Michael White

A 2001 Gallup poll reported that one-third of all Americans believe they have seen a ghost. Is there an explanation for such sightings? Michael White, the author of the following selection, says that many researchers believe the explanation is simple: People who say they see ghosts are simply hallucinating. White explains several types of hallucinations that can cause a person (or even several people at a time) to believe they have seen a ghost. White is a former director of scientific studies at d'Overbroeck's College in Oxford, England, and the science editor of British GQ magazine. He has also written several books on scientific topics and was a consultant for the Discovery Channel's series The Science of the Impossible.

The most interesting of all so-called trivial explanations for ghosts is hallucination, and many researchers-both enthusiasts of the occult and empirically minded...