The next time you walk into a purportedly "haunted" house and sense a ghostly presence, consider that those feelings might be due to vibrating pipes, mechanical or climate control systems, rumbling from traffic, or wind turbines, rather than anything paranormal. That's the conclusion of a new paper published in the journal Frontiers in Behavioral Neuroscience. All of those are sources of infrasound.
Scientists have long sought to find logical explanations for alleged hauntings. In 2003, for instance, University of Hertfordshire psychologist Richard Wiseman conducted two studies that investigated the psychological mechanisms underlying supposed "ghostly" activity. Subjects walked around Hampton Court Palace in Surrey, England, and the South Bridge Vaults in Edinburgh, Scotland—both with reputations for manifesting unusual phenomena—and reported back on which places at those sites they sensed such phenomena. The subjects reported more odd experiences in places rumored to be haunted, regardless of whether the subjects were aware of those rumors or not.
Those areas did, however, feature variances in local magnetic fields, humidity, and lighting levels, suggesting that such sensations are simply people responding to normal environmental factors. Wiseman hypothesized that stronger magnetic fields may affect the brain, similar to how electrical stimulation of the angular gyrus can make one feel as if there is another person standing behind, mimicking one's movements.