Stephen Kellert is a professor emeritus and senior research scholar at Yale University.

JACKI LYDEN, HOST:

It's WEEKENDS on ALL THINGS CONSIDERED from NPR News. I'm Jacki Lyden.

Contact with nature is not some magical elixir, writes Stephen Kellert, but the natural world is the substrate on which we must build our existence. Kellert writes about the environment and its effect on us and ours on it, building on the traditions of Thoreau and John Muir and Rachel Carson.

Kellert is professor emeritus at the Yale School of Forestry and the author of many books. His newest is called "Birthright: People and Nature in the Modern World." Dr. Kellert, welcome to the program.

STEPHEN KELLERT: It's nice to be here.

LYDEN: So, Stephen Kellert, you've written that our capacity, even to be human, to think and feel and communicate and create, depend on this relationship to nature. Can you elaborate on that a little and tell us how?

KELLERT: Well, it's a fairly simple concept. For more than 99 percent of our history as a species, we evolved in a natural - not in an artificial or human constructed or created - world, and therefore we became deeply attuned to the resident rhythms and stimuli that originate in the natural world. And it reveals itself in many ways.

Our attraction to nature, our inclination to find meaning and purpose in life to a relationship to the world beyond ourselves, which is another way of saying nature, and the way in which we symbolize nature and incorporate that into our ability to communicate through language and story and other ways. All these are, you know, very fundamental capacities, and they reflect our affinity for nature, but all these are basic capacities of being a human being.

LYDEN: What about a city street? Are we more likely now to recognize that we need to have at least some contact with a tree canopy, for example?

KELLERT: I think so. We love cities. Eighty-two percent of us in America live in an urban environment, which is the most built and transformed of all habitats. But it's about creating good habitat for people even in our urban settings. Tree planting is part of that, but also the interior of buildings and the facades of buildings can be inspired and mimic and simulate natural patterns and processes, and use materials that remind us of nature and have natural lighting in such a way that even the deepest interior spaces of an urban, built environment can still provoke satisfying experiences of natural patterns.

LYDEN: One of the things you talk about in this book is aversion. And in the 19th century, there was a lot of aversion for, say, wolves because they were perceived as destructive to farms, the passenger pigeon was hunted to extinction. Have we reversed that feeling?

KELLERT: Well, you know, any of these tendencies can be exaggerated to a point where they become dysfunctional. Certainly, our fear of large predators such as wolves was an example of a loathing, a hating of a particular species that went beyond a reasonable response to a threat to perhaps growing livestock or to - settlement on the wilderness. And we made this species an object of fear and loathing to the point where it became an expression of what could be called specicide. We weren't happy until we actually wiped out this creature altogether.

LYDEN: Although you do have a great example in here where you and a colleague are courting a wolf pack. And it is terrifying when you actually begin to hear them.

KELLERT: Well, absolutely. We were out in the deep of night in northern Minnesota. Eventually, we were surrounded by wolves, and I could, you know, feel the terror of being a relatively vulnerable prey species with this large predator. And it, you know, it was a very humbling experience, but at the same time it was an awesome experience. I came to appreciate the wolf in a way that I never had before through my intellectual studies by recognizing its power.

LYDEN: You have written an entire chapter here about children, and you say that a lack of exposure to the natural world really dulls our senses, if you talk about the effect of the natural world on attraction and reason and exploitation. How about children? How much time today do children spend out of doors having contact with nature?

KELLERT: Well, there has been a profound change in this regard, and the average child today spends 52 hours in an average week engaged in electronic media of one sort or another, whether it be television or computer or games. And in an average week, less than 40 minutes outside. And, you know, I'm not - this is not to say that electronic media is bad.

Again, it's a balance. And the experience of the out of doors for children is a richly stimulating one. It's the most information-rich stimulating environment that children will ever encounter and will continue to be integral to their, you know, healthy physical and mental maturation.

LYDEN: Stephen Kellert. He is professor emeritus and senior research scholar at the School of Forestry and Environmental Studies at Yale and the author of his new book "Birthright: People in Nature and the Modern World." It's been a great pleasure. Thank you.

KELLERT: You're welcome, Jacki. Transcript provided by NPR, Copyright NPR.