girls meeting boy girls meeting boy When it comes to meeting new people, we may act a lot like mice. (Photo: Antonio Guillem / Shutterstock)

Scientists discover the 'social switch' that helps us make friends

A molecule in your brain may tell you whether to be friendly to new people or avoid strangers.

Do you ever wonder why some people are always excited to make new friends, and others avoid social interaction like the plague? Scientists may have started peeling back the chemical processes behind how we act around people we don't know.

Researchers from Israel's Weizmann Institute and Germany's Max Planck Institute recently found a molecule in mouse brains that regulates stress. This molecule acts like a "social switch," telling mice to either stick with their friends or meet new mice, the scientists wrote in a recent study published in Nature Neuroscience.

The method they used to figure this out was adorable. The scientists created a "social maze," where mice could choose to interact with other mice behind a mesh. The researchers found that mice with more of a molecule called Urocortin-3 in their brains tended to interact with more strangers. When the scientists blocked the molecule, the mice stuck with their friends.

The scientists also put a bunch of mice in a group and tracked them with cameras for a couple days (we like to think they put tiny cameras on the mice). Then the researchers ran the footage through a computer and used an algorithm to figure out what the mice had been up to. Same story: The mice with more Urocortin-3 made more new friends.

If it's true for mice, is it true for humans? Do your low Urocortin-3 levels make you awkwardly eat snacks in the corner all night during parties?

Granted, humans and mice aren't identical. Humans, for instance, don't have fuzzy whiskers. But human and mouse brains do have the same kind of stress regulating system, so the scientists think humans might have a similar social switch. When something goes wrong with this switch, mice and humans may have trouble dealing with social situations. The scientists think this could explain aspects of some mental disorders like social anxiety, autism and schizophrenia.

Of course, social stress affects just about everyone.

“Most social contacts involve a certain level of social stress or anxiety, even when we interact with people we know well, for example, during a holiday meal with extended family,” explained Dr. Yair Shemesh, one of the researchers. "In fact, from the point of view of evolution, moderate levels of social apprehension are essential for safe and successful social engagement.”

It seems weird that there would be a molecule to make us awkward around new people, but you need to be wary of strangers sometimes.

“In nature, mice live in groups, and the social challenges they face within the group differ from their relationship with intruders," explained Dr. Oren Forkosh, another researcher. "It therefore makes sense for a brain mechanism to produce different types of social coping in these two situations. In humans, this mechanism might be involved whenever we consider moving out of our parents’ home, getting a divorce or changing jobs or apartments.”

There you have it. If you're living in an apartment you're sick of because you're afraid of new roommates, rest assured that your ancestors were probably stuck in the same boat since before humans existed. And next time you see a mouse and freak out, know that she probably feels the same way about you.

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Scientists discover the 'social switch' that helps us make friends
A molecule in your brain may tell you whether to be friendly to new people or avoid strangers.