When you go for a walk outside, what do you hear? The gentle breeze as it filters through the trees? A bird’s song? Or are you too overwhelmed by the sounds of construction and passing cars to hear anything at all? According to new research, when you leave your house, you’re likely not hearing Mother Nature’s chorus. Instead, you’re probably trying to ignore sounds like the car alarm that won’t shut off  — essentially blocking out all the sounds around you.

Kurt Fristrup, a senior scientist at the U.S. National Park Service, explained to the American Association for the Advancement of Science (AAAS) during a meeting in San Jose that noise pollution is becoming so pervasive in the modern world that people are tuning out all the sounds around them. And that includes the sounds of nature.

Fristrup said of the phenomenon: “This learned deafness is a real issue. We are conditioning ourselves to ignore the information coming into our ears.”

“This gift that we are born with – to reach out and hear things hundreds of metres away, all these incredible sounds – is in danger of being lost through a generational amnesia. There is a real danger, both of loss of auditory acuity, where we are exposed to noise for so long that we stop listening, but also a loss of listening habits, where we lose the ability to engage with the environment the way we were built to.”

Fristrup and his colleagues at the park service have been monitoring sound levels at more than 600 sites over the past 10 years, everywhere from Yellowstone, Yosemite and the Grand Canyon in the lower 48, to Denali in Alaska. Not a single site was left free from human noise pollution.

The team created an auditory model that merged data from more remote areas, like national parks, with urban areas to get a sense of the level of noise pollution across the U.S. Based on their findings, the researchers believe that noise pollution will grow faster than the U.S. population and that it will double every 30 years.

Here's a map of what they found, with the deep blue regions representing the quietest places:

Americas quietest places

Graphic: NPS Natural Sounds and Night Skies Division

Another scientist, Derrick Taff from Pennsylvania State University, spoke at the event about what humans are losing by tuning out the sounds of nature. Taff shared findings from a preliminary experiment that suggested that listening to recordings of natural sounds such as flowing water, wind and bird songs helps people to recover from stress. In one of the experiments, researchers found that heart rates and stress hormones decreased more quickly when people listened to natural recordings than when those same recordings were intermingled with man-made sounds.

“We know that natural sounds are very important to people,” says Taff. “They are some of the main reasons people visit protected areas. They want to hear the natural quiet, the birdsong, and the wind and water. We may be losing this as people are listening to the iPods all the time, but I do believe that the public is appreciative of these sounds. My advice is to go to your protected areas and experience what you are missing.”

Due to rising noise pollution, Fristrup also addressed the ways in which people are trying to drown out the large number of sounds by listening to music or wearing headphones.

He said, “It’s not surprising people are putting on earphones or even noise-cancelling earphones to try and create a quieter or more congenial environment.”

“As you raise background sound levels it has the same effect on your hearing that fog would have on your vision. Instead of having this expansive experience of all the sounds around you, you are aware of only a small area around you. Even in most of our cities there are birds and things to appreciate in the environment, and there can be very rich natural choruses to pay attention to. And that is being lost.”

The real loss, according to Fristrup, is for future generations. “If finding peace and quiet becomes difficult enough, many many children will grow up without the experience, and I think it’s a very real problem,” he said.

If you're looking to experience some of those natural sounds without all the interference, check out the map above, which shows the quietest places in the U.S.

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