The experimental setup was deliberately ordinary. Thirty-six undergraduate students filed one at a time into isolated testing rooms and sat alone with a piece of music, either a calming instrumental or a horror-themed ambient track designed to provoke discomfort. Hidden subwoofers, including a 12-inch unit positioned in an adjacent hallway and a 16-inch speaker oriented toward the ceiling in a neighboring room, pumped infrasound at approximately 18 Hz into half those spaces. The participants had no idea. That last point turned out to be rather important. When the team ran the numbers, they found that participants couldn't reliably identify whether infrasound had been present. Their guesses were, statistically speaking, no better than chance. And according to Schmaltz, participants' beliefs about whether the infrasound was on had no detectable effect on their cortisol or mood. The physiological response didn't care what the participants thought was happening. It just happened anyway.
What happened, specifically, was this: those exposed to infrasound reported higher irritability, lower interest in the music, and a tendency to rate the music as sadder, irrespective of whether it was the calming or the horror track. Cortisol levels, measured before and about 20 minutes after exposure, were also elevated. Kale Scatterty, the PhD student who led the work, notes that irritability and cortisol do tend to move together under ordinary stress, but adds that "infrasound exposure had effects on both outcomes that went beyond that natural relationship." That distinction matters more than it might seem. Previous theories about infrasound and paranormal experience have often leaned on anxiety as the explanatory mechanism, the idea that low-frequency sound triggers a kind of free-floating dread that the mind then reaches for supernatural explanations to account for. The new data don't really support that picture. Measures of anxiety didn't budge significantly. What went up was irritability and disinterest, a kind of sour, low-grade aversion rather than fear. That's perhaps a more honest description of how a lot of ghost stories actually feel in the telling: not screaming terror, but wrong atmosphere, a sense of unease that never quite crystallizes into something you can point at. The study has been published this week in Frontiers in Behavioral Neuroscience.
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