Skeptical analysis

Critics of "eyewitness ghost sightings" suggest that limitations of human perception and ordinary physical explanations can account for such sightings; for example, air pressure changes in a home causing doors to slam, or lights from a passing car reflected through a window at night.[13] Pareidolia, an innate tendency to recognize patterns in random perceptions, can cause people to believe they have seen ghosts.[14] Reports of ghosts "seen out of the corner of the eye" may be accounted for by the sensitivity of human peripheral vision. According to skeptical investigator Joe Nickell:
...peripheral vision is very sensitive and can easily mislead, especially late at night, when the brain is tired and more likely to misinterpret sights and sounds.[15]
Nickell also states that a person's belief that a location is haunted may cause them to interpret mundane events as confirmations of a haunting:
Once the idea of a ghost appears in a household . . . no longer is an object merely mislaid. . . . There gets to be a dynamic in a place where the idea that it's haunted takes on a life of its own. One-of-a-kind quirks that could never be repeated all become further evidence of the haunting.[16]
Sound is thought to be another cause of ghost sightings. Frequencies lower than 20 hertz are called infrasound and are normally inaudible, but British scientists Richard Lord and Richard Wiseman have concluded that infrasound can cause humans to feel a "presence" in the room, or unexplained feelings of anxiety or dread. [17]
Carbon monoxide poisoning, which can cause powerful auditory and visual hallucinations, depression, and a generalized sensation of illness and dread,[18] was recognized as a possible explanation for haunted houses as early as 1921.
The traditional perception of ghosts wearing clothing is considered illogical, given the supposed spiritual nature of ghosts, suggesting that the basis of what a ghost is said to look like and consist of is quite dependent on preconceptions made by society.[19] Skeptics also say that, to date, there is no credible scientific evidence that any location is inhabited by spirits of the dead.[20]