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Joker, the Economist

Christopher Nolan’s film The Dark Knight, is critically acclaimed as one of the best movies of all time (ranked fourth on IMDb’s top 250 movies of all time list). The character that is widely recognized as the driving force for this movie is the main villain of the movie, the Joker. The Dark Knight was a transition movie from the prototypical superhero movies, with simple heroic characters that would always defeat the villain, to a new breed of superhero movies where the heroes themselves are complex characters who have to fight against villains who do not necessarily own physical advantages, but villains who have psychological prowess driven by their individual philosophies.

The Joker represents the new wave of villains, and does so with his devout belief in the philosophy that all people will always work for their personal interests. This philosophy works well in setting up games, as it is an underlying principle in the accuracy of game theory. The most commonly referenced “game” in the movie involves the ferry scene, where the population of Gotham is all on one ship, and all of the prisoners are on the other ship. Each ferry is equipped with explosives, and the detonator is in the other ship. The Joker sets up a game such that both ferries have the ability to detonate either boat, and if neither detonates the other boat, then both boats will be blown up. Although the Joker didn’t get his result, in this case the dominant strategy would have been to blow up the other boat. However, his expectation that both ferries would be detonated without him having to detonate both was correct by game theory.

The article that this post is about talks about the opening scene from the Dark Knight, which further shows how the Joker’s philosophy is in accord with game theory and the ideas of power in networks. The article first references a more abstract situation, called the “The Pirate Puzzle”. In this situation, there are three pirates with a set amount of loot. Pirate A is significantly more powerful than Pirate B who is more powerful than Pirate C. Pirate A is allowed to propose how the money is split, and all three vote on the proposition. If A loses, then he is thrown overboard, and the next most powerful pirate, B, would take charge and propose the next plan. Although it would appear in this case that A would be weak (first to be thrown out), if the other players think backwards, he actually is able to assert his power. This is because of the perspective of the weakest link, C. If C votes B out, then there is no gain for him, as B would basically override whatever he says without A. So, keeping A alive is in the interest of C. Therefore C would always vote for A, and A would remain the most powerful.

There is a similar game posed by the Joker in the opening scene of the Dark Knight, in which the Joker and his gang rob a bank, where all of the robbers will split the cost evenly. However, the Joker offers an interesting stipulation: he instructs each robber to kill another after the other’s task is completed. All of the robbers do this without thinking, because by working for their own personal benefit it would make sense to do that: the robber whose task was completed has no value to the team, and is detracting from the total amount of money that an individual robber would make. The Joker used this philosophy without giving himself a task to do but to kill the last remaining robber, and kept all of the money with himself. This was a case where it would have actually made more sense for each of the robbers not to kill each other because the real result of working for their own benefit is themselves getting killed, but without thinking backwards, they were all killed, excepting the Joker, who came up with the plan having thought through the stipulations.

Thus, two concepts from INFO2040 have been exhibited in one scene of the movie. First, game theory is the underlying principle between the Joker’s strategy, and the strategies were discussed above. In addition, the idea of power in networks is clearly shown, as the Joker used his power as a kingpin and the ability to negotiate to end up with all of the winnings at the end of the opening scene. In addition, in the ferry scene, the network was a two node network, with both having equal power, so the result was a 50-50 split of the final payoffs(both living).



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