Ever been reading during a road trip and suddenly felt nauseous? There's a weird reason for that and it has everything to do with our brains. Neuroscientist Dean Burnett, author of Idiot Brain: What Your Head Is Really Up To, told NPR that our brains are actually telling our bodies that we're being poisoned when we're reading while riding in a car. Technically, moving while reading shouldn't make us sick, since we're moving all the time. As Burnett explained, "We're a mobile species." Reading while moving causes a sensory confusion in our brains. Through our thalamus, which holds all of our sensory information, our bodies send signals to various parts of our brains. When we're walking, for instance, our thalamus tells us to lift our legs to move forward. When our bodies are in cars and we read, it causes mixed signals. "[The brain is] getting signals from the muscles and the eyes saying we are still and signals from the balance sensors saying we're in motion. Both of these cannot be correct. There's a sensory mismatch there," Burnett said. "In evolutionary terms, the only thing that can cause a sensory mismatch like that is a neurotoxin or poison. So, the brain thinks, essentially, it's been being poisoned. When it's been poisoned, the first thing it does is get rid of the poison, a.k.a. throwing up."
So, your body tries to throw up the poison, even though you're not being poisoned. This inconvenience is just one of the body's delightfully weird quirks.