How a money transfer becomes a test of trust
In a trust game, the first player has a choice: keep an initial stake or send some of it to another player. The transfer is multiplied, creating more money for the pair to divide. The second player then decides how much, if any, to send back.
That multiplication matters. If the first player sends nothing, there is nothing to divide. If they send money, both players may end up with more—but only if the second player returns enough. The first player cannot enforce repayment, so sending money means accepting a risk of loss in exchange for the chance of a larger payoff.
What the choices reveal—and what they cannot
Researchers can use the amount sent as a measure of willingness to rely on another person despite uncertainty. The amount returned offers a related measure of reciprocity: whether the trustee shares the gains created by the transfer or keeps more for themselves.
The game puts a financial consequence on betrayal, but it does not measure trust in isolation. A player might send money because they expect kindness, because they want to encourage a return, or because they are willing to take a risk. Likewise, a trustee’s decision can reflect generosity, strategic expectations, or a preference for keeping the money. The choices show how people act under the experiment’s incentives, not a single motive behind each action.
Why the tradeoff is useful
The game makes a social question observable: how much value will someone place at another person’s discretion, and how much will that person give back? Because the decisions affect real payoffs in the experiment, they are more consequential than simply asking participants whether they trust strangers.
The revealing moment is the first transfer. It creates money that neither player could divide without cooperation, while leaving the sender exposed to the possibility that the other person will take the gain and return nothing.
