In this blog post, we’ll explore why human altruism exists based on the Repeated Reciprocity Hypothesis presented in ‘The Emergence of the Altruistic Human’, and we’ll examine the implications and limitations of this hypothesis.
Understanding Human Altruism Through the Repeated Reciprocity Hypothesis
The movie ‘Himalaya’, based on a true story, depicts the protagonist risking his life to climb Mount Everest amid a raging blizzard to rescue a stranded colleague. The protagonist of this film can be considered a prime example of an altruistic person who does not seek only his own benefit but helps others. If we look around us, we can easily find people who donate to others, share their food, and willingly give up their own interests.
Yet, the fact that so many altruistic people exist may seem strange at first glance. If altruistic people were to constantly sacrifice themselves solely to benefit others, selfish people would continue to take advantage of them, and the altruistic would always end up at a disadvantage. If this pattern were to repeat itself, altruistic people should have been weeded out in a competitive society and eventually disappeared. However, in reality, there are still many altruistic people, and altruism is deeply rooted in human nature. So how can this phenomenon be explained?
One explanation for this question is the repeated reciprocity hypothesis. The repeated reciprocity hypothesis posits that when someone is repeatedly faced with a choice between altruistic and selfish behavior, they ultimately choose to act altruistically out of fear of future retaliation if they were to act selfishly.
A simple example is a butcher who honestly tells a regular customer, “The meat isn’t in good condition today, so please choose a different cut.” This is because building trust and maintaining a long-term business relationship yields far greater benefits than deceiving the customer for immediate profit. Let’s now examine the repeated reciprocity hypothesis in more detail through the following story.
The Repeated Reciprocity Hypothesis: A Case Study from a School Flea Market
Imagine a school flea market at an elementary school. This flea market is held weekly by each class, and the items for sale consist of goods that students bring from home. The proceeds from sales are divided equally among all students in the class. Therefore, the more items sold, the greater the profit for the entire class. If students bring high-quality items, they can sell them at a higher price, increasing the class’s total profit. Willingly offering items that one could easily use oneself can be viewed as altruistic behavior. Conversely, if a student brings very low-quality items out of a desire to hold onto them, those items may sell for a low price or not sell at all. This type of behavior is considered selfish.
Now, let’s assume your class consists of just two people: you and a friend. You are not the type of person who helps others unconditionally. If your friend brings a good item, you’ll bring a good item next time as well; however, if your friend brings a poor-quality item, you’ll also bring a poor-quality item to the next flea market. This can be seen as retaliatory behavior toward your friend. As this situation repeats, your friend comes to expect that if they bring a poor-quality item this time, you will also bring a poor-quality item next time. Eventually, realizing that their own profits will decrease, they will bring a good-quality item to avoid future losses. In other words, they choose altruistic behavior to avoid retaliation.
For the repetition-reciprocity hypothesis to hold true here, two important premises are necessary. First, situations requiring a choice between altruistic and selfish behavior must occur frequently enough. Second, there must be conditional altruism—where one’s behavior changes based on the other party’s actions—rather than unconditional altruism.
Limitations and Significance of the Repeated Reciprocity Hypothesis
However, the repeated reciprocity hypothesis alone cannot fully explain human altruistic behavior.
We often engage in altruistic behavior even when the situation in which we must choose between altruistic and selfish actions does not recur, and even when we cannot expect any reward for our actions at all. Typical examples include helping an elderly person with their luggage whom we happen to meet on the subway or donating to a Salvation Army collection box.
Furthermore, the repeated reciprocity hypothesis fails to adequately explain the situation in the earlier flea market example when the group consists of multiple people rather than just two. For example, even if I choose not to bring good items to the next flea market to retaliate against a selfish friend, other students may still bring good items. In this case, the loss incurred by the friend who acted selfishly is much smaller than when there were only two people. Therefore, he is likely to choose to act selfishly again without much hesitation. In other words, as the size of the group increases, the effectiveness of an individual’s retaliation inevitably weakens.
Through the previous flea market example, we examined what the repeated reciprocity hypothesis is and what limitations it has. According to the repeated reciprocity hypothesis, assuming that the choice between altruistic and selfish behavior is repeated sufficiently, people choose to act altruistically in order to expect future rewards or to avoid future retaliation.
Of course, this hypothesis alone cannot explain all human altruistic behavior. Nevertheless, the repeated reciprocity hypothesis is one of the theories that offers a relatively convincing explanation of human altruism. For example, the explanation that people behave more altruistically toward those with whom they share closer kinship ties does not sufficiently account for the various altruistic behaviors observed even among people with no kinship ties. In contrast, the repeated reciprocity hypothesis has the advantage of being applicable to transactions or cooperative relationships between people with no kinship ties whatsoever.
Ultimately, the repeated reciprocity hypothesis is a meaningful theory that explains how human altruistic behavior—which at first glance may seem purely irrational—can in fact be a rational choice made with future cooperation and trust in mind.
