WHEN A 1999 CYCLONE in India left millions of people in danger of starvation, some activists denounced relief societies for distributing a nutritious grain meal because it contained genetically modified varieties of corn and soybeans (varieties that had been eaten without apparent harm in the United States). These activists are also opposed to “golden rice,” a genetically modified variety that could prevent blindness in millions of children in the developing world and alleviate vitamin A deficiency in a quarter of a billion more.26 Other activists have vandalized research facilities at which the safety of genetically modified foods is tested and new varieties are developed. For these people, even the possibility that such foods could be safe is unacceptable.
A 2001 report by the European Union reviewed eighty-one research projects conducted over fifteen years and failed to find any new risks to human health or to the environment posed by genetically modified crops.27 This is no surprise to a biologist. Genetically modified foods are no more dangerous than “natural” foods because they are not fundamentally different from natural foods. Virtually every animal and vegetable sold in a health-food store has been “genetically modified” for millennia by selective breeding and hybridization. The wild ancestor of carrots was a thin, bitter white root; the ancestor of corn had an inch-long, easily shattered cob with a few small, rock-hard kernels. Plants are Darwinian creatures with no particular desire to be eaten, so they did not go out of their way to be tasty, healthy, or easy for us to grow and harvest. On the contrary: they did go out of their way to deter us from eating them, by evolving irritants, toxins, and bitter-tasting compounds.28 So there is nothing especially safe about natural foods. The “natural” method of selective breeding for pest resistance simply increases the concentration of the plant’s own poisons; one variety of natural potato had to be withdrawn from the market because it proved to be toxic to people.29 Similarly, natural flavors—defined by one food scientist as “a flavor that’s been derived with an out-of-date technology”—are often chemically indistinguishable from their artificial counterparts, and when they are distinguishable, sometimes the natural flavor is the more dangerous one. When “natural” almond flavor, benzaldehyde, is derived from peach pits, it is accompanied by traces of cyanide; when it is synthesized as an “artificial flavor,” it is not.30
A blanket fear of all artificial and genetically modified foods is patently irrational on health grounds, and it could make food more expensive and hence less available to the poor. Where do these specious fears come from? Partly they arise from the carcinogen-du-jour school of journalism that uncritically reports any study showing elevated cancer rates in rats fed megadoses of chemicals. But partly they come from an intuition about living things that was first identified by the anthropologist James George Frazer in 1890 and has recently been studied in the lab by Paul Rozin, Susan Gelman, Frank Keil, Scott Atran, and other cognitive scientists.31
People’s intuitive biology begins with the concept of an invisible essence residing in living things, which gives them their form and powers. These essentialist beliefs emerge early in childhood, and in traditional cultures they dominate reasoning about plants and animals. Often the intuitions serve people well. They allow preschoolers to deduce that a raccoon that looks like a skunk will have raccoon babies, that a seed taken from an apple and planted with flowers in a pot will produce an apple tree, and that an animal’s behavior depends on its innards, not on its appearance. They allow traditional peoples to deduce that different-looking creatures (such as a caterpillar and a butterfly) can belong to the same kind, and they impel them to extract juices and powders from living things and try them as medicines, poisons, and food supplements. They can prevent people from sickening themselves by eating things that have been in contact with infectious substances such as feces, sick people, and rotting meat.32
But intuitive essentialism can also lead people into error.33 Children falsely believe that a child of English-speaking parents will speak English even if brought up in a French-speaking family, and that boys will have short hair and girls will wear dresses even if they are brought up with no other member of their sex from which they can learn those habits. Traditional peoples believe in sympathetic magic, otherwise known as voodoo. They think similar-looking objects have similar powers, so that a ground-up rhinoceros horn is a cure for erectile dysfunction. And they think that animal parts can transmit their powers to anything they mingle with, so that eating or wearing a part of a fierce animal will make one fierce.
Educated Westerners should not feel too smug. Rozin has shown that we have voodoolike intuitions ourselves. Most Americans won’t touch a sterilized cockroach, or even a plastic one, and won’t drink juice that the roach has touched for even a fraction of a second.34 And even Ivy League students believe that you are what you eat. They judge that a tribe that hunts turtles for their meat and wild boar for their bristles will be good swimmers, and that a tribe that hunts turtles for their shells and wild boar for their meat will be tough fighters.35 In his history of biology, Ernst Mayr showed that many biologists originally rejected the theory of natural selection because of their belief that a species was a pure type defined by an essence. They could not wrap their minds around the concept that species are populations of variable individuals and that one can blend into another over evolutionary time.36
In this context, the fear of genetically modified foods no longer seems so strange: it is simply the standard human intuition that every living thing has an essence. Natural foods are thought to have the pure essence of the plant or animal and to carry with them the rejuvenating powers of the pastoral environment in which they grew. Genetically modified foods, or foods containing artificial additives, are thought of as being deliberately laced with a contaminant tainted by its origins in an acrid laboratory or factory. Arguments that invoke genetics, biochemistry, evolution, and risk analysis are likely to fall on deaf ears when pitted against this deep-rooted way of thinking.
Essentialist intuitions are not the only reason that perceptions of danger can be off the mark. Risk analysts have discovered to their bemusement that people’s fears are often way out of line with objective hazards. Many people avoid flying, though car travel is eleven times more dangerous. They fear getting eaten by a shark, though they are four hundred times more likely to drown in their bathtub. They clamor for expensive measures to get chloroform and trichloroethylene out of drinking water, though they are hundreds of times more likely to get cancer from a daily peanut butter sandwich (since peanuts can carry a highly carcinogenic mold).37 Some of these risks may be misestimated because they tap into our innate fears of heights, confinement, predation, and poisoning.38 But even when people are presented with objective information about danger, they may not appreciate it because of the way the mind assesses probabilities.
A statement like “The chance of dying of botulism poisoning in a given year is .000001” is virtually incomprehensible. For one thing, magnitudes with lots of zeroes at the beginning or end are beyond the ken of our number sense. The psychologist Paul Slovic and his colleagues found that people are unmoved by a lecture on the hazards of not wearing a seat belt which mentions that a fatal collision occurs once in every 3.5 million person-trips. But they say they will buckle up when the odds are recalculated to show that their lifetime chance of dying in a collision is one percent.39
The other reason for the incomprehensibility of many statistics is that the probability of a single event, such as my dying in a plane crash (as opposed to the frequency of some events relative to others, such as the proportion of all airline passengers who die in crashes), is a genuinely puzzling concept, even to mathematicians. What sense can we make of the odds offered by expert bookmakers for particular events, such as that the Archbishop of Canterbury will confirm the second coming within a year (1000 to 1), that a Mr. Braham of Luton, England, will invent a perpetual motion machine (250 to 1), or that Elvis Presley is alive and well (1000 to l)?40 Either Elvis is alive or he isn’t, so what
does it mean to say that the probability that he is alive is .001? Similarly, what should we think when aviation safety analysts tell us that on average a single landing in a commercial airliner reduces one’s life expectancy by fifteen minutes? When the plane comes down, either my life expectancy will be reduced by a lot more than fifteen minutes or it won’t be reduced at all. Some mathematicians say that the probability of a single event is more like a gut feeling of confidence, expressed on a scale of 0 to 1, than a meaningful mathematical quantity.41
The mind is more comfortable in reckoning probabilities in terms of the relative frequency of remembered or imagined events.42 That can make recent and memorable events—a plane crash, a shark attack, an anthrax infection—loom larger in one’s worry list than more frequent and boring events, such as the car crashes and ladder falls that get printed beneath the fold on page Β14. And it can lead risk experts to speak one language and ordinary people to hear another. In hearings for a proposed nuclear waste site, an expert might present a fault tree that lays out the conceivable sequences of events by which radioactivity might escape. For example, erosion, cracks in the bedrock, accidental drilling, or improper sealing might cause the release of radioactivity into groundwater. In turn, groundwater movement, volcanic activity, or an impact of a large meteorite might cause the release of radioactive wastes into the biosphere. Each train of events can be assigned a probability, and the aggregate probability of an accident from all the causes can be estimated. When people hear these analyses, however, they are not reassured but become more fearful than ever—they hadn’t realized there are so many ways for something to go wrong! They mentally tabulate the number of disaster scenarios, rather than mentally aggregating the probabilities of the disaster scenarios.43
None of this implies that people are dunces or that “experts” should ram unwanted technologies down their throats. Even with a complete understanding of the risks, reasonable people might choose to forgo certain technological advances. If something is viscerally revolting, a democracy should allow people to reject it whether or not it is “rational” by some criterion that ignores our psychology. Many people would reject vegetables grown in sanitized human waste and would avoid an elevator with a glass floor, not because they believe these things are dangerous but because the thought gives them the willies. If they have the same reaction to eating genetically modified foods or living next to a nuclear power plant, they should have the option of rejecting them, too, as long as they do not try to force their preferences on others or saddle them with the costs.
Also, even if technocrats provide reasonable estimates of a risk (which is itself an iffy enterprise), they cannot dictate what level of risk people ought to accept. People might object to a nuclear power plant that has a minuscule risk of a meltdown not because they overestimate the risk but because they feel that the costs of the catastrophe, no matter how remote, are too dreadful. And of course any of these tradeoffs may be unacceptable if people perceive that the benefits would go to the wealthy and powerful while they themselves absorb the risks.
Nonetheless, understanding the difference between our best science and our ancient ways of thinking can only make our individual and collective decisions better informed. It can help scientists and journalists explain a new technology in the face of the most common misunderstandings. And it can help all of us understand the technology so that we can accept or reject it on grounds that we can justify to ourselves and to others.
IN The Wealth OF Nations, Adam Smith wrote that there is “a certain propensity in human nature… to truck, barter, and exchange one thing for another.” The exchange of goods and favors is a human universal and may have an ancient history. In archaeological sites tens of millennia old, pretty seashells and sharp flints are found hundreds of miles from their sources, which suggests that they got there by networks of trade.44
The anthropologist Alan Fiske has surveyed the ethnographic literature and found that virtually all human transactions fall into four patterns, each with a distinctive psychology.45 The first is Communal Sharing: groups of people, such as the members of a family, share things without keeping track of who gets what. The second is Authority Ranking: dominant people confiscate what they want from lower-ranking ones. But the other two types of transactions are defined by exchanges.
The most common kind of exchange is what Fiske calls Equality Matching. Two people exchange goods or favors at different times, and the traded items are identical or at least highly similar or easily comparable. The trading partners assess their debts by simple addition or subtraction and are satisfied when the favors even out. The partners feel that the exchange binds them in a relationship, and often people will consummate exchanges just to maintain it. For example, in the trading rings of the Pacific Islands, gifts circulate from chief to chief, and the original giver may eventually get his gift back. (Many Americans suspect that this is what happens to Christmas fruitcakes.) When someone violates an Equality Matching relationship by taking a benefit without returning it in kind, the other party feels cheated and may retaliate aggressively. Equality Matching is the only mechanism of trade in most hunter-gatherer societies. Fiske notes that it is supported by a mental model of tit-for-tat reciprocity, and Leda Cosmides and John Tooby have shown that this way of thinking comes easily to Americans as well.46 It appears to be the core of our intuitive economics.
Fiske contrasts Equality Matching with a very different system called Market Pricing, the system of rents, prices, wages, and interest rates that underlies modern economies. Market Pricing relies on the mathematics of multiplication, division, fractions, and large numbers, together with the social institutions of money, credit, written contracts, and complex divisions of labor. Market Pricing is absent in hunter-gatherer societies, and we know it played no role in our evolutionary history because it relies on technologies like writing, money, and formal mathematics, which appeared only recently. Even today the exchanges carried out by Market Pricing may involve causal chains that are impossible for any individual to grasp in full. I press some keys to enter characters into this manuscript today and entitle myself to receive some groceries years from now, not because I will barter a copy of The Blank Slate to a banana grower but because of a tangled web of third and fourth and fifth parties (publishers, booksellers, truckers, commodity brokers) that I depend on without fully understanding what they do.
When people have different ideas about which of these four modes of interacting applies to a current relationship, the result can range from blank incomprehension to acute discomfort or outright hostility. Think about a dinner guest offering to pay the host for her meal, a person barking an order to a friend, or an employee helping himself to a shrimp off the boss’s plate. Misunderstandings in which one person thinks of a transaction in terms of Equality Matching and another thinks in terms of Market Pricing are even more pervasive and can be even more dangerous. They tap into very different psychologies, one of them intuitive and universal, the other rarefied and learned, and clashes between them have been common in economic history.
Economists refer to “the physical fallacy”: the belief that an object has a true and constant value, as opposed to being worth only what someone is willing to pay for it at a given place and time.47 This is simply the difference between the Equality Matching and Market Pricing mentalities. The physical fallacy may not arise when three chickens are exchanged for one knife, but when the exchanges are mediated by money, credit, and third parties, the fallacy can have ugly consequences. The belief that goods have a “just price” implies that it is avaricious to charge anything higher, and the result has been mandatory pricing schemes in medieval times, communist regimes, and many Third World countries. Such attempts to work around the law of supply and demand have usually led to waste, shortages, and black markets. Another consequence of the physical fallacy is the widespread practice of outlawing interest, which comes from the intuition that it is rapacious to demand additional money from someone who has paid bac
k exactly what he borrowed. Of course, the only reason people borrow at one time and repay it later is that the money is worth more to them at the time they borrow it than it will be at the time they repay it. So when regimes enact sweeping usury laws, people who could put money to productive use cannot get it, and everyone’s standards of living go down.48
Just as the value of something may change with time, which creates a niche for lenders who move valuable things around in time, so it may change with space, which creates a niche for middlemen who move valuable things around in space. A banana is worth more to me in a store down the street than it is in a warehouse a hundred miles away, so I am willing to pay more to the grocer than I would to the importer—even though by “eliminating the middleman” I could pay less per banana. For similar reasons, the importer is willing to charge the grocer less than he would charge me.
But because lenders and middlemen do not cause tangible objects to come into being, their contributions are difficult to grasp, and they are often thought of as skimmers and parasites. A recurring event in human history is the outbreak of ghettoization, confiscation, expulsion, and mob violence against middlemen, often ethnic minorities who learned to specialize in the middleman niche.49 The Jews in Europe are the most familiar example, but the expatriate Chinese, the Lebanese, the Armenians, and the Gujeratis and Chettyars of India have suffered similar histories of persecution.