According to science writer Terence Hines, cold spots, creaking sounds, and odd noises are typically present in any home, especially older ones, and "such noises can easily be mistaken for the sound of footsteps by those inclined to imagine the presence of a deceased tenant in their home."
David Turner, a retired chemist, suggested that ball lightning could cause inanimate objects to move erratically.
Skeptical investigator Joe Nickell writes that in most cases he investigated, he found plausible explanations for haunting phenomena, such as physical illusions, waking dreams, and the effects of memory. According to Nickell, the power of suggestion along with confirmation bias plays a large role in perceived hauntings. "As a house, inn, or other place becomes thought of as "haunted," more and more ghostly encounters are reported" says Nickell, "When people are given to expect paranormal events, they tend to notice those conditions that would confirm their expectations."
Toxicologist Albert Donnay believes that chronic exposure to substances such as carbon monoxide, pesticide, and formaldehyde can lead to hallucinations of the type associated with haunted houses. Donnay speculates on the connection between the prevalence of gas lamps during the Victorian era and start of the 20th century stories of ghost sightings and hauntings, describing it as the "Haunted House Syndrome". Donnay says that carbon monoxide poisoning has been linked to haunted houses since at least the 1920s, citing a 1921 journal article published about a family who suffered headaches, auditory hallucinations, fatigue, melancholy, and other symptoms associated with haunted houses.
Michael Persinger, Jason Braithewaite, and others, suggested that perceived apparitions, cold spots, and ghostly touches are perceptual anomalies caused by variations in naturally occurring or man-made magnetic fields. However, a study by psychologist Chris French and others that attempted to replicate Persinger's findings found no link.
Commercial haunted houses