Ghostbusters: When Science Meets The Supernatural

While some dismiss it completely out of hand, others believe inexplicably in the spirit world. We ask the experts to weigh in

-  Helen Foster

Belief in the supernatural and questions about whether ghosts are real have intrigued humanity forever. But are the spirits that may walk among us actually the souls of the departed, or the result of more downto-earth phenomena? While science and spirits might not seem to go hand in hand, you'll be surprised how many evidence-based explanations for spooky sightings there are. We ask some ghostbusters in white coats for alternative ideas about why things might go bump in the night.

THE SLEEP EXPERT

Sleep paralysis is a condition where you wake at night unable to move. It affects around 20 per cent of people at some point and sleep specialist Dr Baland Jalal from Harvard University in the US feels it could explain some ghost sightings. "The stage of sleep called REM sleep is when we have our most vivid dreams and, to protect us from acting these out, we go into a state of paralysis," he says. "If you wake up at this point you can see and hear, but your body can't move. And, our research has found that about 40 per cent of people start to see things when this happens."

The sightings are the brain trying to make sense of this. It's telling your arms and legs to move and expecting feedback from them as to where they are 'in space! When it doesn't get that feedback, cells in the brain called mirror neurons start to draw a picture of what should be happening. "And in its confusion we can visualize this image as something in front of us," says Dr Jalal. "Some people experience this as an out-of-body experience, where they look down upon themselves in bed, others impose another explanation-you're seeing a ghost."

The good news is you can treat sleep paralysis with a four-step method Dr Jalal has created: the first step of which is just closing your eyes so the mirror neurons can't create their picture. Without this the 'ghost' can't appear.