In this blog post, we’ll explore the question of why people engage in altruistic behavior through the “costly signaling hypothesis.”
Deer have large antlers on their heads, which are also well known as “deer velvet.” The larger a male deer’s antlers are, the more does he can lead; if he loses his antlers in a fight, he may be completely ostracized from the deer herd. However, this is something that isn’t easily understood at first glance. This is because larger antlers make it easier for predators to spot them and inevitably hinder their ability to flee. Nevertheless, the reason a male deer’s massive antlers serve as a measure of attractiveness is that the male is essentially demonstrating to female deer through his physical appearance: “Because of these large antlers, I’ve survived even though I’ve been in far more dangerous situations than that male with smaller antlers. That’s how capable I am as a stag.” This is a prime example of the “costly signaling hypothesis.” We’re examining this hypothesis because it offers one possible answer to why people engage in altruistic behavior.
Before we find the answer to the question above, let’s take a look at the “costly signaling hypothesis.” The core of this hypothesis is that “the cost of a signal guarantees its authenticity.” Let’s imagine a situation where I confess my feelings to a guy I have a crush on. I would want to convey the message to him that “I’m someone worth dating,” because that increases the likelihood of my confession succeeding. To signal that I’m financially well-off, I prepare an expensive gift.
In this scenario, two main situations are possible. The first is when I am actually financially well-off, so the cost of preparing the gift isn’t much of a burden. In this case, even if I buy the gift, I don’t have to give up much. Even though there is a cost, the benefit of having my financial standing recognized and starting a relationship with the other person outweighs that cost, so I’m likely to prepare an expensive gift, confess my feelings, and succeed.
Conversely, the second scenario is when someone is not actually financially well-off but wants to appear that way. In this case, the cost of sending the signal is very high, as they must save their allowance for several months just to afford a single expensive gift. The sacrifices required to pretend to have means when one does not are excessively great. Ultimately, if they determine that the cost of sending the signal outweighs the benefits of dating the other person, they are likely to give up on confessing their feelings altogether.
To summarize, the recipient of the signal comes to believe that only those with actual means can send expensive signals. Consequently, they place greater trust in the financial standing of the person who prepared the expensive gift and accept that signal as genuine.
Now, let’s move on to the topic of altruistic humans. In fact, how altruistic behavior evolved in human society remains a subject of ongoing research in evolutionary biology and evolutionary psychology. This is because if someone acts altruistically toward me, it seems more advantageous for me to receive the benefit without paying any cost. Nevertheless, in reality, many people live their lives engaging in various altruistic behaviors, such as donating or volunteering. Several theories have been proposed to explain this phenomenon, and one of them is the “costly signaling hypothesis” we examined earlier.
For example, let’s imagine a man who wants to signal to a woman that he is financially well-off and generous in order to win her favor. Simply saying, “I’m financially well-off, and I can buy you anything you want,” incurs almost no cost to send the signal. Therefore, it is difficult for the other person to easily trust that statement.
Conversely, if he says, “I donated this much to an animal shelter,” the situation changes. If the donation actually took place, the cost of the signal is proportional to the amount donated. Donating is not an action that directly benefits one’s livelihood. Nevertheless, the fact that he can donate a substantial amount serves as a signal that he is financially well-off. Therefore, the other person is much more likely to trust this action than mere words.
So far, we have examined the “costly signaling hypothesis” as one explanation for why people engage in altruistic behavior. As examples, we looked at the case of male deer, which are more popular the larger their antlers, and the case of someone preparing an expensive gift to demonstrate their capabilities to a romantic interest. Furthermore, we have seen that altruistic behaviors, such as charitable giving, can also serve as costly signals to demonstrate one’s hidden abilities or qualities to others.
Ultimately, according to this hypothesis, altruistic behavior is not performed solely for the sake of others, as the dictionary definition suggests, but may also be an action intended to reveal one’s attractiveness or abilities and gain favor. This perspective is significant in that it interprets altruistic behavior differently from conventional views. In other words, rather than viewing altruistic behavior at face value, it focuses on the individual’s self-interest and the signaling function underlying such behavior.
However, the “costly signaling hypothesis” has clear limitations. It is difficult to fully explain the behavior of people who perform good deeds without anyone knowing solely through this hypothesis. Therefore, to understand human altruism, it is necessary to examine it comprehensively in conjunction with various evolutionary theories, such as the theory of reciprocity and kin selection theory.
