In the case of motion sickness, vomiting is an impressive lot of bother for no apparent reason. Vomiting makes sense as a bodily response to poisoned or contaminated food – gets it out of you ASAP – but as a reaction to sensory conflict? Pointless, says Oman. He says it’s just an unfortunate evolutionary accident that the emetic brain happened to evolve right next to the part of the brain that oversees balance. Motion sickness is most likely a case of crosstalk between the two. “Just one of God’s jokes,” says Pat Cowings.
