This blog post explores how altruistic behavior contributes to human survival and prosperity, and what its limits are, using the group selection hypothesis.
On September 8, 2016, police in Busan, South Korea, handed out plaques of appreciation to 11 citizens and a kindergarten teacher who rescued kindergarten students from a school bus rollover accident in the Gomnae Tunnel. These people put themselves at risk of a second accident to save the children in the overturned bus and disappeared without expecting any reward. It’s not uncommon to hear about people doing good things for others without expecting anything in return. We refer to these behaviors as altruistic. Altruistic is defined as “of or relating to the benefit of others rather than self-interest”. But how do we understand altruistic behavior in situations where it’s not strange to be selfish, such as helping someone else by risking your own car and safety instead of pretending you didn’t see the accident? In this article, we’ll discuss the group selection hypothesis, one of the hypotheses that explains why altruistic behavior has allowed humans to survive.
Altruistic behavior is thought to be difficult for natural selection (or, more specifically, individual selection) to select against because it involves doing something for the benefit of others that doesn’t immediately benefit you. Here’s an easy example. If there is a global drought and food is scarce, it is natural to think that someone who puts themselves first and eats whenever food is available is more likely to survive the drought than someone who is altruistic and shares food with others when it is available. However, these natural assumptions are based on a simplistic view of natural selection that focuses on individual survival.
The group selection hypothesis offers a different perspective. The process of natural selection doesn’t only involve individual selection, but also group selection. The group selection hypothesis explains the existence of altruistic human behavior from an evolutionary perspective. The theory of group selection is explained through three rationales. First, when human societies were tribal, tribal wars were common. In tribal wars, people with altruistic personalities would have fought more aggressively for the good of their tribe than people with selfish personalities. This explains why altruistic behavior would have been co-selected, as a tribe with more altruistic individuals would have a greater chance of winning the war and the tribe would have a greater chance of survival.
Second, when human societies were hunter-gatherers, hunting was a key factor in maintaining tribes. Explain that hunting success depends on how altruistically people cooperate in the hunt, so in societies prior to agriculture, groups with more altruistic personalities would have been more successful at hunting, and thus would have been selected for. Third, explain that it would have been difficult for humans to survive in such harsh environments on their own during the Ice Age, so groups with more altruistic individuals who helped each other through the harsh conditions would have been naturally selected for. This process would have allowed altruistic traits to be maintained within human groups, which would have been an important contribution to the development of human societies.
However, it’s easy to wonder whether selfishness might be more easily naturally selected for in situations of conflict between individuals than in events such as ice ages or tribal wars, since they occur much more frequently and take less time. To address this question, the collective selection hypothesis must explain that groups can select for altruism faster than individuals can select for selfishness, or at least reduce the rate difference so that altruistic behavior can be selected for through collective selection. Collective choice theory explains this through “institutions.
To illustrate, imagine a village with two groups of people: Group A, which consists of selfish people who get rich by taking advantage of immediate benefits, and Group B, which consists of people who live altruistically and have relatively little wealth because they don’t care about immediate benefits. In a society that does not have a system that reduces the income gap between group A and group B, there is a strong tendency for people in group B to imitate the behavior of very wealthy people in group A to increase their wealth. In addition, it is difficult to agree on projects that are public goods that benefit everyone because of the opposition of group A. This makes it harder to reduce the already large income gap, and it is harder to reduce the tendency of people in group B to copy the behavior of people in group A. However, if there is a system that reduces the income gap between people in group A and group B, people in group B will not feel the need to imitate people in group A who do not have a large wealth gap with them. In such a society, social consensus on projects that are public goods is also easier to achieve because there is not much difference in wealth between the members of the society. For both of these reasons, people in group B retain their characteristic altruistic behavior. Collective selection theory explains that altruistic humans can survive by collective selection because institutions exist to ensure that altruistic people continue to live that way, reducing the difference between the rates of individual and collective selection.
As with any hypothesis, there are several objections to the theory of group selection. First, as mentioned above, the speed of group selection is limited in that while it can reduce the gap between the speeds of individual selection, it cannot eventually catch up. Also, in natural selection theory, there must be a gap between groups for selection to occur. However, if selection continues, eventually there will be no difference in the level of altruism between groups, and selection will no longer occur.
Nevertheless, group selection theory remains one of the leading hypotheses to explain the existence of altruistic human behavior. It explains human traits as social animals through groups as a product of sociality, and it does not limit the scope of altruistic behavior to parent-child relationships and kin groups. It can also be applied and understood in a variety of contexts, as it can explain altruistic behavior even when there is no opportunity for future reward for altruistic behavior.
