RH describes each Enneagram as having a basic fear. Vaguely speaking, the more at peace with this central issue a person becomes the healthier they become. They seem more like another type because the issue holding them back has been lessened. I consider my core type to play a large role in the level of trust to each type showing through, but the the core type works autonomously within my own state of mind. When you become obsessed by your basic fear or begin to lose faith in your ability to work against the fear then you start disintegrating, and happen to look like another type as you pick up a few of their characteristics.