Is your house haunted? Alberta scientists think they know the reason

If you’ve ever felt tense, irritable or even freaked out in a supposedly haunted house, the reason might be more normal than paranormal. Canadian scientists have discovered that “infrasound,” frequencies of noise that are too low for the human ear to detect, may still create an emotional response in people, possibly a haunted feeling.

The team of researchers was led by Dr. Rodney Schmaltz , a full professor in the Department of Psychology at MacEwan University in Edmonton. His research focuses on the psychology of belief, with a particular interest in how people evaluate extraordinary claims.

The researchers recruited 36 people and had them to sit alone in a room while listening to one of two kinds of music. During a call with National Post, Schmaltz described one as “relaxing” and the other as “kind of spooky.” Half the participants were also exposed to hidden subwoofers that produced infrasound at 18 Hertz. (Humans can’t hear below 20 Hertz.)

Participants were then asked to describe how they felt, rate the emotional tone of the music, and indicate whether they believed infrasound had been played. They also provided saliva samples before and after the session. (Salivary cortisol is a biomarker used to assess psychological stress.)

“We found that participants in the infrasound-on condition reported higher irritation, lower interest, and rated the stimulus (music) as sadder than those in the infrasound-off condition,” the researchers wrote .

“Infrasound also raised salivary cortisol levels, both independently and in conjunction with irritation and discomfort. These self-report differences and cortisol changes were not influenced by music type nor self-reported perception of the presence of infrasound.” (Participants did not correctly identify infrasound at a level above chance.)

Schmaltz said detecting infrasound can be tricky, requiring an expensive specialized microphone.

“But if you want to see if there’s infrasound, what you can do is, if you have a lighter or a match, and if the flame seems to kind of bend in the middle, and there’s no breeze or anything there, that’s a sign there could be infrasound.”

His team’s study noted: “Infrasound has been postulated to cause aversion and feelings of fear in supposedly haunted locations and to contribute to anxiety, distress, and reduced well-being in the vicinity of energy infrastructures such as wind turbines.” It cited several studies, including one, “The Ghost in the Machine,” from as far back as 1998.

That paper described how the presence of “a 19 Hz standing air wave may under certain conditions create sensory phenomena suggestive of a ghost,” concluding: “Our advice for researchers in the future is to be very wary of ghosts reported to haunt long, windy corridors!”

“Infrasound also occurs naturally, generated, for example, by tectonic or volcanic activity, convective storms and air-water interactions such as during upstream water discharges,” the Alberta study noted. “Infrasound is also, however, prevalent in urban areas near ventilation systems, air conditioning, low-rumbling pipes, traffic and building power, heating, mechanical systems.”

As to whether ghosts might also be able to create such noise, Schmaltz was dismissive.

“We need to think about it in terms of what would be the simpler explanation,” he said. “So we see an old boiler. We can feel something. We know that old boilers or low-rumbling pipes cause infrasound. We can measure the infrasound. So it’s a much more rational explanation.”

He added: “And as somebody who’s helped build an infrasound speaker, I’m not sure how the ghosts would do it. It’s very hard to generate it. So, I would be very skeptical of that perspective.”

Still, he was willing to leave the door to a paranormal explanation open just a little. (And nothing is creepier than a door just slightly ajar.)

“We haven’t disproven the existence of ghosts,” he said. “But the next time you walk into an old building and it kind of feels creepy like that, feels like it could be something ghostly, well now you have a rational explanation. I definitely think that it’s valuable in the sense that we’re giving people a rational explanation for what might feel like a paranormal event.”

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