This is why we side-eye, as explained by evolution

Though it feels as though side-eye has been alive and well since the beginning of time, that’s apparently not the case – especially if evolution has anything to say about it.

For her “The Science of Side-Eye” video, Cristen Conger took the time to figure out exactly when (and how!) the side-eye came to be. Interestingly enough, it turns out that phrases such as “eye-rolling” have only become popular since the 1980s. During this time, these terms quickly became associated with women, which would explain why we’re more likely to see the statement “rolled her eyes” instead of “rolled his eyes.”


Evolutionary psychologist Dr. Tracy Vaillancourt has her own theories when it comes to the purpose of the ever-popular side-eye. Using her background in the study of female competition, Dr. Vaillancourt believes that side-eye is a low-risk form of aggression representing our survival instinct. Specifically, women use side-eye because they do not want to physically fight. Why? So they can stick around to care for their babies.

“Women typically don’t use verbal or physical aggression,” Vaillancourt told Vice. “There’s many different reasons for this, but I think that there would have been some selection pressure involved. There are more benefits to indirect aggression. For example, you could harass competitors, and attract more mates, all without engaging in a physical confrontation.” 


As for those who are on the receiving end of an eye-roll or side-eye, it can actually trigger a flight-or-fight reaction. This means that side-eye is basically a form of psychological warfare that can cause a powerful reaction in women.

Plus, researchers have stated that negative facial expressions such as side-eye can potentially predict whether or not a couple is going to get divorced. By studying thousands of couples’ facial expressions, comments, and body language, psychology professor John Gotten concluded that happy couples have at least a 5:1 ratio of positive to negative interactions. When this begins to decrease, the marriage starts to enter divorce territory.

The takeaway: Side-eye is way more powerful than we realized and we must use this weapon wisely.

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