This paper presents a new approach to understanding mental models for complex industrial systems. Using the Abstraction Hierarchy (AH) framework as a way to describe mental models, we propose an approach to assess ecological compatibility between an operator's internal mental model and a model of the environment. In order to do so, we have combined and built upon the previous work of Rasmussen (1979) and Moray (1996). We believe that this new approach can assess ecological compatibility and ultimately provide the operator with a more accurate and complete internal mental model that reflects the reality of the environment. We argue that Ecological Interface Design (EID) is a way to link mental models and the environment. Future work will be needed in order to assess ecological compatibility. This includes capturing and examining operators' internal mental models, and comparing them with models of the environment.