There are many examples of human cooperation for mutual benefit, such as firefighters working together or dividing household work. It is not obvious that any other great apes cooperate in such a way. If I can reduce the cost of my cooperation by deception—pretending to contribute in a group project while still reaping the benefits—why wouldn’t I? This is known as the free-rider problem.

Some research has found that chimpanzees cooperated in group hunting 2 million years ago, but they worked primarily for their own benefit. They did not bring food back to a central location. However, the environment has changed, and foraging individually is no longer an optimal solution. Collaboration has become necessary. In human hunting, the free-rider problem does not arise in the same way. Collaborative hunting not only provides food but also serves as a way to show off or send costly signals. The idea is that the receiver of the signal can determine when the sender is honest about their abilities because of the costs involved—a lower-quality individual wouldn’t be able to afford engaging in risky hunting.

In the stag hunt theory, both players must choose whether to hunt a stag or a hare. They decide simultaneously, so neither knows what the other will choose. They can only successfully hunt the stag if both choose to cooperate. If one chooses to hunt the stag alone, they will get nothing, while the other person who hunts the hare will get a small payoff. If both go for hunting hares, they will each receive a low reward. This game illustrates that when individuals fail to cooperate, they miss out on future beneficial interactions.

In human societies, mechanisms like reputation, trust, and social norms help to minimize the free-rider problem. People who consistently cooperate are rewarded with stronger social ties and better access to resources, while those who deceive or shirk responsibility often face social consequences. Thus, cooperation, when maintained, can lead to greater long-term benefits for everyone involved.