Why do humans act altruistically? (Human and animal altruism and group selection theory)

This article explores the differences in altruistic behavior between humans and animals and explains how altruism spread through group selection theory. It discusses how a variety of factors play a role in promoting altruism in human societies, including cooperative behavior in early humans, equitable income distribution, and adaptive cultural transmission.

 

Why do we act altruistically, and how does human altruism differ from that of animals? In biology, altruism is when an individual helps another individual, even at the expense of their own resources (energy, food, etc.). It’s easy to assume that behavior that involves wasting one’s resources for the sake of others would be eliminated by natural selection, but altruistic behavior is actually common in both animals and humans. There are many hypotheses to explain this unusual behavior, but one that is particularly applicable to humans is the group selection hypothesis. In this article, we’ll look at the influences that have led to the spread of altruism in human society.
If we look at human history and culture, we can see that altruistic behavior has been the foundation of society. Early humans formed communities through cooperation and division of labor to survive, and this cooperative behavior naturally promoted altruism. For example, sharing resources from hunting and gathering increased the survivability of the group as a whole. Altruistic behaviors strengthened social bonds and promoted trust and cooperation within the group. Altruistic behaviors thus became more than just personal goodwill; they were essential for the survival and prosperity of the group.
First of all, group selection is the process by which a group with a certain trait has an advantage over a group without it, and that trait eventually spreads throughout society. In contrast, individual selection is the process by which individuals with a trait have an advantage over individuals without that trait, and the trait spreads. In nature, this is usually done genetically, where individuals with favorable traits reproduce more, but in human societies, it is also done culturally, where individuals without favorable traits copy the success strategies of individuals with favorable traits.
Before we get into the nitty gritty, think of raids in RPG games. A raid is a hunt for a large monster that drops much better items than a normal monster, but can only be captured by a group of dozens of people working together. If you were one of the people participating in a raid to kill a very powerful monster, what would be the simplest strategy to survive the hunt? Be a passive participant in the hunt without being seen. If you focus on sneaking around while everyone else is actively attacking monsters and getting attacked, you’ll be less likely to die, and you’ll get an equal share of the loot for participating in the raid. On an individual level, selfishness favors the selfish, so individual choice works in favor of more selfish traits. However, from a guild’s perspective, a guild with more people actively participating in raids has a better chance of succeeding in raids. In other words, collective selection favors altruistic traits.
As you can see, individual selection and group selection work in different directions for the trait of altruism. It is difficult to use group selection to explain altruism in animals because the forces of individual selection are generally stronger than those of group selection. In human societies, however, we can use collective selection because there are regulations that slow down individual selection and strengthen collective selection.
One such system that slows down individual selection is equal income distribution. Going back to the raid example, you’re a dedicated raider, and you notice that one person is doing nothing but running away. At first, you’re angry, but then you think about how you’d rather be that selfish. You calculate the actual gain that Yamcha would get from running around and dodging attacks, and it seems to be about the same as the effort it would take to participate fully, and at most, you’d probably save a health potion or two by taking one or two fewer hits. So you don’t bother to follow the selfish strategy and continue to participate fully in the group’s hunting success.
The smaller the gain from selfish behavior, the smaller the power of individual choice. When there is less disparity between individuals through equal income distribution, the likelihood of adopting a selfish strategy that does not result in a large payoff is smaller, and the pressure for individual choice is lower. Many hunter-gatherer tribes that still exist in remote parts of the world have strong equality of income distribution, which suggests that collective rather than individual selection may have been stronger than individual selection until about 10,000 years ago, when most of humanity was still dependent on hunter-gatherers.
Another reason why group selection is so strong in human societies is called ‘acculturation’. In a nutshell, it’s a process in which the higher the proportion of altruistic people, the smaller the spread of selfish strategies, and the higher the proportion of selfish people, the faster the spread of selfish strategies. For example, if the proportion of altruistic people is 60% of the population, it’s easy to think that a random selection of people to learn altruism or selfishness would have a 40% chance of selecting a selfish person, but in reality, the probability of selecting a selfish person is much smaller than 40%. The reason for this phenomenon is that if there is a majority of altruistic people, they will try to spread altruism through the media, schooling, etc. To use the raid analogy again, before a raid, most of the altruistic members will be influenced by the process of encouraging and convincing each other to participate. However, a single selfish Yamcha will have little effect on the group because most members will not even know it exists.
The effect of conformist transmission on group selection is as follows. If conforming cultural transmission works, selfish groups will have a faster rate of individual selection, and altruistic members will disappear very quickly, leaving most of the group with selfish behavior. The altruistic group, on the other hand, has a slower rate of individual selection, which means that altruistic members are lost more slowly. Eventually, the gap in the proportion of altruistic members between the two groups becomes wider than it was at the beginning, and the effect of group selection becomes stronger.
So far, we have seen how group selection and individual selection affect the propagation of altruism and the two bases for amplifying the effect of group selection in human societies. Let’s return to our initial question. Humans have always lived in groups (tribes, villages, etc.), and the nature of these groups can be explained by the fact that they tend to exhibit group selection, which is difficult to see in animals, and have evolved towards altruism where the group benefit is greater.