Try this experiment right now—block one of your nostrils with your finger and snort to your little heart’s content out of the other nostril. (Some of you may snort better than others depending on your, uh, “extracurricular activities).

Done? Now switch sides.

Unless you’re a unique snowflake outlier, you’ll notice that it’s easier to breathe from one nostril. Consider that nostril your “alpha” nostril. In fact, scientists actually call it the “dominant nostril” since it actually does most of the breathing.

So what’s the point of a dominant nostril?

Is the other nostril just lazy, unable to pull itself up by its own snot straps? Are our nostrils socialist?

We have a dominant nostril due to a naturally occurring process called the “nasal cycle,” according to a 2015 study by David White, Ph.D, the senior lecturer and director at Auckland University of Technology’s Design for Respiratory Health Lab.

Not everyone has a dominant nostril. The number of people that do experience a nasal cycle can be as high as up to 80 percent of the total population, according to White’s paper. (But we can’t really give you a concrete number since each study measures it differently).

During the nasal cycle, each of your nostrils takes turns being the dominant nostril (switching every 90-minutes or so, but it varies from person to person). You’re still able to breathe out of the blocked nostril—the airflow is just very limited thanks to “erectile tissue” in your nose.

I know what you’re thinking—and you’re right—it’s sort of similar to a penis erection. The erectile tissue swells with blood, blocking airflow.

Why do we even have a nasal cycle?

A 1999 Stanford study suggests that the nasal cycle helps you smell better (ironically, the blocked nostril can smell certain things better than the dominant nostril).

White agrees with that theory and suggests that the nasal cycle also allows each nostril to perform different duties.

The blocked nostril transports viruses and dust away while the dominant nostril does the “heating and humidifying duties,” preventing your airways from drying out.

This is just a hypothesis, since the truth is, nobody really knows for sure why we have a nasal cycle. Scientists suggest that the reason we have two nostrils in the first place is because of the cycle, but it’s still a nose-blowing mystery.