Understanding the Impact of Infrasound on Human Behavior
Very low-frequency sounds, known as infrasound, are a type of sound that humans cannot hear but can have significant effects on the body. These sounds, which fall below 20 Hertz (Hz), can be generated by both natural and human-made sources. Natural sources include storms, while human-made sources may involve traffic or industrial machinery. Research suggests that exposure to infrasound can lead to increased irritability and higher levels of cortisol, a hormone associated with stress.
In a recent study published in the journal Frontiers in Behavioral Neuroscience, researchers explored how these inaudible sounds might influence mood and behavior. The findings suggest that even brief exposure to infrasound could alter emotional states and elevate cortisol levels. This raises intriguing questions about why some locations are perceived as “haunted” or unsettling.
The Role of Infrasound in Perceived Hauntings
Dr. Rodney Schmaltz, one of the authors of the study, explains that in old buildings, especially in basements, infrasound is likely present due to aging pipes and ventilation systems. He notes that such sounds are common in everyday environments, often found near ventilation systems, traffic, and industrial machinery.
“If you were told the building was haunted, you might attribute that agitation to something supernatural. In reality, you may simply have been exposed to infrasound,” he said. This idea challenges the traditional belief that strange sensations in certain places are caused by supernatural forces.
Experimental Insights into Infrasound Effects
To investigate the effects of infrasound, researchers conducted an experiment involving 36 participants. They were asked to sit alone in a room while either calming or unsettling music was played. For half of the participants, hidden subwoofers emitted infrasound at 18 Hz. After the session, participants were asked to report their feelings, rate the music emotionally, and indicate whether they thought the infrasound was present.
Saliva samples were collected before and after the session to measure cortisol levels. The results showed that participants who were exposed to infrasound had higher salivary cortisol levels. They also reported feeling more irritable and less interested, and believed the music was sadder, even though they couldn’t identify the presence of infrasound.
The Science Behind Stress Responses
Dr. Schmaltz explained that increased irritability and higher cortisol levels are naturally linked. When people feel stressed or irritated, cortisol tends to rise as part of the body’s normal stress response. However, the study found that participants could not reliably identify whether infrasound was present, and their beliefs about its presence had no detectable effect on their cortisol or mood.
The findings confirm that humans can sense infrasound without being able to identify it. While the exact mechanism remains unclear, scientists hope to conduct further research with more participants to explore whether prolonged exposure to infrasound could impact health through consistently elevated cortisol levels.
Long-Term Implications of Cortisol Levels
Trevor Hamilton, another author of the study from MacEwan University, highlighted the role of cortisol in the body’s response to stress. “Increased cortisol levels help the body respond to immediate stressors by inducing a state of vigilance,” he said. This evolutionary-adapted response can be beneficial in many situations. However, prolonged cortisol release is not ideal. It can lead to various physiological conditions and affect mental health.
Future Research Directions
The latest research focused on the effects of 18 Hz infrasound. Researchers suspect that different low frequencies and combinations might have unique effects. Dr. Schmaltz, who studies pseudoscience and misinformation, emphasized that infrasound produces real, measurable reactions without any visible or audible source.
“So, the next time something feels inexplicably off in a basement or old building, consider that the cause might be vibrating pipes rather than restless spirits,” he said.
