A new perspective on the social functions of emotions: Gratitude and the witnessing effect.

We propose a novel theoretical and empirical approach to studying group-level social functions of emotions and use it to make new predictions about social consequences of gratitude. Here, we document the witnessing effect: In social groups, emotional expressions are often observed by third-party witnesses-family members, coworkers, friends, and neighbors. Emotional expressions coordinate group living by changing third-party witnesses' behavior...