The Science Behind Soothing, Stressful, And Sleep-Inducing Sounds

Whether it’s waves lapping at the shore, the hooks in the newest pop song, or the hum of a white noise machine, sound is received by our ears in the same way. But why do some sounds make us feel soothed and relaxed, while others leave us annoyed and on edge?

Technically, sound is sound — “mechanical vibrations in the air, which the eardrum picks up and transfers to the cochlea” before being converted to electrical signals to be analyzed by the brain, Maria Geffen, PhD, an assistant professor of otorhinolaryngology at the University of Pennsylvania’s Perelman School of Medicine, explains to Yahoo Health.

But that doesn’t mean our brains interpret all sounds the same way. Factors include “our inherent reaction to the frequency and predictability of the rhythm, plus our past experiences and emotions hearing it,”Don Vaughn, a neuroscientist and DJ in Los Angeles, tells Yahoo Health. In general, our brains tend to feel more relaxed and at ease in response to lower frequencies of sound, as well as repetitive sounds (the brain prefers predictability,” says Vaughn). Culture is also a factor — a sound that’s considered positive in one culture might be taboo in another, and can influence how we react to it.

Some sounds are more notoriously annoying than others (hello, loud chewer, now please go away), while others are more calming (any white noise machine users out there?). Check out what makes some certain sounds soothing, stressful, and even sleep-inducing.