deSouza, Darcey K., Song Hee Park, Wan Wei, Kaicheng Zhan, Galina B. Bolden, Alexa Hepburn, Jenny Mandelbaum, Lisa Mikesell, and Jonathan Potter. 2021. “The Gratitude Opportunity Space: The Timing of Gratitude Expressions in Object Passes”. Social Interaction. Video-Based Studies of Human Sociality 4 (1). https://doi.org/10.7146/si.v4i1.122437.