Furthermore, even within one individual, the mental model changes with time and with the flow of conversation. The human mind assembles a few relationships to fit the context of a discussion. As the subject shifts, so does the model. Even as a single topic is being discussed, each participant in a conversation is using a different mental model through which to interpret the subject. And it is not surprising that consensus leads to actions which produce unintended results.
Fundamental assumptions differ but are never brought out into the open.
Towards conceptual models of requisite complexity These structured models have to be applied to any serially ordered data in card files, computer printout or reference books to make sense of that data. The greater the complexity, however, the more difficult it is to use mental models. I can't remember what is happening in one place long enough to see what is going to happen somewhere else. My model evaporates. If I could somehow represent that abstract model in the computer to see a circuit in animation, my abstraction wouldn't evaporate.