Monday, March 05, 2007

Persistence of Religion

March 4, 2007

Darwin’s God

God has always been a puzzle for Scott Atran. When he was 10 years old, he scrawled a plaintive message on the wall of his bedroom in Baltimore. “God exists,” he wrote in black and orange paint, “or if he doesn’t, we’re in trouble.” Atran has been struggling with questions about religion ever since — why he himself no longer believes in God and why so many other people, everywhere in the world, apparently do.

Call it God; call it superstition; call it, as Atran does, “belief in hope beyond reason” — whatever you call it, there seems an inherent human drive to believe in something transcendent, unfathomable and otherworldly, something beyond the reach or understanding of science. “Why do we cross our fingers during turbulence, even the most atheistic among us?” asked Atran when we spoke at his Upper West Side pied-à-terre in January. Atran, who is 55, is an anthropologist at the National Center for Scientific Research in Paris, with joint appointments at the University of Michigan and the John Jay College of Criminal Justice in New York. His research interests include cognitive science and evolutionary biology, and sometimes he presents students with a wooden box that he pretends is an African relic. “If you have negative sentiments toward religion,” he tells them, “the box will destroy whatever you put inside it.” Many of his students say they doubt the existence of God, but in this demonstration they act as if they believe in something. Put your pencil into the magic box, he tells them, and the nonbelievers do so blithely. Put in your driver’s license, he says, and most do, but only after significant hesitation. And when he tells them to put in their hands, few will.

If they don’t believe in God, what exactly are they afraid of?

Atran first conducted the magic-box demonstration in the 1980s, when he was at Cambridge University studying the nature of religious belief. He had received a doctorate in anthropology from Columbia University and, in the course of his fieldwork, saw evidence of religion everywhere he looked — at archaeological digs in Israel, among the Mayans in Guatemala, in artifact drawers at the American Museum of Natural History in New York. Atran is Darwinian in his approach, which means he tries to explain behavior by how it might once have solved problems of survival and reproduction for our early ancestors. But it was not clear to him what evolutionary problems might have been solved by religious belief. Religion seemed to use up physical and mental resources without an obvious benefit for survival. Why, he wondered, was religion so pervasive, when it was something that seemed so costly from an evolutionary point of view?

The magic-box demonstration helped set Atran on a career studying why humans might have evolved to be religious, something few people were doing back in the ’80s. Today, the effort has gained momentum, as scientists search for an evolutionary explanation for why belief in God exists — not whether God exists, which is a matter for philosophers and theologians, but why the belief does.

This is different from the scientific assault on religion that has been garnering attention recently, in the form of best-selling books from scientific atheists who see religion as a scourge. In “The God Delusion,” published last year and still on best-seller lists, the Oxford evolutionary biologist Richard Dawkins concludes that religion is nothing more than a useless, and sometimes dangerous, evolutionary accident. “Religious behavior may be a misfiring, an unfortunate byproduct of an underlying psychological propensity which in other circumstances is, or once was, useful,” Dawkins wrote. He is joined by two other best-selling authors — Sam Harris, who wrote “The End of Faith,” and Daniel Dennett, a philosopher at Tufts University who wrote “Breaking the Spell.” The three men differ in their personal styles and whether they are engaged in a battle against religiosity, but their names are often mentioned together. They have been portrayed as an unholy trinity of neo-atheists, promoting their secular world view with a fervor that seems almost evangelical.

Lost in the hullabaloo over the neo-atheists is a quieter and potentially more illuminating debate. It is taking place not between science and religion but within science itself, specifically among the scientists studying the evolution of religion. These scholars tend to agree on one point: that religious belief is an outgrowth of brain architecture that evolved during early human history. What they disagree about is why a tendency to believe evolved, whether it was because belief itself was adaptive or because it was just an evolutionary byproduct, a mere consequence of some other adaptation in the evolution of the human brain.

Which is the better biological explanation for a belief in God — evolutionary adaptation or neurological accident? Is there something about the cognitive functioning of humans that makes us receptive to belief in a supernatural deity? And if scientists are able to explain God, what then? Is explaining religion the same thing as explaining it away? Are the nonbelievers right, and is religion at its core an empty undertaking, a misdirection, a vestigial artifact of a primitive mind? Or are the believers right, and does the fact that we have the mental capacities for discerning God suggest that it was God who put them there?

In short, are we hard-wired to believe in God? And if we are, how and why did that happen?

“All of our raptures and our drynesses, our longings and pantings, our questions and beliefs . . . are equally organically founded,” William James wrote in “The Varieties of Religious Experience.” James, who taught philosophy and experimental psychology at Harvard for more than 30 years, based his book on a 1901 lecture series in which he took some early tentative steps at breaching the science-religion divide.

In the century that followed, a polite convention generally separated science and religion, at least in much of the Western world. Science, as the old trope had it, was assigned the territory that describes how the heavens go; religion, how to go to heaven.

Anthropologists like Atran and psychologists as far back as James had been looking at the roots of religion, but the mutual hands-off policy really began to shift in the 1990s. Religion made incursions into the traditional domain of science with attempts to bring intelligent design into the biology classroom and to choke off human embryonic stem-cell research on religious grounds. Scientists responded with counterincursions. Experts from the hard sciences, like evolutionary biology and cognitive neuroscience, joined anthropologists and psychologists in the study of religion, making God an object of scientific inquiry.

The debate over why belief evolved is between byproduct theorists and adaptationists. You might think that the byproduct theorists would tend to be nonbelievers, looking for a way to explain religion as a fluke, while the adaptationists would be more likely to be believers who can intuit the emotional, spiritual and community advantages that accompany faith. Or you might think they would all be atheists, because what believer would want to subject his own devotion to rationalism’s cold, hard scrutiny? But a scientist’s personal religious view does not always predict which side he will take. And this is just one sign of how complex and surprising this debate has become.

Angels, demons, spirits, wizards, gods and witches have peppered folk religions since mankind first started telling stories. Charles Darwin noted this in “The Descent of Man.” “A belief in all-pervading spiritual agencies,” he wrote, “seems to be universal.” According to anthropologists, religions that share certain supernatural features — belief in a noncorporeal God or gods, belief in the afterlife, belief in the ability of prayer or ritual to change the course of human events — are found in virtually every culture on earth.

This is certainly true in the United States. About 6 in 10 Americans, according to a 2005 Harris Poll, believe in the devil and hell, and about 7 in 10 believe in angels, heaven and the existence of miracles and of life after death. A 2006 survey at Baylor University found that 92 percent of respondents believe in a personal God — that is, a God with a distinct set of character traits ranging from “distant” to “benevolent.”

When a trait is universal, evolutionary biologists look for a genetic explanation and wonder how that gene or genes might enhance survival or reproductive success. In many ways, it’s an exercise in post-hoc hypothesizing: what would have been the advantage, when the human species first evolved, for an individual who happened to have a mutation that led to, say, a smaller jaw, a bigger forehead, a better thumb? How about certain behavioral traits, like a tendency for risk-taking or for kindness?

Atran saw such questions as a puzzle when applied to religion. So many aspects of religious belief involve misattribution and misunderstanding of the real world. Wouldn’t this be a liability in the survival-of-the-fittest competition? To Atran, religious belief requires taking “what is materially false to be true” and “what is materially true to be false.” One example of this is the belief that even after someone dies and the body demonstrably disintegrates, that person will still exist, will still be able to laugh and cry, to feel pain and joy. This confusion “does not appear to be a reasonable evolutionary strategy,” Atran wrote in “In Gods We Trust: The Evolutionary Landscape of Religion” in 2002. “Imagine another animal that took injury for health or big for small or fast for slow or dead for alive. It’s unlikely that such a species could survive.” He began to look for a sideways explanation: if religious belief was not adaptive, perhaps it was associated with something else that was.

Atran intended to study mathematics when he entered Columbia as a precocious 17-year-old. But he was distracted by the radical politics of the late ’60s. One day in his freshman year, he found himself at an antiwar rally listening to Margaret Mead, then perhaps the most famous anthropologist in America. Atran, dressed in a flamboyant Uncle Sam suit, stood up and called her a sellout for saying the protesters should be writing to their congressmen instead of staging demonstrations. “Young man,” the unflappable Mead said, “why don’t you come see me in my office?”

Atran, equally unflappable, did go to see her — and ended up working for Mead, spending much of his time exploring the cabinets of curiosities in her tower office at the American Museum of Natural History. Soon he switched his major to anthropology.

Many of the museum specimens were religious, Atran says. So were the artifacts he dug up on archaeological excursions in Israel in the early ’70s. Wherever he turned, he encountered the passion of religious belief. Why, he wondered, did people work so hard against their preference for logical explanations to maintain two views of the world, the real and the unreal, the intuitive and the counterintuitive?

Maybe cognitive effort was precisely the point. Maybe it took less mental work than Atran realized to hold belief in God in one’s mind. Maybe, in fact, belief was the default position for the human mind, something that took no cognitive effort at all.

While still an undergraduate, Atran decided to explore these questions by organizing a conference on universal aspects of culture and inviting all his intellectual heroes: the linguist Noam Chomsky, the psychologist Jean Piaget, the anthropologists Claude Levi-Strauss and Gregory Bateson (who was also Margaret Mead’s ex-husband), the Nobel Prize-winning biologists Jacques Monod and Francois Jacob. It was 1974, and the only site he could find for the conference was at a location just outside Paris. Atran was a scraggly 22-year-old with a guitar who had learned his French from comic books. To his astonishment, everyone he invited agreed to come.

Atran is a sociable man with sharp hazel eyes, who sparks provocative conversations the way other men pick bar fights. As he traveled in the ’70s and ’80s, he accumulated friends who were thinking about the issues he was: how culture is transmitted among human groups and what evolutionary function it might serve. “I started looking at history, and I wondered why no society ever survived more than three generations without a religious foundation as its raison d’être,” he says. Soon he turned to an emerging subset of evolutionary theory — the evolution of human cognition.

Some cognitive scientists think of brain functioning in terms of modules, a series of interconnected machines, each one responsible for a particular mental trick. They do not tend to talk about a God module per se; they usually consider belief in God a consequence of other mental modules.

Religion, in this view, is “a family of cognitive phenomena that involves the extraordinary use of everyday cognitive processes,” Atran wrote in “In Gods We Trust.” “Religions do not exist apart from the individual minds that constitute them and the environments that constrain them, any more than biological species and varieties exist independently of the individual organisms that compose them and the environments that conform them.”

At around the time “In Gods We Trust” appeared five years ago, a handful of other scientists — Pascal Boyer, now at Washington University; Justin Barrett, now at Oxford; Paul Bloom at Yale — were addressing these same questions. In synchrony they were moving toward the byproduct theory.

Darwinians who study physical evolution distinguish between traits that are themselves adaptive, like having blood cells that can transport oxygen, and traits that are byproducts of adaptations, like the redness of blood. There is no survival advantage to blood’s being red instead of turquoise; it is just a byproduct of the trait that is adaptive, having blood that contains hemoglobin.

Something similar explains aspects of brain evolution, too, say the byproduct theorists. Which brings us to the idea of the spandrel.

Stephen Jay Gould, the famed evolutionary biologist at Harvard who died in 2002, and his colleague Richard Lewontin proposed “spandrel” to describe a trait that has no adaptive value of its own. They borrowed the term from architecture, where it originally referred to the V-shaped structure formed between two rounded arches. The structure is not there for any purpose; it is there because that is what happens when arches align.

In architecture, a spandrel can be neutral or it can be made functional. Building a staircase, for instance, creates a space underneath that is innocuous, just a blank sort of triangle. But if you put a closet there, the under-stairs space takes on a function, unrelated to the staircase’s but useful nonetheless. Either way, functional or nonfunctional, the space under the stairs is a spandrel, an unintended byproduct.

“Natural selection made the human brain big,” Gould wrote, “but most of our mental properties and potentials may be spandrels — that is, nonadaptive side consequences of building a device with such structural complexity.”

The possibility that God could be a spandrel offered Atran a new way of understanding the evolution of religion. But a spandrel of what, exactly?

Hardships of early human life favored the evolution of certain cognitive tools, among them the ability to infer the presence of organisms that might do harm, to come up with causal narratives for natural events and to recognize that other people have minds of their own with their own beliefs, desires and intentions. Psychologists call these tools, respectively, agent detection, causal reasoning and theory of mind.

Agent detection evolved because assuming the presence of an agent — which is jargon for any creature with volitional, independent behavior — is more adaptive than assuming its absence. If you are a caveman on the savannah, you are better off presuming that the motion you detect out of the corner of your eye is an agent and something to run from, even if you are wrong. If it turns out to have been just the rustling of leaves, you are still alive; if what you took to be leaves rustling was really a hyena about to pounce, you are dead.

A classic experiment from the 1940s by the psychologists Fritz Heider and Marianne Simmel suggested that imputing agency is so automatic that people may do it even for geometric shapes. For the experiment, subjects watched a film of triangles and circles moving around. When asked what they had been watching, the subjects used words like “chase” and “capture.” They did not just see the random movement of shapes on a screen; they saw pursuit, planning, escape.

So if there is motion just out of our line of sight, we presume it is caused by an agent, an animal or person with the ability to move independently. This usually operates in one direction only; lots of people mistake a rock for a bear, but almost no one mistakes a bear for a rock.

What does this mean for belief in the supernatural? It means our brains are primed for it, ready to presume the presence of agents even when such presence confounds logic. “The most central concepts in religions are related to agents,” Justin Barrett, a psychologist, wrote in his 2004 summary of the byproduct theory, “Why Would Anyone Believe in God?” Religious agents are often supernatural, he wrote, “people with superpowers, statues that can answer requests or disembodied minds that can act on us and the world.”

A second mental module that primes us for religion is causal reasoning. The human brain has evolved the capacity to impose a narrative, complete with chronology and cause-and-effect logic, on whatever it encounters, no matter how apparently random. “We automatically, and often unconsciously, look for an explanation of why things happen to us,” Barrett wrote, “and ‘stuff just happens’ is no explanation. Gods, by virtue of their strange physical properties and their mysterious superpowers, make fine candidates for causes of many of these unusual events.” The ancient Greeks believed thunder was the sound of Zeus’s thunderbolt. Similarly, a contemporary woman whose cancer treatment works despite 10-to-1 odds might look for a story to explain her survival. It fits better with her causal-reasoning tool for her recovery to be a miracle, or a reward for prayer, than for it to be just a lucky roll of the dice.

A third cognitive trick is a kind of social intuition known as theory of mind. It’s an odd phrase for something so automatic, since the word “theory” suggests formality and self-consciousness. Other terms have been used for the same concept, like intentional stance and social cognition. One good alternative is the term Atran uses: folkpsychology.

Folkpsychology, as Atran and his colleagues see it, is essential to getting along in the contemporary world, just as it has been since prehistoric times. It allows us to anticipate the actions of others and to lead others to believe what we want them to believe; it is at the heart of everything from marriage to office politics to poker. People without this trait, like those with severe autism, are impaired, unable to imagine themselves in other people’s heads.

The process begins with positing the existence of minds, our own and others’, that we cannot see or feel. This leaves us open, almost instinctively, to belief in the separation of the body (the visible) and the mind (the invisible). If you can posit minds in other people that you cannot verify empirically, suggests Paul Bloom, a psychologist and the author of “Descartes’ Baby,” published in 2004, it is a short step to positing minds that do not have to be anchored to a body. And from there, he said, it is another short step to positing an immaterial soul and a transcendent God.

The traditional psychological view has been that until about age 4, children think that minds are permeable and that everyone knows whatever the child himself knows. To a young child, everyone is infallible. All other people, especially Mother and Father, are thought to have the same sort of insight as an all-knowing God.

But at a certain point in development, this changes. (Some new research suggests this might occur as early as 15 months.) The “false-belief test” is a classic experiment that highlights the boundary. Children watch a puppet show with a simple plot: John comes onstage holding a marble, puts it in Box A and walks off. Mary comes onstage, opens Box A, takes out the marble, puts it in Box B and walks off. John comes back onstage. The children are asked, Where will John look for the marble?

Very young children, or autistic children of any age, say John will look in Box B, since they know that’s where the marble is. But older children give a more sophisticated answer. They know that John never saw Mary move the marble and that as far as he is concerned it is still where he put it, in Box A. Older children have developed a theory of mind; they understand that other people sometimes have false beliefs. Even though they know that the marble is in Box B, they respond that John will look for it in Box A.

The adaptive advantage of folkpsychology is obvious. According to Atran, our ancestors needed it to survive their harsh environment, since folkpsychology allowed them to “rapidly and economically” distinguish good guys from bad guys. But how did folkpsychology — an understanding of ordinary people’s ordinary minds — allow for a belief in supernatural, omniscient minds? And if the byproduct theorists are right and these beliefs were of little use in finding food or leaving more offspring, why did they persist?

Atran ascribes the persistence to evolutionary misdirection, which, he says, happens all the time: “Evolution always produces something that works for what it works for, and then there’s no control for however else it’s used.” On a sunny weekday morning, over breakfast at a French cafe on upper Broadway, he tried to think of an analogy and grinned when he came up with an old standby: women’s breasts. Because they are associated with female hormones, he explained, full breasts indicate a woman is fertile, and the evolution of the male brain’s preference for them was a clever mating strategy. But breasts are now used for purposes unrelated to reproduction, to sell anything from deodorant to beer. “A Martian anthropologist might look at this and say, ‘Oh, yes, so these breasts must have somehow evolved to sell hygienic stuff or food to human beings,’ ” Atran said. But the Martian would, of course, be wrong. Equally wrong would be to make the same mistake about religion, thinking it must have evolved to make people behave a certain way or feel a certain allegiance.

That is what most fascinated Atran. “Why is God in there?” he wondered.

The idea of an infallible God is comfortable and familiar, something children readily accept. You can see this in the experiment Justin Barrett conducted recently — a version of the traditional false-belief test but with a religious twist. Barrett showed young children a box with a picture of crackers on the outside. What do you think is inside this box? he asked, and the children said, “Crackers.” Next he opened it and showed them that the box was filled with rocks. Then he asked two follow-up questions: What would your mother say is inside this box? And what would God say?

As earlier theory-of-mind experiments already showed, 3- and 4-year-olds tended to think Mother was infallible, and since the children knew the right answer, they assumed she would know it, too. They usually responded that Mother would say the box contained rocks. But 5- and 6-year-olds had learned that Mother, like any other person, could hold a false belief in her mind, and they tended to respond that she would be fooled by the packaging and would say, “Crackers.”

And what would God say? No matter what their age, the children, who were all Protestants, told Barrett that God would answer, “Rocks.” This was true even for the older children, who, as Barrett understood it, had developed folkpsychology and had used it when predicting a wrong response for Mother. They had learned that, in certain situations, people could be fooled — but they had also learned that there is no fooling God.

The bottom line, according to byproduct theorists, is that children are born with a tendency to believe in omniscience, invisible minds, immaterial souls — and then they grow up in cultures that fill their minds, hard-wired for belief, with specifics. It is a little like language acquisition, Paul Bloom says, with the essential difference that language is a biological adaptation and religion, in his view, is not. We are born with an innate facility for language but the specific language we learn depends on the environment in which we are raised. In much the same way, he says, we are born with an innate tendency for belief, but the specifics of what we grow up believing — whether there is one God or many, whether the soul goes to heaven or occupies another animal after death — are culturally shaped.

Whatever the specifics, certain beliefs can be found in all religions. Those that prevail, according to the byproduct theorists, are those that fit most comfortably with our mental architecture. Psychologists have shown, for instance, that people attend to, and remember, things that are unfamiliar and strange, but not so strange as to be impossible to assimilate. Ideas about God or other supernatural agents tend to fit these criteria. They are what Pascal Boyer, an anthropologist and psychologist, called “minimally counterintuitive”: weird enough to get your attention and lodge in your memory but not so weird that you reject them altogether. A tree that talks is minimally counterintuitive, and you might believe it as a supernatural agent. A tree that talks and flies and time-travels is maximally counterintuitive, and you are more likely to reject it.

Atran, along with Ara Norenzayan of the University of British Columbia, studied the idea of minimally counterintuitive agents earlier this decade. They presented college students with lists of fantastical creatures and asked them to choose the ones that seemed most “religious.” The convincingly religious agents, the students said, were not the most outlandish — not the turtle that chatters and climbs or the squealing, flowering marble — but those that were just outlandish enough: giggling seaweed, a sobbing oak, a talking horse. Giggling seaweed meets the requirement of being minimally counterintuitive, Atran wrote. So does a God who has a human personality except that he knows everything or a God who has a mind but has no body.

It is not enough for an agent to be minimally counterintuitive for it to earn a spot in people’s belief systems. An emotional component is often needed, too, if belief is to take hold. “If your emotions are involved, then that’s the time when you’re most likely to believe whatever the religion tells you to believe,” Atran says. Religions stir up emotions through their rituals — swaying, singing, bowing in unison during group prayer, sometimes working people up to a state of physical arousal that can border on frenzy. And religions gain strength during the natural heightening of emotions that occurs in times of personal crisis, when the faithful often turn to shamans or priests. The most intense personal crisis, for which religion can offer powerfully comforting answers, is when someone comes face to face with mortality.

In John Updike’s celebrated early short story “Pigeon Feathers,” 14-year-old David spends a lot of time thinking about death. He suspects that adults are lying when they say his spirit will live on after he dies. He keeps catching them in inconsistencies when he asks where exactly his soul will spend eternity. “Don’t you see,” he cries to his mother, “if when we die there’s nothing, all your sun and fields and what not are all, ah, horror? It’s just an ocean of horror.”

The story ends with David’s tiny revelation and his boundless relief. The boy gets a gun for his 15th birthday, which he uses to shoot down some pigeons that have been nesting in his grandmother’s barn. Before he buries them, he studies the dead birds’ feathers. He is amazed by their swirls of color, “designs executed, it seemed, in a controlled rapture.” And suddenly the fears that have plagued him are lifted, and with a “slipping sensation along his nerves that seemed to give the air hands, he was robed in this certainty: that the God who had lavished such craft upon these worthless birds would not destroy His whole Creation by refusing to let David live forever.”

Fear of death is an undercurrent of belief. The spirits of dead ancestors, ghosts, immortal deities, heaven and hell, the everlasting soul: the notion of spiritual existence after death is at the heart of almost every religion. According to some adaptationists, this is part of religion’s role, to help humans deal with the grim certainty of death. Believing in God and the afterlife, they say, is how we make sense of the brevity of our time on earth, how we give meaning to this brutish and short existence. Religion can offer solace to the bereaved and comfort to the frightened.

But the spandrelists counter that saying these beliefs are consolation does not mean they offered an adaptive advantage to our ancestors. “The human mind does not produce adequate comforting delusions against all situations of stress or fear,” wrote Pascal Boyer, a leading byproduct theorist, in “Religion Explained,” which came out a year before Atran’s book. “Indeed, any organism that was prone to such delusions would not survive long.”

Whether or not it is adaptive, belief in the afterlife gains power in two ways: from the intensity with which people wish it to be true and from the confirmation it seems to get from the real world. This brings us back to folkpsychology. We try to make sense of other people partly by imagining what it is like to be them, an adaptive trait that allowed our ancestors to outwit potential enemies. But when we think about being dead, we run into a cognitive wall. How can we possibly think about not thinking? “Try to fill your consciousness with the representation of no-consciousness, and you will see the impossibility of it,” the Spanish philosopher Miguel de Unamuno wrote in “Tragic Sense of Life.” “The effort to comprehend it causes the most tormenting dizziness. We cannot conceive of ourselves as not existing.”

Much easier, then, to imagine that the thinking somehow continues. This is what young children seem to do, as a study at the Florida Atlantic University demonstrated a few years ago. Jesse Bering and David Bjorklund, the psychologists who conducted the study, used finger puppets to act out the story of a mouse, hungry and lost, who is spotted by an alligator. “Well, it looks like Brown Mouse got eaten by Mr. Alligator,” the narrator says at the end. “Brown Mouse is not alive anymore.”

Afterward, Bering and Bjorklund asked their subjects, ages 4 to 12, what it meant for Brown Mouse to be “not alive anymore.” Is he still hungry? Is he still sleepy? Does he still want to go home? Most said the mouse no longer needed to eat or drink. But a large proportion, especially the younger ones, said that he still had thoughts, still loved his mother and still liked cheese. The children understood what it meant for the mouse’s body to cease to function, but many believed that something about the mouse was still alive.

“Our psychological architecture makes us think in particular ways,” says Bering, now at Queens University in Belfast, Northern Ireland. “In this study, it seems, the reason afterlife beliefs are so prevalent is that underlying them is our inability to simulate our nonexistence.”

It might be just as impossible to simulate the nonexistence of loved ones. A large part of any relationship takes place in our minds, Bering said, so it’s natural for it to continue much as before after the other person’s death. It is easy to forget that your sister is dead when you reach for the phone to call her, since your relationship was based so much on memory and imagined conversations even when she was alive. In addition, our agent-detection device sometimes confirms the sensation that the dead are still with us. The wind brushes our cheek, a spectral shape somehow looks familiar and our agent detection goes into overdrive. Dreams, too, have a way of confirming belief in the afterlife, with dead relatives appearing in dreams as if from beyond the grave, seeming very much alive.

Belief is our fallback position, according to Bering; it is our reflexive style of thought. “We have a basic psychological capacity that allows anyone to reason about unexpected natural events, to see deeper meaning where there is none,” he says. “It’s natural; it’s how our minds work.”

Intriguing as the spandrel logic might be, there is another way to think about the evolution of religion: that religion evolved because it offered survival advantages to our distant ancestors. This is where the action is in the science of God debate, with a coterie of adaptationists arguing on behalf of the primary benefits, in terms of survival advantages, of religious belief.

The trick in thinking about adaptation is that even if a trait offers no survival advantage today, it might have had one long ago. This is how Darwinians explain how certain physical characteristics persist even if they do not currently seem adaptive — by asking whether they might have helped our distant ancestors form social groups, feed themselves, find suitable mates or keep from getting killed. A facility for storing calories as fat, for instance, which is a detriment in today’s food-rich society, probably helped our ancestors survive cyclical famines.

So trying to explain the adaptiveness of religion means looking for how it might have helped early humans survive and reproduce. As some adaptationists see it, this could have worked on two levels, individual and group. Religion made people feel better, less tormented by thoughts about death, more focused on the future, more willing to take care of themselves. As William James put it, religion filled people with “a new zest which adds itself like a gift to life . . . an assurance of safety and a temper of peace and, in relation to others, a preponderance of loving affections.”

Such sentiments, some adaptationists say, made the faithful better at finding and storing food, for instance, and helped them attract better mates because of their reputations for morality, obedience and sober living. The advantage might have worked at the group level too, with religious groups outlasting others because they were more cohesive, more likely to contain individuals willing to make sacrifices for the group and more adept at sharing resources and preparing for warfare.

One of the most vocal adaptationists is David Sloan Wilson, an occasional thorn in the side of both Scott Atran and Richard Dawkins. Wilson, an evolutionary biologist at the State University of New York at Binghamton, focuses much of his argument at the group level. “Organisms are a product of natural selection,” he wrote in “Darwin’s Cathedral: Evolution, Religion, and the Nature of Society,” which came out in 2002, the same year as Atran’s book, and staked out the adaptationist view. “Through countless generations of variation and selection, [organisms] acquire properties that enable them to survive and reproduce in their environments. My purpose is to see if human groups in general, and religious groups in particular, qualify as organismic in this sense.”

Wilson’s father was Sloan Wilson, author of “The Man in the Gray Flannel Suit,” an emblem of mid-’50s suburban anomie that was turned into a film starring Gregory Peck. Sloan Wilson became a celebrity, with young women asking for his autograph, especially after his next novel, “A Summer Place,” became another blockbuster movie. The son grew up wanting to do something to make his famous father proud.

“I knew I couldn’t be a novelist,” said Wilson, who crackled with intensity during a telephone interview, “so I chose something as far as possible from literature — I chose science.” He is disarmingly honest about what motivated him: “I was very ambitious, and I wanted to make a mark.” He chose to study human evolution, he said, in part because he had some of his father’s literary leanings and the field required a novelist’s attention to human motivations, struggles and alliances — as well as a novelist’s flair for narrative.

Wilson eventually chose to study religion not because religion mattered to him personally — he was raised in a secular Protestant household and says he has long been an atheist — but because it was a lens through which to look at and revivify a branch of evolution that had fallen into disrepute. When Wilson was a graduate student at Michigan State University in the 1970s, Darwinians were critical of group selection, the idea that human groups can function as single organisms the way beehives or anthills do. So he decided to become the man who rescued this discredited idea. “I thought, Wow, defending group selection — now, that would be big,” he recalled. It wasn’t until the 1990s, he said, that he realized that “religion offered an opportunity to show that group selection was right after all.”

Dawkins once called Wilson’s defense of group selection “sheer, wanton, head-in-bag perversity.” Atran, too, has been dismissive of this approach, calling it “mind blind” for essentially ignoring the role of the brain’s mental machinery. The adaptationists “cannot in principle distinguish Marxism from monotheism, ideology from religious belief,” Atran wrote. “They cannot explain why people can be more steadfast in their commitment to admittedly counterfactual and counterintuitive beliefs — that Mary is both a mother and a virgin, and God is sentient but bodiless — than to the most politically, economically or scientifically persuasive account of the way things are or should be.”

Still, for all its controversial elements, the narrative Wilson devised about group selection and the evolution of religion is clear, perhaps a legacy of his novelist father. Begin, he says, with an imaginary flock of birds. Some birds serve as sentries, scanning the horizon for predators and calling out warnings. Having a sentry is good for the group but bad for the sentry, which is doubly harmed: by keeping watch, the sentry has less time to gather food, and by issuing a warning call, it is more likely to be spotted by the predator. So in the Darwinian struggle, the birds most likely to pass on their genes are the nonsentries. How, then, could the sentry gene survive for more than a generation or two?

To explain how a self-sacrificing gene can persist, Wilson looks to the level of the group. If there are 10 sentries in one group and none in the other, 3 or 4 of the sentries might be sacrificed. But the flock with sentries will probably outlast the flock that has no early-warning system, so the other 6 or 7 sentries will survive to pass on the genes. In other words, if the whole-group advantage outweighs the cost to any individual bird of being a sentry, then the sentry gene will prevail.

There are costs to any individual of being religious: the time and resources spent on rituals, the psychic energy devoted to following certain injunctions, the pain of some initiation rites. But in terms of intergroup struggle, according to Wilson, the costs can be outweighed by the benefits of being in a cohesive group that out-competes the others.

There is another element here too, unique to humans because it depends on language. A person’s behavior is observed not only by those in his immediate surroundings but also by anyone who can hear about it. There might be clear costs to taking on a role analogous to the sentry bird — a person who stands up to authority, for instance, risks losing his job, going to jail or getting beaten by the police — but in humans, these local costs might be outweighed by long-distance benefits. If a particular selfless trait enhances a person’s reputation, spread through the written and spoken word, it might give him an advantage in many of life’s challenges, like finding a mate. One way that reputation is enhanced is by being ostentatiously religious.

“The study of evolution is largely the study of trade-offs,” Wilson wrote in “Darwin’s Cathedral.” It might seem disadvantageous, in terms of foraging for sustenance and safety, for someone to favor religious over rationalistic explanations that would point to where the food and danger are. But in some circumstances, he wrote, “a symbolic belief system that departs from factual reality fares better.” For the individual, it might be more adaptive to have “highly sophisticated mental modules for acquiring factual knowledge and for building symbolic belief systems” than to have only one or the other, according to Wilson. For the group, it might be that a mixture of hardheaded realists and symbolically minded visionaries is most adaptive and that “what seems to be an adversarial relationship” between theists and atheists within a community is really a division of cognitive labor that “keeps social groups as a whole on an even keel.”

Even if Wilson is right that religion enhances group fitness, the question remains: Where does God come in? Why is a religious group any different from groups for which a fitness argument is never even offered — a group of fraternity brothers, say, or Yankees fans?

Richard Sosis, an anthropologist with positions at the University of Connecticut and Hebrew University of Jerusalem, has suggested a partial answer. Like many adaptationists, Sosis focuses on the way religion might be adaptive at the individual level. But even adaptations that help an individual survive can sometimes play themselves out through the group. Consider religious rituals.

“Religious and secular rituals can both promote cooperation,” Sosis wrote in American Scientist in 2004. But religious rituals “generate greater belief and commitment” because they depend on belief rather than on proof. The rituals are “beyond the possibility of examination,” he wrote, and a commitment to them is therefore emotional rather than logical — a commitment that is, in Sosis’s view, deeper and more long-lasting.

Rituals are a way of signaling a sincere commitment to the religion’s core beliefs, thereby earning loyalty from others in the group. “By donning several layers of clothing and standing out in the midday sun,” Sosis wrote, “ultraorthodox Jewish men are signaling to others: ‘Hey! Look, I’m a haredi’ — or extremely pious — ‘Jew. If you are also a member of this group, you can trust me because why else would I be dressed like this?’ ” These “signaling” rituals can grant the individual a sense of belonging and grant the group some freedom from constant and costly monitoring to ensure that their members are loyal and committed. The rituals are harsh enough to weed out the infidels, and both the group and the individual believers benefit.

In 2003, Sosis and Bradley Ruffle of Ben Gurion University in Israel sought an explanation for why Israel’s religious communes did better on average than secular communes in the wake of the economic crash of most of the country’s kibbutzim. They based their study on a standard economic game that measures cooperation. Individuals from religious communes played the game more cooperatively, while those from secular communes tended to be more selfish. It was the men who attended synagogue daily, not the religious women or the less observant men, who showed the biggest differences. To Sosis, this suggested that what mattered most was the frequent public display of devotion. These rituals, he wrote, led to greater cooperation in the religious communes, which helped them maintain their communal structure during economic hard times.

In 1997, Stephen Jay Gould wrote an essay in Natural History that called for a truce between religion and science. “The net of science covers the empirical universe,” he wrote. “The net of religion extends over questions of moral meaning and value.” Gould was emphatic about keeping the domains separate, urging “respectful discourse” and “mutual humility.” He called the demarcation “nonoverlapping magisteria” from the Latin magister, meaning “canon.”

Richard Dawkins had a history of spirited arguments with Gould, with whom he disagreed about almost everything related to the timing and focus of evolution. But he reserved some of his most venomous words for nonoverlapping magisteria. “Gould carried the art of bending over backward to positively supine lengths,” he wrote in “The God Delusion.” “Why shouldn’t we comment on God, as scientists? . . . A universe with a creative superintendent would be a very different kind of universe from one without. Why is that not a scientific matter?”

The separation, other critics said, left untapped the potential richness of letting one worldview inform the other. “Even if Gould was right that there were two domains, what religion does and what science does,” says Daniel Dennett (who, despite his neo-atheist label, is not as bluntly antireligious as Dawkins and Harris are), “that doesn’t mean science can’t study what religion does. It just means science can’t do what religion does.”

The idea that religion can be studied as a natural phenomenon might seem to require an atheistic philosophy as a starting point. Not necessarily. Even some neo-atheists aren’t entirely opposed to religion. Sam Harris practices Buddhist-inspired meditation. Daniel Dennett holds an annual Christmas sing-along, complete with hymns and carols that are not only harmonically lush but explicitly pious.

And one prominent member of the byproduct camp, Justin Barrett, is an observant Christian who believes in “an all-knowing, all-powerful, perfectly good God who brought the universe into being,” as he wrote in an e-mail message. “I believe that the purpose for people is to love God and love each other.”

At first blush, Barrett’s faith might seem confusing. How does his view of God as a byproduct of our mental architecture coexist with his Christianity? Why doesn’t the byproduct theory turn him into a skeptic?

“Christian theology teaches that people were crafted by God to be in a loving relationship with him and other people,” Barrett wrote in his e-mail message. “Why wouldn’t God, then, design us in such a way as to find belief in divinity quite natural?” Having a scientific explanation for mental phenomena does not mean we should stop believing in them, he wrote. “Suppose science produces a convincing account for why I think my wife loves me — should I then stop believing that she does?”

What can be made of atheists, then? If the evolutionary view of religion is true, they have to work hard at being atheists, to resist slipping into intrinsic habits of mind that make it easier to believe than not to believe. Atran says he faces an emotional and intellectual struggle to live without God in a nonatheist world, and he suspects that is where his little superstitions come from, his passing thought about crossing his fingers during turbulence or knocking on wood just in case. It is like an atavistic theism erupting when his guard is down. The comforts and consolations of belief are alluring even to him, he says, and probably will become more so as he gets closer to the end of his life. He fights it because he is a scientist and holds the values of rationalism higher than the values of spiritualism.

This internal push and pull between the spiritual and the rational reflects what used to be called the “God of the gaps” view of religion. The presumption was that as science was able to answer more questions about the natural world, God would be invoked to answer fewer, and religion would eventually recede. Research about the evolution of religion suggests otherwise. No matter how much science can explain, it seems, the real gap that God fills is an emptiness that our big-brained mental architecture interprets as a yearning for the supernatural. The drive to satisfy that yearning, according to both adaptationists and byproduct theorists, might be an inevitable and eternal part of what Atran calls the tragedy of human cognition.

Robin Marantz Henig, a contributing writer, has written recently for the magazine about the neurobiology of lying and about obesity.

Tuesday, February 06, 2007

Measured Inequality

Incomes and Inequality: What the Numbers Don’t Tell Us

The growing inequality in wealth and income has led many people to question whether the contemporary American economy is rigged in favor of the rich. While there is little doubt that the gap between the wealthy and everybody else has widened in recent years, the situation is not as unfair as some of the numbers seem to imply.

Much of the measured growth in income inequality has resulted from natural demographic trends. In general, there is more income inequality among older populations than among younger populations, if only because older people have had more time to experience rising or falling fortunes.

Furthermore, more-educated groups show greater income inequality than less-educated groups. Uneducated people are more likely to be clustered in a tight range of relatively low incomes. But the educated will include a greater range of highly motivated breadwinners and relaxed bohemians, and a greater range of winning and losing investors. A result is a greater variety of incomes. Since the United States is growing older and also more educated, income inequality will naturally rise.

Thomas Lemieux, professor of economics at the University of British Columbia, estimates that these demographic effects account for about three-quarters of the observed rise in income inequality for men and 69 to 95 percent of the observed rise in income inequality for women (“Increasing Residual Wage Inequality: Composition Effects, Noisy Data, or Rising Demand for Skill?” The American Economic Review, June 2006). In other words, rising income inequality is not just a result of unfairness or bad public policy.

Alan Reynolds, senior fellow at the Cato Institute, goes further in his recent book “Income and Wealth.” Mr. Reynolds argues that many measures of income inequality do not adequately account for government aid to lower-income groups. Furthermore, he says, the rich appear to be getting so much richer because of the tax-induced shifting of income from the corporate sector to the personal sector in the wake of the 1980s tax changes.

He describes the observed rise in income inequality as a statistical illusion. The consensus of professional economists is that Mr. Reynolds goes too far. The long-term trend of rising income inequality is evident in many different studies, including those of executive compensation, even if some estimates are exaggerated.

In any case, as Mr. Reynolds and others point out, income is not the only — or even the most — important measure of inequality. For instance, inequality of consumption — the difference between what the poor consume and what the rich consume — does not show a significant upward trend (Dirk Krueger and Fabrizio Perri, “Does Income Inequality Lead to Consumption Inequality?” The Review of Economic Studies, January 2006). Consumption, of course, is not an ideal indicator of well-being; a high or steady level of purchases may reflect growing debt, and the ease of buying a big-screen TV does not reflect a comparable ease in buying good health care.

Happiness, possibly the most relevant variable for a study of inequality, is also the hardest to measure. Nonetheless, inequality of happiness is usually less marked than inequality of income, at least in wealthy societies. A man earning $500,000 a year is not usually 10 times as happy as a man earning $50,000 a year. The $50,000 earner still enjoys most of the conveniences of the modern world. Even if more money makes people happier, it appears to do so at a declining rate, which places a natural check on the inequality of happiness.

Studies of personal happiness, based on questionnaires and self-reporting, indicate that the inequality of happiness is not growing over time in the United States. Furthermore, the United States has an inequality of happiness roughly comparable to that of Sweden or Denmark, two nations with strongly egalitarian reputations. (See the symposium in Journal of Happiness Studies, December 2005.) American society offers good opportunities for people to be happy, even if not everyone becomes rich.

If we look at leisure, from 1965 to 2003, less-educated groups experienced a bigger boost in free time than more-educated groups (Mark Aguiar and Erik Hurst, “Measuring Trends in Leisure: The Allocation of Time Over Five Decades,” Federal Reserve Bank of Boston Working Paper). In other words, the high earners are working hard for their money and perhaps they are having less fun.

So matters are not as bad as the critics have suggested. The dollars in our bank accounts are one measure of societal value, and it hardly seems fair that the very wealthy should receive more and more. But for the rest of us, life on the ground is not so terrible. Income and wealth inequality measures, taken alone, provide a misleadingly pessimistic picture.

The broader philosophical question is why we should worry about inequality — of any kind — much at all. Life is not a race against fellow human beings, and we should discourage people from treating it as such. Many of the rich have made the mistake of viewing their lives as a game of relative status. So why should economists promote this same zero-sum worldview? Yes, there are corporate scandals, but it remains the case that most American wealth today is produced rather than taken from other people.

What matters most is how well people are doing in absolute terms. We should continue to improve opportunities for lower-income people, but inequality as a major and chronic American problem has been overstated.

Tyler Cowen is a professor of economics at George Mason University and co-author of a blog at www.marginalrevolution.com.

Copyright 2007 The New York Times Company

Thursday, February 01, 2007

Just Keeps Truckin'

What Slowdown? February 1, 2007; Page A16

If the U.S. economy keeps growing like it is, Rodney Dangerfield is going to have to rise from the dead and file a patent claim. The expansion that gets no respect keeps cruising along -- past $70 oil, above rising interest rates, and now apparently around even the housing and auto slumps.

Yesterday's report that fourth quarter GDP rose a healthy 3.5% was merely the most recent repudiation of the media and Beltway bears who have predicted a recession in each of the past four years. The latest scare came last fall, as the decline in housing accelerated and many of Wall Street's Keynesian forecasters predicted the consumer would slump along with it. (We hope someone offered smelling salts to the economists at Goldman Sachs yesterday.)

[Chart]

To the contrary, the consumer remains confident, clocking in with a strong 4.4% spending growth rate in the quarter. Clearly the strong job market and rising wage levels are offsetting any fear among consumers that their home values have flattened or fallen. Without housing and autos, real GDP rose 5.8%.

At the same time, U.S. exports are booming, as growth elsewhere accelerates. Exports rose 10% in the quarter and a very robust 9.2% for the year, adding 1.64 percentage points to GDP growth. By the way, exports to China alone rose by more than 30% in the first 11 months of last year, even without a major change in China's policy to peg the yuan closely to the U.S. dollar. Members of Congress pounded Treasury Secretary Hank Paulson yesterday for not doing enough to get China to revalue the yuan, but maybe China's growing economy is more important for American exporters than devaluing the greenback. Just a thought.

The most bullish economists yesterday also hailed the GDP report's inflation signals, which were muted. But we're not convinced the current inflation cycle has played itself out -- not with gold back near $650 an ounce, commodities in general rising again and the dollar weak. For its part, the Federal Reserve held its target fed funds rate at 5.25% yesterday, but played inflation down the middle. "Inflation pressures seem likely to moderate over time, its statement said, but "some inflation risks remain." In other words, they have no idea.

Our own view -- which we noted at the time -- is that the Fed would have done better to keep raising rates last year. It's clear today that the economy was fundamentally healthy, and the question now is whether the Fed will decide it has no choice but to raise rates again later this year if inflation reaccelerates. We'd note that even yesterday's benign price data showed that so-called "core inflation," less food and energy, was up 2.1%. The core rate has risen by at least 2% for more than two years. Chairman Ben Bernanke may end up regretting that he hasn't run a tighter policy.

For now, though, the economy remains healthy, defying its many critics at home and abroad. As the chart above shows, growth since the Bush tax cuts passed in mid-2003 has averaged more than 3.6%, helping to drive prosperity around the world but without the U.S. getting any credit for this remarkable performance. By comparison, whenever growth reaches even 2% in Europe these days, they throw a party.

The biggest threats to this expansion aren't the trade deficit, or "global imbalances," or the savings rate, or the yuan-dollar peg, or any of the other bugbears we hear so much about. The threats are policy mistakes -- such as a tax increase or protectionism from the new Democratic Congress, or the discovery by the Fed that it still hasn't lassoed inflation expectations. Let's hope Democrats don't mess with a good thing.

URL for this article: http://online.wsj.com/article/SB117029802401294547.html
Copyright 2007 Dow Jones & Company, Inc. All Rights Reserved

Wednesday, January 31, 2007

Nutritionism

Unhappy Meals

Eat food. Not too much. Mostly plants.

That, more or less, is the short answer to the supposedly incredibly complicated and confusing question of what we humans should eat in order to be maximally healthy. I hate to give away the game right here at the beginning of a long essay, and I confess that I’m tempted to complicate matters in the interest of keeping things going for a few thousand more words. I’ll try to resist but will go ahead and add a couple more details to flesh out the advice. Like: A little meat won’t kill you, though it’s better approached as a side dish than as a main. And you’re much better off eating whole fresh foods than processed food products. That’s what I mean by the recommendation to eat “food.” Once, food was all you could eat, but today there are lots of other edible foodlike substances in the supermarket. These novel products of food science often come in packages festooned with health claims, which brings me to a related rule of thumb: if you’re concerned about your health, you should probably avoid food products that make health claims. Why? Because a health claim on a food product is a good indication that it’s not really food, and food is what you want to eat.

Uh-oh. Things are suddenly sounding a little more complicated, aren’t they? Sorry. But that’s how it goes as soon as you try to get to the bottom of the whole vexing question of food and health. Before long, a dense cloud bank of confusion moves in. Sooner or later, everything solid you thought you knew about the links between diet and health gets blown away in the gust of the latest study.

Last winter came the news that a low-fat diet, long believed to protect against breast cancer, may do no such thing — this from the monumental, federally financed Women’s Health Initiative, which has also found no link between a low-fat diet and rates of coronary disease. The year before we learned that dietary fiber might not, as we had been confidently told, help prevent colon cancer. Just last fall two prestigious studies on omega-3 fats published at the same time presented us with strikingly different conclusions. While the Institute of Medicine stated that “it is uncertain how much these omega-3s contribute to improving health” (and they might do the opposite if you get them from mercury-contaminated fish), a Harvard study declared that simply by eating a couple of servings of fish each week (or by downing enough fish oil), you could cut your risk of dying from a heart attack by more than a third — a stunningly hopeful piece of news. It’s no wonder that omega-3 fatty acids are poised to become the oat bran of 2007, as food scientists micro-encapsulate fish oil and algae oil and blast them into such formerly all-terrestrial foods as bread and tortillas, milk and yogurt and cheese, all of which will soon, you can be sure, sprout fishy new health claims. (Remember the rule?)

By now you’re probably registering the cognitive dissonance of the supermarket shopper or science-section reader, as well as some nostalgia for the simplicity and solidity of the first few sentences of this essay. Which I’m still prepared to defend against the shifting winds of nutritional science and food-industry marketing. But before I do that, it might be useful to figure out how we arrived at our present state of nutritional confusion and anxiety.

The story of how the most basic questions about what to eat ever got so complicated reveals a great deal about the institutional imperatives of the food industry, nutritional science and — ahem — journalism, three parties that stand to gain much from widespread confusion surrounding what is, after all, the most elemental question an omnivore confronts. Humans deciding what to eat without expert help — something they have been doing with notable success since coming down out of the trees — is seriously unprofitable if you’re a food company, distinctly risky if you’re a nutritionist and just plain boring if you’re a newspaper editor or journalist. (Or, for that matter, an eater. Who wants to hear, yet again, “Eat more fruits and vegetables”?) And so, like a large gray fog, a great Conspiracy of Confusion has gathered around the simplest questions of nutrition — much to the advantage of everybody involved. Except perhaps the ostensible beneficiary of all this nutritional expertise and advice: us, and our health and happiness as eaters.

FROM FOODS TO NUTRIENTS

It was in the 1980s that food began disappearing from the American supermarket, gradually to be replaced by “nutrients,” which are not the same thing. Where once the familiar names of recognizable comestibles — things like eggs or breakfast cereal or cookies — claimed pride of place on the brightly colored packages crowding the aisles, now new terms like “fiber” and “cholesterol” and “saturated fat” rose to large-type prominence. More important than mere foods, the presence or absence of these invisible substances was now generally believed to confer health benefits on their eaters. Foods by comparison were coarse, old-fashioned and decidedly unscientific things — who could say what was in them, really? But nutrients — those chemical compounds and minerals in foods that nutritionists have deemed important to health — gleamed with the promise of scientific certainty; eat more of the right ones, fewer of the wrong, and you would live longer and avoid chronic diseases.

Nutrients themselves had been around, as a concept, since the early 19th century, when the English doctor and chemist William Prout identified what came to be called the “macronutrients”: protein, fat and carbohydrates. It was thought that that was pretty much all there was going on in food, until doctors noticed that an adequate supply of the big three did not necessarily keep people nourished. At the end of the 19th century, British doctors were puzzled by the fact that Chinese laborers in the Malay states were dying of a disease called beriberi, which didn’t seem to afflict Tamils or native Malays. The mystery was solved when someone pointed out that the Chinese ate “polished,” or white, rice, while the others ate rice that hadn’t been mechanically milled. A few years later, Casimir Funk, a Polish chemist, discovered the “essential nutrient” in rice husks that protected against beriberi and called it a “vitamine,” the first micronutrient. Vitamins brought a kind of glamour to the science of nutrition, and though certain sectors of the population began to eat by its expert lights, it really wasn’t until late in the 20th century that nutrients managed to push food aside in the popular imagination of what it means to eat.

No single event marked the shift from eating food to eating nutrients, though in retrospect a little-noticed political dust-up in Washington in 1977 seems to have helped propel American food culture down this dimly lighted path. Responding to an alarming increase in chronic diseases linked to diet — including heart disease, cancer and diabetes — a Senate Select Committee on Nutrition, headed by George McGovern, held hearings on the problem and prepared what by all rights should have been an uncontroversial document called “Dietary Goals for the United States.” The committee learned that while rates of coronary heart disease had soared in America since World War II, other cultures that consumed traditional diets based largely on plants had strikingly low rates of chronic disease. Epidemiologists also had observed that in America during the war years, when meat and dairy products were strictly rationed, the rate of heart disease temporarily plummeted.

Naïvely putting two and two together, the committee drafted a straightforward set of dietary guidelines calling on Americans to cut down on red meat and dairy products. Within weeks a firestorm, emanating from the red-meat and dairy industries, engulfed the committee, and Senator McGovern (who had a great many cattle ranchers among his South Dakota constituents) was forced to beat a retreat. The committee’s recommendations were hastily rewritten. Plain talk about food — the committee had advised Americans to actually “reduce consumption of meat” — was replaced by artful compromise: “Choose meats, poultry and fish that will reduce saturated-fat intake.”

A subtle change in emphasis, you might say, but a world of difference just the same. First, the stark message to “eat less” of a particular food has been deep-sixed; don’t look for it ever again in any official U.S. dietary pronouncement. Second, notice how distinctions between entities as different as fish and beef and chicken have collapsed; those three venerable foods, each representing an entirely different taxonomic class, are now lumped together as delivery systems for a single nutrient. Notice too how the new language exonerates the foods themselves; now the culprit is an obscure, invisible, tasteless — and politically unconnected — substance that may or may not lurk in them called “saturated fat.”

The linguistic capitulation did nothing to rescue McGovern from his blunder; the very next election, in 1980, the beef lobby helped rusticate the three-term senator, sending an unmistakable warning to anyone who would challenge the American diet, and in particular the big chunk of animal protein sitting in the middle of its plate. Henceforth, government dietary guidelines would shun plain talk about whole foods, each of which has its trade association on Capitol Hill, and would instead arrive clothed in scientific euphemism and speaking of nutrients, entities that few Americans really understood but that lack powerful lobbies in Washington. This was precisely the tack taken by the National Academy of Sciences when it issued its landmark report on diet and cancer in 1982. Organized nutrient by nutrient in a way guaranteed to offend no food group, it codified the official new dietary language. Industry and media followed suit, and terms like polyunsaturated, cholesterol, monounsaturated, carbohydrate, fiber, polyphenols, amino acids and carotenes soon colonized much of the cultural space previously occupied by the tangible substance formerly known as food. The Age of Nutritionism had arrived.

THE RISE OF NUTRITIONISM

The first thing to understand about nutritionism — I first encountered the term in the work of an Australian sociologist of science named Gyorgy Scrinis — is that it is not quite the same as nutrition. As the “ism” suggests, it is not a scientific subject but an ideology. Ideologies are ways of organizing large swaths of life and experience under a set of shared but unexamined assumptions. This quality makes an ideology particularly hard to see, at least while it’s exerting its hold on your culture. A reigning ideology is a little like the weather, all pervasive and virtually inescapable. Still, we can try.

In the case of nutritionism, the widely shared but unexamined assumption is that the key to understanding food is indeed the nutrient. From this basic premise flow several others. Since nutrients, as compared with foods, are invisible and therefore slightly mysterious, it falls to the scientists (and to the journalists through whom the scientists speak) to explain the hidden reality of foods to us. To enter a world in which you dine on unseen nutrients, you need lots of expert help.

But expert help to do what, exactly? This brings us to another unexamined assumption: that the whole point of eating is to maintain and promote bodily health. Hippocrates’s famous injunction to “let food be thy medicine” is ritually invoked to support this notion. I’ll leave the premise alone for now, except to point out that it is not shared by all cultures and that the experience of these other cultures suggests that, paradoxically, viewing food as being about things other than bodily health — like pleasure, say, or socializing — makes people no less healthy; indeed, there’s some reason to believe that it may make them more healthy. This is what we usually have in mind when we speak of the “French paradox” — the fact that a population that eats all sorts of unhealthful nutrients is in many ways healthier than we Americans are. So there is at least a question as to whether nutritionism is actually any good for you.

Another potentially serious weakness of nutritionist ideology is that it has trouble discerning qualitative distinctions between foods. So fish, beef and chicken through the nutritionists’ lens become mere delivery systems for varying quantities of fats and proteins and whatever other nutrients are on their scope. Similarly, any qualitative distinctions between processed foods and whole foods disappear when your focus is on quantifying the nutrients they contain (or, more precisely, the known nutrients).

This is a great boon for manufacturers of processed food, and it helps explain why they have been so happy to get with the nutritionism program. In the years following McGovern’s capitulation and the 1982 National Academy report, the food industry set about re-engineering thousands of popular food products to contain more of the nutrients that science and government had deemed the good ones and less of the bad, and by the late ’80s a golden era of food science was upon us. The Year of Eating Oat Bran — also known as 1988 — served as a kind of coming-out party for the food scientists, who succeeded in getting the material into nearly every processed food sold in America. Oat bran’s moment on the dietary stage didn’t last long, but the pattern had been established, and every few years since then a new oat bran has taken its turn under the marketing lights. (Here comes omega-3!)

By comparison, the typical real food has more trouble competing under the rules of nutritionism, if only because something like a banana or an avocado can’t easily change its nutritional stripes (though rest assured the genetic engineers are hard at work on the problem). So far, at least, you can’t put oat bran in a banana. So depending on the reigning nutritional orthodoxy, the avocado might be either a high-fat food to be avoided (Old Think) or a food high in monounsaturated fat to be embraced (New Think). The fate of each whole food rises and falls with every change in the nutritional weather, while the processed foods are simply reformulated. That’s why when the Atkins mania hit the food industry, bread and pasta were given a quick redesign (dialing back the carbs; boosting the protein), while the poor unreconstructed potatoes and carrots were left out in the cold.

Of course it’s also a lot easier to slap a health claim on a box of sugary cereal than on a potato or carrot, with the perverse result that the most healthful foods in the supermarket sit there quietly in the produce section, silent as stroke victims, while a few aisles over, the Cocoa Puffs and Lucky Charms are screaming about their newfound whole-grain goodness.

EAT RIGHT, GET FATTER

So nutritionism is good for business. But is it good for us? You might think that a national fixation on nutrients would lead to measurable improvements in the public health. But for that to happen, the underlying nutritional science, as well as the policy recommendations (and the journalism) based on that science, would have to be sound. This has seldom been the case.

Consider what happened immediately after the 1977 “Dietary Goals” — McGovern’s masterpiece of politico-nutritionist compromise. In the wake of the panel’s recommendation that we cut down on saturated fat, a recommendation seconded by the 1982 National Academy report on cancer, Americans did indeed change their diets, endeavoring for a quarter-century to do what they had been told. Well, kind of. The industrial food supply was promptly reformulated to reflect the official advice, giving us low-fat pork, low-fat Snackwell’s and all the low-fat pasta and high-fructose (yet low-fat!) corn syrup we could consume. Which turned out to be quite a lot. Oddly, America got really fat on its new low-fat diet — indeed, many date the current obesity and diabetes epidemic to the late 1970s, when Americans began binging on carbohydrates, ostensibly as a way to avoid the evils of fat.

This story has been told before, notably in these pages (“What if It’s All Been a Big Fat Lie?” by Gary Taubes, July 7, 2002), but it’s a little more complicated than the official version suggests. In that version, which inspired the most recent Atkins craze, we were told that America got fat when, responding to bad scientific advice, it shifted its diet from fats to carbs, suggesting that a re-evaluation of the two nutrients is in order: fat doesn’t make you fat; carbs do. (Why this should have come as news is a mystery: as long as people have been raising animals for food, they have fattened them on carbs.)

But there are a couple of problems with this revisionist picture. First, while it is true that Americans post-1977 did begin binging on carbs, and that fat as a percentage of total calories in the American diet declined, we never did in fact cut down on our consumption of fat. Meat consumption actually climbed. We just heaped a bunch more carbs onto our plates, obscuring perhaps, but not replacing, the expanding chunk of animal protein squatting in the center.

How did that happen? I would submit that the ideology of nutritionism deserves as much of the blame as the carbohydrates themselves do — that and human nature. By framing dietary advice in terms of good and bad nutrients, and by burying the recommendation that we should eat less of any particular food, it was easy for the take-home message of the 1977 and 1982 dietary guidelines to be simplified as follows: Eat more low-fat foods. And that is what we did. We’re always happy to receive a dispensation to eat more of something (with the possible exception of oat bran), and one of the things nutritionism reliably gives us is some such dispensation: low-fat cookies then, low-carb beer now. It’s hard to imagine the low-fat craze taking off as it did if McGovern’s original food-based recommendations had stood: eat fewer meat and dairy products. For how do you get from that stark counsel to the idea that another case of Snackwell’s is just what the doctor ordered?

BAD SCIENCE

But if nutritionism leads to a kind of false consciousness in the mind of the eater, the ideology can just as easily mislead the scientist. Most nutritional science involves studying one nutrient at a time, an approach that even nutritionists who do it will tell you is deeply flawed. “The problem with nutrient-by-nutrient nutrition science,” points out Marion Nestle, the New York University nutritionist, “is that it takes the nutrient out of the context of food, the food out of the context of diet and the diet out of the context of lifestyle.”

If nutritional scientists know this, why do they do it anyway? Because a nutrient bias is built into the way science is done: scientists need individual variables they can isolate. Yet even the simplest food is a hopelessly complex thing to study, a virtual wilderness of chemical compounds, many of which exist in complex and dynamic relation to one another, and all of which together are in the process of changing from one state to another. So if you’re a nutritional scientist, you do the only thing you can do, given the tools at your disposal: break the thing down into its component parts and study those one by one, even if that means ignoring complex interactions and contexts, as well as the fact that the whole may be more than, or just different from, the sum of its parts. This is what we mean by reductionist science.

Scientific reductionism is an undeniably powerful tool, but it can mislead us too, especially when applied to something as complex as, on the one side, a food, and on the other, a human eater. It encourages us to take a mechanistic view of that transaction: put in this nutrient; get out that physiological result. Yet people differ in important ways. Some populations can metabolize sugars better than others; depending on your evolutionary heritage, you may or may not be able to digest the lactose in milk. The specific ecology of your intestines helps determine how efficiently you digest what you eat, so that the same input of 100 calories may yield more or less energy depending on the proportion of Firmicutes and Bacteroidetes living in your gut. There is nothing very machinelike about the human eater, and so to think of food as simply fuel is wrong.

Also, people don’t eat nutrients, they eat foods, and foods can behave very differently than the nutrients they contain. Researchers have long believed, based on epidemiological comparisons of different populations, that a diet high in fruits and vegetables confers some protection against cancer. So naturally they ask, What nutrients in those plant foods are responsible for that effect? One hypothesis is that the antioxidants in fresh produce — compounds like beta carotene, lycopene, vitamin E, etc. — are the X factor. It makes good sense: these molecules (which plants produce to protect themselves from the highly reactive oxygen atoms produced in photosynthesis) vanquish the free radicals in our bodies, which can damage DNA and initiate cancers. At least that’s how it seems to work in the test tube. Yet as soon as you remove these useful molecules from the context of the whole foods they’re found in, as we’ve done in creating antioxidant supplements, they don’t work at all. Indeed, in the case of beta carotene ingested as a supplement, scientists have discovered that it actually increases the risk of certain cancers. Big oops.

What’s going on here? We don’t know. It could be the vagaries of human digestion. Maybe the fiber (or some other component) in a carrot protects the antioxidant molecules from destruction by stomach acids early in the digestive process. Or it could be that we isolated the wrong antioxidant. Beta is just one of a whole slew of carotenes found in common vegetables; maybe we focused on the wrong one. Or maybe beta carotene works as an antioxidant only in concert with some other plant chemical or process; under other circumstances, it may behave as a pro-oxidant.

Indeed, to look at the chemical composition of any common food plant is to realize just how much complexity lurks within it. Here’s a list of just the antioxidants that have been identified in garden-variety thyme:

4-Terpineol, alanine, anethole, apigenin, ascorbic acid, beta carotene, caffeic acid, camphene, carvacrol, chlorogenic acid, chrysoeriol, eriodictyol, eugenol, ferulic acid, gallic acid, gamma-terpinene isochlorogenic acid, isoeugenol, isothymonin, kaempferol, labiatic acid, lauric acid, linalyl acetate, luteolin, methionine, myrcene, myristic acid, naringenin, oleanolic acid, p-coumoric acid, p-hydroxy-benzoic acid, palmitic acid, rosmarinic acid, selenium, tannin, thymol, tryptophan, ursolic acid, vanillic acid.

This is what you’re ingesting when you eat food flavored with thyme. Some of these chemicals are broken down by your digestion, but others are going on to do undetermined things to your body: turning some gene’s expression on or off, perhaps, or heading off a free radical before it disturbs a strand of DNA deep in some cell. It would be great to know how this all works, but in the meantime we can enjoy thyme in the knowledge that it probably doesn’t do any harm (since people have been eating it forever) and that it may actually do some good (since people have been eating it forever) and that even if it does nothing, we like the way it tastes.

It’s also important to remind ourselves that what reductive science can manage to perceive well enough to isolate and study is subject to change, and that we have a tendency to assume that what we can see is all there is to see. When William Prout isolated the big three macronutrients, scientists figured they now understood food and what the body needs from it; when the vitamins were isolated a few decades later, scientists thought, O.K., now we really understand food and what the body needs to be healthy; today it’s the polyphenols and carotenoids that seem all-important. But who knows what the hell else is going on deep in the soul of a carrot?

The good news is that, to the carrot eater, it doesn’t matter. That’s the great thing about eating food as compared with nutrients: you don’t need to fathom a carrot’s complexity to reap its benefits.

The case of the antioxidants points up the dangers in taking a nutrient out of the context of food; as Nestle suggests, scientists make a second, related error when they study the food out of the context of the diet. We don’t eat just one thing, and when we are eating any one thing, we’re not eating another. We also eat foods in combinations and in orders that can affect how they’re absorbed. Drink coffee with your steak, and your body won’t be able to fully absorb the iron in the meat. The trace of limestone in the corn tortilla unlocks essential amino acids in the corn that would otherwise remain unavailable. Some of those compounds in that sprig of thyme may well affect my digestion of the dish I add it to, helping to break down one compound or possibly stimulate production of an enzyme to detoxify another. We have barely begun to understand the relationships among foods in a cuisine.

But we do understand some of the simplest relationships, like the zero-sum relationship: that if you eat a lot of meat you’re probably not eating a lot of vegetables. This simple fact may explain why populations that eat diets high in meat have higher rates of coronary heart disease and cancer than those that don’t. Yet nutritionism encourages us to look elsewhere for the explanation: deep within the meat itself, to the culpable nutrient, which scientists have long assumed to be the saturated fat. So they are baffled when large-population studies, like the Women’s Health Initiative, fail to find that reducing fat intake significantly reduces the incidence of heart disease or cancer.

Of course thanks to the low-fat fad (inspired by the very same reductionist fat hypothesis), it is entirely possible to reduce your intake of saturated fat without significantly reducing your consumption of animal protein: just drink the low-fat milk and order the skinless chicken breast or the turkey bacon. So maybe the culprit nutrient in meat and dairy is the animal protein itself, as some researchers now hypothesize. (The Cornell nutritionist T. Colin Campbell argues as much in his recent book, “The China Study.”) Or, as the Harvard epidemiologist Walter C. Willett suggests, it could be the steroid hormones typically present in the milk and meat; these hormones (which occur naturally in meat and milk but are often augmented in industrial production) are known to promote certain cancers.

But people worried about their health needn’t wait for scientists to settle this question before deciding that it might be wise to eat more plants and less meat. This is of course precisely what the McGovern committee was trying to tell us.

Nestle also cautions against taking the diet out of the context of the lifestyle. The Mediterranean diet is widely believed to be one of the most healthful ways to eat, yet much of what we know about it is based on studies of people living on the island of Crete in the 1950s, who in many respects lived lives very different from our own. Yes, they ate lots of olive oil and little meat. But they also did more physical labor. They fasted regularly. They ate a lot of wild greens — weeds. And, perhaps most important, they consumed far fewer total calories than we do. Similarly, much of what we know about the health benefits of a vegetarian diet is based on studies of Seventh Day Adventists, who muddy the nutritional picture by drinking absolutely no alcohol and never smoking. These extraneous but unavoidable factors are called, aptly, “confounders.” One last example: People who take supplements are healthier than the population at large, but their health probably has nothing whatsoever to do with the supplements they take — which recent studies have suggested are worthless. Supplement-takers are better-educated, more-affluent people who, almost by definition, take a greater-than-normal interest in personal health — confounding factors that probably account for their superior health.

But if confounding factors of lifestyle bedevil comparative studies of different populations, the supposedly more rigorous “prospective” studies of large American populations suffer from their own arguably even more disabling flaws. In these studies — of which the Women’s Health Initiative is the best known — a large population is divided into two groups. The intervention group changes its diet in some prescribed manner, while the control group does not. The two groups are then tracked over many years to learn whether the intervention affects relative rates of chronic disease.

When it comes to studying nutrition, this sort of extensive, long-term clinical trial is supposed to be the gold standard. It certainly sounds sound. In the case of the Women’s Health Initiative, sponsored by the National Institutes of Health, the eating habits and health outcomes of nearly 49,000 women (ages 50 to 79 at the beginning of the study) were tracked for eight years. One group of the women were told to reduce their consumption of fat to 20 percent of total calories. The results were announced early last year, producing front-page headlines of which the one in this newspaper was typical: “Low-Fat Diet Does Not Cut Health Risks, Study Finds.” And the cloud of nutritional confusion over the country darkened.

But even a cursory analysis of the study’s methods makes you wonder why anyone would take such a finding seriously, let alone order a Quarter Pounder With Cheese to celebrate it, as many newspaper readers no doubt promptly went out and did. Even the beginner student of nutritionism will immediately spot several flaws: the focus was on “fat,” rather than on any particular food, like meat or dairy. So women could comply simply by switching to lower-fat animal products. Also, no distinctions were made between types of fat: women getting their allowable portion of fat from olive oil or fish were lumped together with woman getting their fat from low-fat cheese or chicken breasts or margarine. Why? Because when the study was designed 16 years ago, the whole notion of “good fats” was not yet on the scientific scope. Scientists study what scientists can see.

But perhaps the biggest flaw in this study, and other studies like it, is that we have no idea what these women were really eating because, like most people when asked about their diet, they lied about it. How do we know this? Deduction. Consider: When the study began, the average participant weighed in at 170 pounds and claimed to be eating 1,800 calories a day. It would take an unusual metabolism to maintain that weight on so little food. And it would take an even freakier metabolism to drop only one or two pounds after getting down to a diet of 1,400 to 1,500 calories a day — as the women on the “low-fat” regimen claimed to have done. Sorry, ladies, but I just don’t buy it.

In fact, nobody buys it. Even the scientists who conduct this sort of research conduct it in the knowledge that people lie about their food intake all the time. They even have scientific figures for the magnitude of the lie. Dietary trials like the Women’s Health Initiative rely on “food-frequency questionnaires,” and studies suggest that people on average eat between a fifth and a third more than they claim to on the questionnaires. How do the researchers know that? By comparing what people report on questionnaires with interviews about their dietary intake over the previous 24 hours, thought to be somewhat more reliable. In fact, the magnitude of the lie could be much greater, judging by the huge disparity between the total number of food calories produced every day for each American (3,900 calories) and the average number of those calories Americans own up to chomping: 2,000. (Waste accounts for some of the disparity, but nowhere near all of it.) All we really know about how much people actually eat is that the real number lies somewhere between those two figures.

To try to fill out the food-frequency questionnaire used by the Women’s Health Initiative, as I recently did, is to realize just how shaky the data on which such trials rely really are. The survey, which took about 45 minutes to complete, started off with some relatively easy questions: “Did you eat chicken or turkey during the last three months?” Having answered yes, I was then asked, “When you ate chicken or turkey, how often did you eat the skin?” But the survey soon became harder, as when it asked me to think back over the past three months to recall whether when I ate okra, squash or yams, they were fried, and if so, were they fried in stick margarine, tub margarine, butter, “shortening” (in which category they inexplicably lump together hydrogenated vegetable oil and lard), olive or canola oil or nonstick spray? I honestly didn’t remember, and in the case of any okra eaten in a restaurant, even a hypnotist could not get out of me what sort of fat it was fried in. In the meat section, the portion sizes specified haven’t been seen in America since the Hoover administration. If a four-ounce portion of steak is considered “medium,” was I really going to admit that the steak I enjoyed on an unrecallable number of occasions during the past three months was probably the equivalent of two or three (or, in the case of a steakhouse steak, no less than four) of these portions? I think not. In fact, most of the “medium serving sizes” to which I was asked to compare my own consumption made me feel piggish enough to want to shave a few ounces here, a few there. (I mean, I wasn’t under oath or anything, was I?)

This is the sort of data on which the largest questions of diet and health are being decided in America today.

THE ELEPHANT IN THE ROOM

In the end, the biggest, most ambitious and widely reported studies of diet and health leave more or less undisturbed the main features of the Western diet: lots of meat and processed foods, lots of added fat and sugar, lots of everything — except fruits, vegetables and whole grains. In keeping with the nutritionism paradigm and the limits of reductionist science, the researchers fiddle with single nutrients as best they can, but the populations they recruit and study are typical American eaters doing what typical American eaters do: trying to eat a little less of this nutrient, a little more of that, depending on the latest thinking. (One problem with the control groups in these studies is that they too are exposed to nutritional fads in the culture, so over time their eating habits come to more closely resemble the habits of the intervention group.) It should not surprise us that the findings of such research would be so equivocal and confusing.

But what about the elephant in the room — the Western diet? It might be useful, in the midst of our deepening confusion about nutrition, to review what we do know about diet and health. What we know is that people who eat the way we do in America today suffer much higher rates of cancer, heart disease, diabetes and obesity than people eating more traditional diets. (Four of the 10 leading killers in America are linked to diet.) Further, we know that simply by moving to America, people from nations with low rates of these “diseases of affluence” will quickly acquire them. Nutritionism by and large takes the Western diet as a given, seeking to moderate its most deleterious effects by isolating the bad nutrients in it — things like fat, sugar, salt — and encouraging the public and the food industry to limit them. But after several decades of nutrient-based health advice, rates of cancer and heart disease in the U.S. have declined only slightly (mortality from heart disease is down since the ’50s, but this is mainly because of improved treatment), and rates of obesity and diabetes have soared.

No one likes to admit that his or her best efforts at understanding and solving a problem have actually made the problem worse, but that’s exactly what has happened in the case of nutritionism. Scientists operating with the best of intentions, using the best tools at their disposal, have taught us to look at food in a way that has diminished our pleasure in eating it while doing little or nothing to improve our health. Perhaps what we need now is a broader, less reductive view of what food is, one that is at once more ecological and cultural. What would happen, for example, if we were to start thinking about food as less of a thing and more of a relationship?

In nature, that is of course precisely what eating has always been: relationships among species in what we call food chains, or webs, that reach all the way down to the soil. Species co-evolve with the other species they eat, and very often a relationship of interdependence develops: I’ll feed you if you spread around my genes. A gradual process of mutual adaptation transforms something like an apple or a squash into a nutritious and tasty food for a hungry animal. Over time and through trial and error, the plant becomes tastier (and often more conspicuous) in order to gratify the animal’s needs and desires, while the animal gradually acquires whatever digestive tools (enzymes, etc.) are needed to make optimal use of the plant. Similarly, cow’s milk did not start out as a nutritious food for humans; in fact, it made them sick until humans who lived around cows evolved the ability to digest lactose as adults. This development proved much to the advantage of both the milk drinkers and the cows.

“Health” is, among other things, the byproduct of being involved in these sorts of relationships in a food chain — involved in a great many of them, in the case of an omnivorous creature like us. Further, when the health of one link of the food chain is disturbed, it can affect all the creatures in it. When the soil is sick or in some way deficient, so will be the grasses that grow in that soil and the cattle that eat the grasses and the people who drink the milk. Or, as the English agronomist Sir Albert Howard put it in 1945 in “The Soil and Health” (a founding text of organic agriculture), we would do well to regard “the whole problem of health in soil, plant, animal and man as one great subject.” Our personal health is inextricably bound up with the health of the entire food web.

In many cases, long familiarity between foods and their eaters leads to elaborate systems of communications up and down the food chain, so that a creature’s senses come to recognize foods as suitable by taste and smell and color, and our bodies learn what to do with these foods after they pass the test of the senses, producing in anticipation the chemicals necessary to break them down. Health depends on knowing how to read these biological signals: this smells spoiled; this looks ripe; that’s one good-looking cow. This is easier to do when a creature has long experience of a food, and much harder when a food has been designed expressly to deceive its senses — with artificial flavors, say, or synthetic sweeteners.

Note that these ecological relationships are between eaters and whole foods, not nutrients. Even though the foods in question eventually get broken down in our bodies into simple nutrients, as corn is reduced to simple sugars, the qualities of the whole food are not unimportant — they govern such things as the speed at which the sugars will be released and absorbed, which we’re coming to see as critical to insulin metabolism. Put another way, our bodies have a longstanding and sustainable relationship to corn that we do not have to high-fructose corn syrup. Such a relationship with corn syrup might develop someday (as people evolve superhuman insulin systems to cope with regular floods of fructose and glucose), but for now the relationship leads to ill health because our bodies don’t know how to handle these biological novelties. In much the same way, human bodies that can cope with chewing coca leaves — a longstanding relationship between native people and the coca plant in South America — cannot cope with cocaine or crack, even though the same “active ingredients” are present in all three. Reductionism as a way of understanding food or drugs may be harmless, even necessary, but reductionism in practice can lead to problems.

Looking at eating through this ecological lens opens a whole new perspective on exactly what the Western diet is: a radical and rapid change not just in our foodstuffs over the course of the 20th century but also in our food relationships, all the way from the soil to the meal. The ideology of nutritionism is itself part of that change. To get a firmer grip on the nature of those changes is to begin to know how we might make our relationships to food healthier. These changes have been numerous and far-reaching, but consider as a start these four large-scale ones:

From Whole Foods to Refined. The case of corn points up one of the key features of the modern diet: a shift toward increasingly refined foods, especially carbohydrates. Call it applied reductionism. Humans have been refining grains since at least the Industrial Revolution, favoring white flour (and white rice) even at the price of lost nutrients. Refining grains extends their shelf life (precisely because it renders them less nutritious to pests) and makes them easier to digest, by removing the fiber that ordinarily slows the release of their sugars. Much industrial food production involves an extension and intensification of this practice, as food processors find ways to deliver glucose — the brain’s preferred fuel — ever more swiftly and efficiently. Sometimes this is precisely the point, as when corn is refined into corn syrup; other times it is an unfortunate byproduct of food processing, as when freezing food destroys the fiber that would slow sugar absorption.

So fast food is fast in this other sense too: it is to a considerable extent predigested, in effect, and therefore more readily absorbed by the body. But while the widespread acceleration of the Western diet offers us the instant gratification of sugar, in many people (and especially those newly exposed to it) the “speediness” of this food overwhelms the insulin response and leads to Type II diabetes. As one nutrition expert put it to me, we’re in the middle of “a national experiment in mainlining glucose.” To encounter such a diet for the first time, as when people accustomed to a more traditional diet come to America, or when fast food comes to their countries, delivers a shock to the system. Public-health experts call it “the nutrition transition,” and it can be deadly.

From Complexity to Simplicity. If there is one word that covers nearly all the changes industrialization has made to the food chain, it would be simplification. Chemical fertilizers simplify the chemistry of the soil, which in turn appears to simplify the chemistry of the food grown in that soil. Since the widespread adoption of synthetic nitrogen fertilizers in the 1950s, the nutritional quality of produce in America has, according to U.S.D.A. figures, declined significantly. Some researchers blame the quality of the soil for the decline; others cite the tendency of modern plant breeding to select for industrial qualities like yield rather than nutritional quality. Whichever it is, the trend toward simplification of our food continues on up the chain. Processing foods depletes them of many nutrients, a few of which are then added back in through “fortification”: folic acid in refined flour, vitamins and minerals in breakfast cereal. But food scientists can add back only the nutrients food scientists recognize as important. What are they overlooking?

Simplification has occurred at the level of species diversity, too. The astounding variety of foods on offer in the modern supermarket obscures the fact that the actual number of species in the modern diet is shrinking. For reasons of economics, the food industry prefers to tease its myriad processed offerings from a tiny group of plant species, corn and soybeans chief among them. Today, a mere four crops account for two-thirds of the calories humans eat. When you consider that humankind has historically consumed some 80,000 edible species, and that 3,000 of these have been in widespread use, this represents a radical simplification of the food web. Why should this matter? Because humans are omnivores, requiring somewhere between 50 and 100 different chemical compounds and elements to be healthy. It’s hard to believe that we can get everything we need from a diet consisting largely of processed corn, soybeans, wheat and rice.

From Leaves to Seeds. It’s no coincidence that most of the plants we have come to rely on are grains; these crops are exceptionally efficient at transforming sunlight into macronutrients — carbs, fats and proteins. These macronutrients in turn can be profitably transformed into animal protein (by feeding them to animals) and processed foods of every description. Also, the fact that grains are durable seeds that can be stored for long periods means they can function as commodities as well as food, making these plants particularly well suited to the needs of industrial capitalism.

The needs of the human eater are another matter. An oversupply of macronutrients, as we now have, itself represents a serious threat to our health, as evidenced by soaring rates of obesity and diabetes. But the undersupply of micronutrients may constitute a threat just as serious. Put in the simplest terms, we’re eating a lot more seeds and a lot fewer leaves, a tectonic dietary shift the full implications of which we are just beginning to glimpse. If I may borrow the nutritionist’s reductionist vocabulary for a moment, there are a host of critical micronutrients that are harder to get from a diet of refined seeds than from a diet of leaves. There are the antioxidants and all the other newly discovered phytochemicals (remember that sprig of thyme?); there is the fiber, and then there are the healthy omega-3 fats found in leafy green plants, which may turn out to be most important benefit of all.

Most people associate omega-3 fatty acids with fish, but fish get them from green plants (specifically algae), which is where they all originate. Plant leaves produce these essential fatty acids (“essential” because our bodies can’t produce them on their own) as part of photosynthesis. Seeds contain more of another essential fatty acid: omega-6. Without delving too deeply into the biochemistry, the two fats perform very different functions, in the plant as well as the plant eater. Omega-3s appear to play an important role in neurological development and processing, the permeability of cell walls, the metabolism of glucose and the calming of inflammation. Omega-6s are involved in fat storage (which is what they do for the plant), the rigidity of cell walls, clotting and the inflammation response. (Think of omega-3s as fleet and flexible, omega-6s as sturdy and slow.) Since the two lipids compete with each other for the attention of important enzymes, the ratio between omega-3s and omega-6s may matter more than the absolute quantity of either fat. Thus too much omega-6 may be just as much a problem as too little omega-3.

And that might well be a problem for people eating a Western diet. As we’ve shifted from leaves to seeds, the ratio of omega-6s to omega-3s in our bodies has shifted, too. At the same time, modern food-production practices have further diminished the omega-3s in our diet. Omega-3s, being less stable than omega-6s, spoil more readily, so we have selected for plants that produce fewer of them; further, when we partly hydrogenate oils to render them more stable, omega-3s are eliminated. Industrial meat, raised on seeds rather than leaves, has fewer omega-3s and more omega-6s than preindustrial meat used to have. And official dietary advice since the 1970s has promoted the consumption of polyunsaturated vegetable oils, most of which are high in omega-6s (corn and soy, especially). Thus, without realizing what we were doing, we significantly altered the ratio of these two essential fats in our diets and bodies, with the result that the ratio of omega-6 to omega-3 in the typical American today stands at more than 10 to 1; before the widespread introduction of seed oils at the turn of the last century, it was closer to 1 to 1.

The role of these lipids is not completely understood, but many researchers say that these historically low levels of omega-3 (or, conversely, high levels of omega-6) bear responsibility for many of the chronic diseases associated with the Western diet, especially heart disease and diabetes. (Some researchers implicate omega-3 deficiency in rising rates of depression and learning disabilities as well.) To remedy this deficiency, nutritionism classically argues for taking omega-3 supplements or fortifying food products, but because of the complex, competitive relationship between omega-3 and omega-6, adding more omega-3s to the diet may not do much good unless you also reduce your intake of omega-6.

From Food Culture to Food Science. The last important change wrought by the Western diet is not, strictly speaking, ecological. But the industrialization of our food that we call the Western diet is systematically destroying traditional food cultures. Before the modern food era — and before nutritionism — people relied for guidance about what to eat on their national or ethnic or regional cultures. We think of culture as a set of beliefs and practices to help mediate our relationship to other people, but of course culture (at least before the rise of science) has also played a critical role in helping mediate people’s relationship to nature. Eating being a big part of that relationship, cultures have had a great deal to say about what and how and why and when and how much we should eat. Of course when it comes to food, culture is really just a fancy word for Mom, the figure who typically passes on the food ways of the group — food ways that, although they were never “designed” to optimize health (we have many reasons to eat the way we do), would not have endured if they did not keep eaters alive and well.

The sheer novelty and glamour of the Western diet, with its 17,000 new food products introduced every year, and the marketing muscle used to sell these products, has overwhelmed the force of tradition and left us where we now find ourselves: relying on science and journalism and marketing to help us decide questions about what to eat. Nutritionism, which arose to help us better deal with the problems of the Western diet, has largely been co-opted by it, used by the industry to sell more food and to undermine the authority of traditional ways of eating. You would not have read this far into this article if your food culture were intact and healthy; you would simply eat the way your parents and grandparents and great-grandparents taught you to eat. The question is, Are we better off with these new authorities than we were with the traditional authorities they supplanted? The answer by now should be clear.

It might be argued that, at this point in history, we should simply accept that fast food is our food culture. Over time, people will get used to eating this way and our health will improve. But for natural selection to help populations adapt to the Western diet, we’d have to be prepared to let those whom it sickens die. That’s not what we’re doing. Rather, we’re turning to the health-care industry to help us “adapt.” Medicine is learning how to keep alive the people whom the Western diet is making sick. It’s gotten good at extending the lives of people with heart disease, and now it’s working on obesity and diabetes. Capitalism is itself marvelously adaptive, able to turn the problems it creates into lucrative business opportunities: diet pills, heart-bypass operations, insulin pumps, bariatric surgery. But while fast food may be good business for the health-care industry, surely the cost to society — estimated at more than $200 billion a year in diet-related health-care costs — is unsustainable.

BEYOND NUTRITIONISM

To medicalize the diet problem is of course perfectly consistent with nutritionism. So what might a more ecological or cultural approach to the problem recommend? How might we plot our escape from nutritionism and, in turn, from the deleterious effects of the modern diet? In theory nothing could be simpler — stop thinking and eating that way — but this is somewhat harder to do in practice, given the food environment we now inhabit and the loss of sharp cultural tools to guide us through it. Still, I do think escape is possible, to which end I can now revisit — and elaborate on, but just a little — the simple principles of healthy eating I proposed at the beginning of this essay, several thousand words ago. So try these few (flagrantly unscientific) rules of thumb, collected in the course of my nutritional odyssey, and see if they don’t at least point us in the right direction.

1. Eat food. Though in our current state of confusion, this is much easier said than done. So try this: Don’t eat anything your great-great-grandmother wouldn’t recognize as food. (Sorry, but at this point Moms are as confused as the rest of us, which is why we have to go back a couple of generations, to a time before the advent of modern food products.) There are a great many foodlike items in the supermarket your ancestors wouldn’t recognize as food (Go-Gurt? Breakfast-cereal bars? Nondairy creamer?); stay away from these.

2. Avoid even those food products that come bearing health claims. They’re apt to be heavily processed, and the claims are often dubious at best. Don’t forget that margarine, one of the first industrial foods to claim that it was more healthful than the traditional food it replaced, turned out to give people heart attacks. When Kellogg’s can boast about its Healthy Heart Strawberry Vanilla cereal bars, health claims have become hopelessly compromised. (The American Heart Association charges food makers for their endorsement.) Don’t take the silence of the yams as a sign that they have nothing valuable to say about health.

3. Especially avoid food products containing ingredients that are a) unfamiliar, b) unpronounceable c) more than five in number — or that contain high-fructose corn syrup.None of these characteristics are necessarily harmful in and of themselves, but all of them are reliable markers for foods that have been highly processed.

4. Get out of the supermarket whenever possible. You won’t find any high-fructose corn syrup at the farmer’s market; you also won’t find food harvested long ago and far away. What you will find are fresh whole foods picked at the peak of nutritional quality. Precisely the kind of food your great-great-grandmother would have recognized as food.

5. Pay more, eat less. The American food system has for a century devoted its energies and policies to increasing quantity and reducing price, not to improving quality. There’s no escaping the fact that better food — measured by taste or nutritional quality (which often correspond) — costs more, because it has been grown or raised less intensively and with more care. Not everyone can afford to eat well in America, which is shameful, but most of us can: Americans spend, on average, less than 10 percent of their income on food, down from 24 percent in 1947, and less than the citizens of any other nation. And those of us who can afford to eat well should. Paying more for food well grown in good soils — whether certified organic or not — will contribute not only to your health (by reducing exposure to pesticides) but also to the health of others who might not themselves be able to afford that sort of food: the people who grow it and the people who live downstream, and downwind, of the farms where it is grown.

“Eat less” is the most unwelcome advice of all, but in fact the scientific case for eating a lot less than we currently do is compelling. “Calorie restriction” has repeatedly been shown to slow aging in animals, and many researchers (including Walter Willett, the Harvard epidemiologist) believe it offers the single strongest link between diet and cancer prevention. Food abundance is a problem, but culture has helped here, too, by promoting the idea of moderation. Once one of the longest-lived people on earth, the Okinawans practiced a principle they called “Hara Hachi Bu”: eat until you are 80 percent full. To make the “eat less” message a bit more palatable, consider that quality may have a bearing on quantity: I don’t know about you, but the better the quality of the food I eat, the less of it I need to feel satisfied. All tomatoes are not created equal.

6. Eat mostly plants, especially leaves. Scientists may disagree on what’s so good about plants — the antioxidants? Fiber? Omega-3s? — but they do agree that they’re probably really good for you and certainly can’t hurt. Also, by eating a plant-based diet, you’ll be consuming far fewer calories, since plant foods (except seeds) are typically less “energy dense” than the other things you might eat. Vegetarians are healthier than carnivores, but near vegetarians (“flexitarians”) are as healthy as vegetarians. Thomas Jefferson was on to something when he advised treating meat more as a flavoring than a food.

7. Eat more like the French. Or the Japanese. Or the Italians. Or the Greeks. Confounding factors aside, people who eat according to the rules of a traditional food culture are generally healthier than we are. Any traditional diet will do: if it weren’t a healthy diet, the people who follow it wouldn’t still be around. True, food cultures are embedded in societies and economies and ecologies, and some of them travel better than others: Inuit not so well as Italian. In borrowing from a food culture, pay attention to how a culture eats, as well as to what it eats. In the case of the French paradox, it may not be the dietary nutrients that keep the French healthy (lots of saturated fat and alcohol?!) so much as the dietary habits: small portions, no seconds or snacking, communal meals — and the serious pleasure taken in eating. (Worrying about diet can’t possibly be good for you.) Let culture be your guide, not science.

8. Cook. And if you can, plant a garden. To take part in the intricate and endlessly interesting processes of providing for our sustenance is the surest way to escape the culture of fast food and the values implicit in it: that food should be cheap and easy; that food is fuel and not communion. The culture of the kitchen, as embodied in those enduring traditions we call cuisines, contains more wisdom about diet and health than you are apt to find in any nutrition journal or journalism. Plus, the food you grow yourself contributes to your health long before you sit down to eat it. So you might want to think about putting down this article now and picking up a spatula or hoe.

9. Eat like an omnivore. Try to add new species, not just new foods, to your diet. The greater the diversity of species you eat, the more likely you are to cover all your nutritional bases. That of course is an argument from nutritionism, but there is a better one, one that takes a broader view of “health.” Biodiversity in the diet means less monoculture in the fields. What does that have to do with your health? Everything. The vast monocultures that now feed us require tremendous amounts of chemical fertilizers and pesticides to keep from collapsing. Diversifying those fields will mean fewer chemicals, healthier soils, healthier plants and animals and, in turn, healthier people. It’s all connected, which is another way of saying that your health isn’t bordered by your body and that what’s good for the soil is probably good for you, too.

Michael Pollan, a contributing writer, is the Knight professor of journalism at the University of California, Berkeley. His most recent book, “The Omnivore’s Dilemma,” was chosen by the editors of The New York Times Book Review as one of the 10 best books of 2006.