Why do humans and animals act altruistically, even at the risk of their own survival?

Altruistic behavior is defined as sacrificing oneself for the benefit of others. This behavior is not simply due to moral education, but can be explained from an evolutionary perspective by the hypothesis of group selection, which is the process of increasing the survival rate of a group. Altruistic behavior increases the survival rate of a group, and social institutions and norms serve to encourage this behavior.

 

Altruistic behavior refers to sacrificing oneself for the benefit of others. We often see this behavior in the news when we hear about people sacrificing themselves to help others, such as those who raise money and volunteer to help people in countries affected by natural disasters like earthquakes and tsunamis, or those who die saving people who are about to fall on railroad tracks. But what causes altruistic behavior? From an evolutionary perspective, altruistic behavior is not a survival advantage at all. Organisms evolve to behave in ways that favor their own survival. This is evolutionary theory as we know it.
If acting in our own self-interest rather than helping others is a survival advantage, why do we act altruistically? Is it because of the moral education that we’ve been pounded into our ears since childhood: ‘Be good,’ ‘be kind,’ ‘be considerate and helpful? If altruistic behavior were a human phenomenon, it could be explained by education. However, altruistic behavior is not unique to humans. It’s also common in other animals, such as worker bees who spend their entire lives working for their queen, or vampire bats who share their blood with fellow bats who have failed in a hunt. So why is it that when it’s not enough to act in a way that favors their own survival, they’ll do so altruistically when it threatens their own survival?
One of the hypotheses that can answer this question is the group selection hypothesis. Before explaining the group selection hypothesis, let’s talk about evolution. The prevailing theory of evolution is natural selection. The idea is that the traits that are best suited to the environment will survive and those that are not will disappear. Imagine a group of people who can’t bend their arms, and because they can’t bend their arms, they have no choice but to starve unless someone helps them. In this situation, people with altruistic tendencies will help others, while people with selfish tendencies will just take what others give them. In this case, selfish people will have a better chance of survival. It’s important to note in this example that selfishness is an individual trait, not a group trait. As individual traits confer survival advantages, individuals with favorable traits survive, while those without favorable traits die out. In other words, the universal evolutionary process is individual selection.
However, group selection means that the process of natural selection described above occurs not only in individuals, but also in groups. When the survivability of a group depends on what traits it possesses, or how many individuals possess those traits, and thus determines whether those traits will spread throughout the population or disappear, this process is called group selection. As defined earlier, altruistic behavior is defined as the act of sacrificing oneself for the benefit of others. According to this definition, a group with more altruistic individuals will have a higher chance of survival than a group with fewer.
To illustrate how altruistic behavior can increase a group’s survival rate, let’s look at an example. Consider the Zerg from our favorite childhood game, StarCraft. One of the Zerg units is called the Defiler. This defiler is a unit that has several skills that reduce damage to allies and damage to opponents. These abilities require mana, and the skill that restores this mana is Concentration. Concentration is a skill that restores mana by sacrificing an allied unit. After sacrificing an ally to recover mana, it reduces damage to other allies, ensuring their victory and survival. This is an example of the group selection hypothesis, in that sacrificing an ally for Consumption increases the survival rate of the group as a whole. These examples are not limited to virtual reality. In real-world warfare, it is even more evident that selfless behavior increases the chances of victory and survival for allies. Risking your own life to infiltrate enemy lines, assassinate a leader, or conduct espionage can be the key to winning a war. These are selfless acts of selflessness, performed at the risk of one’s own life to ensure the victory of an ally.
However, if a group consists of only selfish individuals, that is, individuals who act only for their own benefit, the group cannot guarantee victory, and the survival rate of the group will be lower than that of a group that acts altruistically. Therefore, the more individuals who act altruistically, the higher the survival rate of the group. As altruistic groups are more likely to survive than non-altruistic groups, the process of natural selection takes place, which explains why altruistic behavior emerges.
However, it doesn’t fully explain the emergence of altruistic behavior. Another argument against the group selection hypothesis is the speed problem. The speed problem is that the speed of group selection does not keep up with the speed of individual selection. This means that the rate at which a selfish group can acquire the tendencies of an altruistic group is absurdly slow compared to the rate at which an individual can acquire the success strategies of another individual. To solve this problem, humans introduced and evolved the concept of “institutions” to slow down individual selection and speed up group selection.
For example, altruistic behavior has become more frequent by creating systems that encourage and reward altruistic behavior through social institutions and norms. These institutions include laws, education, and culture, and are structured to ensure that individuals receive positive rewards for altruistic behavior. This is an important factor in how altruistic behavior becomes a social survival strategy rather than simply an individual moral choice.
The group selection hypothesis explains why altruistic behavior can exist using the examples of StarCraft and warfare. The more people who are willing to sacrifice themselves for the good of the group, the more prosperous and survivable the group will be, which suggests that altruistic behavior emerged because it is more survivable than selfish behavior. However, the group selection hypothesis alone does not fully explain the emergence of altruistic behavior. To solve this problem, the concept of “institutions” was introduced. The fact that the group selection hypothesis does not solve the problem of speed does not make it a meaningless hypothesis, because human history has developed based on this “institution.” In addition, the group selection hypothesis is a powerful enough hypothesis to explain altruistic behavior toward strangers, which is not explained by the kin selection hypothesis, and to explain altruistic behavior in situations where there is no revenge or repetition, which is not explained by the repetition-reciprocity hypothesis.