How Prolonged Exposure to Sweet, Blessed Silence Benefits the Brain

Photo: May Xiong/Getty Images

I write this to the soundtrack of a literal chainsaw; there are men at work outside my window attempting to – well, I’m not exactly sure what they’re attempting to do. Cut down a tree? Cut down branches of a tree? Whatever it is they’re doing, they are making an awful lot of noise as they do it.

Much has been written about “noise pollution,” a phrase coined in the 1960s, when scientists discovered that everyday exposure to the loudness of highways and airports was linked with a variety of health concerns: heart disease, sleep problems, high blood pressure, and, least surprisingly, hearing loss. And, as Maggie Koerth-Baker reminds in FiveThirtyEight this week, sounds can become so intense that they can even cause much more immediate damage, strong enough to tear a hole in your eardrums or even bowl you right over.

So: Excessive noisiness is bad. Its opposite — silence — has largely been understood for what it is not; it is not noise. It is the absence of sound. If too much exposure to loud sounds is bad for us, lack of sound means a lack of that physical harm caused by noise pollution. Silence is neutral. But as science writer Daniel A. Gross writes in a feature included in a recent Nautilus series on noise, some recent research is suggesting that prolonged and repeated exposure to silence may result in improved health, just like prolonged and repeated exposure to noisiness can result in poorer health.

What’s especially fascinating about the scientific study of silence is how much of it came about by accident. For many of the researchers Gross interviews for his piece (which, by the way, was republished by Nautilus this week, but originally posted in 2014), findings about the benefits of quiet came as a surprise — several of them initially set out to study the neuroscience of sound, or of music in particular. One mouse study led by Imke Kirste, a biologist at Duke University, found that “even though all the sounds had short-term neurological effects, not one of them had a lasting impact,” Gross writes. “Yet to her great surprise, Kirste found that two hours of silence per day prompted cell development in the hippocampus, the brain region related to the formation of memory involving the senses.”

This was, of course, a study in mice; mice, in case you haven’t heard, are not people. It’s early days in this line of research, in other words, but some scientists are hopeful that these findings may lead the way to some potential treatments for people with disorders associated with a slowing of cell growth in the hippocampus, like dementia or depression. But so far, at least, the neuroscience of silence seems to be suggesting this: To the brain, quiet is much more than what it isn’t.

How Exposure to Silence Benefits the Brain