Haunted houses, horror and the sound of dread

The house is quiet, but never quite silent. In the small hours, when the world outside has fallen silent, it seems to acquire a secret life of its own. Shadows deepen, floorboards creak unexpectedly. The air acquires a watchfulness, as if someone is lingering just beyond the closed door, waiting to be let in. Recall the oppressive interiors of The Haunting of Hill House, or the slow, encroaching dread of The Turn of the Screw: For years and years, this unease — and the conviction that one is not alone — has come to define the imagination of the the uncanny or the supernatural. Turns out not all of it relates to the paranormal.

Recent research by psychologists at MacEwan University in Canada, published in Frontiers in Behavioural Neuroscience, suggests that such atmospheres may be engineered not by spirits but by sound too low to be audible to the naked ear. Infrasound, those subterranean frequencies produced by ageing systems of heat and ventilation, assumes a life of its own when ambient noise dies down. The house is not haunted so much as it is resonant, its antiquated mechanisms generating a continuous hum that the mind struggles to interpret. For those predisposed to horror, the body’s subtle distress manifests through restlessness and a prickling sense of being observed. For the more intrepid, however, it may simply show up as irritation, and the annoyance that comes with figuring out the maintenance of an old house.

The explanation, however, does not entirely dismiss the paranormal. If anything, it relocates the source of dread from the unknown outside to the nervous system. Or, what the British philosopher Gilbert Ryle called the “ghost in the machine” in his critique of Descartes’ doctrine of mind-body dualism: That there is such seamless coherence between body and mind that the faintest physical disturbance can ripple outward into meaning – and in, this case, into trepidation.