London - Travelling makes us feel sick because modern transport tricks the brain into thinking we have been poisoned, a neuroscientist has said.
Being in a car, train, boat or plane causes conflicting signals in the brain which trigger a reaction similar to that which occurs when someone is poisoned.
Dr Dean Burnett, of Cardiff University, said the feeling of nausea is caused because the brain thinks the body needs to remove a toxin through vomiting.
But in fact, the “poisoning” effect is caused by the mixed messages from the muscles – which tell the brain the body is motionless – and the ears, which sense movement.
Speaking on the US radio show Fresh Air, Dr Burnett said the body had not yet evolved to cope with the sensation of being in vehicles, where the body is being moved without performing movements itself.
He said: “When we’re in a vehicle like a car or a train or a ship especially, you’re not actually physically moving. Your muscles are saying ‘we are stationary’. If you are sitting in a ship, you’re looking at a static environment, so there’s no information for the eyes to say ‘we are moving’. But fluids in your ears obey the laws of physics. They are sort of sloshing around because you are actually moving.
“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.”