Saturday, January 03, 2009

Footprint of the Fittest - On Cultural Evolution

Very cool article/review of The Dominant Animal by Paul and Anne Ehrlich. It's interesting to look at the differences and similarities between ourselves and our primate cousins to get a glimpse of how we may have evolved as a species. This is a book certain to be on wish list at Amazon.

Can we identify how cultures evolve — and if so, can we change our collective course for the good of the planet?

In 2005 Paul Ehrlich, along with Donald Kennedy, editor-in-chief of Science, proposed that the nations of the world launch a Millennium Assessment of Human Behavior, a project intended to emphasize that changing our behavior, our "individual motives and values," is as pivotal for long-term sustainability as tallying carbon levels and degrees of temperature rise. Ehrlich and Kennedy noted a striking disconnect between the scientific recommendations most of us can dutifully recite — arrest population growth, curb greenhouse-gas emissions, limit consumption — and the measures that we are willing to adopt in our day-to-day lives (and that our politicians are willing to endorse, perhaps especially in an election year). How, they asked, might human cultures evolve to permit the kinds of behavioral changes that bootstrap a sustainable and equitable global society?

A long view of cultural evolution reveals that an edgy coexistence between people and place has shaped our species right from the start. Early humans, since the time of the great "lineage split" from our ape-like ancestors about 6 million years ago, lived off the land. In small groups they gath- ered plants, nuts, and tubers, and later hunted game. People continuously altered their environments — all animals do, from beavers to bonobos — but the pace picked up greatly at the advent of agriculture. From 10,000 years ago on, coexistence shifted toward control. More species, indeed more of the world, came under the human power to reshape, and increasingly, to harm. In The Dominant Animal, Paul and Anne Ehrlich trace this evolutionary trajectory and consider the problems that today beleaguer us, "a small-group animal striving to live in a gigantic global civilization."

Alpha male and female of contemporary science (he a member of the National Academy of Sciences, she of the American Academy of Arts and Sciences, both at Stanford University), the Ehrlichs convey a message at once chilling and hopeful. Their overarching theme is environmental, about the planetary peril we face: Our closest primate relatives, the apes, are heading straight for extinction. Within a few decades, the world's seas will be devoid of harvestable wild fish. Worldwide, malnutrition contributes to the deaths of 6 million children every year.

The Ehrlichs' point of departure is in how they frame these familiar facts, enabling us to understand our current predicament as the result of a dynamic interplay among genes, culture, and environment — an environment humans not only adapt to, but simultaneously help to shape. "It was genetic evolution that produced brilliant, behaviorally flexible, highly social apes —  ourselves," they point out. But "it was cultural evolution, building on those accomplishments, that determined most aspects of our environment-building behavior." Not even the genetic part is straightforward. Natural selection rarely influences "just one thing," and genes "aren't quite the discrete entities once thought." The Ehrlichs' sophistication in genetics, combined with their recognition of the complex and contingent forces of cultural evolution (learning and information sharing not passed along genetically) provides a welcome contrast to gene-based claims of evolutionary psychology, a field that excitably anoints past selection pressures with the power to explain all kinds of modern human behavior. The Ehrlichs note dryly just how "unlikely" it is that behaviors like rape or "seeking spouses with big bank accounts" are the direct result of natural selection, as evolutionary psychologists claim. They suggest instead that emergent complexity — the unfolding of patterns that are unpredictable from the properties of their components — will offer more-nuanced explanations, given that it spans both biological and cultural evolution.

If most books on evolution underplay the power of culture and the reciprocity of geneenvironment interactions, most books on the environment — including the recent raft of cli- mate-change press — take little note of evolutionary principles. Why, for instance, aren't more of us scared to death about melting ice sheets and dying frogs, and doing something about them? Because, say the Ehrlichs, our brand of ape has evolved to attend keenly to sudden changes in our environment. A person's rapid response to a greedy predator loping toward her group earned immediate payoffs in the past, in a way that attending to long-term shifts never did. "The most serious threats now faced by humanity are slow, deleterious changes in the environmental background itself, changes our perceptual systems have evolved to encourage us to ignore." Here is grist for an applied-anthropology mill: If we can grasp a species-wide perceptual tendency, we can battle against its ill effects in a bid for what the Ehrlichs call "conscious evolution."

On the heels of theory, the authors provide a broad suite of solutions to environmental problems. They cover familiar territory like carbon taxes and capand- trade agreements but also address fresher ideas about "natural capital" — that is, agricultural soils, groundwater, and biodiversity — and new efforts to recognize the economic value of goods long assumed to be free. Our attempts to rescue biodiversity, the Ehrlichs insist, must go beyond an obsession with endangered species. It's at the population level, after all, that plants and animals deliver to us so-called "ecosystem services," things like freshwater, flood control, and natural pest control.

The big ideas and the tenor of The Dominant Animal are right on. The book rejects starry-eyed insistence on new technology as humankind's savior in favor of socially responsible, if admittedly difficult-to-enact, prescriptions. But the Ehrlichs leave us with an odd disconnect. Now and again they touch on the idea of conscious evolution, bringing home their message that our species is poorly equipped to handle non-linearities and long lag times. They fail, however, to address the questions that naturally follow. Do our evolved tendencies to ignore gradual change undercut any chances for real success of the proposed solutions? Must we, in effect, trick ourselves by attaching something with immediacy — like money — to our environmental resolutions, or is it possible as cultured, information-sharing creatures to recalibrate our own sense of "crisis" in a more fundamental way?

Also disappointing, from an anthropologist's perspective, is the authors' underestimation of the cognitive abilities of our primate relatives. The book reduces tool-making, symbol-using and theory-of-mind-equipped chimpanzees, bonobos, and gorillas to "speechless and illiterate apes whose only tools are sticks and rocks." And the authors readily accept the Great Leap Forward, a hypothesized event 50,000 years ago that caused the "explosion" of technology and shell, bead, and ivory objects, and thus "one of the most dramatic and abrupt" transformations in human history. But solid evidence points to a much more gradual series of technological and aesthetic changes. At the South African cave of Blombos, for example, Homo sapiens 75,000 years ago shaped bone tools, inscribed ochre, and crafted personal ornamentation from perforated mollusk shells.

The irony, then, is clear. The behavioral and symbolic complexities of human life evolved gradually — even more gradually than the Ehrlichs credit. Yet we are the species of unprecedented cultural transformation, and it's urgent that we ramp up that kind of transformation now. The Ehrlichs are not na├»ve; they know that today's dominant economic forces push strongly in the opposite direction, and that even the most complete picture of our evolutionary legacy cannot alone prepare us for our future. Nonetheless, we somehow need to sense and respond to the growing environmental danger as if it were a hungry predator bearing down on our family — and to understand that it's our own behaviors, chosen moment by moment and population by population, that will best shift the course ahead. Great leap forward, anyone?

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