According to Pew Research Center, close to one-fifth of Americans believe they’ve seen a ghost. With that--and Halloween--in mind, Gizmodo reached out to a number of psychologists and neuroscientists to figure out why this might be. Here are the findings:
- Sleep paralysis. According to University of London professor Christopher French, sleep paralysis affects eight percent of the general population and involves being half awake and half asleep. It typically lasts a few seconds, but symptoms like hallucinations can make for a much scarier experience.
- “Pareidolia.” Michael Nees, assistant professor of psychology at Lafayette College, notes that a common version of pareidolia is perceiving human faces in random configurations of physical objects; a classic example is when people claim to see the face of Jesus in a piece of toast.
- The survival hypothesis. As explained by Manchester Metropolitan University senior lecturer Ken Drinkwater, this theory proposes a disembodied consciousness (soul) survives bodily death. Thus, seeing ghosts in this context confirms belief in life after death and produces reassurance.
- “Agency-detection mechanisms.” In other words, if an individual believes that an encounter with a ghost is a possibility, then ghosts may become the explanation that gets used to resolve uncertainty.
- The unknown. The word “ghost” is often used as a convenient (if sloppy) label for “an experience someone doesn’t understand.”