According to a study conducted by researchers from the Swiss Federal Institute of Technology and published in the journal Current Biology, the sensation of a ghostly presence is usually felt when the body experiences extreme conditions—for instance while mountaineering—or by people who suffer from neurological problems. The researchers claim that ‘ghosts’ are probably just an illusion created by the mind when it momentarily loses track of the body’s location because of illness, exertion or stress.
The researchers set up an experiment in which volunteers’ movements and brain signals were mixed up. In the first part, the brain scans of 12 individuals with neurological disorders who had reported experiencing a paranormal presence revealed that all of them had some form of damage in the parts of the brain linked to self-awareness, movement and the body’s position in space. In the second part of the experiment, 48 healthy volunteers who hadn’t reported experiencing any ghostly presence were blindfolded, and asked to manoeuvre a robot with their hands, while another robot traced the same movements on their backs. When both sets of movements took place simultaneously, it created the illusion that the volunteers were caressing their own backs. But when there was a delay, the volunteers claimed they felt they were being watched and touched by one or more ghostly presences. One third of them reported feeling the presence of invisible people being close to them, with some even claiming they felt the presence of four ghosts.
According to the researchers, the experiment affected the brain functions related to self-awareness and perception of the body’s position. They claim that when a person feels the presence of a ghost, it is really the brain miscalculating the body’s own position and identifying it as someone else’s.