How to Outsmart the Prisoner’s Dilemma

TED-Ed. (2020, August 27). How to outsmart the Prisoner’s Dilemma – Lucas Husted [Video]. YouTube. https://www.youtube.com/watch?v=emyi4z-O0ls

This video provides a very good summary of the reasoning behind the infinite prisoner’s dilemma game. It begins with setting up the prisoner’s dilemma scenario with two gingerbread men who are having limbs eaten by a fox. If they both choose to spare, they each lose one limb, if one scarifies the other, the sacrificed one is eaten and the one that sacrificed goes free. If they both sacrifice the other, the fox eats three of their limbs. Since the game is a simultaneous complete information game (the moves happen at the same time and all outcomes are known), for both of the other player’s moves, the best option is to sacrifice. Both of the gingerbread men sacrificing results in the “Nash Equilibrium” being to sacrifice, since nothing can be gained if you cooperate. The video then goes on to look at infinite games, where each round is a repeat of the last. Since the gingerbread men now also have to value their future limbs and can use the past actions to inform their decisions, choosing to sacrifice now can be used as a punishment if the other player ever deviates. A new equilibrium can now be calculated, this time focusing on how much the players values their future limbs compared to their current limbs.

• This video helped explain to me what causes the Nash Equilibrium. Since the equilibrium is caused by only the single interaction and looking at the best outcome for one individual based on what the other choses, that’s why the rational equilibrium of the game is to betray.
• I had never seen the equation to calculate how much the players would need to value their future situation to affect the equilibrium of their current situation. This is incredibly helpful to viewing what would happen in a continuous game, especially when looking at how different people, who have different values, would act differently.

This is helpful to my guiding question because it provides a very good summary and example of the prisoner’s dilemma and shows how it would play out in a concise way. Most of the examples that I found were focused on being very technical and looking at it from a more math heavy focus, while this is working to present the game in a simple to understand way.