Last week news headlines from outlets across the globe announced that a mundane explanation had been found for haunted houses: infrasound (ie. sounds of a frequency beneath the typical threshold of conscious human hearing, which roughly spans 20Hz to 20KHz).
The titles of these articles were convincing: “Study: Infrasound likely a key factor in alleged hauntings” (Ars Technica); “Haunted by Ghosts? New Study Provides a Surprising Explanation” (Gizmodo); “Spooky feelings in old houses may be caused by boiler sounds, study suggests” (The Guardian).
Which is weird, because if you read the articles – including quotes from the researchers involved – things seem a whole lot more tentative.
“It’s not that infrasound is ‘causing’ hauntings, I want to be very clear on that,” Rodney Schmaltz, co-author of the study, told Ars Technica. “We’re definitely not saying we’ve solved hauntings. But in some of these older buildings, there could be low rumbling pipes [producing infrasound], and if somebody already has the expectation that something spooky might happen, the infrasound might drive that a bit.”
And it’s not just that the titles hype the actual results of the research (“Infrasound exposure is linked to aversive responding, negative appraisal, and elevated salivary cortisol in humans” in Frontiers in Behavioral Neuroscience). The results themselves actually offered no evidence that infrasound caused fear or anxiety, the most common emotions we associate with a haunted house – instead, the emotional responses that appear to have been evoked were annoyance, frustration, and disinterest.
That’s not to say the results weren’t interesting: it’s a cool experiment with some fascinating conclusions, and the idea that hidden forces (infrasound, magnetism, electromagnetic radiation etc) might be affecting our state of mind and perception – while we remain ignorant to many others – is one that I love to read about.
As The Guardian summarizes it:
36 volunteers listened to calming instrumentals or the kind of unsettling music played at haunted house attractions. Half the time, without the participants knowing, the researchers also played infrasound through hidden subwoofers…the researchers describe how volunteers could not tell when the infrasound was on, but when it was, tests suggested they felt more irritated and annoyed, rated the music as sadder, and had higher levels of cortisol in their saliva.
“Whether they were listening to calming instrumental music or something more unsettling, the infrasound shifted their mood and their stress response in a negative direction,” Schmaltz said. “In plain terms, you cannot hear infrasound, but your body and your mood appear to respond to it anyway, and the response tends to be unpleasant.”
So yes, there does seem to be an interesting unconscious response to infrasound. But not only does infrasound not seem to inspire feelings of fear or dread, as many people feel in a haunted house, but this study certainly didn’t find the slightest bit of evidence for the other aspects commonly reported by experiencers, such as temperature drops, apparitions, poltergeist activity, sulphurous smells, and sounds/voices.
It’s also worth noting that this topic has been investigated previously: way back in 2008 we reported on ‘The Haunt Project‘, an attempt to build a ‘haunted room’ by saturating various parts of it with electromagnetic fields and infrasound to see how research subjects would react to those invisible forces. But in that case as well, there seemed to be no correlation between spooky feelings and the presence of either EMF or infrasound.
