INFRASOUND

 A

The claim refers to infrasound—very low-frequency sound waves below about 20 Hz, which are generally below the threshold of human hearing.

What the research found

A 2026 study exposed participants to 18 Hz infrasound while they listened to music. Although they could not reliably tell when the infrasound was present, researchers found:

• Increased cortisol (a stress hormone)

• Greater irritability

• More negative emotional responses to the music

Participants' bodies reacted even though they were not consciously aware of the sound. (Medical Xpress)

Why it might feel "paranormal"

Infrasound can be produced by:

• Old pipes and boilers

• Ventilation systems

• Traffic and industrial machinery

• Wind and storms

If a person enters an old building with persistent infrasound, they may experience:

• Unease

• Anxiety

• A sense that "something isn't right"

• Heightened vigilance

The brain then tries to explain these unusual bodily sensations. In a setting already associated with ghosts or hauntings, people may interpret the feelings as a supernatural presence. (earthsky.org)

Neurobiology behind the effect

A plausible mechanism is:

Infrasound → subconscious sensory detection → stress response → altered perception

This may involve:

• Activation of autonomic nervous system pathways

• Increased cortisol release

• Greater amygdala sensitivity (threat detection)

• Enhanced pattern-seeking by the brain

When the brain is in a mildly stressed state, ambiguous sounds, shadows, or sensations can feel more significant or threatening than they otherwise would.

Important limitation

The research does not show that infrasound causes full-blown hallucinations or proves that all paranormal reports are explained by sound. It mainly demonstrates measurable changes in mood and stress physiology. Researchers caution that experiences such as seeing moving objects or detailed apparitions are not explained by this study alone. (The Guardian)

Connection to spiritual experiences

An interesting question is whether infrasound could also influence some religious or mystical experiences. Neuroscience would say that any stimulus that changes arousal, emotional salience, or body awareness can alter consciousness. However, that does not determine the meaning of the experience. The neurobiology can describe how the brain and body respond, but it cannot determine whether a spiritual interpretation is true or false.

So the key finding is: humans may not consciously hear certain very low-frequency sounds, yet their nervous systems can still react to them, potentially creating feelings that some people interpret as paranormal. (earthsky.org)