Prosocial behaviour towards unrelated others is communally beneficial but can be individually costly. The emotion of gratitude mitigates this cost by encouraging direct as well as "upstream" reciprocity, thereby facilitating cooperation. A widely used method for measuring trait gratitude is the Gratitude Questionnaire (GQ6) [McCullough, M., Emmons, R., & Tsang, J. (2002). The grateful disposition: A conceptual and empirical topography. Journal of Personality and Social Psychology, 82, 112-127. Retrieved from https://doi.org/10.1037/0022-3514.82.1.112 ]. Here we undertake an assessment of the external validity of the GQ6 by examining its relationship with two incentivized economic games that serve as face valid indices of generosity and reciprocity. In two studies (total N = 501) we find that trait gratitude as measured by the GQ6 predicts greater donations in a charity donation task as well as greater transfers and returns in an incentivized trust game. These results support the hypothesis that individuals with higher trait gratitude are more generous and trusting on average, and provide initial evidence as to the predictive validity of the GQ6.
Keywords: Gratitude; dictator game; generosity; predictive validity; trust game.