This Is What Happens to Your Brain When You Fall in Love, According to Science

This explains a lot.

woman with bleached dreadlocks and man with beard nuzzling each other

Love at first sight is hard to explain. Some people swear they’ve fallen prey to its mystical power (sometimes more than once), while others chalk it up to folklore and too many viewings of Baz Luhrmann’s Romeo + Juliet (or reading Shakespeare’s original). We tend to gravitate toward the latter category, being the doubting, scientific-minded realists we are, but recently, we came across a fascinating study from Stephanie Cacioppo titled Neuroimaging of Love: fMRI Meta-Analysis Evidence Toward New Perspectives in Sexual Medicine. Cacioppo (whose last name was Ortigue at the time) led a team of researchers who examined exactly what occurs in the brain when you fall in love and lust. Some crazy findings right off the bat? 12—yes, 12areas of your brain work together to release chemicals and hormones that induce the feeling of falling in love, all of which happens in just a fifth of a second, eliciting “floating on cloud nine” feelings similar to that of euphoria-inducing drugs (though there are key differences, which we’ll explain later). Yeah, we’ll let you process that for a second.

Because we found the study and science behind love so fascinating, we asked Cacioppo to explain everything in further detail for us—you’re welcome—and also reached out to Leigh Winters for further elaboration on the matter. Keep scrolling to find out the science behind falling in love.

Meet the Expert

  • Stephanie Cacioppo is a neuroscientist and director of the Brain Dynamics Lab at the University of Chicago Pritzker School of Medicine.
  • Leigh Winters is a neuroscientist and holistic wellness expert.

There's a Scientific Definition


We all recognize the telltale signs of falling in love, like butterflies and not being able to get them off of your brain. Anyway, Cacioppo says that love carries many definitions, but the one used nowadays in science “characterizes love not only as a basic instinct and emotion but also a complex psychological emotional mental state which involves four dimensions.” Those four dimensions are chemistry, cognition, preference/rewarding mechanisms, and an intention to be with a significant other.

Cacioppo cites a study by Hatfield & Rapson from 1987, which says that passionate love is defined as “a state of intense longing for union with another,” that is characterized by a “motivated and goal-directed mental state.” What exactly does that mean? Basically, she’s saying that if you were to describe the concept of falling in love, it would be “the awareness of being in love” with someone. “Our research on love suggests that love is a two-stage process, the first of which is subconscious,” she explains. “Based on our findings on love, we make the hypothesis that the concept of falling in love could correspond to the awareness (consciousness) of being in love with someone.” So—the first part is subconscious, but the actual process of falling in love requires you to actually be aware of what’s happening. Which takes us to our next point…

Love is Built From Lust and Infatuation


“Desire for someone is defined as an increase in the frequency and intensity of sexual thoughts and fantasies, either spontaneous or in response to erotic stimuli,” Cacioppo says, quoting from a study by psychiatrist Rosemary Basson, MD. “Desire corresponds to a basic instinct/emotion and a complex psychological emotional mental state, which involves, like passionate love does, three dimensions: chemistry, cognition, and preference/rewarding mechanisms.” Sound familiar? Yes, those are the exact same dimensions Cacioppo mentioned earlier when it came to describing love—but unlike lust and desire, love has a fourth dimension: the intention to be with that particular significant other. In other words, love is different from lust because you actually have to desire to be with that person. Let’s take this even further, and examine what differentiates love and lust in the brain.

“Overall, fMRI studies demonstrate that both passion and sexual desire spark increased activity in the subcortical brain areas that are associated with euphoria, reward, and motivation, as well as in the cortical brain areas that are involved in self-representation and social cognition,” Cacioppo says, quoting her own study from 2012. We won’t get into all the technical terms and areas of the brain, but we’ll just say this: There are a lot of areas of the brain that respond similarly when measuring lust and love. However, when it comes to measuring love vs. lust, activity is diminished in the ventral striatum, hypothalamus, amygdala, somatosensory cortex, and IPL. What exactly does that imply? Cacioppo says that these reductions are in line with the idea that sexual desire and lust is a motivational state with a very specific, embodied goal, while love is a more abstract, flexible, and behaviorally complex goal that is less dependent on the physical presence of someone else.

Ready to go even deeper? Let’s examine how love makes you feel the giddy feelings you do. Cacioppo says love is associated with a more intense activation of dopamine-rich regions in your brain, generally involved in motivation, reward expectancy, and habit formation. This is in line with psychological studies that define love as a rewarding, positive, and motivating experience. Also, different parts of your brain are activated by feelings of love rather than sexual desire, which Cacioppo says is in line with the fact that love is an abstract construct, “partly based on the mental representation of past emotional moments with another.” Whoa—what? She explains: “This specific pattern of activation suggests that love builds upon a neural circuit for emotions and pleasure, adding regions associated with reward expectancy, habit formation, and feature detection.” She says that the way your brain shows love and lust suggests that love grows out of and is a more abstract representation of the “pleasant sensorimotor experiences” that characterize desire. The final conclusion? Basically, you can see love and lust on a spectrum, with love growing from the visceral sensations of lust into a complicated, ultimate feeling incorporating everything from reward expectancy to habit learning. Whew! Love is a many-splendored thing, no?


Love at First Sight Might Not Exist

“Great partnerships are like plants,” continues Winters. “To keep a plant alive, you have to nurture it with water and sunlight and be flexible in taking care of it should issues arise. Love is the same way. Love at first sight is largely a myth. I won’t knock anyone’s hopelessly romantic story about seeing their significant other for the first time and instantly knowing they were ‘soulmates,’ but projection is a real psychological phenomenon.” A key point, may we add, in understanding that achy-breaky physicality we experience when a relationship we had high hopes for doesn’t ultimately work out. And apparently, our habit to idealize and embellish the high points of a person or relationship can also create obstacles in the way we understand (or possibly even misinterpret) love versus lust.

“When it comes to love, our memory can be a little hazy, and it’s easy to embellish the overall experience,” expressed Winters. “Some memory research shows that our first memory of meeting our romantic partners may very well be a projection of our current feelings onto past memories. You have to ask yourself: Can you really love someone without ever talking to them or getting to know them?” According to Winters, probably not.

But it Still Feels Like Love at First Sight


Now that we’ve examined the effect love has on your brain, what about that beating organ in your chest? According to Cacioppo, it makes perfect sense why your heart would be associated with feelings of love. “Because love is a powerful mental state that has different physiological manifestations, like butterflies in the stomach or in the chest, increased heart rate, euphoria, loss of appetite, hyperactivity, loss of self-control, and a decreased need for sleep*, it comes to no one’s surprise that the origin of love has often been associated with the organ that is generating such a physiological response.”

But as Winters points out, love is much more than just a physical symptom manifesting in organs like the heart and the brain. As she explains to us, true love is also something that develops spiritually and soulfully, and unlike lust, it will likely take some time.

“There is no magic potion that will make you fall in love with someone or give you a telltale physical sign that a person is right for you. Trust your gut and do what feels right in your heart. The four-year itch is also a myth. For years, evolutionary biologists speculated that intense love only lasted long enough for partners to meet, mate, and raise a baby into childhood. After that, romantic lovers were thought to become companions.” However, on the contrary, Winters iterates that the literature and recent brain imaging research indicates that intense and romantic love can actually span for decades.

*Aron et al., 2005; Buss, 2003; Sternberg & Barnes, 1988; Hatfield & Walster, 1978

You Can Love Someone You Aren't Immediately Attracted To


With all this talk of love versus lust at first sight, we were curious. What happens if we’re not attracted to someone upon first glance? Is there still potential? According to Winters, however, this is the million dollar question. Yes, there is legitimacy behind age-old adages like “this person is ‘the one’” or “when you know, you know,” but if the chemistry or attraction isn’t 100% right off the bat, it doesn’t mean the potential for a meaningful relationship is doomed before it’s even had a chance to blossom.

“In the last century, ideals around love, marriage, and family have shifted enormously. First, it’s hard to track down truly reputable data on arranged marriages and their success rate, which means that most proponents for such arranged marriages might often be speaking from anecdotal evidence,” explains Winters who also highlights the relevance of cultural context, family influences, finances, and the like.

“Some data show that approximately half of marriages might end in divorce and the number one reason for seeking divorce in the U.S. is money. There is so much more than love at play in romantic, monogamous partnerships,” Winters reports. “Money is reportedly the leading cause of stress in relationships.” Therefore, it could be surmised that arranged marriages may offer greater stability and financial security in the long run—ultimately keeping us more fulfilled and happy than a relationship initially built on lust and attraction. But again, who’s to know?

Is Love a Drug?


Remember how we mentioned earlier that love can triggers activity in areas of the brain similar to euphoria-inducing drugs? Well, Cacioppo makes it clear that love is actually quite different from drug addiction because it “recruits higher-order brain areas involved in complex functions like emotion, reward, goal-directed behavior, and decision making.” As she explains, “Love is one of the deepest forms of human endeavor. Although love partly activates some of the brain areas that are also activated during drug addiction, love is so more than an addiction.”

“When you’re going gaga over a good-looking person, your body certainly has a way of telling you,” Winters confirms. “It may sound counterintuitive, but finding someone attractive activates your stress response; your heart races, your mouth becomes dry, and you might start to sweat.” (All thanks to quickly rising levels of adrenaline and cortisol). Plus, Winters adds, if you have an intense attraction to someone, this will trigger your dopamine levels to spike, which, like a lusty game of dominoes, will naturally awaken our body’s desire and reward response.

“Dopamine is the neurotransmitter responsible for triggering our desire and reward response, which is part of the neural circuit that allows us to feel pleasure. If you’ve been so love struck that you were buzzing with extra energy and heightened attention, you’ve definitely experienced this surge of heightened dopamine.” So yes, while Winters and Cacioppo confirm that both love and drugs trigger a certain type of high, physiologically, the phenomena is much different.

This post was originally published at an earlier date and has since been updated by Erin Jahns and Carolyn Hanson.

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