The evolution of politeness

How politeness evolved

By Alan Boyle

Taking turns isn't just a nice idea. It may be as much a part of the theory of evolution as survival of the fittest - at least that's the conclusion that British researchers reached after running a genetic simulation through thousands of generations of evolutionary change.

Turn-taking behavior seem to come naturally to humans, whether it's standing in line or deciding who's going to do the dishes tonight. But such behavior has been observed in a wide variety of other species as well: Chimps take turns grooming each other, for example, and penguins take turns minding their eggs.

"It is far from obvious how turn-taking evolved without language or insight in animals shaped by natural selection to pursue their individual self-interests," University of Leicester psychologist Andrew Colman said last week in a news release about the research.

Colman and a university colleague of his, Lindsay Browning, looked into the evolution of politeness for a paper published in the September issue of the journal Evolutionary Ecology Research - not by studying actual monkeys, penguins or line-standers, but by setting up a series of genetic simulations where they could dictate the rules of the evolutionary game.

The experiment was as much an exercise in game theory as in evolutionary biology. Colman and Browning programmed a computer to play a variety of games in which the payoff varied depending on whether the simulated players made the same or different choices.

One of the best-known games in this genre is the Prisoner's Dilemma, in which two prisoners receive different penalties depending on whether they defect or stay loyal to each other. Under the most common rules of the game, the most frequent outcome is for the prisoners to rat on each other, even though they would have been better off if they had both stayed loyal.

"The Prisoner's Dilemma, which is being used to study cooperation almost exclusively to date, doesn't ever give any advantage to automata that take turns," Colman told me. "In fact, it's created a blind spot in studying this issue, in our opinion."

He and Browning mixed up the repertoire by using six games, including the Prisoner's Dilemma as well as variations of cooperative games known as the Battle of the Sexes and Stag Hunt. They also built in a little mathematical mutation to duplicate what biologists have found happens in real life. Then they ran the simulation through 2,000 evolutionary generations. Each 2,000-generation simulation was repeated 10 times to check the stability of the results.

Here's how the experiment turned out: Under the right conditions, different players locked themselves into a pattern of mutually beneficial turn-taking that could sustain itself indefinitely.

"They didn't have the benefit of language to plan any strategy such as that," Colman said. "It could be something that just evolves through natural selection, just with hard wiring."

One factor was key, he said: "You've got to have two different types, because they've got to behave in different ways in the same situation in order to initiate this behavior. Without this genetic diversity, the behavior cannot evolve."

Even though game theorists may cast this diversity as a battle of the sexes (for example, she likes opera, he likes boxing), Colman emphasized that the diversity he had in mind was not necessarily a gender split, a la "Men Are From Mars, Women Are From Venus."

"I always tell my students, 'Women are from Earth, men are from Earth ... deal with it,'" he joked.

Rather, the diversity may take the form of different responses to environment changes (for example, becoming more dormant to conserve energy vs. becoming more active to seek out new food sources). Colman said turn-taking appears to be an instance of the "invisible hand" of natural selection at work.

"The assumption in the early days of evolutionary theory was that evolution would tend to make all organisms conform to an optimal form, and this would tend to reduce diversity. ... That turned out to be a primitive idea and not sufficiently subtle," he told me.

The fact that so many species exhibit turn-taking behavior suggests that the genetic code for cooperative behavior goes way back, Colman said. And that's a good thing, whether you're a yeast organism trying to metabolize sugar, an eel hunting for food in a coral reef ... or a filmgoer standing in line to see the latest "Harry Potter" movie.

"Humans obviously engage in turn-taking behavior. Queueing is an elaborate example of it," Colman said. "What this shows is that it's probably deep in our DNA. You don't have to necessarily assume that this is something that developed recently just because we're a civilized species."

Now it's your turn: Does this research shed new light on evolutionary theory? Is it merely a case of scientists stating the obvious? Or do you think "survival of the fittest" really doesn't explain turn-taking and other forms of altruistic behavior? Feel free to weigh in with your comments below.

2009/07/14/1996118.aspx

The evolutionary origin of depression

Mild and bitter
Jun 25th 2009
From The Economist print edition
CLINICAL depression is a serious ailment, but almost everyone gets mildly depressed from time to time. Randolph Nesse, a psychologist and researcher in evolutionary medicine at the University of Michigan, likens the relationship between mild and clinical depression to the one between normal and chronic pain. He sees both pain and low mood as warning mechanisms and thinks that, just as understanding chronic pain means first understanding normal pain, so understanding clinical depression means understanding mild depression.

Dr Nesse’s hypothesis is that, as pain stops you doing damaging physical things, so low mood stops you doing damaging mental ones—in particular, pursuing unreachable goals. Pursuing such goals is a waste of energy and resources. Therefore, he argues, there is likely to be an evolved mechanism that identifies certain goals as unattainable and inhibits their pursuit—and he believes that low mood is at least part of that mechanism.

It is a neat hypothesis, but is it true? A study published in this month’s issue of the Journal of Personality and Social Psychology suggests it might be. Carsten Wrosch from Concordia University in Montreal and Gregory Miller of the University of British Columbia studied depression in teenage girls. They measured the “goal adjustment capacities” of 97 girls aged 15-19 over the course of 19 months. They asked the participants questions about their ability to disengage from unattainable goals and to re-engage with new goals. They also asked about a range of symptoms associated with depression, and tracked how these changed over the course of the study.

Their conclusion was that those who experienced mild depressive symptoms could, indeed, disengage more easily from unreachable goals. That supports Dr Nesse’s hypothesis. But the new study also found a remarkable corollary: those women who could disengage from the unattainable proved less likely to suffer more serious depression in the long run.

Mild depressive symptoms can therefore be seen as a natural part of dealing with failure in young adulthood. They set in when a goal is identified as unreachable and lead to a decline in motivation. In this period of low motivation, energy is saved and new goals can be found. If this mechanism does not function properly, though, severe depression can be the consequence.

The importance of giving up inappropriate goals has already been demonstrated by Dr Wrosch. Two years ago he and his colleagues published a study in which they showed that those teenagers who were better at doing so had a lower concentration of C-reactive protein, a substance made in response to inflammation and associated with an elevated risk of diabetes and cardiovascular disease. Dr Wrosch thus concludes that it is healthy to give up overly ambitious goals. Persistence, though necessary for success and considered a virtue by many, can also have a negative impact on health.

Dr Nesse believes that persistence is a reason for the exceptional level of clinical depression in America—the country that has the highest depression rate in the world. “Persistence is part of the American way of life,” he says. “People here are often driven to pursue overly ambitious goals, which then can lead to depression.” He admits that this is still an unproven hypothesis, but it is one worth considering. Depression may turn out to be an inevitable price of living in a dynamic society.
http://www.economist.com/sciencetechnology/displayStory.cfm?story_id=13899022&fsrc=nwlgafree

Evolution and cooking

Books of The Times
Why Are Humans Different From All Other Apes? It’s the Cooking, Stupid
BYDWIGHT GARNER
Published: May 26, 2009
Human beings are not obviously equipped to be nature’s gladiators. We have no claws, no armor. That we eat meat seems surprising, because we are not made for chewing it uncooked in the wild. Our jaws are weak; our teeth are blunt; our mouths are small. That thing below our noses? It truly is a pie hole.

A Conversation With Richard Wrangham: From Studying Chimps, a Theory on Cooking (April 21, 2009) To attend to these facts, for some people, is to plead for vegetarianism or for a raw-food diet. We should forage and eat the way our long-ago ancestors surely did. For Richard Wrangham, a professor of biological anthropology at Harvard and the author of “Catching Fire,” however, these facts and others demonstrate something quite different. They help prove that we are, as he vividly puts it, “the cooking apes, the creatures of the flame.”

Apes began to morph into humans, and the species Homo erectus emerged some two million years ago, Mr. Wrangham argues, for one fundamental reason: We learned to tame fire and heat our food.

“Cooked food does many familiar things,” he observes. “It makes our food safer, creates rich and delicious tastes and reduces spoilage. Heating can allow us to open, cut or mash tough foods. But none of these advantages is as important as a little-appreciated aspect: cooking increases the amount of energy our bodies obtain from food.”

He continues: “The extra energy gave the first cooks biological advantages. They survived and reproduced better than before. Their genes spread. Their bodies responded by biologically adapting to cooked food, shaped by natural selection to take maximum advantage of the new diet. There were changes in anatomy, physiology, ecology, life history, psychology and society.” Put simply, Mr. Wrangham writes that eating cooked food — whether meat or plants or both —made digestion easier, and thus our guts could grow smaller. The energy that we formerly spent on digestion (and digestion requires far more energy than you might imagine) was freed up, enabling our brains, which also consume enormous amounts of energy, to grow larger. The warmth provided by fire enabled us to shed our body hair, so we could run farther and hunt more without overheating. Because we stopped eating on the spot as we foraged and instead gathered around a fire, we had to learn to socialize, and our temperaments grew calmer.

There were other benefits for humanity’s ancestors. He writes: “The protection fire provided at night enabled them to sleep on the ground and lose their climbing ability, and females likely began cooking for males, whose time was increasingly free to search for more meat and honey. While other habilines” — tool-using prehumans — “elsewhere in Africa continued for several hundred thousand years to eat their food raw, one lucky group became Homo erectus — and humanity began.”

You read all this and think: Is it really possible that this is an original bit of news? Mr. Wrangham seems as surprised as we are. “What is extraordinary about this simple claim,” he writes, “is that it is new.”

Mr. Wrangham arrives at his theory by first walking us through the work of other anthropologists and naturalists, including Claude Lévi-Strauss and Darwin, who did not pay much attention to cooking, assuming that humans could have done pretty well without it.

He then delivers a thorough, delightfully brutal takedown of the raw-food movement and its pieties. He cites studies showing that a strict raw-foods diet cannot guarantee an adequate energy supply, and notes that, in one survey, 50 percent of the women on such a diet stopped menstruating. There is no way our human ancestors survived, much less reproduced, on it. He seems pleased to be able to report that raw diets make you urinate too often, and cause back and hip problems.

Even castaways, he writes, have needed to cook their food to survive: “I have not been able to find any reports of people living long term on raw wild food.” Thor Heyerdahl, traveling by primitive raft across the Pacific, took along a small stove and a cook. Alexander Selkirk, the model for Robinson Crusoe, built fires and cooked on them.

Mr. Wrangham also dismisses, for complicated social and economic reasons, the popular Man-the-Hunter hypothesis about evolution, which posits that meat-eating alone was responsible. Meat eating “has had less impact on our bodies than cooked food,” he writes. “Even vegetarians thrive on cooked diets. We are cooks more than carnivores.”

Among the most provocative passages in “Catching Fire” are those that probe the evolution of gender roles. Cooking made women more vulnerable, Mr. Wrangham ruefully observes, to male authority.

“Relying on cooked food creates opportunities for cooperation, but just as important, it exposes cooks to being exploited,” he writes. “Cooking takes time, so lone cooks cannot easily guard their wares from determined thieves such as hungry males without their own food.” Women needed male protection.

Marriage, or what Mr. Wrangham calls “a primitive protection racket,” was a solution. Mr. Wrangham’s nuanced ideas cannot be given their full due here, but he is not happy to note that cooking “trapped women into a newly subservient role enforced by male-dominated culture.”

“Cooking,” he writes, “created and perpetuated a novel system of male cultural superiority. It is not a pretty picture.” As a student, Mr. Wrangham studied with the primatologist Jane Goodall in Gombe, Tanzania, and he is the author, with Dale Peterson, of a previous book called “Demonic Males: Apes and the Origins of Human Violence.” In “Catching Fire” he has delivered a rare thing: a slim book — the text itself is a mere 207 pages — that contains serious science yet is related in direct, no-nonsense prose. It is toothsome, skillfully prepared brain food.

“Zoologists often try to capture the essence of our species with such phrases as the naked, bipedal or big-brained ape,” Mr. Wrangham writes. He adds, in a sentence that posits Mick Jagger as an anomaly and boils down much of his impressive erudition: “They could equally well call us the small-mouthed ape.”

source:http://www.nytimes.com/2009/05/27/books/27garn.html?_r=1&pagewanted=all