Skip to main content

Verified by Psychology Today


Romeo, Juliet and the Science of Love

What's really happening when you fall in love?

Romeo and Juliet has been captivating audiences around the world for over 400 years. Not only for the moving story and beautiful language but because it expresses the ecstatic and overpowering force of falling in love so brilliantly. But what’s going on inside us when we fall in love? This has always been a mystery. But now there’s an embryonic science of love offering some answers.

ShortCutstv / Free-Photos at Pixabay
The Science of Love
Source: ShortCutstv / Free-Photos at Pixabay

So, let’s take another look at English literature’s most famous love story; this time through the lens of neuroscience.

The Story

When we first see Romeo, he’s sullen, sorry for himself, and pining for a girl called Rosaline who has no interest in him. But then he sees Juliet and everything changes. It’s as if a light has been switched on inside him.

‘Did my heart love till now?’ he asks himself.

It’s a magical moment. It comes out of the blue, yet feels as if was destined to happen. It’s something a majority of people say they’ve experienced, and describe with familiar phrases such as, I just knew; it was meant to be; it was love at first sight.

Romeo and Juliet quickly become entranced in mutual worship of each other. And this is cleverly picked up in the text. Romeo likens his lips to two blushing pilgrims and, by kissing her, their sin might be purged. Juliet’s happy for their sin to be purged. Continuing the religious metaphor, she tells Romeo, "You kiss by the book," meaning flirtatiously, is that the best you can do?

Even when Romeo and Juliet discover to their horror they’re from two families literally at war with each other, and that it’s dangerous for them even to be seen together, it doesn’t deter them. What they’re beginning to feel is something much more powerful than physical attraction.

Juliet is shocked that she "must love someone" from a "hated enemy." But she says "must love." It’s her fate, out of her control. It’s the same for Romeo.

Later that evening, he risks his life breaking into the grounds of Juliet’s family home just in the hope of seeing her. And she’s on her balcony thinking about him:

"Wherefore art thou Romeo?"

The awesome power of romantic love is beginning to wrap its arms around them; a power that, for them, will override family loyalty, society, and, in the end, life itself.

But where does this love come from? And why do people feel such a lack of control when they’re falling in love?

The Science of Love

'The unique thing about human love,' says Dr. Anna Machin from the Department of Experimental Psychology at Oxford University, ‘is that it exists at two levels, the conscious and the unconscious. The amazing feelings you have at the start of a romantic relationship are being driven by the more primitive areas of the brain that lie below our conscious thinking processes.'

When people newly and madly in love are placed in fMRI brain scanners and asked to look at pictures of their beloved, or even just think about them, the areas that light up and show increased activity are down in the sub-cortical, dopamine-rich areas of the brain’s reward system.

What’s happening is that dopamine-producing neurons in the ventral tegmental area (VTA), a little chemical factory buried deep in the mid-brain, are transmitted to the brain’s higher-level reward centres, such as the nucleus accumbens that helps detect and expect rewards, and the caudate nucleus that motivates the pursuit of rewards. Effectively, your brain is telling you that something very important is happening.

It’s theorised in biological anthropology that what we now call falling in love evolved over millions of years to direct courtship to a particular partner and bind them together long enough to raise offspring who will be vulnerable for years.

The brain in love does this with a cocktail of chemicals. A rush of dopamine and oxytocin, the so-called "happy hormones," create feelings of euphoria and emotions of closeness, care, and commitment to your love. Activated by the reward system, it quickly becomes something you want over and over again. You give and receive.

This is beautifully captured by Juliet in the famous balcony scene where she and Romeo declare their love for each other. 'My bounty is as boundless as the sea, my love as deep,' she tells Romeo, 'The more I give to you, the more I have, for both are infinite.'

So it’s not really a surprise that the brain of someone madly in love looks very similar to one on cocaine.

'Love’s not like an addiction,' says Helen Fisher of the Kinsey Institute, Indiana University. 'It is an addiction. You think about your love and keep coming back for more.'

But addiction is not enough for the brain in love. It wants more control. So as dopamine and oxytocin levels rise with romantic love, levels of serotonin fall.

Dr. Donatella Marazziti of the University of Pisa found, to her surprise, that a sample of participants who had just fallen in love had serotonin levels as low as people with obsessive-compulsive disorder. This is significant because serotonin is a key hormone that stabilizes our mood and provides us with a sense of being in control.

The fall in serotonin helps explain why people newly in love often become obsessed with their beloved and think and talk about little else, and why they are often compelled to keep trying to verify their beloved feels the same way.

'If I ask you if you love me,' Juliet says to Romeo, ‘I know you will say you do. But even if you swear you do, you may prove false.’

But the brain in love isn’t finished yet. There are good neurological reasons for the idea that love is blind, or at least partially sighted.

Romeo and Juliet are lovely characters, but they have their flaws. Both are very impulsive and, as we see, prone to temper tantrums. (They’re adolescents!) Yet they only see perfection in each other. Even when Romeo kills Juliet’s cousin in a duel, he has done no wrong in her eyes.

The reason for the 'blindness' of love is that the ventromedial prefrontal cortex, which neuroscientists think is responsible for critical judgment, de-activates when we fall in love.

'You lose the ability to mentalise, or mind-read,' says Anna Machin, 'Your friends might be saying, ‘This person is completely wrong for you.’ But you can’t see it because the area of your brain that makes judgments isn’t working. So love is a form of blindness, a form of madness.'

There is, of course, nothing new in the idea that falling in love is madness. Poets, philosophers, and playwrights, including Shakespeare in several of his plays, have been telling us this for centuries.

What neuroscience offers that’s new is first, an understanding of the biological processes driving romantic love and secondly, that there is a method in the madness of love. It’s a drive evolved to enable the human race to continue. Love may be full of irrationally on the surface, but there’s biological rationality underlying it.

Where Did Our Love Go?

Of course, the madness of love is temporary. After a few years, or sometimes only a few months, the brain develops more tolerance to the pleasure stimulants; serotonin levels return to normal and the ventromedial prefrontal cortex reactivates. The mists clear and you actually get to see who you’ve fallen in love with.

Relationships may then end very quickly, continue unhappily for a while, or evolve into a long-term romantic attachment. You’re still in love, it’s just a different kind of love, less passionate and more compassionate. There’s a different balance of chemicals and the conscious brain is playing a much bigger part. You’ve fallen in love, and now you’re learning to stand in love and work at it.

The good news is that fMRI scans of couples in long-term relationships have found much the same activity in dopamine-rich areas of the brain that are seen in people newly in love. The passion can still be retrieved, but the craving, the obsession, and the blindness have gone. It’s the pot of gold at the end of the rainbow. And, on average, couples in long-term relationships are happier, healthier, and live longer.

While working on the script of a film on Romeo and Juliet, I found myself wondering, if fate hadn’t been against them, would Romeo and Juliet have made it to attachment love; hair now flecked with grey, looking back and smiling at their crazy Verona days? But, of course, we’ll never know.


It’s important to put the science of love into perspective.

First, it hasn’t found that love is addictive, obsessive, crazy, painful, etc. We knew that.

Second, to date, samples have been relatively small and methodologically, there are limitations to generalising from fMRI scans to everyday life. The science of love is a work in progress.

Third, human love can’t be reduced to neuroscience. There are too many other variables — genetic, psychological, and cultural — also shaping how human love works, so neuroscience is contributing parts of the puzzle.

Those concerned that science might take away the mysteries of love have nothing to worry about.


More from Steven Taylor Ph.D.
More from Psychology Today