This article explains human altruistic behavior with the repetition-reciprocity hypothesis and explores the reasons and limitations of why people still follow social norms in situations where this hypothesis does not apply.
In the movie Titanic, the male protagonist, Jack Dawson, sacrifices himself to save the woman he loves when the ship he is on sinks. Most people who see this scene will be moved by his sacrifice. However, if we question his sacrifice, we can understand the act of cooperation in human society.
Although the above example is extreme, it is a type of “altruism”. An altruistic act is an act that benefits others, but not the actor himself. To understand altruism, consider a situation where a high school student, A, borrows a gym uniform from his friend, B, who is also a high school student. From B’s perspective, this is an altruistic act that requires sacrifice on B’s part because the gym clothes will get sweaty and dirty, so it’s in B’s best interest not to lend them out. Even if A has lent B a lot of gym clothes in the past, or has often bought B delicious food, it doesn’t change the fact that it is in B’s self-interest not to lend B gym clothes now. Nevertheless, B lends A the gym clothes, and we take this decision for granted. Why?
This question can be explained by the repetition-reciprocity hypothesis, one of the models that explain human altruism. According to this hypothesis, human altruism is based on the principle that “I am only willing to help someone if he has helped me before.” In other words, if you have lent me a gym shirt, I will lend you a gym shirt, or if I help you now, you will help me later. The principle of “an eye for an eye and a tooth for a tooth” is the basis of reciprocity. Another way to look at the principle of reciprocity is that I lend you my gym clothes now because I’m afraid you won’t lend me your gym clothes later (retaliation).
Let’s look at cooperation when a third party is involved. If B asks A to lend him his gym clothes, C doesn’t know A, so there’s no chance that C will be able to help him later. However, even in this case, C is likely to lend A the gym clothes. This is due to indirect reciprocity. According to indirect reciprocity, if your betrayal is known not only to your opponent but also to his or her circle of people, you will refrain from betrayal because it will result in greater retaliation. In other words, if C doesn’t lend A the gym clothes, B and C’s cooperation will be ruined, so C will cooperate with A. This indirect reciprocity is more effective in small groups where the ties between members are stronger.
The principle of reciprocity requires that the interaction between actors will continue. If there is no longer a need to cooperate in the future, i.e., if there is no retaliation, it is more beneficial to betray. Therefore, the repetition-reciprocity hypothesis can only explain situations where the interaction between actors continues, or is repeated with high probability, and it is not known when the interaction will end.
This is where the repetition-reciprocity hypothesis has its limitations. Altruistic tipping occurs even in situations that will never be repeated, such as eating at a restaurant in a travel destination. In this case, not tipping will not be retaliated against in the future, so even though it is in the individual’s interest not to tip, people tip at a loss. Altruistic behavior in the absence of retaliation cannot be explained by the repetition-reciprocity hypothesis. This is because the reciprocity hypothesis assumes “conservative” humans, where agents try to maximize their own self-interest. Conservative agents are limited in that they cannot take social norms or consensus into account.
In addition, retaliation under the reciprocity hypothesis is difficult to enforce in systems with multiple interactors, such as human societies. If a betrayal occurs in a multi-party transaction, it is difficult to identify the betrayer. In this case, it is impossible to retaliate against the traitor, so betrayal is in the best interest of the group. Even if the traitor can be identified, it is difficult for anyone to take the initiative to retaliate if it is costly to punish the traitor.
As we have seen, the repetition-reciprocity hypothesis, which states that cooperation occurs because betrayal is detrimental to long-run transactions when transactions between actors are repeated, requires two premises. The probability of repeated transactions between two actors must be high, and actors must act according to the reciprocity principle of an eye for an eye and a tooth for a tooth. The repetition-reciprocity hypothesis is appealing because it can explain altruistic behavior in many of the situations that recur in our daily lives. However, it has limitations in that not all situations in which altruistic behavior occurs are repeated, and the principle of reciprocity does not work well in transactions between many people. The reason the repetition-reciprocity hypothesis is limited is that humans are not conservative. Even in non-recurring situations, humans tend to align themselves with social norms and social conventions. To address the limitations of the repetition-reciprocity hypothesis, we need to consider this aspect of human behavior.
