Why do children get carsick faster?

One hundred and twenty on the highway, and then a kid who says, “I’m going to throw up!” Why do children get carsick earlier than adults? And why do they sit radiantly in a merry-go-round, on a swing or in the roller coaster?

The place where all those discomforts arise is our vestibular system. That is a wonderful little organ in the inner ear, right next to the cochlea of ​​the hearing organ, about half a centimeter in size.

The vestibular system consists of three semicircular tubes, or channels, which are interconnected. They are perpendicular to each other, in three dimensions. Liquid flows in these channels and there is a cover with microscopic hairs, which are connected to nerves that run to the brain. When you move your head, the fluid lags behind your head movement, causing the hairs to bend and trigger the nerves.

Two sacs are attached to these semicircular canals: the saccule and the utricle, both a millimeter in diameter. Also in these sacs are nerve hairs, connected to tiny ear stones, or otoliths. They register vertical and horizontal acceleration. With that total package we can observe self-movement and orientation in three dimensions. Our brains combine that input with information that comes in from our eyes (sight) and the position of our body parts (‘proprioception’).

So much for the anatomy lesson. What goes wrong with car sickness? “No sense is perfect,” says medical physicist Jelte Bos. He works at the TNO research institute and the VU Amsterdam, where he investigates, among other things, why pilots sometimes become disoriented and we become nauseous with movement. “To compensate for that imperfect perception, our brain starts filling in things,” he says. “It combines factual observations with expectations based on previous experience. It is a learning system that continuously updates itself.”

You get nauseous when the signals your senses transmit to your brain don’t match what you expect, Bos explains. “That car doesn’t move in a way that we are evolutionarily adapted to. Over time, your brain learns to adjust those expectations based on experiences.”

This also explains why the driver becomes less nauseous than the co-driver: the driver unconsciously anticipates the feeling that will follow before steering or braking. For the co-driver, perception and expectation are further apart. And especially with young, inexperienced passengers.

In young children, motion sickness strikes even more because their movement and orientation system is still developing, Bos notes. It kind of starts when a toddler stands up and walks. Before that time, the system does not have to work at all, and there are no wrong expectations either. “That’s why babies don’t get carsick,” says Bos. “That adaptation only really works when the body and nervous system are fully grown, around your twenties.” According to Bos, the fact that children enjoy attractions so much in the meantime does not mean that they feel great in them. “Children love to try new things.”

But what about those adults who still get nauseous in attractions later in life? “Just as the number of things decreases over the years, our movement perception and adaptability also deteriorate,” says Bos. “It is therefore logical that over the years we can still get sick of things we are no longer used to, such as that swing or roller coaster.”