Why Some Monkeys Would Rather Throw Away Food Than Accept an “Unfair” Deal

Imagine a monkey does not want a certain type of food, especially if it has just worked for it, going as far as throwing it away? Sounds irrational? Yes, in most cases!

However, this has nothing to do with hunger but with a more profound appreciation of fairness, according to research. It has been observed that some of them are sensitive to the distribution of rewards, in studies done with different species of monkeys.

Monkeys feel a certain frustration if they feel they are not treated equitably for their efforts. Is it surprising? That’s what Science says!

Inequity Aversion in Capuchins and Chimpanzees

In a study, where monkeys were trained to exchange tokens for food, this came out as a famous instance of this phenomenon. When one monkey got a desirable treat such as a grape, while another monkey got an undesirable treat, such as a cucumber.

In most cases, the latter monkey frequently refused the treat or even tossed it back. This phenomenon is known as “inequity aversion.”

If you’re wondering if it’s just one animal, you’re wrong! Chimpanzees have similar behaviors, in fact, slightly more complex ones. They will not only refuse to participate if they are treated less favorably than another animal, but they will even refuse to take a reward if they are treated more favorably. This phenomenon shows that chimpanzees are aware of fairness.

Additionally, research has found that macaques have no reaction towards unequal rewards, but there have also been studies, including ones published on PubMed, which have found that long-tailed macaques have refused unequal rewards when they see other macaques receiving better ones.

Cooperation Versus Competition

Bonobos and marmosets display different behavioral patterns that can be explained by their social structures, in contrast to capuchin and chimpanzee behavior. Bonobos have more cooperative and less hierarchical social structures.

They also tend to share food more easily and display less opposition to unequal distribution, and their social structures minimize competition and promote group harmony.

Marmosets display no inequity aversion at all, as per Frontiers for Young Minds. This shows that species that rely on cooperative behavior to survive may have different priorities.

All that Social Pressure

There is also a social component to the behavior of primates when it comes to food and not just a matter of fairness. Some primates are more likely to share food when others are present who are likely to harass them, according to research cited in PubMed.

Other research published in Nature suggests that chimpanzees may also be strategic in their behavior by controlling access to food and ensuring that others do not receive rewards in the future.

The fact that these monkeys show a preference based on the concept of fairness rather than their levels of hunger is a significant lead in the evolutionary development of human social behavior. This behavior may already be considered a moral judgment wherein an individual judges not only the outcome but also the circumstances surrounding the outcome.

A Behavior Shaped by Context

It should be mentioned that not all monkeys will refuse an unfair reward every time, and this may vary according to various contexts such as the availability of resources, social status, and past experiences. For example, if the environment is such that there is a shortage of food, monkeys may be more willing to accept inequality.

Thus, it can be concluded that the behavior of monkeys is not static; rather, it varies according to various contexts.

What may appear to be an innocent, straightforward, and seemingly menial task of discarding food is, in fact, a window into the social intelligence of primates, which shows us that fairness, comparison, and even justice may not be uniquely human after all.

What are your thoughts?