Everyone Thinks of Themselves. And Everyone Can Lose

The Paradox of the Prisoner’s Dilemma. When Everyone Chooses Themselves

In social psychology, but also in game theory – a field known to both sociologists and philosophers – researchers discuss a concept of behavior that can seem paradoxical, even absurd. Yet people often choose it. The dilemma formulated by Albert Tucker in 1950 showed that when people have the opportunity to cooperate, they often choose selfishness, testifying against the other person, betrayal, and informing on them.

The paradox is that the rational decision of each individual leads to an outcome that is worse for both. Each person in this paradox thinks: “If they betray me, I’d better betray them first. If they remain silent, I will still gain by betraying them.” As a result, both choose betrayal – their own interests – even though cooperation would bring them a greater benefit. What does this tell us about human nature and the intentions that guide us?

What Exactly Did Albert W. Tucker Do?

In 1950, Albert Tucker (1905–1995), a Canadian mathematician, was on a research sabbatical at Stanford. He was supposed to give psychologists a lecture on game theory. He already knew the model developed shortly before by two other American mathematicians, Merrill Flood and Melvin Dresher, at RAND Corporation. They had created a mathematical structure for a game in which two players could choose either to cooperate or to act against each other – that is, to enter into conflict.

The essence of this model was a paradox showing that each player individually benefits from choosing betrayal. At the same time, when both players pursue their own individual interests, they end up with a worse result than they would have achieved by cooperating.

Tucker decided that an example involving two criminals questioned separately would be much more vivid for psychologists. He ultimately gave the game its famous “prisoners” form and the name “prisoner’s dilemma.”

It is worth emphasizing that this was not an experiment involving actual prisoners. Researchers examined the behavior of people playing a game structured around the prisoner’s dilemma. In practice, two participants played against each other 100 times, communicating only their choices. Their compensation depended on the results they achieved.

What Did the Prisoner’s Dilemma Show?

The prisoner’s dilemma is a classic example from game theory that illustrates a situation in which the rational action of each individual leads to a worse result for both than they would achieve if they could cooperate.

Let us turn to a concrete example: Two suspects are arrested, but the police do not have enough evidence, so they make each of them the following offer separately:

• If both remain silent → each gets 1 year in prison.
• If one testifies against the other while the other remains silent → the one who testifies goes free, while the silent suspect gets 5 years.
• If both testify against each other → each gets 3 years.

Where Is the Dilemma?

Imagine that you are Prisoner A. If B remains silent, it makes sense for you to testify: instead of a year, you go free. If B testifies, it also makes sense for you to testify: you get 3 years instead of 5. In other words, regardless of what the other prisoner does, testifying is individually more advantageous for you. B follows the same reasoning.

As a result, both testify and receive 3 years, even though they would each receive only 1 year if they both remained silent. And that is precisely where the paradox lies: Each person acts in their own interest, yet both end up in a worse situation than the one they could have achieved through cooperation.

This is what made the experiment so important to the later development of experimental game theory. Tucker did not discover the prisoner’s dilemma first. His contribution was to recognize that Flood and Dresher’s abstract mathematical matrix could be presented in a broader context: as a conflict between individual interests and the possibility of cooperation among people. His interpretation later gave rise to a vast field of research into cooperation, trust, altruism, morality, and rationality.

What Can We Take From This Experiment Today?

From a philosophical and psychological perspective, the prisoner’s dilemma is particularly rich in its possible interpretations. On the one hand, it revealed the tension between individual interest and the common good; on the other, between individual rationality and collective rationality.

Today, researchers use the insights from this experiment not only in economics and game theory. They also apply them in social philosophy and ethics. The model can help us analyze trust, cooperation, competition, and interpersonal conflicts in a broader sense.

The prisoner’s dilemma shows that trust becomes necessary when an individual’s interests may conflict with the common interest. Each participant must decide whether to trust the other person and cooperate, or protect their own interests through “betrayal.” If both sides trust each other, they can achieve a better common outcome than if they both choose an egoistic strategy.

The problem, however, is that either side may fear that the other will take advantage of their trust. This raises a purely ethical question: why do we find it so difficult to trust another person? Why do we find it easier to choose conflict than cooperation that, in the long term, would be more beneficial to us?

Perhaps this is because cooperation requires more than recognizing a common interest. It also requires believing that the other side will cooperate as well.

When the Dilemma Is Repeated Many Times

The dilemma also shows that competition does not necessarily result from ill will. It can be a rational response to a situation in which each side tries to protect its own interests. Importantly, in a one-time prisoner’s dilemma, the rational strategy leads to betrayal. But when the situation repeats many times, cooperation can emerge. This happens because participants can reward cooperation and “reciprocate” betrayal.

This leads to a very interesting question: how can stable cooperation emerge from the selfish actions of individuals? When a situation repeats many times, participants can learn to cooperate because they remember their partner’s previous behavior and can develop flexible ways of responding. In this way, reputation, reciprocity, and predictability become mechanisms that sustain cooperation.

Self-Interest and Cooperation

The prisoner’s dilemma therefore shows that lasting cooperation does not always require giving up one’s own interests. Instead, it can emerge when self-interest becomes connected to the interests of the other person.

In a broader sense, this model also shows that trust and cooperation can help overcome situations in which rational decisions made separately lead to an outcome that is worse for everyone. This makes the prisoner’s dilemma a useful tool for analyzing social relationships.

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