Like many movements that started out on grassroots power, conservation has become big business. Virtually every branch of government has its own officials charged with looking after the health of plants, animals, and entire ecosystems. Nonprofit groups with conservation missions flourish. Universities have devoted increased attention to departments focusing on environmental studies, environmental ethics, and the relations of humans to their surroundings.

In the rush to establish conservation institutions the question Why conserve? is often overlooked. Many Americans view the preservation of wild animals and wild places as an inherent good. Rush Limbaugh sees conservation for conservation’s sake as a threat to the American way of life. Positions on both sides have hardened.

Among the most effective arguments for the conservation of animals and landscapes have been the purely economic or utilitarian. For example, the thousands of birdwatchers who flock to see bald eagles wintering on the Mississippi each year provide a significant economic boost to riverfront towns in Illinois, Iowa, and Missouri. Reintroducing wild turkeys to woodlands across the country has raised a great deal of money in hunting fees. And so on. But the problem with such economic arguments is that they have no moral weight. And besides, economic arguments have probably been used most often against conservation.

Wilderness philosophers like Henry David Thoreau, John Muir, and Aldo Leopold long championed the preservation of wild places on less tangible grounds. But their eloquent defense of the spiritual salve provided by untrammeled nature has often been dismissed as overly sentimental–at least by those more interested in economics.

In 1984 Harvard biologist Edward O. Wilson attempted to explain human interest in conservation with Biophilia, a slender volume in which he defined the term he’d coined for his title as “the innate [human] tendency to focus on life and lifelike processes . . . . Life of any kind is infinitely more interesting than almost any conceivable variety of inanimate matter.” He suggested that humans have an inborn affinity for nature–an affinity that transcends culture and isn’t tied to any direct exposure to wild animals or “natural” landscapes. Having wild animals and landscapes around, he claimed, is vital for our well-being.

Wilson’s impeccable hard-science credentials made it difficult for critics to label him a sentimentalist. But he still saw the need for an in-depth, critical look at his idea. A new book, The Biophilia Hypothesis–a collection of essays edited by Wilson and Stephen Kellert, a Yale professor who has extensively studied human perceptions of the environment–is an effort by researchers in a variety of fields to lend some credence to what was essentially one scientist’s manifesto.

The contributors come from a variety of academic disciplines, though all seem to be biophiliacs who lean strongly toward believing in an inborn link between people and nature. Nature tugs at them, and they’ve set out to support the idea that it tugs at all of us. Their activist agenda fuels the book, whose goal is to provide a psychological rationale for the preservation of wild animals and landscapes.

Kellert phrases the hypothesis this way: “Human identity and personal fulfillment somehow depend on our relationship to nature. The human need for nature is linked not just to the material exploitation of the environment but also to the influence of the natural world on our emotional, cognitive, aesthetic, and even spiritual development. Even the tendency to avoid, reject, and, at times, destroy elements of the natural world can be viewed as an extension of an innate need to relate deeply and intimately with the vast spectrum of life about us.”

Much of the research the contributors cite or have carried out supports this idea (unfortunately, most of it is described in turgid, soulless academic prose). Consider the aesthetics of landscape. Real estate prices in the leafy suburbs of the North Shore make it clear that members of our society value the presence of large shade trees, grassy lawns, and bodies of water. In recent years psychologists in North America, Europe, and Asia have tried to establish whether such affinities are culturally learned or genetically inherent, using tests in which subjects are shown slides of different urban and natural settings and asked which scenes they prefer. Test subjects from a wide range of cultures have preferred scenes that depict open parklike settings, a scattering of large trees, and bodies of water. Other tests aimed at detecting “biophobia” have found equally strong degrees of dislike for snakes, spiders, and extremely dense, cramped forest settings with no view of the distance.

Most of the contributors to this volume believe that these likes and dislikes are genetically inherited, not culturally taught. Humans evolved on the savannas of east Africa, their argument goes, in a parklike setting that had a number of survival advantages. Open spaces allowed humans to see dangerous predators, such as lions and other large cats, at a distance; predators could hide too easily in close, cramped places. Groves of scattered trees with low branches presented an escape route if a predator attacked; they also provided shade. Places with water were desirable because they generally supported a good supply of food plants and animals. And those humans who reacted fastest to the presence of a poisonous snake or spider were most likely to survive.

Psychologist Judith H. Heerwagen and zoologist Gordon H. Orians elaborate further in their essay. They asked test subjects to rank their responses to photographs of trees with different shapes. Subjects preferred trees that had low branches and spreading canopies–trees that are easy to climb and offer maximum protection from sun and rain, according to the authors. “Although flowers, grazing deer, and climbable trees are no longer as crucial to survival as they once were, our emotional attachment to these amenities has persisted across the gulf of time and space that now separates us from our hunting and gathering ancestors.”

Various studies have also explored the human affinity with animals, including one in which people who had difficulty in social situations, such as autistic or hyperactive children, were exposed to pets or captive animals. After the contact the test subjects were better able to concentrate and more relaxed and more sociable–which will come as no surprise to anyone who’s walked a dog in a park and seen how a friendly animal increases the chances of meeting people.

Animals fit into the hypothesis, the biophiliacs say, because so often they were prey (deer or antelope) or predators (lions). The presence of large predators also could have suggested the presence of other prey animals. “Using social intelligence to make inferences about the environment facilitated hunting, gathering, avoidance of predators, and prediction of weather,” write Aaron Katcher and Gregory Wilkins, who go on to make a broader claim about the role animals came to play. “At some time, however, the animals became more than sentient. They were adopted into human society . . . . Animals became a mirror reflecting the human social world . . . . Creating a kinship with animals did more than illuminate the complexity of human social relationships, however; it made the world a more comfortable place by reducing human isolation.”

The French philosopher Rousseau claimed that language began with the creation of metaphors about animals. Kellert claims here that “animals constitute more than 90 percent of the characters employed in language acquisition and counting in children’s preschool books.” The technological artifacts that have come to dominate much of human life–cars, TV dinners, Nintendo–haven’t been around long enough to claim hold of our subconscious, let alone our genes, says Kellert.

A number of criticisms can be leveled at this sort of research. For starters, it’s extremely difficult to distinguish between the genetic and cultural influences that affect our likes and dislikes. Western cultural norms have spread so widely through the world that it’s hard to find places where a spacious, manicured lawn and large shade trees aren’t considered pleasant status symbols. Indeed, these comfortable surroundings have been installed in many places where they make no ecological sense, such as Phoenix, where they waste a great deal of valuable desert water.

To their credit, the book’s editors have included several essays that raise objections to the basic hypothesis. Jared Diamond, an animal physiologist who has worked extensively with the indigenous peoples of New Guinea, points out that forest dwellers there appear to have no genetic predilection for savanna environments. They feel at home in the densest rain forest, where their ancestors have lived for millennia. But this criticism may simply suggest that New Guineans have been in one place long enough to evolve different likes and dislikes based on their particular environment. It would be interesting to test the affinities of other peoples for savanna landscapes–the Inuit, say, who’ve lived on treeless Arctic tundra for many generations.

Wilson’s central hypothesis–that humans feel a unique affinity with living things–also comes under fire. Biologist Madhav Gadgil relates how his son loved playing with frogs, lizards, birds, and other animals–until he discovered his father’s personal computer. “Soon he was hooked on the world of artifacts, in part at the cost of his fascination for the natural world,” Gadgil concludes, accurately reflecting the current state of society. He suggests that humans may have a natural interest in any complex item, whether it’s another person, an animal, a scenic landscape, a computer, or a monster truck. Life in itself may not be inherently more interesting than nonliving things.

Most of the contributors argue that biophilia provides a strong selfish rationale for conservation: we have an emotional need to be exposed to wild animals and landscapes. But one problem with using this hypothesis as an argument for conservation is that it splits the world into places we inherently like and those we dislike. Tropical rain forests may be extremely important from a strictly ecological perspective, but if a majority of the world’s people have an inborn aversion to close, cramped places it may be extremely difficult to muster much public support for protecting them. (Conversely, the popularity of savanna-restoration projects around Chicago might be ascribed partly to the subconscious appeal of that kind of landscape.)

One of the book’s most insightful essays comes from Dorion Sagan and Lynn Margulis, a biochemist who’s one of the primary proponents of the “Gaia hypothesis,” which posits that the organisms living on earth have adapted the environment to themselves as much as they’ve adapted themselves to the environment. In other words, living organisms have always changed their environment to suit their needs. Seen in this light, the alterations humans are making to landscapes and ecosystems aren’t necessarily bad. Rats, cockroaches, and dandelions are all testimony that we couldn’t wipe out all life on earth even if we tried. “So let us cut through the salvationist hyperbole,” Sagan and Margulis write, “and see that talk of saving the world really means saving that part of the planetary environment which has traditionally and comfortably supported human beings.”

Throughout most of human existence that traditional and comfortable support has come largely from the wild nature surrounding us. What’s new is how fully we’ve replaced wild settings with manicured lawns, shopping malls, and other environments where nature is rigorously controlled. In doing so we have wreaked havoc on many aspects of nature, including large wild animals and unspoiled landscapes, that have lent us physical, aesthetic, even spiritual support.

In one of the book’s concluding essays David Orr (not the county clerk, but the chairman of the environmental studies department at Oberlin College) cites the work of anthropologist Colin Turnbull, who worked with the Ik tribe of Uganda. When tribal members were forcibly moved from their homeland they lost all ties to the natural world and became “utterly loveless, cruel, and despicable.” If relations in our society are often violent, perhaps they echo our toward nature.

Orr claims that a life removed from wild nature is simply not as good as a life surrounded by nature. “Biophobia is not OK for the same reason that misanthropy or sociopathy are not OK,” he writes. “We recognize these aberrations as the result of deformed childhoods that create unloving and often violent adults. Biophobia in all its forms shrinks the range of experience and joys in life in the same way that the inability to achieve close and loving relationships limits a human life.

Later he writes, “We have good reason to believe that the sense of awe toward the creation had a great deal to do with the origin of language and why early hominids wanted to talk, sing, and write poetry in the first place. I think it is impossible to unravel natural diversity without undermining human intelligence as well.”

Orr is treading in the footsteps of Thoreau and Muir and Leopold, who knew in their bones that contact with nature was good for them. They believed that when humans have too little exposure to nature, something is missing in their lives. Ultimately this remains a matter of belief that all the academic firepower mustered in The Biophilia Hypothesis can’t prove by any purely rational standard. Yet the reader comes away with the idea that this belief is in itself a measure of our humanity.

The Biophilia Hypothesis, edited by Stephen R. Kellert and Edward O. Wilson, Island Press, $27.50.

Art accompanying story in printed newspaper (not available in this archive): illustration/Patti Green.