisher from Rutgers University described it as, “a basic human drive…a basic mating drive, which allows you to focus on one mating partner at a time.”
Due to this intimate and profound attachment, oxytocin also exerts control driving humans to the point of pathetic direness. Ever been dumped by your significant other and experienced loneliness? According to Knopp, this is due to withdrawals from dopamine from the lack of oxytocin. Memories can also stir up this sense of nostalgia, demonstrating the strong chemical effect.
Fisher remarked that even Plato said the god of love lives in a state of need.
“Love is a homeostatic need…like food or water,” Fisher said. “Romantic love [due to its strong chemical nature] is also an addiction — a perfectly wonderful addiction when it’s going well and a perfectly horrible addiction when it isn’t.”
Fisher said romantic love exhibits the three characteristics of a drug—craving, withdrawal and relapse.
However, humans are not fully impulsive or dependent on these physiological reactions.
“We still have choices,” Knopp said. “It’s like hunger. You can choose to eat or not. It doesn’t stop you from being hungry. I think we as a species have the capability of making choices, so we are not essentially driven and taken over by this process.”
The mystery of romantic love will not be cracked solely by science, but the biochemical and physiological processes can help in understanding this powerful emotion.
“I believe that love is more than a chemical or physical reaction. The chemicals, like dopamine or endorphins don’t necessary mean love,” Matt Jeffries, a sophomore in business and management, said. “Some philosophers argue the mind-body connection. You can have dopamine and eat chocolate, but that doesn’t mean you’re in love. You need one for the other, but just because you have dopamine doesn’t mean you have love. However, if you have love, you’ll get that physical response. There’s something more to it.”
In light of Valentine’s Day, the chemistry doesn’t take away from the mystery of the emotion.
“Certainly coming back to the theme of Valentine’s Day, there is a whole lot that we don’t know, indeed,” Godwin said. “I would say it’s interesting that people look at this like it’s a dissection of the happenings between neurons and in terms of gene expression and say it’s taking the magic out of something like love or maternal attachment. For people in our field, it doesn’t diminish the experience, but rather it makes it, if anything, more fascinating.”
