by Katherine Wu
Figura de Tito Adhikary
In 1993 Haddaway asked the world: "What is love?I'm not sure I ever got his answer, but today you can have yours.
Kind of.
Scientists in fields ranging from anthropology to neuroscience have been asking the same question (albeit less eloquently) for decades. It turns out that the science behind love is both simpler and more complex than we think.
Google the phrase "biology of love" and you'll get answers that run the gamut of accuracy. It goes without saying that the science behind love is often sensational, and like most science, we don't know enough to draw any firm conclusions about every piece of the puzzle. What we do know, however, is so much lovemayobe explained by chemistry. So if there really is a "formula" for love, what is it and what does it mean?
total eclipse of the brain
Think about the last time you met someone you found attractive. You may have stuttered, your palms may have sweated; You may have said something incredibly stupid and tripped spectacularly trying to walk away (or is it just me?). And most likely, your heart was pounding in your chest. It's no surprise that for centuries people thought that love (and most other emotions) came from the heart. It turns out that love is all about the brain, which in turn interferes with the rest of your body.
According to a team of scientists led by Dr. Helen Fisher of Rutgers, romantic love can be divided into different categories.three categories: Lust, attraction and attachment. Each category is characterized by its own set of brain-derived hormones (Table 1).
let's get chemical
Lujuriait is driven by the desire for sexual gratification. The evolutionary basis for this stems from our need to reproduce, a need shared by all living things. Through reproduction, organisms pass on their genes and thus contribute to the survival of their species.
The brain's hypothalamus, which stimulates the production of sex hormones, plays an important role in this.testosteroneYestrogenof the testicles and ovaries (Figure 1). While these chemicals are often stereotyped as "masculine" and "feminine" respectively, they both play a role in males and females. It turns out that testosterone increases libido in almost everyone. The effects are less pronounced with estrogen, but some women report being more sexually motivated around the time of ovulation, when estrogen levels are highest.
Love is its own reward.
Meanwhile,attractionappears to be a separate, though closely related, phenomenon. While we may long for someone we are attracted to and vice versa, one can happen without the other. Attraction affects pathways in the brain that control "reward" behavior (Figure 1), which partly explains why the first few weeks or months of a relationship can be so exciting, even exhausting.
dopamine, produced by the hypothalamus, is a particularly well-known player in the brain's reward pathway: it's released when we do things that make us feel good. In this case, this includes spending time with loved ones and having sex. High levels of dopamine and a related hormone,norepinephrine, are released during the pull. These chemicals make us dizzy, energized and euphoric, and even cause decreased appetite and insomnia, which means you can actually be so "in love" that you can't eat or sleep. In fact, norepinephrine, also known as norepinephrine, may sound familiar as it plays a very important role in thefight or flightResponse that goes into overdrive when stressed and keeps us on our toes. In fact, brain scans of lovers have shown that the brain's primary "reward centers," including the ventral tegmental area and caudate nucleus,fire like crazywhen people are shown a photo of someone they're very attracted to versus someone they're neutral with (like an old acquaintance from high school).
Finally, the attraction seems to lead to a reduction in inactivity.serotonin, a hormone known to be involved in appetite and mood. Interestingly, people with OCD also have low serotonin levels, leading scientists to suspect that this may be the reason for the overwhelming infatuation that characterizes the early stages of love.
the friend zone
Last but not least,AdjunctIt is the predominant factor in long-term relationships. While lust and attraction are fairly unique to romantic entanglements, attachment mediates friendships, parent-child bonding, social friendliness, and many other intimacies. The two primary hormones seem to be here.oxytocinYvasopressin(Illustration 1).
Oxytocin is often referred to as the "cuddle hormone" for this reason. Like dopamine, oxytocin is produced by the hypothalamus and released in large amounts during sexual intercourse, lactation, and childbirth. This may seem like a very strange selection of activities, not all of them necessarily fun, but the common factor here is that all of these events are precursors to bonding. It also makes it pretty clear why it's important to have separate areas for attachment, lust, and attraction: we're attached to our immediate family, but those other emotions have no place there (and let's just say the people who mess with that havedoes not have the best track record).
Love Hurts
It all paints a pretty rosy picture of love: hormones are released, making us feel good, rewarded, and close to our romantic partners. But that can't be the whole story: love is often accompanied by jealousy, erratic behavior, and irrationality, along with a host of other less-than-positive emotions and moods. It seems that our friendly cohort of hormones is also responsible for the downsides of love.
Dopamine, for example, is the hormone responsible for the vast majority of reward pathways in the brain, and that means controlling both the good and the bad. We experience dopamine surges for our virtuesYour vices. In fact, the dopamine pathway is particularly well-studied when it comes to addiction. The same regions that light up when we are attracted light up when drug addicts use cocaine and when we eat candy. for example cocainemaintains dopamine signalingmuch more than usual, resulting in a temporary "high". The attraction is in a way like an addiction to another human being. Similarly, the same brain regions fire up when we become dependent on material goods as when we become emotionally dependent on our partners (Figure 2). And addicts going to rehab are no different than people in love who long for the company of someone they can't see.
With oxytocin, the story is similar: too much of a good thing can be bad. Recent studies on party drugs like MDMA and GHB show that oxytocin could be the hormone behind it.beneficial social effectsproduce these chemicals. In this case, these positive feelings are taken to the extreme, causing the user to isolate themselves from their environment and act in a savage and ruthless manner. Furthermore, the role of oxytocin as a "bonding" hormone appears to applyhelp reinforce positive feelingsWe already feel towards the people we love. That is, as we become more attached to our families, friends, and significant others, oxytocin works in the background, reminding us why we like those people and increasing our affection for them. While this can be good for monogamy, such associations aren't always positive. For example, it has also been suggested that oxytocin plays a role in ethnocentrism, increasing our love for people in our already established cultural groups and making people who do not fit us seem more alien (Figure 2). Therefore, like dopamine, oxytocin can be a double-edged sword.
And finally, what would love be without shame? Sexual arousal (but not necessarily attachment) appears to beto switch offRegions of our brain that regulate critical thinking, self-awareness, and rational behavior, including parts of the prefrontal cortex (Figure 2). In short, love makes us stupid. Have you ever done something while you were in love that you later regretted? Maybe not. I would ask a certain star cruisershakespearean couple, but it's a little late for them.
In short, there is a kind of "formula" for love. However, it is still a work in progress and many questions remain unanswered. And as we've since established, it's not just the hormonal side of the equation that's tricky. Love can be both the best and the worst for you: it can be what gets us up in the morning or what keeps us from waking up anymore. I'm not sure I could define "love" for you if I kept you here for another ten thousand pages.
In the end, everyone can define love for themselves. And, for better or worse, when it comes to hormones, maybe we can all have "chemistry" with just about everyone. But whether or not to continue is up to the rest of you.
Happy Valentines Day!
Katherine Wu is a third-year graduate student at Harvard University. She loves science with all her mind.
Other reading
- For an in-depth human interest story on love, check out National Geographic's coverage of"True love"
- For a very comprehensive (and well done!) introduction to the brain and its many, many chemicals, check this outNIH Brain Basics Page
- Ask The New York Times Opinion On Falling In Love With Someone36 questions