system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are people more likely to become carsick when riding in the backseat?
gpt
Motion sickness comes about when the brain receives conflicting sensory signals. If you sit in the back of the car and stare at the head rest in front of you, read, play on your phone, whatever, your inner ear is sensing the motion of the car, but your eyes aren't passing that same information on - as far as the eyes are concerned you're staying still.

In evolutionary terms, the only thing that could induce this difference in inputs was some kind of poison, so the body's response is to feel nauseated to try and make you throw up whatever it is you ate.

When you're in the front of the car, you're more likely to look up at where you're going, and even if you don't, your peripheral vision is more likely to pick up the movement of the car with the added view through the windshield.

So if you don't want to get carsick in the back, make sure you look up and out of the window regularly so your brain doesn't get conflicting signals.