Feeling eerie at old, haunted forts? Scientists say it might not be ghosts

Some scientists have an explanation for people feeling eerie in and around old, debilitated and haunted buildings and the answer is surprisingly not ghosts or phantom figures lurking around the dark. It could be the kind of sounds people get exposed to in these archaic places.

Ultra low frequency sounds, not audible to the human ear, are present around people all the time. They could be anywhere from traffic to old buildings and affect the levels of cortisol in the blood, the hormone regulating the stress response. When people come in close contact with infra sounds, they are more likely to become irritable, less engaged and stressful, a study has found out.

The findings suggest that human bodies can sense these vibrations without any conscious awareness. These sounds become more prominent in isolated or worn-out buildings.

Infrasound is a very low frequency sound wave that is below 20 Hz. Though it is not hearable, it can be felt in the form of sensations. These sound waves have an ability to get around obstacles without getting dissipated much and can travel up to long distances.

More than just sound

Led by professor Rodney Schmaltz of MacEwan University, senior author of the article published in Frontiers, his team conducted a small experiment on around 36 people. Each participant was asked to sit in a room, listening to either calming music or unpleasant sounds. Half of the group was secretly exposed to infrasound having a frequency of 18 Hz. 

Towards the end, the participants were asked to describe the quality of the sound and also if they suspected listening to infrasound waves.

In fact, their saliva samples were also taken before and after the experiment to test cortisol level changes in the blood.

It was found that people exposed to infrasound waves showed higher salivary cortisol and reported the music to have a sad element to it. Though they felt irritable, none of them could tell if they were exposed to infrasound.

The scientists said the bodies might respond to low frequency sounds even when they can’t consciously hear it.

Fear inducing sounds

As per the study, the infrasound waves have been studied to cause feelings of aversion and feelings of fear in places deemed as haunted or isolated.

This reduced well-being around places where aging pipes and worn out ventilation systems release low frequency sounds can generate feelings of eeriness and make people feel something is off but they can’t just point it out.

Also, infra sounds are also associated with earthquakes (movement of tectonic plates), low rumbling pipes, wind mills and other mechanical systems. 

The study suggested these sounds aren’t harmless and can cause physical uneasiness, anxiety and initiate a stress response.