Why Do We Get Motion and VR Sickness?

Why Do We Get Motion Sickness?

The first time you experienced motion sickness was probably in the back of a car, trying to read a book (or smartphone?) on the road. Or perhaps you first experienced it while out on a boat or on a carnival ride. Whatever the case, you’re likely familiar with it. So why do we get motion sickness to begin with?

Human Balance

You can thank your ears for your sense of balance–you can also thank your ears for losing it. The whole balance system inside of your ear has a more sophisticated name than “balance bit.” We call it the vestibular system.

The vestibular system is made up of two otolith organs, found inside the inner ear. They’re not unique to humans, in case you wanted to say that we were extra special. All this stuff is tucked neatly in the inner ear, inside what is actually referred to as the bony labyrinth. No, we don’t have a mini minotaur protecting our ears from invaders.

Trivia Fact: Fish have rings in their otoliths like trees, and we can use them to gauge their age.

Within the inner ear, we’ve got 3 canals (6 if you want to be all “we have 2 ears”), with each one structure dedicated to specific movements. Inside each structure there’s a pretty penny of liquid, and each structure is lined with very sensitive hairs. So when that liquid sloshes around, the hairs deep in your ear can garner your orientation based on the way the liquid moves. 

It’s what also gives you your sense of “down,” since liquid is subject to gravity. Pretty genius. 

Oh, and you have one canal for vertical tilting of the head, horizontal tilting of the head, and straight up just turning it. You can move your head around for a bit and you’ll figure out that this covers all axes of movement.

Why Do We Get Motion Sickness?

So, like many of our modern ailments, motion sickness is largely caused by human lifestyles and technology evolving faster than the human body can. When you’re in a car, or plane, you don’t really feel like you’re moving. You can thank physics and relativity for that. 

But here’s the thing, your ears aren’t the only thing that contribute to your sense of balance. You also know where your arms and legs are, and you can feel when they’re moving. You also have your eyes. In normal circumstances, these details match up within acceptable degrees. 

When you’re in a boat, your ears are sloshing around–and they’re pretty sensitive. That alone might be enough to knock out some people. It’s also why ear infections can leave you perpetually woozy until they sort themselves out.

Anyway, in a car (the easiest example), your arms and legs don’t really feel like they’re moving. You can thank the relativity we mentioned earlier. Your eyes, if you’re looking out the window know you’re in motion. Otherwise if you’re reading they might as well be a null data point.

Your inner ear? Well it definitely knows you’re in motion.

In a plane, it’s the same principle. Basically, all of your balance senses are sending your brain conflicting data, which your brain really doesn’t like. Thus, dizziness. 

That’s also why looking out the window in a car, specifically at the horizon, helps way more than reading a book. Makes your senses corroborate each other a little better.

VR Sickness

If you’re wealthy enough to be in that scene, go you. But the advent of VR technology has brought in a new sense of sickness. It’s called VR sickness but it’s really just motion sickness you feel after strapping that toaster to your face.

Nobody really knows what’s up with VR sickness, but one of the leading theories of course involves the vestibular system. It’s the same principle as before. Your vestibular system doesn’t detect you moving around, since you’re just jumping around inside of your living room. 

Your eyes do see you moving around, and your limbs are… Well flailing about.

So again, your perception of balance and self-motion run head-to-head against each other, and your brain doesn’t like that. So you get sick.

There’s also some technology to it, specifically when your VR headset doesn’t show a healthy amount of frames per second. If you have a friend who builds computers you’ve definitely heard them kick and scream about it.

Anyway, movies work by showing you a bunch of images really fast, on average about 24 per second. That’s just fast enough to allow the brain to perceive motion in the images. VR headsets work much in the same way–except we can tell something is wrong if something is showing us at or less than 30 frames per second deep down. So you’re basically throwing the wrench of “mildly stuttery vision” into the ring along with the dissonance between balance and motion. 

Just don’t throw up on the several-hundred-dollar face screen. 

With all of this ear talk, try seeing if you can identify all the parts of the ear here.