prisoners+dilemma

__Prisoner’s Dilemma__

Description: The prisoner’s dilemma is most easily explained through the following example… Two men, Rick and Bob, have been arrested for a crime that was recently committed. Rick and Bob are isolated in different rooms and given an opportunity to confess, (betray their partner in crime). The prison sentence is determined by what each man says in isolation. The following matrix summarizes the possibilities:




 * || __Bob Quiet__ || __Bob Betrays__ ||
 * __Rick Quiet__ || Both get 1 yr. || Bob free, Rick gets 10 yrs. ||
 * __Rick Betrays__ || Rick free, Bob gets 10 yrs. || Both get 3 yrs. ||



Each man wants to avoid jail time, however if both men attempt to sellout the other they end up getting a longer sentence than they would have if they both would have stayed quiet. The prisoner’s dilemma scenario is driven by greed, as a result rarely creates the best possible situation for both parties involved.

Real Life Examples: The Tour de France, the world’s most celebrated cycling race, has a version of the prisoner’s dilemma. Most of the riders move along the course in a big group called the pelaton. However, two riders often sprint ahead of the pelaton by themselves to try to win the stage or gain a time advantage. Once ahead of the pelaton, the two riders must take turns riding in the front to maintain or build on the lead that was created by sprinting ahead of the pack. The rider in the front does most of the hard work, while the second rider recovers energy by staying out of the wind (drafting). If both riders do not take equal amount of time in the front, the pair will slow down and the pelaton will catch back up and likely pass them. But if both riders share the front position equally, the lead will be maintained and the pair will finish 1st and 2nd. Another real example is advertising when there are only two major competitors. If the two companies produce equal products, revenue depends on the amount of advertising that is done. Both companies would be profitable doing very little or no advertising. If Company A advertises and Company B doesn’t, Company A would benefit greatly, and vice versa. The worst scenario would be for both companies to advertise extensively and neither company receive larger market shares, (only increase costs).

References: Anonymous (2003, August 11). //Prisoner's Dilemma//. Retrieved March 1, 2007 from Stanford, Encyclopedia of Philosophy Web site: http://plato.stanford.edu/entries/prisoner-dilemma

Analysis of prisoner’s dilemma scenarios by Robert Axelrod has indicated that over a long period of time with many different players several conditions may exist in successful strategies.

First, all top scoring strategies were “nice”. One might assume that most players would adopt a strategy of defecting before the opponent does, this was not the case in most winning strategies, as taking a purely selfish stance for “greedy” purposes did not do as well as those that were “nice”. While this may lead one to a strategy of “always cooperate”, Axelrod also found that “retaliation” was also an important part of winning strategies. The third aspect of winning strategies was to be “forgiving” this is to get back to a mode of cooperation if the other player does not continue to defect. The last quality was to be “non-envious”. This means not striving to score more than the opponent, another aspect of attempting to reach a mode of cooperation.

The real life example given was an arms race between two countries. Even though both countries continued to increase military spending, a form of retaliation, they both fell back to cooperation to end a continuous string of “defects”. This is an example of using the forgiving and non-envious characteristics to end a long running string of revenge and counter-revenge, which may have resulted in the two countries going to war with each other.