The next time you feel a chill in a “haunted” house and suspect a specter is nearby, scientists would like you to consider a more mundane culprit: vibrating pipes, rumbling traffic, or that wind turbine down the road. A new paper in Frontiers in Behavioral Neuroscience points a finger at infrasound - sound waves below the range of human hearing - as a likely contributor to those spooky sensations.
Researchers have long sought logical explanations for alleged hauntings. Back in 2003, psychologist Richard Wiseman of the University of Hertfordshire marched subjects through Hampton Court Palace and the South Bridge Vaults in Edinburgh, both famed for ghostly activity. Participants reported more odd experiences in areas rumored to be haunted - whether they knew the rumors or not. Wiseman found those spots had variances in magnetic fields, humidity, and lighting, suggesting people were just responding to normal environmental factors. He hypothesized that stronger magnetic fields might tickle the brain much like electrical stimulation of the angular gyrus can make you feel a phantom presence behind you. In a related study of Mary King’s Close, 70 percent of subjects reported sudden cold, being watched, or unexplained footsteps - in areas with markedly lower humidity. So the sensations are real; the ghosts, not so much.
The late Vic Tandy, an engineer at Coventry University, proposed another culprit: infrasound at 18.9 Hz. While too low for human ears, research suggests we may subconsciously sense it. Tandy blamed infrasound for a spooky experience in his Warwick lab - he felt his hair rise and glimpsed a gray apparition - only to find a newly installed extractor fan was the likely source. He died in 2005 before he could investigate further, especially why some people are affected and others aren't.
Enter Rodney Schmaltz of MacEwan University, co-author of the latest study. Schmaltz had long discussed infrasound in his course on science and pseudoscience, even taking students on “ghost hunts” to debunk standard ghost-hunting tools. He and his students built infrasound speakers and took them to a commercial haunted house during off-hours. When they turned on the infrasound, people walked faster through the house. “It was interesting, but it certainly was not enough to definitively say what impact infrasound was having,” he said.
A conversation with neuroscientist Kale Scatterty - who co-authored a 2023 study showing zebrafish avoid infrasound - inspired a lab experiment. Thirty-six participants sat alone in a room, exposed to either calming yoga-like music or unsettling ambient tunes, with half also getting infrasound from hidden subwoofers. The results: across the board, participants felt more irritated and unsettled when infrasound was on, regardless of the music, and their cortisol levels spiked significantly. None could reliably tell when infrasound was present. So yes, humans can have a physiological freak-out to sounds they can’t consciously hear.
But infrasound isn’t the whole story. “It’s not that infrasound is ‘causing’ hauntings,” Schmaltz clarified. “We’re definitely not saying we’ve solved hauntings. But in some older buildings, low rumbling pipes [producing infrasound] might drive that a bit if someone already expects something spooky.” He’s skeptical about Tandy’s visual illusion, noting his own experiments hit 75 - 78 dB without producing anything like that.
Schmaltz admits the study has a small, homogenous sample - cortisol testing is pricey, and he only had an $8,000 grant. He’d love to expand, but for now his team is visiting supposedly haunted locations and measuring infrasound levels. “We’re not finding much,” he admitted. Future studies might test a wider frequency range; this one used 17 - 19 Hz, typical of rumbling pipes or traffic. “We’re built to believe,” Schmaltz said. “I’m just trying to promote tools to help people become better consumers of information, to identify when something sounds scientific but isn’t.”
The paper appears in Frontiers in Behavioral Neuroscience, 2026, DOI: 10.3389/fnbeh.2026.1729876.