Have you ever stepped into a location that evokes an unsettling sensation? While a supernatural explanation might seem more captivating, an alternative reason could be responsible for that creeping disquiet.
This phenomenon is termed infrasound, and recent research elucidates how this occurrence demonstrably influences human stress responses and increases irritability, at least in the short term.
“Envision exploring a purportedly haunted edifice. Your disposition might alter, a sense of agitation might arise, yet nothing discernible visually or audibly presents itself,” explains the study’s principal author, Rodney Schmaltz, a psychologist affiliated with MacEwan University in Canada.
“Within an aged structure, the presence of infrasound is highly probable, especially in subterranean areas where antiquated plumbing and HVAC systems generate low-frequency oscillations,” Schmaltz elaborates.
“If the premise of the building being haunted was provided, one might readily attribute such discomposure to spectral influences. In reality, the cause may simply stem from exposure to infrasound.”
Any acoustic vibrations falling below the audible range for human perception, approximately 20 hertz and below, are classified as infrasound. These sound waves possess a remarkable capacity to traverse impediments without significant attenuation, thus extending their reach considerably.
They can originate from aging pipeworks and industrial equipment – accounting for the association with haunted locales – but also emerge from natural phenomena such as meteorological disturbances, seismic events, volcanic activity, and auroral displays. Certain fauna even integrate infrasound into their methods of communication and spatial orientation.
Infrasound is also prevalent in contemporary built environments. It can be generated by vehicular traffic, industrial machinery, and building ventilation networks, all of which are ubiquitous in modern existence. However, not all infrasound constitutes a detrimental factor; it represents a broad spectrum, and careful consideration of context is crucial.
Nevertheless, its pervasive nature necessitates that scientific inquiry give due attention to infrasound. Given its frequent presence in our surroundings, if specific frequencies indeed induce a state of heightened physiological vigilance, any potential long-term ramifications warrant thorough investigation.
Schmaltz, along with a cohort of researchers from MacEwan University, recruited 36 undergraduate students to participate in an investigation designed to assess the impact of infrasound on human physiological stress levels.
These subjects were individually situated in an enclosed space, subjected to either tranquil or disconcerting auditory stimuli. For precisely half of these participants, concealed subwoofers emitted infrasound at an 18-hertz frequency, without their conscious awareness.
Following the auditory exposure period, participants completed a questionnaire detailing their subjective experience of the music’s influence. Furthermore, salivary samples were collected from them both before and after the session, which the researchers utilized to quantify cortisol levels, a recognized biomarker for stress in the human organism.
It is acknowledged that this constitutes a rather modest participant pool, with a demographic predominantly comprising female individuals. While an expansive study incorporating a greater number of participants is requisite for broader generalization of the findings, they nonetheless hold considerable interest.
“Our discoveries indicate that even a transient exposure can elicit mood alterations and elevate cortisol concentrations, underscoring the imperative of comprehending infrasound’s influence on individuals within real-world contexts,” observes Schmaltz.
Individuals exposed to infrasound reported heightened feelings of irritation, discomfort, and perceived the musical selections as more melancholic – irrespective of whether they were presented with calming or unsettling compositions. Crucially, they were incapable of discerning the presence of the sub-audible vibrations.
Prior investigations had already posited that infrasound might exert a chilling influence, but the novel contribution of the current study lies in its elucidation of the correlation with cortisol, which exhibited a statistically significant increase in the presence of infrasound.
“Elevated irritability and increased cortisol are intrinsically linked, as heightened feelings of agitation or stress naturally lead to a rise in cortisol as part of the body’s adaptive stress response,” states Kale Scatterty, a behavioral neuroscientist at the University of Alberta and the study’s lead author.
“However, the exposure to infrasound demonstrated effects on both these parameters that extended beyond this inherent physiological relationship.”
It is a natural biological process for cortisol levels to fluctuate and ascend periodically. As a stress hormone, its function is to alert us to potential hazards, thereby facilitating an appropriate reactive response.
There exist theoretical frameworks suggesting that certain animal species exhibit responses to the infrasound generated by natural catastrophes like earthquakes and tsunamis prior to the actual onset of disaster.
This phenomenon might offer a comparable evolutionary rationale for humans experiencing adverse reactions to infrasound; it could be an innate predisposition to avoid such stimuli for self-preservation.
These findings possess the potential to enhance our understanding of the underlying causes of ostensibly paranormal phenomena, and may also inform the formulation of stricter acoustic regulations and improved architectural design standards.
“This research, in many respects, represents an initial stride toward comprehending the multifaceted effects of infrasound on human physiology,” cautions Scatterty.
“To date, our investigations have been confined to a singular frequency. It is conceivable that a multitude of other frequencies and their combinatorial interactions could yield distinct and varied effects.”
