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Science
Apr 27, 2026
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The Physics of Fear: How Infrasound Explains the Paranormal

AI Summary
Scientists at MacEwan University have discovered that infrasound—inaudible sound waves generated by old pipes and boilers—can trigger physiological stress responses, including increased cortisol levels and irritability. This research suggests that the 'spooky' sensations often reported in haunted locations may be a result of these low-frequency vibrations rather than supernatural entities.

The Lead

Believers in the paranormal often attribute unsettling sensations in old buildings to spirits, but new research from MacEwan University suggests a more grounded explanation: infrasound. This inaudible sound phenomenon, generated by aging infrastructure like pipes and boilers, may be the physiological trigger behind feelings of dread and irritation, effectively providing the 'bodily discomfort' that fuels ghostly suspicions.

The Inaudible Threat: Infrasound and the Boiler Effect

The study focuses on infrasound, sound waves that fall below the 20Hz threshold of human hearing. While the human ear cannot detect these frequencies, the body can. Prof. Rodney Schmaltz and his team investigated whether these low-frequency vibrations, commonly found in the basements of old houses, could impact human mood and stress levels.

  • Source Identification: The primary sources of infrasound identified are old pipes, boilers, and ventilation systems.
  • Frequency Range: The waves operate below 20Hz, making them completely inaudible to the human ear.
  • Location: These vibrations are most prevalent in older buildings where infrastructure is aging.

Physiological Data: Stress Hormones and Irritability

In a controlled experiment involving 36 volunteers, researchers played calming or unsettling music while simultaneously emitting infrasound through hidden subwoofers. The results revealed a distinct physiological shift despite the participants being unaware of the sound's presence.

  • Stress Response: Participants exhibited higher levels of cortisol (the stress hormone) in their saliva.
  • Mood Shift: Volunteers rated the music as sadder and reported feeling more irritated and annoyed.
  • Blindness to Source: Crucially, participants could not identify when the infrasound was active, proving the effect is subconscious.

The Psychology of Belief: Priming the Paranormal

The research highlights the concept of 'priming,' where a pre-existing belief influences how a person interprets a sensation. For someone already inclined to believe in ghosts, the physical discomfort caused by infrasound provides a tangible explanation for their unease.

  • The Skeptic's View: A non-believer would likely attribute the feeling to a 'stuffy, uncomfortable old building.'
  • The Believer's View: For someone primed to expect a haunting, the same irritation is interpreted as proof of a spirit or presence.
  • Attachment Theory: Infrasound supplies the physical discomfort, allowing a 'ghost or haunting explanation' to attach itself to the experience.

Future Outlook and Scientific Validation

While the findings are promising, experts like Chris French note that larger studies are required to fully confirm the scope of this effect. While infrasound may explain vague discomfort and 'vague haunting' phenomena, it is unlikely to account for more intense poltergeist activity or visual hallucinations, which require more substantial evidence.