I believe that our distant nomadic ancestors came forward and survived because they could hear distant, faint birdsong as an acoustic navigational beacon, if you will, and by moving toward the birdsong, they were able to find places with shelter, food, and water, and a prosperous growing region. Indeed, birdsong is the number one indicator of habitats prosperous to humans.

Healthy areas that are richest in information are those areas in the wild where we can get all the information that's available to us within our human hearing range. The most valuable information throughout human evolution has been faint sounds. We tend to think in our modern world that if it's loud, if it grabs our attention, it's important. We get a lot of that in advertising. But in nature, it's the faintest sound that's important; it has determined, in the past of our ancestors, perhaps, if they will live or die. Faint sounds are the earliest clues of newly arriving information.

You can listen to a birdsong, and from the content of the birdsong, you will be able to determine whether or not the bird grew up in a noise-polluted environment or whether it grew up in a pristine, clean environment. Isn't that incredible?

The Hoh Valley is an incredibly secure area. Any event occurs around us, we will instantly become informed of that event. This can even happen at a distance. When the body recognizes that you have a very large listening area, and you're getting all the information, the body relaxes. You can breathe more gently, the cortisol levels that are created by stress in our bloodstream dissipate, and we actually become healthier. And as a result, if we are actually fortunate enough to live in a place like that, we will live longer.

Not only does the modern person often think that sight is more important than sound - there's no objective evidence to indicate that. Many people, even audiologists who study the science of human speech and hearing, have assumed for a long time that the human ear evolved to hear the human voice, rather than the voice changing to fit the human ear. And the human ear is actually not a perfect match if we map its sensitivity to the different frequencies in the human range of hearing; it's an unequal curve, it's kind of a wavy line.

The most sensitive frequencies are at the resonant frequencies of the auditory canal. In other words, the ear has shaped itself to naturally amplify certain bandwidth. And that corresponds to sounds in that bandwidth that were most important to our evolving ancestors to hear, in order to survive. And it doesn't match the human voice. It matches birdsong.

Acoustic ecology is the study of information systems: the shared acoustic environment and how species send and receive messages in this shared acoustic environment. What these messages mean - meaning, what are the consequences and the changes of behavior in any species. And it has as much to do with us individually and biologically as it does with the shaping of cultures and beliefs.