Dr Paul Stevens of the Koestler Parapsychology Unit at Edinburgh University measured residual magnetic fields at sites where ghosts had been reported regularly.
The sites, at the South Bridge Vaults in Edinburgh's city centre and at Hampton Court Palace in Surrey, were found to have higher magnetic fields than surrounding buildings.
Dr Stevens said, "It is known that in some people high magnetic resonance can have an effect on temporal lobe activity.
"Some people subjected to this have reported feelings such as being 'touched by God' while others have seen and heard things that were not there."
One of those being helped by the Ghost Detectives at present, Jackie Williams of Trallwn, Swansea, believes her security cameras have picked up ghostly faces of babies, dogs and even that of Osama bin Laden.
The 55-year-old former hairdresser and care assistant said, "It's hard getting people to believe you, so we called in the Ghost Detectives.
"I've got an open mind on it at the moment."