Infrasonic waves—sound frequencies below 20Hz—can trigger physical discomfort and stress responses that people often mistake for paranormal activity in old buildings, according to research published in Frontiers in Behavioral Neuroscience. These undetectable sounds shift mood and increase cortisol levels, creating a feeling of dread.
Infrasonic waves trigger stress responses in old buildings
Low-frequency sound waves, known as infrasonics, can create a sense of dread or “haunting” in old structures, CNN Indonesia reported. These waves operate below 20Hz, which is generally outside the range of human hearing, but the body still detects them subconsciously.
Research from Frontiers in Behavioral Neuroscience indicates that these waves often emanate from boilers, pipes, and plumbing systems found in older buildings. This physical stimulus can negatively affect a person’s mood, leading to feelings of anxiety and restlessness.
Did you know? Infrasonics are undetectable to the ear, but they can cause a measurable biological stress response in the human body.
Rodney Schmaltz links physical discomfort to ghost stories
Psychologist Rodney Schmaltz of MacEwan University in Canada argues that infrasonics provide a physical discomfort that people then rationalize through a supernatural lens. He notes that while a person not prone to believing in ghosts might simply feel a building is “stuffy” or uncomfortable, someone already conditioned to believe in the paranormal may view the same sensation as evidence of a spirit.
To test this, Schmaltz conducted an experiment where participants walked through a haunted house attraction equipped with infrasonic speakers. The data showed that participants walked faster when the infrasonic speakers were active.
Cortisol levels rise during infrasonic exposure
In a more controlled study involving 36 participants, researchers played both calming and eerie music. Infrasonic sounds were introduced during these sessions without the participants’ knowledge. While the subjects could not hear the infrasonics, they reported feeling more anxious when the waves were active, regardless of whether the music was calming or scary.
The study found a physical marker for this stress: increased levels of cortisol in the participants’ saliva. High cortisol is a primary indicator that the body’s stress response has been activated.
Schmaltz added that in simple terms, a person cannot hear infrasonics, but their body and mood seem to respond to it, and that response tends to be unpleasant.
Unresolved factors in paranormal perceptions
Researchers clarify that infrasonics are not the sole explanation for all “haunted” experiences. The feeling of a building being eerie likely results from a combination of factors. Current findings do not explain why some individuals report visual hallucinations or sightings in these locations.
Further research is required to determine if locations widely regarded as haunted actually possess higher intensities of infrasonic waves compared to standard buildings.
Can humans hear infrasonics and what causes them?
Can humans hear infrasonic waves?
No, infrasonics are below 20Hz, which is generally below the threshold of human hearing, though the body can detect them subconsciously.
What causes infrasonics in old houses?
According to the research, vibrations from basement pipes and other mechanical systems common in older buildings can generate these low-frequency waves.
Does infrasound cause visual hallucinations?
The study mentioned by CNN Indonesia does not explain visual sightings, noting that further research is needed to address why some people see apparitions.