Social norms shape individual behaviors and impact group performance. Understanding how norms operate and evolve is key to understanding human evolutionary history and contemporary cultural change. In this talk, I summarize the data and findings from my Derung norm shift project, which aims to document individual norm decision-making algorithms and link them to societal norm change. The presentation will contain three sections. 1. Overview of Derung Ethnography: I will briefly introduce the Derung community, its history and its culture, to encourage cross-cultural collaborations. 2. Findings on individual norm decision-making: In the context of cooperative farming, most Derung people dislike the current norm as the general rule, and know most others dislike it. But they still follow the norm because “when we do things, we do what we have always been doing”, and because the default behavior set by the norm carries the social signal that the partner households have a close cooperative bond. 3. Future data analysis plans: I will introduce the data sets on three other norms, as well as the co-farming norm in another Derung village.