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A review by raoul_g
The Evolution of Cooperation: Revised Edition by Robert Axelrod
5.0
This book is wholly and totally concerned with the (iterated) Prisoner's Dilemma. In case you don't know, the Prisoner's Dilemma is a mathematical game analyzed in Game Theory. Albert W. Tucker presented it as follows:
"Two members of a criminal organization are arrested and imprisoned. Each prisoner is in solitary confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:
The punishments could of course also be configured differently. But what makes this situation really interesting is to let these two prisoners meet again and again in the same situation while they are fully aware of the actions the other prisoner took in the past interactions. This, then, is called the Iterated Prisoner's Dilemma.
Axelrod wanted to know which strategies would get the best result in such an iterated game, especially when the total number of rounds to be played would not be known by the players in advance. To find this out he organized a tournament in which people from different disciplines should submit strategies to be used by the players in the game. He then let those strategies play against each other.
Although there is no strategy that always gets the best result, as the success is dependent on the kind of strategy the other player is using, one strategy has emerged as a clear winner in Axelrod's tournaments. This strategy is called Tit for Tat. This strategy is very simple and works like this: the player initially cooperates and afterwards always replicates the action of the other player in the last move. This means there is always an equivalent retaliation for defections. But what makes this strategy so successful? First of all, it is nice: It is never the first to defect which means it prevents unnecessary trouble (for example if the other player also uses a nice strategy). The second thing is, it is provocable: If it is defected against, it retaliates with the next occasion, which should discourage the other side from continuing defecting. Another important property of the strategy is that it is forgiving, meaning it does not keep defecting if the other side is cooperating after defection. This allows to restore mutual cooperation. Finally, Tit for Tat is a clear and easy to recognize strategy. Once the other player sees the pattern behind the strategy, it can easily realize that cooperation is the best way of dealing with it.
You might think that these theoretical games are far removed from reality, but the author successfully shows that this is not the case. A real-life example of the Prisoner's Dilemma was seen in the trench warfare in France during WW1. There a live-and-let-live system, that is described in more detail in the book, emerged between the enemy fronts. This shows that cooperation can emerge even between antagonists under suitable circumstances.
Furthermore, there are also a great deal of interesting examples from the field of biology. The author puts cooperation in a evolutionary perspective and shows how it is likely to have evolved even in environments of competition and selfish actors.
What starts as interesting theoretical games in the first half of book, turns into solid wisdom applicable to many situations in life in the last chapters. While most people think about life as a zero-sum game, actually most of the time this is not the case. There are countless situations where both sides can do well and mutual cooperation would be possible. The only thing standing in the way of this often times is envy and the thinking that one must be more successful than the other to be successful. The results of the tournament teach an important lesson here:
"TIT FOR TAT achieves either the same score as the other player, or a little less. TIT FOR TAT won the tournament, not by beating the other player, but by eliciting behavior from the other player which allowed both to do well. TIT FOR TAT was so consistent at eliciting mutually rewarding outcomes that it attained a higher overall score than any other strategy."
Besides giving the reader a small taste of the world of game theory, this book offers a lens through which many interactions can be understood and it proposes concrete measures to increase the chances for successful cooperation in different situations. It also makes for an overall interesting read and is still very relevant even though it was published in 1984.
"Two members of a criminal organization are arrested and imprisoned. Each prisoner is in solitary confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:
- If A and B each betray the other, each of them serves two years in prison
- If A betrays B but B remains silent, A will be set free and B will serve three years in prison
- If A remains silent but B betrays A, A will serve three years in prison and B will be set free
- If A and B both remain silent, both of them will serve only one year in prison (on the lesser charge)".
The punishments could of course also be configured differently. But what makes this situation really interesting is to let these two prisoners meet again and again in the same situation while they are fully aware of the actions the other prisoner took in the past interactions. This, then, is called the Iterated Prisoner's Dilemma.
Axelrod wanted to know which strategies would get the best result in such an iterated game, especially when the total number of rounds to be played would not be known by the players in advance. To find this out he organized a tournament in which people from different disciplines should submit strategies to be used by the players in the game. He then let those strategies play against each other.
Although there is no strategy that always gets the best result, as the success is dependent on the kind of strategy the other player is using, one strategy has emerged as a clear winner in Axelrod's tournaments. This strategy is called Tit for Tat. This strategy is very simple and works like this: the player initially cooperates and afterwards always replicates the action of the other player in the last move. This means there is always an equivalent retaliation for defections. But what makes this strategy so successful? First of all, it is nice: It is never the first to defect which means it prevents unnecessary trouble (for example if the other player also uses a nice strategy). The second thing is, it is provocable: If it is defected against, it retaliates with the next occasion, which should discourage the other side from continuing defecting. Another important property of the strategy is that it is forgiving, meaning it does not keep defecting if the other side is cooperating after defection. This allows to restore mutual cooperation. Finally, Tit for Tat is a clear and easy to recognize strategy. Once the other player sees the pattern behind the strategy, it can easily realize that cooperation is the best way of dealing with it.
You might think that these theoretical games are far removed from reality, but the author successfully shows that this is not the case. A real-life example of the Prisoner's Dilemma was seen in the trench warfare in France during WW1. There a live-and-let-live system, that is described in more detail in the book, emerged between the enemy fronts. This shows that cooperation can emerge even between antagonists under suitable circumstances.
Furthermore, there are also a great deal of interesting examples from the field of biology. The author puts cooperation in a evolutionary perspective and shows how it is likely to have evolved even in environments of competition and selfish actors.
What starts as interesting theoretical games in the first half of book, turns into solid wisdom applicable to many situations in life in the last chapters. While most people think about life as a zero-sum game, actually most of the time this is not the case. There are countless situations where both sides can do well and mutual cooperation would be possible. The only thing standing in the way of this often times is envy and the thinking that one must be more successful than the other to be successful. The results of the tournament teach an important lesson here:
"TIT FOR TAT achieves either the same score as the other player, or a little less. TIT FOR TAT won the tournament, not by beating the other player, but by eliciting behavior from the other player which allowed both to do well. TIT FOR TAT was so consistent at eliciting mutually rewarding outcomes that it attained a higher overall score than any other strategy."
Besides giving the reader a small taste of the world of game theory, this book offers a lens through which many interactions can be understood and it proposes concrete measures to increase the chances for successful cooperation in different situations. It also makes for an overall interesting read and is still very relevant even though it was published in 1984.