In this blog post, we will look at the evolutionary reasons why humans show altruistic behavior even to strangers who are not related to them.
Can a person survive on their own from the moment they are born without any help from others? Not only would they not be able to find food right away, but they would also be exposed to various external dangers, making it unlikely that they would survive. Not only humans, but almost all living things are born into a safe nest of their parents and grow up to be able to live independently. Without the protection of their parents, many of them would die as soon as they are born. For example, baby turtles run at full speed toward the sea as soon as they hatch, but most of them are eaten by predators and only a few survive. This is a good example of how difficult it is for individuals born without parental protection to survive in nature.
In addition, as can be seen from the articles about “the hero who saved a child who fell on the subway tracks” and “the faceless angel who donates to help the underprivileged,” which appear in newspapers every day, all living things receive help from numerous beings other than their parents during their lifetime. There is no doubt that people with altruistic motives are often found in our society. For example, during the COVID-19 pandemic that swept the world in 2020, numerous medical staff and volunteers risked their lives to help others. They worked selflessly in dangerous situations even though they did not receive any direct benefits. This selfless behavior occurs frequently in our daily lives, reminding us once again that humans are not beings who simply pursue personal gain.
However, it is a great mystery that the selfless cooperative behavior of humans, which appeared long ago, continues to this day, considering that the most profitable behavior for an individual is simply receiving help from others and reaping the benefits. Why do we sacrifice ourselves for the sake of altruistic acts? How did altruistic cooperation ultimately survive and evolve in competition with selfish humans in our human society? I would like to help you understand the motives of human altruistic acts, which are difficult to understand with common sense, by examining the concept and limitations of the “kin selection hypothesis,” one of the various hypotheses that explain the causes of altruistic behavior.
The blood-bonding hypothesis was formalized by a biologist named William Hamilton in 1963, and there is no better way to express the blood-bonding hypothesis than with the saying, “Blood is thicker than water.” In other words, it is natural for us to help those with whom we share blood. To understand this in detail, we first need to know what “blood” means here. When we say that we have “shared blood” with our family, siblings, and relatives, we do not actually mean that we have shared the same blood with them through blood donation, but that we “share the same genes.” So what exactly is a gene? Genes are the elements that determine the traits of an organism, such as “tall” or “fair-skinned,” and are called genes because they are the substances that are passed down from parent to child. Words like “You look just like your mother!” that we often hear around us are words that arise because the child has inherited the genes from the parents. Therefore, since the genes that the child has are only inherited from the parents, the parents, the child, and the siblings share the same genes.
Let’s get back to the topic at hand and learn about the “Blood-Choice Hypothesis.” As the idea in the book “The Selfish Gene” (Richard Dawkins) suggests, if we think about the behavior of living things from the perspective of genes rather than living things, genes will have the goal of spreading themselves as much as possible into the world. And to achieve that goal, the more children there are who are likely to share genes with each other, the better. Therefore, altruistic behavior toward a being with whom we share blood will help that being survive and, ultimately, increase the probability of spreading the genes we share. In this way, altruistic behavior is no different from the result of genes’ extremely selfish motives. In other words, the “kin selection hypothesis” starts from the premise that an act that seems altruistic to us may not actually be altruistic, ironically. This hypothesis can explain the altruistic behavior seen in the world of bees. All the worker bees in a bee colony are sisters, and the queen bee is the “chosen one” among these sisters, so all the eggs that the queen bee lays become the niece of the worker bees. At this time, rather than eating raw food, worker bees work hard to raise their sisters, who were born by the queen bee, and feed their relatives. This is advantageous for them to pass on more of their genes to their descendants. Therefore, the extreme altruism shown by worker bees, who work only for their entire lives, is not a sacrifice from the perspective of genes if the blood-choice hypothesis is applied.
But is this hypothesis really true? If it is, we will live a cold and dry life in which we no longer need to feel warmth and gratitude in all future acts of altruism. But fortunately, there is a big flaw in this hypothesis when it comes to explaining acts of altruism. Above all, this hypothesis cannot explain the altruistic acts provided by beings who are not even a drop of blood apart. Just as mixing water with paint dilutes and thins the paint, the proportion of genes shared between me and my offspring will decrease as I have children through marriage with a spouse who does not share my genes, and as those children have children of their own, and so on. From a genetic standpoint, helping an individual with a high proportion of genes in common with oneself is ultimately more beneficial for spreading those genes, so according to the kin selection hypothesis, we should help those who are more closely related to us, and for the same reason, we should not help those who are not related to us. However, in reality, as we see in newspaper articles, there are many cases of helping people we don’t know at all. In addition, according to Tim Clutton-Brock of the University of Cambridge, meerkats who are not related to each other take turns standing guard and, when an intruder appears, they loudly warn of the danger of revealing their location. Through various counterexamples that exist, it can be seen that the ‘Blood-Choice Hypothesis’ has limitations in explaining altruistic acts that occur between beings that are not related by blood.
As such, the kin selection hypothesis provides a new perspective that altruistic acts are motivated by selfish genes by looking at altruistic acts from the perspective of genes rather than the perspective of individuals. However, this hypothesis has a fatal limitation in that it cannot explain good deeds that occur between beings who are not related by blood. However, it is clear that the theory of kin selection is a very strong argument in explaining the altruistic behavior of individuals found in particularly highly organized bee or termite colonies. In addition, our ancestors have lived in kin-based groups for a very long time in human history, so the process of kin selection must have influenced the maintenance and evolution of our altruistic traits. Considering this, the kin selection hypothesis is significant in that it is the first hypothesis to provide an important key to explaining the motivation for altruistic behavior that everyone has been curious about. If this hypothesis is supplemented with a hypothesis that explains altruistic behavior between individuals who are not related, it is expected that it will perfectly explain why the altruistic cooperation that has led to long-term research and debate has been able to be competitive evolutionarily.
