Infrasound: The Science Behind the 'Haunted' Feeling in Old Buildings

For centuries, tales of haunted houses have captivated imaginations, but a new study suggests the eerie feelings associated with such places may stem from something far less supernatural. Researchers have identified inaudible infrasound waves—emitted by old boilers, pipes, and plumbing—as a potential cause of discomfort, unease, and even perceived ghostly encounters.

How Infrasound Influences Perception

Infrasound refers to sound waves below 20 Hz, a frequency range typically inaudible to humans. However, studies indicate that people can subconsciously detect these vibrations, which may trigger physical and emotional responses. Rodney Schmaltz, a psychologist at MacEwan University in Canada and coauthor of the study published in Frontiers in Behavioral Neuroscience, explains:

"What infrasound may do is supply a bit of bodily discomfort that a ghost or haunting explanation can then attach itself to. For someone who is not inclined to think in terms of ghosts, the same sensation would probably just register as a stuffy, uncomfortable old building. For someone who is already primed, it might feel like proof of a spirit or presence."

Schmaltz previously tested this theory in an experiment where participants walked through a haunted house attraction equipped with infrasound speakers. When the speakers were activated, participants moved through the building faster, suggesting heightened unease.

Experimental Evidence: Infrasound’s Impact on Mood and Stress

To further investigate, researchers conducted a study with 36 volunteers. Participants listened to either calming or unsettling music while exposed to infrasound during half of the sessions. The results were striking:

• Participants could not detect when infrasound was being emitted.
• Those exposed to infrasound reported feeling more irritated and unsettled, regardless of the music playing.
• They also rated both types of music as sadder compared to the control group.
• Saliva tests revealed higher cortisol levels in the infrasound group, indicating an activated stress response.

Schmaltz summarized the findings:

"Whether they were listening to calming instrumental music or something more unsettling, the infrasound shifted their mood and their stress response in a negative direction. In plain terms, you cannot hear infrasound, but your body and your mood appear to respond to it anyway, and the response tends to be unpleasant."

Could Old Buildings Be the Source of Ghostly Experiences?

Schmaltz speculates that the low rumbling of pipes in basements or vibrations in decrepit buildings could produce infrasound, contributing to the unsettling atmosphere often associated with haunted locations. However, he cautions that infrasound is likely just one factor among many in creating the perception of hauntings. It does not explain visual sightings of apparitions or other supernatural claims.

The study underscores the complex interplay between environment and perception, suggesting that what we interpret as ghostly encounters may sometimes be the result of subconscious physiological responses to unseen forces.