That ghostly presence may just be bad plumbing
Every day you encounter sounds that you technically can’t hear. Some of these are produced at incredibly high heights, but many others occur as infrasound. This ultra-low frequency range below 20 Hertz (Hz) is found everywhere: during thunderstorms, inside factories and even during rush hours. But growing evidence suggests that infrasound is regularly detectable in scarier situations. Specifically, seemingly imperceptible tones can frequently appear in “haunted” hot spots.
This is not to say that ghosts generate ultra-low growls like crocodiles. Instead, the researchers writing in the journal Frontiers of behavioral neuroscience suggest that infrasound may help explain why some places simply seem more frightening or ominous than others.
“Consider visiting a supposedly haunted building. Your mood changes, you feel agitated, but you can’t see or hear anything unusual,” Rodney Schmaltz, a psychologist at Canada’s MacEwan University and co-author of the study, said in a statement. “In an older building, there is a good chance that infrasound will be present, particularly in basements where aging pipes and ventilation systems produce low-frequency vibrations. »
To better understand the potential relationship between unconscious auditory influences and human psychology, Schmaltz’s team asked 36 volunteers to sit alone in a room and listen to disturbing or calming music videos. During half of the sessions, the study authors also exposed their volunteers to 18 Hz infrasound tones through hidden subwoofer speakers. Each person then completed a questionnaire to record their emotional reactions to the music, as well as whether or not they suspected infrasound exposure. Finally, they provided a saliva sample to assess their cortisol levels.
The researchers found that participants’ salivary cortisol was higher in the presence of infrasound, regardless of whether the individual was successful in detecting low-frequency sounds. Volunteers also reported higher levels of irritability and rated the music as sadder overall. Interestingly, there was no statistical evidence to suggest that people could reliably identify infrasound.
“Participants could not reliably identify whether infrasound was present, and their beliefs about its activation had no detectable effect on their cortisol or mood,” Schmaltz explained.
Although cortisol levels are directly linked to irritability and stress in humans, experience has indicated that the hormone can also be influenced by more subtle influences.
“This study suggests that the body can respond to infrasound even when we cannot consciously hear it,” Schmaltz added.
Previous research supports their theory, including a famous incident that occurred more than 40 years ago. During the 1980s, a British engineer named Vic Tandy began noticing strange shapes at the corners of his field of vision while working in a medical equipment factory. Colleagues had long claimed that the building itself was haunted. However, Tandy’s “visions” disappeared shortly after discovering and deactivating a nearby fan that was generating infrasound rumblings.
“As someone who studies pseudoscience and misinformation, what strikes me is that infrasound produces real, measurable reactions without any visible or audible source,” Schmaltz said.
The study authors emphasize that they have not yet reached definitive conclusions, citing the small sample and focusing on a single frequency. That said, their work is further indication that a ghost might not be what’s making the hairs on the back of your neck stand up, it might just be faulty plumbing.
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