Chimpanzees and the Ultimatum Game
http://www.pnas.org/content/110/6/2070.full.pdf+html
In 2012, scientists wanted to test the outcomes of the Ultimatum Game on chimpanzees, to assess if humans were the only species capable of compassion and the desire to share. To accomplish this, the scientists set up an Ultimatum Game for the chimpanzees, in which they chose tokens that would be exchanged for food. When the one chimp offered the token to the second, the second chimp could either refuse the offer by not handing the token back to the experimenter, or accept the offer by handing it back to the experimenter. If the chimp accepted the offer, both chimps shared the food they earned, but if no offer was accepted, neither chimp received anything. Mirroring the results of human experiments, the chimpanzees were more likely to accept the offers during Ultimatum Games, when they knew they were working together for a mutual reward. However, during a Dictator Game, in which the chimp does not rely on another animal to receive an award, the chimps acted more selfishly. This also reflects human behavior, as in Dictator Games, humans are more inclined to propose an uneven split of money, when they know that they are not harming a person on the other end of the trade.
This experiment relates to our in-class discussion regarding game theory and dominant strategies. The Ultimatum Game is, as implied, a game, and requires the cooperation of both sides to reach the maximum payoff. The chimpanzees were capable of realizing that splitting the food was, in fact, a dominant strategy. The reason for this discovery could be twofold, as the researchers demonstrated. The chimps could have been acting out of pure empathy, as they realized that by accepting the offer and splitting the food, they were benefitting the other chimp. Conversely, they could have also been acting out of their own self-interest. Perhaps, the chimps recognized that if they refused the offer, then they themselves would not reap any reward from the game. Either explanation demonstrates that splitting the offer of food was always a best response, and therefore a dominant strategy.