What is love?

I hate Valentine’s Day.

There, I said it. I’ll say it again for everyone in the back too intimidated by the Valentine lovers’ propaganda to voice their agreement: Valentine’s Day is just awful. The only element redeeming Valentine’s Day has been the overpriced, individually packaged chocolates that as 7-year-olds we eagerly passed out to classmates, with “To” and “From” labels no one ever bothers to fill out. Having outgrown elementary school, I’ve realized to my horror that no longer do customary sentiments of “love” and goodwill hide their falseness behind pink Fun Dip—they just don’t appear at all. And what have I learned from all this? Sugar can buy friendship. Happy Valentine’s Day, suckers.

As I have on occasion let a Valentine’s lover utter a few sentences before cutting them off, I have been told that Valentine’s Day is about (their words, not mine) demonstrating love for others. Please join me in resisting the urge to retch. But since I am both a scientist and a severe skeptic, and the whole point of my column is to write about sciency stuff, I know I must begrudgingly submit to the pink and take a deep dive into the science of love. Roar.

It turns out this isn’t the easiest thing to do. In every discipline, scientists have for decades been asking, what is love? (Baby don’t hurt me…) Is it a feeling or a physical attraction or a fallback Shakespeare essay topic? Does it even pertain to the realm of the quantitative?

Helen Fisher’s lab at Rutgers has devoted itself to answering, or at least trying to answer, that question. Dr. Fisher defines romantic love (think The Notebook) as the intersection of three emotional categories: lust, attraction, and attachment. Different hormones in your brain control each category, putting your brain firmly in charge of regulating love; ergo, the heart has absolutely nothing to do with it. Apologies to the aphorisms.

Let’s start with lust, a.k.a. the “S” part of “S&R.” As with all living things, lust derives from our evolutionary need to reproduce and keep alive our species. Lust begins with the hypothalamus, an almond-size cluster of nuclei linking the nervous system (your brain) to the endocrine system (your hormones). If your body temperature, hunger and thirst levels, ingrained attachment behaviors, tiredness, or sleep-wake cycles are out of whack, you know what to blame. The hypothalamus stimulates the testes (men) and ovaries (ladies) to produce the sex hormones testosterone and estrogen. Both men and women make and use both estrogen and testosterone! And the more testosterone and estrogen produced, the more “S” we want to have.

Next up: attraction. Unlike lust, which is all about sex, attraction results from neural pathways that control reward behavior. In other words, when we look across the room at the seventh-grade snowball dance and see the object of our dreams, we not only feel happy and giddy but want to keep feeling that way. During attraction, the hypothalamus releases dopamine, the primary reward hormone, and norepinephrine, which, interestingly, does double duty as the fight-or-flight hormone, raising our pulse, energizing us, and making us euphoric. Given that lust and attraction both hinder the prefrontal cortex, which regulates rational behavior, it’s not a surprise we all find ourselves sweaty-palmed and tongue-tied when faced with “The One.”

Lastly, let’s look at attachment. Attachment isn’t exclusive to romantic love, instead having a more general role mediating how much we like to spend time with others. Oxytocin and vasopressin play the major roles in attachment. In fact, oxytocin, the “cuddle hormone,” has an extremely potent effect on social bonding, as a 2012 Public Library of Science study showed. Individuals given extra oxytocin demonstrated much higher desire to fight for and protect members of their own group; long story short, oxytocin makes us far more likely to sit down in a circle and sing “Kumbaya.” Maybe they should give that out instead of Fun Dip.

There you have it: 500 words on the science of love. But I’m no closer to elucidating what love is than I was before throwing big science words into the mix, and I don’t know if scientists ever will be. That’s what chills me about Valentine’s Day and about love itself: this day reminds me that love will always be a puzzle that we humans can never really solve. As much as I believe in science, I’ve lived and learned enough to realize that love exists in a realm higher than the quantitative, transcending what we can observe and measure. So, eat your heart-shaped Reese’s, give someone a hug, think about your dopaminergic pathways. I’ll still be sitting in a corner with my fellow skeptics, questioning a “holiday” that equates buying a 48-pack of pink-packaged M&Ms with the chemical, scientific, and metaphysical intricacies of love. But to everyone else, Happy Valentine’s.

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