Tuesday, August 07, 2007

Free Phone Calls?

State Of the Art

Get Your Free Net Phone Calls Here

Published: August 2, 2007

The price of home phone service has dropped 30 percent since 1999. Surely, say the analysts, that trend line will eventually plummet all the way to zero. Surely, thanks to the Internet’s ability to carry your voice, landline phone calls will soon be free.

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Stuart Goldenberg

An Ooma box allows free calls to anyone in the United States, linking the home phone to broadband. It also provides a free second line.

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A Theory of Wealth

In Dusty Archives, a Theory of Affluence

By NICHOLAS WADE

Published: August 7, 2007

For thousands of years, most people on earth lived in abject poverty, first as hunters and gatherers, then as peasants or laborers. But with the Industrial Revolution, some societies traded this ancient poverty for amazing affluence.

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Alan Baker

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Breaking Out of a Malthusian Trap

Historians and economists have long struggled to understand how this transition occurred and why it took place only in some countries. A scholar who has spent the last 20 years scanning medieval English archives has now emerged with startling answers for both questions.

Gregory Clark, an economic historian at the University of California, Davis, believes that the Industrial Revolution — the surge in economic growth that occurred first in England around 1800 — occurred because of a change in the nature of the human population. The change was one in which people gradually developed the strange new behaviors required to make a modern economy work. The middle-class values of nonviolence, literacy, long working hours and a willingness to save emerged only recently in human history, Dr. Clark argues.

Because they grew more common in the centuries before 1800, whether by cultural transmission or evolutionary adaptation, the English population at last became productive enough to escape from poverty, followed quickly by other countries with the same long agrarian past.

Dr. Clark’s ideas have been circulating in articles and manuscripts for several years and are to be published as a book next month, “A Farewell to Alms” (Princeton University Press). Economic historians have high praise for his thesis, though many disagree with parts of it.

“This is a great book and deserves attention,” said Philip Hoffman, a historian at the California Institute of Technology. He described it as “delightfully provocative” and a “real challenge” to the prevailing school of thought that it is institutions that shape economic history.

Samuel Bowles, an economist who studies cultural evolution at the Santa Fe Institute, said Dr. Clark’s work was “great historical sociology and, unlike the sociology of the past, is informed by modern economic theory.”

The basis of Dr. Clark’s work is his recovery of data from which he can reconstruct many features of the English economy from 1200 to 1800. From this data, he shows, far more clearly than has been possible before, that the economy was locked in a Malthusian trap _ — each time new technology increased the efficiency of production a little, the population grew, the extra mouths ate up the surplus, and average income fell back to its former level.

This income was pitifully low in terms of the amount of wheat it could buy. By 1790, the average person’s consumption in England was still just 2,322 calories a day, with the poor eating a mere 1,508. Living hunter-gatherer societies enjoy diets of 2,300 calories or more.

“Primitive man ate well compared with one of the richest societies in the world in 1800,” Dr. Clark observes.

The tendency of population to grow faster than the food supply, keeping most people at the edge of starvation, was described by Thomas Malthus in a 1798 book, “An Essay on the Principle of Population.” This Malthusian trap, Dr. Clark’s data show, governed the English economy from 1200 until the Industrial Revolution and has in his view probably constrained humankind throughout its existence. The only respite was during disasters like the Black Death, when population plummeted, and for several generations the survivors had more to eat.

Malthus’s book is well known because it gave Darwin the idea of natural selection. Reading of the struggle for existence that Malthus predicted, Darwin wrote in his autobiography, “It at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. ... Here then I had at last got a theory by which to work.”

Given that the English economy operated under Malthusian constraints, might it not have responded in some way to the forces of natural selection that Darwin had divined would flourish in such conditions? Dr. Clark started to wonder whether natural selection had indeed changed the nature of the population in some way and, if so, whether this might be the missing explanation for the Industrial Revolution.

The Industrial Revolution, the first escape from the Malthusian trap, occurred when the efficiency of production at last accelerated, growing fast enough to outpace population growth and allow average incomes to rise. Many explanations have been offered for this spurt in efficiency, some economic and some political, but none is fully satisfactory, historians say.

Dr. Clark’s first thought was that the population might have evolved greater resistance to disease. The idea came from Jared Diamond’s book “Guns, Germs and Steel,” which argues that Europeans were able to conquer other nations in part because of their greater immunity to disease.

In support of the disease-resistance idea, cities like London were so filthy and disease ridden that a third of their populations died off every generation, and the losses were restored by immigrants from the countryside. That suggested to Dr. Clark that the surviving population of England might be the descendants of peasants.

A way to test the idea, he realized, was through analysis of ancient wills, which might reveal a connection between wealth and the number of progeny. The wills did that, , but in quite the opposite direction to what he had expected.

Generation after generation, the rich had more surviving children than the poor, his research showed. That meant there must have been constant downward social mobility as the poor failed to reproduce themselves and the progeny of the rich took over their occupations. “The modern population of the English is largely descended from the economic upper classes of the Middle Ages,” he concluded.

As the progeny of the rich pervaded all levels of society, Dr. Clark considered, the behaviors that made for wealth could have spread with them. He has documented that several aspects of what might now be called middle-class values changed significantly from the days of hunter gatherer societies to 1800. Work hours increased, literacy and numeracy rose, and the level of interpersonal violence dropped.

Another significant change in behavior, Dr. Clark argues, was an increase in people’s preference for saving over instant consumption, which he sees reflected in the steady decline in interest rates from 1200 to 1800.

“Thrift, prudence, negotiation and hard work were becoming values for communities that previously had been spendthrift, impulsive, violent and leisure loving,” Dr. Clark writes.

Around 1790, a steady upward trend in production efficiency first emerges in the English economy. It was this significant acceleration in the rate of productivity growth that at last made possible England’s escape from the Malthusian trap and the emergence of the Industrial Revolution.

In the rest of Europe and East Asia, populations had also long been shaped by the Malthusian trap of their stable agrarian economies. Their workforces easily absorbed the new production technologies that appeared first in England.

It is puzzling that the Industrial Revolution did not occur first in the much larger populations of China or Japan. Dr. Clark has found data showing that their richer classes, the Samurai in Japan and the Qing dynasty in China, were surprisingly unfertile and so would have failed to generate the downward social mobility that spread production-oriented values in England.

After the Industrial Revolution, the gap in living standards between the richest and the poorest countries started to accelerate, from a wealth disparity of about 4 to 1 in 1800 to more than 50 to 1 today. Just as there is no agreed explanation for the Industrial Revolution, economists cannot account well for the divergence between rich and poor nations or they would have better remedies to offer.

Many commentators point to a failure of political and social institutions as the reason that poor countries remain poor. But the proposed medicine of institutional reform “has failed repeatedly to cure the patient,” Dr. Clark writes. He likens the “cult centers” of the World Bank and International Monetary Fund to prescientific physicians who prescribed bloodletting for ailments they did not understand.

If the Industrial Revolution was caused by changes in people’s behavior, then populations that have not had time to adapt to the Malthusian constraints of agrarian economies will not be able to achieve the same production efficiencies, his thesis implies.

Dr. Clark says the middle-class values needed for productivity could have been transmitted either culturally or genetically. But in some passages, he seems to lean toward evolution as the explanation. “Through the long agrarian passage leading up to the Industrial Revolution, man was becoming biologically more adapted to the modern economic world,” he writes. And, “The triumph of capitalism in the modern world thus may lie as much in our genes as in ideology or rationality.”

What was being inherited, in his view, was not greater intelligence — being a hunter in a foraging society requires considerably greater skill than the repetitive actions of an agricultural laborer. Rather, it was “a repertoire of skills and dispositions that were very different from those of the pre-agrarian world.”

Reaction to Dr. Clark’s thesis from other economic historians seems largely favorable, although few agree with all of it, and many are skeptical of the most novel part, his suggestion that evolutionary change is a factor to be considered in history.

Historians used to accept changes in people’s behavior as an explanation for economic events, like Max Weber’s thesis linking the rise of capitalism with Protestantism. But most have now swung to the economists’ view that all people are alike and will respond in the same way to the same incentives. Hence they seek to explain events like the Industrial Revolution in terms of changes in institutions, not people.

Dr. Clark’s view is that institutions and incentives have been much the same all along and explain very little, which is why there is so little agreement on the causes of the Industrial Revolution. In saying the answer lies in people’s behavior, he is asking his fellow economic historians to revert to a type of explanation they had mostly abandoned and in addition is evoking an idea that historians seldom consider as an explanatory variable, that of evolution.

Most historians have assumed that evolutionary change is too gradual to have affected human populations in the historical period. But geneticists, with information from the human genome now at their disposal, have begun to detect ever more recent instances of human evolutionary change like the spread of lactose tolerance in cattle-raising people of northern Europe just 5,000 years ago. A study in the current American Journal of Human Genetics finds evidence of natural selection at work in the population of Puerto Rico since 1513. So historians are likely to be more enthusiastic about the medieval economic data and elaborate time series that Dr. Clark has reconstructed than about his suggestion that people adapted to the Malthusian constraints of an agrarian society.

“He deserves kudos for assembling all this data,” said Dr. Hoffman, the Caltech historian, “but I don’t agree with his underlying argument.”

The decline in English interest rates, for example, could have been caused by the state’s providing better domestic security and enforcing property rights, Dr. Hoffman said, not by a change in people’s willingness to save, as Dr. Clark asserts.

The natural-selection part of Dr. Clark’s argument “is significantly weaker, and maybe just not necessary, if you can trace the changes in the institutions,” said Kenneth L. Pomeranz, a historian at the University of California, Irvine. In a recent book, “The Great Divergence,” Dr. Pomeranz argues that tapping new sources of energy like coal and bringing new land into cultivation, as in the North American colonies, were the productivity advances that pushed the old agrarian economies out of their Malthusian constraints.

Robert P. Brenner, a historian at the University of California, Los Angeles, said although there was no satisfactory explanation at present for why economic growth took off in Europe around 1800, he believed that institutional explanations would provide the answer and that Dr. Clark’s idea of genes for capitalist behavior was “quite a speculative leap.”

Dr. Bowles, the Santa Fe economist, said he was “not averse to the idea” that genetic transmission of capitalist values is important, but that the evidence for it was not yet there. “It’s just that we don’t have any idea what it is, and everything we look at ends up being awfully small,” he said. Tests of most social behaviors show they are very weakly heritable.

He also took issue with Dr. Clark’s suggestion that the unwillingness to postpone consumption, called time preference by economists, had changed in people over the centuries. “If I were as poor as the people who take out payday loans, I might also have a high time preference,” he said.

Dr. Clark said he set out to write his book 12 years ago on discovering that his undergraduates knew nothing about the history of Europe. His colleagues have been surprised by its conclusions but also interested in them, he said.

“The actual data underlying this stuff is hard to dispute,” Dr. Clark said. “When people see the logic, they say ‘I don’t necessarily believe it, but it’s hard to dismiss.’ ”

Monday, August 06, 2007

Friends, & THEIR friends

Ideas & Trends

You, Your Friends, Your Friends of Friends

Antonin Kratochvil/VII, for The New York Times

By GINA KOLATA

Published: August 5, 2007

IN a way it all seems so obvious. Your friend found a lump in her breast, so you have that long-delayed mammogram. One by one your friends stop smoking, so you stop, too. Of course people are affected by their friends’ habits and their health.

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Find Yourself Packing It On? Blame Friends (July 26, 2007)

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Antonin Kratochvil/VII, for The New York Times

But what seems obvious in the abstract can lead to surprising findings. A recent study found that obesity can spread from friend to friend much like a virus. When one person gains weight, close friends tend to gain weight, too.

The study, published recently in The New England Journal of Medicine, involved a detailed analysis of a large social network of 12,067 people who had been closely followed for 32 years, from 1971 to 2003.

Now, scientists believe that social networks not only can spread diseases, like the common cold, but also may influence many types of behavior — negative and positive — which then affect an individual’s health, as well as a community’s.

“In the past few years we have been seeing a network revolution,” says Albert-Laszlo Barabasi, a physics professor at the University of Notre Dame. “People sensed that networks were out there, but they never had large enough data sets to start understanding them in a quantitative fashion.”

For example, he said, sociologists would go into a classroom and ask students to list their friends. That, he said, can be useful, but social networks are huge, and they evolve over time. They involve you, your family, your friends, your friends’ friends and your friends’ friends’ friends.

The researchers who found the obesity effect stumbled upon the data they needed in the Framingham Heart Study. It has gone on for decades and followed most of the population of Framingham, Mass. As part of the study, participants named friends who could help locate them if researchers lost contact. That link was just what was needed to construct a social network and watch it evolve over decades — a web of friends and friends of friends along with family members.

The striking feature of networks, notes Dr. Nicholas Christakis of Harvard Medical School, is that they amplify whatever effect they are propagating. One person catches a cold and spreads it to 10 friends, each of whom spreads it to 10 more friends.

But obesity? Dr. Christakis and his colleague James H. Fowler, a political scientist at the University of California, San Diego, say they do not know how it happened, but the dynamic was clear — when one person became obese, that person’s friends were more likely to become obese and so were their friends and their friends’ friends.

Obesity was just the start, the researchers say. They have already begun asking about other health-related issues. Smoking, for example — have smokers become more isolated over time?

After all, networks evolve, and if smoking becomes unacceptable, smokers might be expected to cluster in their own little orbits, cut off from the mainstream. That, Dr. Fowler said, is exactly what happened. The Framingham data from the 1970s show smokers embedded in social networks just like everyone else. But by the 1990s, smokers began to be shunted to the side, their links to nonsmokers breaking.

Dr. Fowler and Dr. Christakis are now looking at depression, asking whether it spreads from friend to friend. There are hints from another study that it might.

The network in that case was derived from the federal National Longitudinal Study of Adolescent Health, a study of tens of thousands of teenagers that asks them to name their friends and follows them for years. It turned out, says Peter Bearman, a social scientist at Columbia University, that certain friendships increased the likelihood of suicide or suicidal thoughts in teenage girls.

The risky friendships are what Dr. Bearman calls a contradictory network — a teenage girl has two friends who dislike each other. “It tells you about the importance of social relationships for girls’ health and self-esteem,” Dr. Bearman says. “If you are in an unstable triad, it makes it much more difficult to fit in.”

Now Dr. Bearman and his colleagues are studying autism. The number of autistic children has increased rapidly in recent years, but it is not clear how much resulted from increased diagnosis and how much from an increase in the actual disease.

Dr. Bearman is studying how diagnoses of autism spread. When a child is diagnosed, friends of that child’s parents may wonder whether their child has autism as well, and have their child evaluated. Demand for autism evaluations would increase, and doctors and schools would become more sensitive to the disorder and more likely to suspect it. Schools would then provide services for the autistic children in the community, attracting families from other areas where autism was less common and where schools were not as prepared to help.

“There is an enormously important dynamic that draws people into a diagnostic maelstrom,” Dr. Bearman says. “Autism is real, but the epidemic very likely has a very important social network component.”

The challenge in medicine now is to map out complex dynamic networks, Dr. Barabasi said, and he does not just mean networks of people. The proteins and enzymes in a cell also form a closely connected network, Dr. Barabasi says. And when you tweak one protein, the whole web is affected. “That is why drugs have side effects,” Dr. Barabasi said.

And, he adds, “we will not have cures for obesity or cancer until we understand those networks.”

But he’s an optimist, believing that these cellular networks will be mapped sooner or later. “Right now, this is a work in progress,” Dr. Barabasi says, “but I believe we will get there in 10 years.”

Sunday, August 05, 2007

Cajun Buddhists

Buddhism Cajun style

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Advocate staff photos by MARK SALTZ

Group meditations, called practice groups, draw participants on Sundays and Thursdays at the Katog Choling Tibetan Cultural Center in Lafayette. Front row, from left, are George Blanchard Jr., David Leslie, Martin Arceneaux and Maria Lovullo.

To learn more

For information about the Katog Choling Tibetan Cultural Center, call (337) 447-4922 or go to www.katogcholing.com.

Reception of abbot results in Lafayette center

By BRIAN HUDGINS
Special to The Advocate
Published: Aug 4, 2007 - Page: 1E

LAFAYETTE — Bringing the principles of Buddhism to an eager audience has involved a cross-country journey that united people coast to coast.

When Opelousas natives Fenyx and CeCe Sloan met Khentrul Lodro Thaye Rinpoche in Medford, Ore., in 2003, they invited the Tibetan monastery abbot to come meet their families in Acadiana.

Once Rinpoche accepted that invitation and word spread about his visit roughly four years ago, more than 100 people showed up during a couple of days at the Sloans’ house to meet him.

The warm reception resulted in a return visit by Rinpoche and the eventual establishment of the Katog Choling

Tibetan Cultural Center in 2004. The group meditations at the facility are called practice groups.

“The practice groups in Oregon have been on the West Coast 20 to 25 years,” Fenyx Sloan said. “There are a lot more advanced students of Buddhism there. All the people here were brand new. The biggest difference is there is an excitement here because it is new.”

Paloma Landry, 27, born and raised in southern Oregon, is a translator for Rinpoche. She had never heard of Cajun culture before her initial visit to the state with him.

“The great interest and enthusiasm of people drew him here (to Acadiana),” Landry said by telephone from California. “They had such a genuine heart. He thought it would be beneficial.”

Landry travels throughout the country and abroad with Rinpoche, who frequently visits groups at prisons, schools and other various locations to introduce people to Buddhism.

“I think the West Coast is beautiful,” Landry said. “When I think of land, I think of the West Coast. When I think of people and unity, I think of the South. The closeness and tightness of the family unit in the South is similar to Tibetan culture.”

Katog Choling serves as a centralized meeting place in Lafayette for those interested in Rinpoche’s teachings. A pair of weekly practice meditations are held at the center. The meditation on Thursdays begins with a supplication prayer. Those attending then read a scripture called “The Heart Essence of Sublime Knowing,” a text on absolute nature. A calm meditation — referred to as a shamatha — follows.

Lafayette resident David Leslie, 31, originally from Boston, said his experiences in the area and with the center have introduced a different environment to him.

“It has taken me a bit of time to get used to the openness here,” Leslie said. “People are reticent in New England. People here have a more gentle way of communicating with each other. Coming to the center has softened my perspective, which is always positive.”
Within the different types of Buddhism, the meditations at the center are Vajrayana, which translates as “the diamond vehicle.”

CeCe Sloan said the principles of working toward a path of enlightenment carry over well to students, whether they are in smaller rural towns or in larger cities.

“All of us are Rinpoche’s students,” CeCe Sloan said. “We are all working on something. We are all striving to purify and create virtuous actions.”

During her travels, Landry has also witnessed how Buddhism relates to everyday life in various corners of the country.

“Buddha encourages everyone to have an open heart,” Landry said. “It boils down to: All people want happiness. The material world does not fulfill that in its entirety. That is the purpose of a spiritual path.”

Starting the journey down that path comes later for some students than others.

“It took me a while to grasp the teachings because learning them as adults, we get it at different levels,” CeCe Sloan said. “I got it at 37 years old versus someone that gets it as a baby.”

Those practicing the teachings at the center stressed that Buddhism provides a path open to people of all different faiths.

“We may have a different spiritual lexicon for exploring some of the same concepts,” Leslie said. “Anyone is welcome here even though they are inherent into a different faith. This works for the welfare of all beings. It is very teacher-oriented.”

When Rinpoche and Landry are traveling, she frequently drives them to destinations where their focus is not placed on attending social events or seeing tourist sites. The sole purpose is teaching.

Seeing that process play out is an impressive event to Landry.

“It’s amazing for me to watch (Rinpoche) change people’s lives in subtle ways,” Landry said. “Even the smallest gestures can affect change.”

Wednesday, August 01, 2007

Cooperation & Game Theory

Scientist at Work | Martin Nowak

In Games, an Insight Into the Rules of Evolution

By CARL ZIMMER

Published: July 31, 2007

When Martin Nowak was in high school, his parents thought he would be a nice boy and become a doctor. But when he left for the University of Vienna, he abandoned medicine for something called biochemistry. As far as his parents could tell, it had something to do with yeast and fermenting. They became a little worried. When their son entered graduate school, they became even more worried. He announced that he was now studying games.

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Erik Jacobs for The New York Times

Martin Nowak, a Harvard professor, is studying cooperation.

In the end, Dr. Nowak turned out all right. He is now the director of the Program for Evolutionary Dynamics at Harvard. The games were actually versatile mathematical models that Dr. Nowak could use to make important discoveries in fields as varied as economics and cancer biology.

“Martin has a passion for taking informal ideas that people like me find theoretically important and framing them as mathematical models,” said Steven Pinker, a Harvard linguist who is collaborating with Dr. Nowak to study the evolution of language. “He allows our intuitions about what leads to what to be put to a test.”

On the surface, Dr. Nowak’s many projects may seem randomly scattered across the sciences. But there is an underlying theme to his work. He wants to understand one of the most puzzling yet fundamental features of life: cooperation.

When biologists speak of cooperation, they speak more broadly than the rest of us. Cooperation is what happens when someone or something gets a benefit because someone or something else pays a cost. The benefit can take many forms, like money or reproductive success. A friend takes off work to pick you up from the hospital. A sterile worker bee tends to eggs in a hive. Even the cells in the human body cooperate. Rather than reproducing as fast as it can, each cell respects the needs of the body, helping to form the heart, the lungs or other vital organs. Even the genes in a genome cooperate, to bring an organism to life.

In recent papers, Dr. Nowak has argued that cooperation is one of the three basic principles of evolution. The other two are mutation and selection. On their own, mutation and selection can transform a species, giving rise to new traits like limbs and eyes. But cooperation is essential for life to evolve to a new level of organization. Single-celled protozoa had to cooperate to give rise to the first multicellular animals. Humans had to cooperate for complex societies to emerge.

“We see this principle everywhere in evolution where interesting things are happening,” Dr. Nowak said.

While cooperation may be central to evolution, however, it poses questions that are not easy to answer. How can competing individuals start to cooperate for the greater good? And how do they continue to cooperate in the face of exploitation? To answer these questions, Dr. Nowak plays games.

His games are the intellectual descendants of a puzzle known as the Prisoner’s Dilemma. Imagine two prisoners are separately offered the same deal: if one of them testifies and the other doesn’t talk, the talker will go free and the holdout will go to jail for 10 years. If both refuse to talk, the prosecutor will only be able to put them in jail for six months. If each prisoner rats out the other, they will both get five-year sentences. Not knowing what the other prisoner will do, how should each one act?

The way the Prisoner’s Dilemma pits cooperation against defection distills an important feature of evolution. In any encounter between two members of the same species, each one may cooperate or defect. Certain species of bacteria, for example, spray out enzymes that break down food, which all the bacteria can then suck up. It costs energy to make these enzymes. If one of the microbes stops cooperating and does not make the enzymes, it can still enjoy the meal. It can gain a potential reproductive edge over bacteria that cooperate.

The Prisoner’s Dilemma may be abstract, but that’s why Dr. Nowak likes it. It helps him understand fundamental rules of evolution, just as Isaac Newton discovered that objects in motion tend to stay in motion.

“If you were obsessed with friction, you would have never discovered this law,” Dr. Nowak said. “In the same sense, I try to get rid of what is inessential to find the essential. Truth is simple.”

Dr. Nowak found his first clues to the origin of cooperation in graduate school, collaborating with his Ph.D. adviser, Karl Sigmund. They built a version of the Prisoner’s Dilemma that captured more of the essence of how organisms behave and evolve.

In their game, an entire population of players enters a round-robin competition. The players are paired up randomly, and each one chooses whether to cooperate or defect. To make a choice, they can recall their past experiences with other individual players. Some players might use a strategy in which they had a 90-percent chance of cooperating with a player with whom they have cooperated in the past.

The players get rewarded based on their choices. The most successful players get to reproduce. Each new player had a small chance of randomly mutating its strategy. If that strategy turned out to be more successful, it could dominate the population, wiping out its ancestors.

Dr. Nowak and Dr. Sigmund observed this tournament through millions of rounds. Often the winners used a strategy that Dr. Nowak called, “win-stay, lose-shift.” If they did well in the previous round, they did the same thing again. If they did not do so well, they shifted. Under some conditions, this strategy caused cooperation to become common among the players, despite the short-term payoff of defecting.

In order to study this new version of the Prisoner’s Dilemma, Dr. Nowak had to develop new mathematical tools. It turned out that these tools also proved useful for studying cancer. Cancer and the Prisoner’s Dilemma may seem like apples and oranges, but Dr. Nowak sees an intimate connection between the two. “Cancer is a breakdown of cooperation,” he said.

Mutations sometimes arise in cells that cause them to replicate quickly, ignoring signals to stop. Some of their descendants acquire new mutations, allowing them to become even more successful as cancer cells. They evolve, in other words, into more successful defectors. “Cancer is an evolution you don’t want,” Dr. Nowak said.

To study cancer, however, Dr. Nowak had to give his models some structure. In the Prisoner’s Dilemma, the players usually just bump into each other randomly. In the human body, on the other hand, cells only interact with cells in their neighborhood.

A striking example of these neighborhoods can be found in the intestines, where the lining is organized into millions of tiny pockets. A single stem cell at the bottom of a pocket divides, and its daughter cells are pushed up the pocket walls. The cells that reach the top get stripped away.

Dr. Nowak adapted a branch of mathematics known as graph theory, which makes it possible to study networks, to analyze how cancer arises in these local neighborhoods. “Our tissue is actually organized to delay the onset of cancer,” he said.

Pockets of intestinal cells, for example, can only hold a few cell generations. That lowers the chances that any one will turn cancerous. All the cells in each pocket are descended from a single stem cell, so that there’s no competition between lineages to take over the pocket.

As Dr. Nowak developed this neighborhood model, he realized it would help him study human cooperation. “The reality is that I’m much more likely to interact with my friends, and they’re much more likely to interact with their friends,” Dr. Nowak said. “So it’s more like a network.”

Dr. Nowak and his colleagues found that when they put players into a network, the Prisoner’s Dilemma played out differently. Tight clusters of cooperators emerge, and defectors elsewhere in the network are not able to undermine their altruism. “Even if outside our network there are cheaters, we still help each other a lot,” Dr. Nowak said. That is not to say that cooperation always emerges. Dr. Nowak identified the conditions when it can arise with a simple equation: B/C>K. That is, cooperation will emerge if the benefit-to-cost (B/C) ratio of cooperation is greater than the average number of neighbors (K).

“It’s the simplest possible thing you could have expected, and it’s completely amazing,” he said.

Another boost for cooperation comes from reputations. When we decide whether to cooperate, we don’t just rely on our past experiences with that particular person. People can gain reputations that precede them. Dr. Nowak and his colleagues pioneered a version of the Prisoner’s Dilemma in which players acquire reputations. They found that if reputations spread quickly enough, they could increase the chances of cooperation taking hold. Players were less likely to be fooled by defectors and more likely to benefit from cooperation.

In experiments conducted by other scientists with people and animals, Dr. Nowak’s mathematical models seem to fit. Reputation has a powerful effect on how people play games. People who gain a reputation for not cooperating tend to be shunned or punished by other players. Cooperative players get rewarded.

“You help because you know it gives you a reputation of a helpful person, who will be helped,” Dr. Nowak said. “You also look at others and help them according to whether they have helped.”

The subject of human cooperation is important not just to mathematical biologists like Dr. Nowak, but to many people involved in the current debate over religion and science. Some claim that it is unlikely that evolution could have produced humans’ sense of morality, the altruism of heroes and saints. “Selfless altruism presents a major challenge for the evolutionist,” Dr. Francis S. Collins, the director of the National Human Genome Research Institute, wrote in his 2006 book, “The Language of God.”

Dr. Nowak believes evolutionary biologists should study average behavior rather than a few extreme cases of altruism. “Saintly behavior is unfortunately not the norm,” Dr. Nowak said. “The current theory can certainly explain a population where some people act extremely altruistically.” That does not make Dr. Nowak an atheist, however. “Evolution describes the fundamental laws of nature according to which God chose to unfold life,” he declared in March in a lecture titled “Evolution and Christianity” at the Harvard Divinity School. Dr. Nowak is collaborating with theologians there on a project called “The Evolution and Theology of Cooperation,” to help theologians address evolutionary biology in their own work.

Dr. Nowak sometimes finds his scientific colleagues astonished when he defends religion. But he believes the astonishment comes from a misunderstanding of the roles of science and religion. “Like mathematics, many theological statements do not need scientific confirmation. Once you have the proof of Fermat’s Last Theorem, it’s not like we have to wait for the scientists to tell us if it’s right. This is it.”

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Tuesday, August 07, 2007

Free Phone Calls?

Get Your Free Net Phone Calls Here

Video

A Theory of Wealth

In Dusty Archives, a Theory of Affluence

Multimedia

Breaking Out of a Malthusian Trap

Monday, August 06, 2007

Friends, & THEIR friends

You, Your Friends, Your Friends of Friends

Related

Find Yourself Packing It On? Blame Friends (July 26, 2007)

Sunday, August 05, 2007

Cajun Buddhists

Wednesday, August 01, 2007

Cooperation & Game Theory

In Games, an Insight Into the Rules of Evolution