Thursday, December 22, 2005
design patterns and mental models
There are activity patterns-- the sequencing of tasks, and widget patterns -- how tasks are done within a screen. But patterns are a designer-centric approach. If they are familiar to users it is because designers use them frequently.
Mental models are slightly different. A mental model may be strong in a user's mind, but not often used by designers. It only takes one application to use an approach to develop a new mental model for users. Users develop expectations how something should work based on what they are familiar with. Consider something as ordinary as email. Users have a mental model of email based on what they use regularly. If you use Gmail, you expect email should offer the archiving abilities Gmail offers. If you use Lotus Notes, you see email functionality as incorporating unstructured databases. Outlook might be the most common of its genre, but irrelevant to the mental model of a given user.
What is becoming difficult for UI designers is the proliferation of user mental models. There are many variants of application in use, and one can never be sure what experiences have shaped a user's mental model. What we need is a catalog of interaction behaviors of widely used software applications. We need to be able to easily look up what mental models are being formed, when we ourselves might not be using the applications ourselves.