[♪ INTRO].

It's chilly out, which means it's time to cuddle! No, I mean it.

We're in the thick of what's known as cuffing season. It's the time of year when we're more likely to want to settle down with a romantic partner ...at least for a little while. It runs from approximately October through February for those of us in the northern hemisphere, and the phrase comes from the idea of being literally tied down or “cuffed” to a romantic partner.

Charming. Anyways, as cliche as this sounds, it does seem to be a real phenomenon. And even though I don't want to quote that rather troubling holiday song… it turns out that the reason cuffing season is a thing may be because it's cold outside.

While the phrase “cuffing season” is a gift from pop culture rather than a technical term scientists coined, there's plenty of reason to believe it's a real thing. While humans don't have what you'd typically think of as a mating season, if, when you were growing up, it felt like everyone had birthday parties in the summer or the first few weeks of school... well, you weren't wrong. And you can do the math.

I was born at the end of September - thanks New Years Eve party! Also, thanks to social media, dating apps, and the Google machine, we actually have a lot of data on when people are most couple-y. Facebook has found we're more likely to change our relationship status to “in a relationship” when it's chillier, especially in late December and mid-February.

Or at least, we were in 2010 and 2011. Back when people actually cared about being “Facebook official”... I don't even know where that setting is.

Am I in a relationship? Can someone let me know? And dating app usage also goes up in the winter.

For instance, a 2015 survey of Hinge users found that they were more interested in settling down in the wintertime than in other seasons. So cuffing season is real. But, like, why?

Evolution is probably playing a pretty big role. Lots of animals evolved to have their offspring in the spring and summer, when there are more resources to take care of them. But there's also pretty good evidence that there's a lot going on psychologically which drives this yearning to settle down by the fire, drink some hot cocoa, and cuddle.

Like, winter is… kind of tough on us. We're a lot more likely to be sick, and there are all those holidays to stress over. We also produce less serotonin, a neurotransmitter known to play a role in mood regulation.

And that can lead to the so-called “winter blues,” and their clinically-diagnosable cousin, seasonal affective disorder. But what can help us combat this stress? Why, cuddling!

Cuddling and other forms of consensual social touch release oxytocin, a hormone known to be linked to social bonding. And oxytocin causes the release of dopamine and serotonin in key areas of the brain to help counteract all those lousy, stressful feelings and make us feel less alone. But aside from this pretty intuitive and sensible idea that social touch and bonding can alleviate stress, there's also something else that might be at work.

We might just be literally cold. You see, there are lots of studies that show we mix up social and physical warmth, or substitute them for each other. For example, one 2014 study found that after watching a video where someone was ostracized, participants were less likely to feel lonely if they were able to touch something warm.

And a study from 2012 found that warm and fuzzy TV ads tug on our heartstrings less when we're warm and cozy ourselves. Another looked at people eating alone in the food courts of shopping malls. Because that's what everyone wants while eating slightly wilted French fries by themselves in a mall: to be approached by a stranger running a study.

Yes, I'm cold, Jeff. Let me eat this stupid wilted fry. Anyways, they found that people who were eating with one other person estimated the temperature to be about 2.5 degrees Celsius warmer than the people who were eating alone.

Additional experiments in the same study got even wackier. In one, students were given warm or cool tea and then asked to suggest features for a robot-maid they were told was being developed in Japan. Totally casual.

Those who got the cooler tea were more likely to ask for more social features, like talking, or going for walks together, or… other activities… presumably because they yearned for emotional warmth from their robot-maid. This is all part of what's known as social thermoregulation theory. The idea is that temperature regulation is super important to animals, and one of the ways to warm up is to huddle close to others.

So, given our already-social nature, we may have evolved to seek out others as a way to regulate our body temperature. And somewhere along the way, we ended up conflating physical and emotional warmth. Of course, this all could apply to platonic social bonding.

And hey, definitely don't underestimate platonic cuddling. We're equal opportunity cuddlers. But there's also reason to believe that the cold makes us want romance too.

A 2012 study of 53 undergrads found that iced tea and chilly ambient temperatures both made viewers enjoy romance movies more. The same wasn't true for action, comedies, or thrillers. And people were also more likely to rent romance movies during the coldest months, which makes our collective obsession with ridiculous Christmas romcoms make a bit more sense.

In the Northern Hemisphere. So, if you find yourself wishing you could settle down with someone this winter, there are probably a lot of reasons you're feeling that way. Winter messes with our heads in all sorts of ways.

But the good news is, you're probably not alone. And if you're looking for the perfect gift for that special someone, or just want to impress everyone with your keen fashion sense, might I suggest. SciShow's Pin of the Month.

It's the lovely Mariner 9 probe on its mission to Mars a stylish addition to any winter wardrobe. But you can only get it for a few more days! Once December hits, this baby will be gone.

So if you want to get your hands on this beautiful pin, you better head over to DFTBA.com soon! [♪ OUTRO].