I hoped I would have some time to read (and write!) during vacation, but it didn’t happen. However I was able to catch up on some of the articles I’d saved with Instapaper. One I particularly enjoyed was from the slow web, by which I mean it was an article with long-term relevance that required more time to read and digest than a bite-sized blog post,
Edge master class 2011: The Science of Human Nature. The Evolution Of Cooperation
This article is from 2011, and I don’t remember how it got into my Instapaper. It’s the kind of article that makes me wish I were back in school. Martin Nowak is a mathematical biologist, and the article is a transcript of a talk describing his research into how cooperation can emerge through the process of evolution and natural selection.
The topic is well-known to any student of evolution, a subject that interested me greatly when I took a series of classes on the history of science as electives while completing my Bachelor Degree. The importance of this subject derives from the apparent contradiction between cooperation and evolution: in an evolutionary process in which natural selection favors survival of the fittest, cooperation among individuals should not emerge. To understand why this might be so requires first understanding what is meant by cooperation: one individual’s fitness is diminished by cooperating with a second individual whose fitness is improved. If natural selection favors survival of the fittest, then individuals tending to help others at their own expense will be less fit and the expressed trait (collaboration) will disappear.
Obviously, it makes a big difference whether natural selection operates on individuals, on groups or on populations. Nowak discusses this and I won’t elaborate on that point here. Of course, cooperation does occur so there must be some way to explain how it could evolve. He goes on to discuss several possible mechanisms that would favor collaboration and cites a lovely passage from Darwin, which I will reproduce here,
Here is a beautiful quote from Charles Darwin from his 1871 book, “There can be no doubt that the tribe including many members who are always ready to give aid to each other, and to sacrifice themselves for the common good, would be victorious over other tribes. And this would be natural selection.”
The original quote is from chapter five of The Descent Of Man.
The most fascinating part about the transcript was Nowak’s description of a series of experiments he undertook revolving around a game called The Prisoner’s Dilemma devised to test survival strategies. The game has two players and each can choose between cooperation and defection. It costs a player to cooperate, but if the other player cooperates with him, he receives a payoff. If the other player defects, then he receives no payoff and thus incurs a net loss. It is easy to see that the optimal strategy for both players in a single round of the game is to defect. At worse they neither gain or lose. At best they receive a payoff if the other player cooperates. In any case, cooperation seems to be a risky strategy because of the chance it results in a loss if the other player defects.
Or does it? Since a series of repeated encounters is a better description of interactions between living beings than a single isolated one, Nowak studied strategies for repeated rounds of the Prisoner’s Dilemma. When he looked at the best strategies for playing repeated rounds of the game, he found something quite different: the best strategies for winning a series of encounters involved cooperation and integration of feedback concerning the other player’s actions. In fact, the best strategy was one called “Tit-for-Tat.” To play the game following this strategy, on the first round you start with cooperation, and on subsequent rounds you do the same thing the other player did on the previous round. For example, if you start cooperating in round one and the second player defects, then you defect on round two. If in round one the second player cooperates instead, then on round two, you cooperate again.
Nowak described several different variations of the game and strategies. I’m not going to go into a detailed description of them here. If you’re interested, I highly recommend reading the transcript; it’s time well-spent.
The importance of this work is that it shows so clearly that selfishness is not the best strategy. The person who defects (cheats you) in your first encounter is not being smart. Although he may make off with a temporary gain, in the long-term that strategy will cost him. This statement is true not because such behavior seems morally wrong or because we’d like to think the world is based on fairness, but because Martin Nowak’s study objectively demonstrates that this is so,
What I find very interesting in these games of conditional reciprocity, direct and indirect reciprocity, we can make the point that winning strategies have the following three properties: they must be generous, hopeful and forgiving.
Hopeful is that if there is a new person coming, I start with cooperation. My first move has to be cooperation. If a strategy starts with defection, it’s not a winning strategy.
And forgiving, in the sense that if the other person makes a mistake, there must be a mechanism to get over this and to reestablish cooperation.
This is analysis of just what is a winning strategy. This is not an analysis of what is a nice strategy, this is just an analysis of what is a winning strategy, and it has these properties.
That is simply beautiful. Anyone who’s ever needed to answer the question “Everyone else is acting selfishly so why shouldn’t I?” should find inspiration in these words.
In fact, if everyone had the chance to read and understand this, just maybe the world would be a better place.