WE ARE ALL INTELLIGENT DESIGNISTS NOW:

In Games, an Insight Into the Rules of Evolution (CARL ZIMMER, 7/31/07, NY Times)

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.

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. [...]

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.

All that is required in order to make progress in the field of evolution is that you completely abandon the canard that it is random or Natural.

Posted by Orrin Judd at August 1, 2007 9:31 AM