Ghostbusters show it’s all in the mind

GHOSTLY apparitions have been produced by scientists in a mind experiment that proved so disconcerting for participants that two begged for it to stop.

The research in Switzerland has suggested that ghosts are created by the mind when it loses track of the body’s location because of illness, exertion or stress.

Patients who suffer from neurological or psychiatric conditions often report “strange presences”, while those experiencing extreme physical or emotional pain often claim to have seen spirits or felt that dead loved ones were in the room.

In the study, researchers confused the movements and brain signals of 12 healthy volunteers using a robotic system. They saw up to four phantoms and believed ghosts were touching their backs with invisible fingers.

Professor Olaf Blanke, of the École Polytechnique Federale de Lausanne, said: “Our experiment induced the sensation of a foreign presence in the laboratory. It shows that it can arise under nor- mal conditions, through conflicting sensory-motor signals.”

To manifest the ghosts, the scientists set up a device that allowed volunteers to move a jointed mechanical arm with their index fingers. The movements were copied by another robot arm behind them, which touched their backs.

When both the finger-pushing and back-touching occurred at the same time, it created the illusion that the volunteers were caressing their own backs.

When the back-touching was delayed to become 500 milliseconds out of sync, the volunteers reported feeling as if they were being watched and touched by ghostly presences.

Several reported a strong feeling of invisible people — two on average — being close by. Two of the participants were so disturbed by the experience that they asked the scientists to stop.

Dr Giulio Rognini, a co-author of the study, said: “Our brain possesses several representations of our body in space. Under normal conditions, it is able to assemble a unified self-perception of the self from these representations. But when the system malfunctions because of disease — or, in this case, a robot — this can create a second representation of one’s own body, which is no longer perceived as ‘me’ but as someone else.”

The experiment suggested that “feelings of presence” (FOPs), often interpreted as spirits, angels or demons, were in the mind, said the researchers.

They cite the case of mountaineer Reinhold Messner, who, descending from a Himalayan peak freezing, tired and starved of oxygen, recalled becoming aware of a third climber “descending with us, keeping a regular distance, a little to my right and a few steps away from me”.

The researchers did brain scans of 12 patients with neurological disorders who had encountered FOPs in the past.

They identified disturbances in three brain regions, all involved in self-awareness, movement and sense of position in space. — © The