A case in point would be research into the effects of sounds we can’t even hear. These researchers are studying infrasound, which is too low for us to hear. Sounds pitched too high for humans are called ultrasound. There are many sources of infrasound. We are living unawares in a vast sea of sounds that we can’t hear. It’s been known for awhile that elephants communicate over great distances using subsonic rumbles. Non-elephants go along never knowing that their big neighbors might be talking about them, not behind their backs but below their hearing. Whales are known to produce infrasounds that travel hundreds, or even thousands of kilometers in the ocean. Most of the rest of the creatures of the sea wouldn’t even be aware of it.
Other sources of infrasound are strong storms, which are so powerful that they are identifiable among the jumble of noises in the atmosphere. There’s the “voice of the sea,” an atmospheric background of infrasound noise detectable everywhere. It’s thought to be made by the waves produced in large storms all over the world’s oceans.Just as the wind in your eaves can produce a spooky moaning sound, so the wind can make long-lasting infrasound moans as it blows over mountain ranges. Here’s where some speculation comes in. Data show that in areas such as the Alps or the Rockies, where wind and mountains meet, there are increased psychological disturbances and even suicides among the people living there. Humans might be reacting to the ultra low sounds even though they can’t hear them. This seems to be supported by experiments where subjects listened to music which contained infrasound. Though it sounded the same as the unaltered control music, some listeners reported feeling unsettled or getting chills down their spines while listening to it.
There’s lots of speculation going on now about how much we might be affected by sounds we can’t even hear.