Design for Functional Memory

Understanding of an interactive system is, at least initially, functional (how to use it) rather than structural (how it works). Users organize their functional knowledge of a system by creating mental models like those for long-term structural memories. For the interactive text designer, the lesson is that functional design, like informational design, should reflect several common strategies for organizing information in long-term memory (previous principle). An effective functional design gives the user the ability to concentrate on the difficult task of organizing new content, rather than having to remember how to operate the system.