What’s the point of love? I’m not asking this to set myself up as the troubled lead in a rom-com who, after a series of montages, will eventually learn to open her heart and love again. I’m seriously asking: Why do we love?

Chances are good it poses some evolutionary advantage or love would have faded away with Cro-Magnon foreheads. But why on Earth would we evolve to be overwhelmed by an emotion that makes us act like Logan Paul in a Japanese forest, which is to say, a completely irrational idiot?

Tina Turner isn’t the only one who’s been asking, “What’s love got to do with it?” Scientists have devoted a good amount of time to figuring out the evolutionary point of love, and they’ve come up with a few interesting theories—all of which start with our big-ass heads.

Yes, it seems our oversize craniums are the nexus of love. I don’t mean that figuratively, like our huge egos send us on a quest for companionship. Nope: According to most bioanthroplogists today, our thick skulls literally changed our species and led to an evolutionary need. When humans started walking upright on two feet, the shape of our pelvis changed. And with that change, we had to give birth to smaller babies, or their heads would grow too big to pass through the birth canal. (Feeling amorous yet?)

Anyway, our little pelvises meant that babies had to be born before they could do basically anything. Ever see the birth of a baby deer? That thing’s frolicking all over the place straight out of the womb. Baby deer are almost fully developed immediately after birth. Conversely, human babies are utterly helpless and require a lot of time and care from their parents to live through this vulnerable stage and make it to sexual maturity; we do most of our growing outside the womb, a fact that has led to all kinds of benefits, but is tough on parents.

The fact that humans are born so early in their development led to two major developments: First, since babies grow so much outside of the womb, our brains can grow bigger than other mammals’. Second, the delicate life of a baby requires a lot of work, and the child may be more likely to survive if it has two caretakers. According to an article in Perspectives on Psychological Science, love works as a “commitment device” to motivate pair bonding, and pair bonding helps humans with “the massive investment required to rear children.”

But although love seems to have initially developed as a “commitment device,” we’d recommend against scrawling, “I’m so in a commitment device with you” on your Valentine’s Day cards.

Still, pair bonding can’t explain everything about love. Thankfully, we can look to a similar species to learn more about our amorous behavior: prairie voles. When it comes to love, we aren’t closest to apes, chimps, or monkeys. Our behavior is most similar to prairie voles, which are basically chubby, short-eared field mice. Turns out these Laura Ingalls Wilderian mini mammals are one of the few animals that mate for life and raise babies in a two-parent home. That means we can learn a lot from these loving critters… especially when we take a little time to mess with their brain chemistry.

“You might be surprised how easily one can mimic ‘true love,'” says Don Vaughn, Ph.D., professor of neuroscience at Santa Clara University. The release of oxytocin and vasopressin are thought to be primarily responsible for the deep, attached feelings of romantic love. And when you block those hormones in prairie voles, “they become promiscuous almost immediately,” Vaughn says.

So, even the “til death do us part” prairie voles start incessantly swiping right as soon as oxytocin and vasopressin are out of the picture. But if you crank up those hormones on the voles, Vaughn says that “they bond immediately with the first companion they see, no physical mating needed.”

It’s not so easy to turn the love hormones on and off in humans, so it’s not clear if people would behave in the exact same way as prairie voles. But it does seem pretty clear that oxytocin and vasopressin play a big role in our romantic emotions.

So far, we’ve found that love is mainly used to force two people to stay together so a baby doesn’t die, that it can be turned on and off with some hormone manipulation, and that prairie rodents probably have better marriages than we do.

Once again, we strongly recommend leaving that sentiment off of your Valentine’s cards.

Sadly, this love science doesn’t get any more romantic.

In fact, according to one theory, posited in an article published in Proceedings of the National Academy of Sciences, the primary reason we have love and monogamy is to stop men from killing their babies.

Primates came upon a real problem when mothers had to start taking care of helpless babies, according to the bluntly titled, “Male infanticide leads to social monogamy in primates.” When a mom’s got a baby at her boob all hours of the day, she’s probably not making time to get busy with her mate. So male primates would kill the infants so he could start up his healthy boning schedule again.

But consistently killing off your offspring isn’t exactly a good way to enhance your long-term reproductive success. So primates evolved the capacity to love, thus keeping males from infanticide. If the male loved the female and loved the child, he was less likely to a) abandon the mother and child and b) murder one or both of them. Ah, sweet amour!

It seems clear that love evolved mostly as a way to keep two people together long enough to raise a child. And though we’re constantly finding out more and more about how love affects the brain, we still don’t have all the answers.

One big question remains: Why does love make us so crazy? And I don’t mean the, “He left comments on Stacy’s Instagram, but he hasn’t taken the time to like A SINGLE PICTURE OF MINE. WHY ARE YOU DOING THIS TO ME, JIM, WHY?!?” kind of craziness. I mean ka-ray-zee love.

Take Bill and Linda Pugach, for example. More than 50 years ago, Burt fell in love with Linda and proposed. But Linda got engaged to another man. Poor Burt did what any man would do—hire a guy to splash Linda with lye, leaving her blind and facially disfigured. And we haven’t even gotten to the crazy part yet.

After spending 14 years in jail for planning Linda’s attack, Burt emerged from prison with a heart full of love. He proposed to Linda again… and she said yes. They were married for 38 years until Linda died in 2013.

“Love is the only socially acceptable psychosis,” Elvin Semrad, M.D., once said (as quoted in Psychology Today). Researchers gave MRI scans to people experiencing the first, irrational throws of love and found that the intense emotion wasn’t just excitement: Love looked more like extreme hunger or a craving for drugs, according to reporting in the New York Times.

“The first stage of love is characterized by passion and reward but also by symptoms of anxiety and stress, likely reflecting the relationship’s uncertainty,” Vaughn says. This leads to reduced levels of serotonin (happiness) and increased levels of cortisol (stress). According to Vaughn, that hormone combo is commonly found in people with anxiety disorders or OCD. “This is not surprising, given that early stages of romantic love can be somewhat similar to OCD: There are symptoms of anxiety, obsession, and intrusive thinking.”

So the first phases of love neurologically make you feel like a drug-addled person ready for an anxiety attack. Cool. But it’s true… I’ve felt it. Hell, even Beyoncé has been “Crazy in Love.” And if Beyonce can’t keep her emotions in check, then we mortals don’t have a chance.

As of now, there doesn’t seem to be a direct evolutionary reason why love hits us so intensely. Maybe it’s because the motto of the human race seems to be “go big or go home.”

An article in The Independentstated that humans evolved to have a lust for blood: Over the course of our history, we’ve been six times as likely to kill each other than any other mammal. That’s pretty extreme. We’ve also developed the most advanced language skills and have the biggest brains in the animal kingdom. With all that extra brain space, it seems to make us feel emotions more deeply and sometimes live our lives on the extreme ends of the spectrum.

Love is still a bit of a mystery, but we keep getting closer to figuring out its oddball intricacies. Sure, it’s based on an evolutionary need to pair up and spread our genes, and our hormones are responsible for lots of the craziness, but that doesn’t explain all the volatility and heartbreak that goes along with finding love.

So until we figure out all the ins and outs of amore, take comfort in knowing that love is real and generally beneficial to us. And no matter who you are, at some point, we’ll all feel that tingling glow and say, “Ah, I’m so in a commitment device.”

Amber Petty is a freelance writer in Los Angeles.