Spooks generated by brain-body mismatch (Nature News)

Some people with relatively rare types of brain injury experience a  ‘feeling of a presence’. A study involving a dozen such patients, published today in Current Biology1, suggests that the eerie feeling may arise when a person’s brain fails to integrate properly the different signals it receives from the limbs, such as those generated by touch and information about their position in space. The researchers also reproduced the illusion in healthy volunteers in the lab, with the help of purpose-built robots.