This article explains why humans should act altruistically, and how the group selection hypothesis explains it. It presents the theoretical background for the evolution of altruism, including the conflict between group selection and individual selection.
Why do altruistic people exist in an age where it’s hard to take care of yourself? Is there a reason for me to be altruistic? For people to be altruistic, there has to be a good reason. Otherwise, people will live selfishly, making choices that are convenient for them in the moment. I read The Emergence of Altruism and chose the “group selection hypothesis” as the answer to the question of why we should be altruistic. Let’s look at what the group selection hypothesis is and why it is a good reason to be altruistic.
When asked who would win a war between a group of altruistic people and a group of selfish people, most people would expect the altruistic group to win. This is because people acting for the good of the group makes the group more competitive. In wars and many other survival competitions, the group with the most altruistic people would have an advantage. If this has been the case since the dawn of humans, and if the trait of altruism is inherited, then the proportion of altruistic humans should increase over time. This phenomenon, in which individuals and groups with traits that are favorable for survival survive and leave more offspring, increasing the proportion of individuals and groups with those traits, is called natural selection. For example, if a group of smart, strong individuals and groups compete for limited resources in the same environment with a group of dumb, weak individuals and groups, the former will survive, and they will leave more offspring. This will repeat over many generations, increasing the proportion of stronger and smarter individuals. Natural selection on a group is called population selection. What we’ve described above can also be considered group selection. The hypothesis that the current number of altruistic people is due to such group selection is the group selection hypothesis in The Emergence of Altruistic Humans.
However, this hypothesis is not easily explained completely, because natural selection includes individual selection as well as group selection. If an altruistic person competes with a selfish person, who will survive? To answer this question, let’s set up a situation. A selfless person A and a selfish person B, who are both physically and mentally identical, live in the same group. A distributes food to people as it becomes available, while B stores it all in his warehouse. In this situation, B is much more likely to survive if food suddenly becomes unavailable. In this and many other situations, a clearly selfish person is more likely to survive and leave offspring than an altruistic person. Here we see a conflict between group selection and individual selection. Collective selection is favoring more altruistic humans and individual selection is favoring fewer altruistic humans.
This doesn’t mean that the collective selection hypothesis is an unreasonable explanation. Think of a tug of war: two teams are clearly pulling in opposite directions. Does that mean the rope will stay in place? No, it doesn’t. It will be pulled in the direction of the stronger team. In this topic, think of it as a tug of war between collective and individual selection. If collective selection is stronger, there will be more altruistic humans, and if individual selection is stronger, there will be fewer altruistic humans. It is not easy to prove that group selection is stronger than individual selection, but the authors of The Emergence of Altruism argue that there must be an influence of group selection on the evolution of altruistic humans.
So far, we have discussed the meaning of collective selection, the meaning of individual selection, the definition of the collective selection hypothesis, and the limitations of the collective selection hypothesis. While there are certainly limitations to the group selection hypothesis, it gives us a reason to be altruistic. It suggests that individuals should live altruistically in order for the group we belong to to survive. Of course, this hypothesis is open to refutation. This is because of the conflict with individual choice mentioned earlier. However, with more experiments and observations, it’s likely that this theory will become a more logical and complete explanation.
