You might assume you feel queasy on a long car ride because your belly is getting swirled around from the potholes, speed bumps, and jerky driving, but actually the reason could be a lot stranger than that.
In terms of our evolution, we were never built for car travel. For thousands and thousands of years, our thalamus – the hub of how we process sensory information – became tuned to deal with the sensory input from walking and running. In these processes, our body feels in sync with our wider sense of speed, with our vision and other senses providing a sensory match.
But in a car or train, it’s a different story. Physically, we are sitting still, our muscles aren’t moving, and the air around us feels motionless, yet we have other sensory input that tells us there is a lot of movement going on.
“There's a sensory mismatch there," Dr Burnett explains. "And 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, aka throwing up.”
Head over to the NPR website to hear more about it, as well as other snippets about memory and intelligence.