Group selection solves the riddle of altruism

The group selection hypothesis explains why humans are altruistic.

 

There are many examples of altruistic behavior in our society, such as donating blood or cleaning up alleys. However, this is a puzzle from the perspective of natural selection. This is because altruistic people help others at their own expense, while selfish people can get help without putting in any effort, so altruistic people are bound to be eliminated in the survival competition between the two groups. According to natural selection, members of a society will choose the selfish strategy that favors the survival competition, and eventually selfishness will prevail in our society. However, contrary to what natural selection predicts, there are many examples of altruistic behavior in our society. Where does the ability to suppress selfishness and act altruistically come from, even when it is possible to maximize profit by getting a free ride?
One of the keys to unlocking this mystery is the group selection hypothesis. Simply put, group selection is the hypothesis that the characteristics of a group affect the survival of the group, just as the characteristics of an individual affect the survival of the individual. In other words, natural selection acts on groups rather than individuals. Altruistic behavior, which is a weakness in individual selection, becomes a strength in group selection, giving the group an advantage in the survival competition. If there were many selfish zerglings, no one would be willing to die, and it would be difficult to win a battle between races. On the other hand, if there were many altruistic zerglings, they would be willing to sacrifice themselves and help their species win.
If you look at human history, there’s a lot of room for group selection to work. In primitive tribal societies, tribal wars were frequent and highly lethal. Groups with more altruistic individuals would have been more likely to win intergroup conflicts. In hunter-gatherer societies before agriculture, success in hunting and gathering depended on how selflessly members cooperated. Selfless acts of cooperation, such as finding safe shelter and protecting people from raids, were essential for survival in harsh environments over tens of thousands of years. The more altruistic a group was, the more likely it was to survive in harsh environments.
However, there are still questions to be answered. In individual selection, altruistic individuals are not as successful as selfish individuals and are at risk of extinction, but in group selection, groups with more altruistic individuals are more successful or have a survival advantage over those without. Because individual selection and collective selection work in opposite directions, for the collective selection theory to be convincing, it must be shown that the rate of collective selection has overwhelmed the rate of individual selection.
Humans have slowed down individual selection and amplified the effects of collective selection by creating “institutions” – rules, customs, laws, etc. that affect the interactions between members of society. One of these institutions is equal income distribution. The food-sharing practices of ancient hunter-gatherer tribes acted as an equalizer, reducing the differences between altruistic and selfish individuals, making group selection more likely to occur.
Conformist cultural transmission also strongly favored group selection. Conforming cultural transmission means that if more than half of the people in a group are altruistic, more people will learn altruistic strategies, leading to more altruistic people, and if more than half of the people are selfish, more selfish people will learn selfish strategies, leading to more selfish people. The reason why conformist culture transfer is important is that even small differences within a group can make a big difference between groups. Imagine a group of 55% altruistic people and a group of 45% altruistic people. The difference between the two groups is only 10%, but if conformist culture transfer occurs within the groups, the first group will have more and more altruistic people, and the second group will have fewer and fewer altruistic people. Conformist cultural transmission would create a large gap between the groups, increasing the effectiveness of group selection.
So far, we’ve solved the mystery of how altruistic humans survived by using the theory of group selection. Group selection is the hypothesis that natural selection occurs in groups, and that group characteristics affect the survival of the group, and humans have magnified the effect of group selection through institutions and conformist cultural transmission, creating an environment in which altruistic humans can survive. Although group selection has limitations in that it is not evolutionarily stable, it is a compelling hypothesis that explains how altruistic behavior has evolved in human societies.