Separating trust from cooperation in a dynamic relationship: prisoner’s dilemma with variable dependence

In this article we introduce a new experimental game called Prisoner’s Dilemma with Variable Dependence (PD/D), which allows players to separate their trust in their exchange partners from their cooperation with them in an ongoing relationship. The game allows researchers to observe the emergence of trust and cooperation separately, and ascertain the causal relationship between them. In six studies that use the PD/D design, we find that the players of PD/D consistently achieve very high cooperation rates, sometimes mean cooperation rates of about 95%, which are higher than in standard PD games sharing similar design features. These findings demonstrate that separating trust from cooperation is critical for building trust relations. They also show that the GRIT (Graduated Reciprocation In Tension reduction) strategy helps build such relations in the absence of mutual trust. Our results suggest that it is cooperation which leads to trust, not the other way around.