The line between perceiving and hallucinating isn’t crisp. What we call real perception might be your brain picking one hallucination that best aligns with reality. For all you know, you might hallucinate a picture of a brain on this page right now and never realize it. Spotting a hallucination is easy only when it’s peculiar; you might be hoodwinked the rest of the time.
Welcome to the strange science of hallucinations, where cognitive scientists are using the latest brain scanning technology to pinpoint the causes and characteristics of these psychedelic occurrences. It’s not easy. Hallucinations occur under so many circumstances – sleep deprivation, migraines, and neurological disorders to name a few – that a one-sized-fits-all explanation is impossible.
(This is a feature article for BBC’s print science magazine Focus. To subscribe to BBC Focus click here.)