In 1993, Haddaway released the seminal dance classic What Is Love – a sparkling debut, by any musical metric, which also succinctly encapsulates a question that humanity has been wrestling with since time immemorial. Love has been the muse of playwrights, poets, artists, and composers through the ages; many have tried to quantify, describe, and understand this enigmatic emotion. But is love simply a matter of cold, hard biology?
Plenty of research has looked at the biological underpinnings of maternal and familial love, but we’re going to focus here on romantic love. You know, the head-over-heels, can’t sleep, can’t think straight kind of love. We often describe falling in love as a rollercoaster of emotions; given that, it’s perhaps unsurprising that the poets have arguably done a better job of defining what exactly love is than the scientists have.
However, if we want to examine whether love is a neurochemical construct, we need to get to grips with what's going on in the brain.
It wasn’t until relatively recently that scientists even had the tools to investigate this question. Until the early 21st century, most of the research had focused on the psychology of love and attraction. A 2007 review summarized the early neurobiological studies in this area.
It was already known that the areas of the brain that are specifically involved in feelings of love contained high concentrations of the neurotransmitter dopamine.
As author Semir Zeki explained, “Release of dopamine puts one in a ‘feel good’ state, and dopamine seems to be intimately linked not only to the formation of relationships but also to sex, which consequently comes to be regarded as a rewarding and ‘feel-good’ exercise.”
While dopamine is increased during that first rush of lust, another neurotransmitter appears to be depleted: serotonin. This, according to Zeki, is similar to an effect seen in the brains of those with obsessive-compulsive disorder and is responsible for the single-minded focus on the object of our romantic desires that we can feel in the early stages of a relationship.
Some regions of the brain, too, show decreased activation in response to romantic love. These include the amygdala and areas of the frontal cortex, which Zeki suggests dampens judgment we may feel towards our beloved, allowing us to view them in a more positive light.
When you think of the words "chemicals" and "romance", one of the things that might come to mind first is pheromones. If popular culture - and advertising slogans - are to be believed, humans exude scented signals that make us smell irresistible to potential partners. Studies in the animal kingdom have indeed pointed to the importance of pheromones in some critters’ reproductive cycles – but you might be surprised to learn that the evidence for their existence in humans is scant.
“The idea of human pheromones is intuitively appealing, conjuring up the idea of secret signals that make us irresistible to potential partners,” said psychologist Mark JT Sergeant, writing for The Conversation in 2015. “But this connection of pheromones with sex may be the wrong way to look at the issue – because despite 45 years of study and various claims over the years there’s still not a lot of evidence that human pheromones exist at all.”
Probably not the news you wanted to hear if you're a deodorant manufacturer.
In terms of brain chemicals though, the big hitter that we simply can’t ignore is oxytocin. Mainly because it’s actually nicknamed “the love hormone”.
The first descriptions of oxytocin centered around its vital roles in pregnancy and childbirth. Since then, research has suggested that oxytocin is linked to sexual function, helps mammals to bond with each other, and could even help mend a broken heart. A lot of the work that helped scientists start to understand this “cuddle chemical” came from work on one very special – and, appropriately, very cuddly – rodent.
Prairie voles form monogamous pairs and share nests with their partners, making them perfect for this kind of research. A 2017 study involving these little cuties boldly claimed to have been able to crack the neural code of love, finding a neural network that sends floods of oxytocin (and our old friend dopamine) into the brain’s reward centers during romantic bonding.
Prairie voles have more receptors for both oxytocin and the related hormone vasopressin than their promiscuous cousins, montane voles, which could explain why they find monogamous bonding so rewarding at a neurochemical level.
There’s still a lot that scientists don’t know about how oxytocin, and the closely related hormone vasopressin, are involved in romantic love in humans. Researchers are currently engaged in work to understand this neurochemical system, from its possible origins in our ancient ancestors, to how epigenetic regulation of the oxytocin gene shapes each person's emotional experiences (you can find out more about the science of epigenetics in Issue 7 of our free e-magazine, CURIOUS).
The authors of the 2017 prairie vole study were even able to hijack the neural system they identified, effectively causing the voles to fall in love with each other. Does that mean that love really is just a series of chemical processes that can be manipulated? Reduced down to this, does love not lose some of its magic?
Possibly. Then again, we can choose to look at it as part of that magic. Who could argue that there’s not a sort of magic in a dinosaur that grew so big as to eclipse nine African savannah elephants, or the majesty of an aurora in the sky, even if we can explain these things with science?
So, to return to our question: is love really just a neurochemical construct of the mind? It’s certainly true that there’s a whole load of biochemistry going on behind the scenes when we fall in love. “But to say that love is ‘just’ brain chemistry is like saying Romeo and Juliet is ‘just’ words – it misses the point,” said neurologist Parashkev Nachev, writing for The Conversation.
“Like art, love is more than the sum of its parts.”
All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.