Greg Wilson
This is a short whole-team activity to uncover differences in how people think about the project they are working on or the problem they are trying to solve. As the accompanying image shows, a concept map (here, of a public library, originally drawn by Amy Hodge) shows the key ideas making up someone's mental model and (crucially) the relationships between those ideas as well.
It can be healthy for different members of a team to have different mental models of the problem domain: for example, DevOps or Marketing may think about the software in a different way than Development. However, contradictions between different team members' mental models can also be a source of friction, and missing elements or connections in models can lead to oversights.
This exercise is particularly useful for new team members at the end of their second or third week of onboarding, and again at the end of their first quarter.