How the trust game turns faith into a choice
In a trust game, two people make decisions in sequence. The first player sends some of their starting resources to the second. That transfer is typically multiplied, so the second player receives more than the first gave up. The second then chooses whether to return some of the enlarged amount or keep it.
The first player’s decision is risky because the transfer happens before there is any guarantee of repayment. Sending nothing avoids that risk but also rules out the possibility of gaining from cooperation. Sending more creates a larger potential benefit—and gives the second player more to exploit.
The payoff reveals more than generosity
The second player faces a different tradeoff. Returning resources leaves them with less than keeping everything in the immediate round, but it rewards the first player’s willingness to take a chance. The first player, in turn, must decide how much to send based on expectations about an unknown partner.
That sequence makes the game useful for studying trust as a real economic decision rather than simply asking people whether they trust others. Researchers can observe how much someone risks, how much the recipient returns, and how those choices affect each other. A small transfer may signal caution; a substantial return may show that the recipient is willing to honor the first player’s risk.
Why reciprocity matters
The game also shows why cooperation can be difficult to sustain: the person who acts first pays the cost of trusting, while the person who acts second has the immediate opportunity to take the gain. Yet keeping everything can undermine future cooperation, because a betrayed player may be less willing to trust again. In everyday exchanges, the same tension appears whenever one party commits money, time, or effort before the other has delivered in return.
