Mental Models

Mental Models

They are representations of reality that people use to understand specific phenomena.

    * A mental model is based on belief, not facts: that is, it's a model of what users know (or think they know) about a system e.g. a website. Hopefully, users' thinking is closely related to reality because they base their predictions about the system on their mental models and thus plan their future actions based on how that model predicts the appropriate course. It's a prime goal for designers to make the user interface communicate the system's basic nature well enough that users form reasonably accurate (and thus useful) mental models.

    

 * Individual users each have their own mental model. A mental model is internal to each user's brain, and different users might construct different mental models of the same user interface. Further, one of usability's big dilemmas is the common gap between designers' and users' mental models. Because designers know too much, they form wonderful mental models of their own creations, leading them to believe that each feature is easy to understand. Users' mental models of the U(user interface)I are likely to be somewhat more deficient, making them more likely to make mistakes and find the design much more difficult to use.

"In interacting with the environment, with others, and with the artifacts of technology, people form internal, mental models of themselves and of the things with which they are interacting. These models provide predictive and explanatory power for understanding the interaction."          -Norman (in Gentner & Stevens, 1983)

They are internal representations of thinking process. Mental models represent how well an individual organizes content in meaningful ways. Model analysis reveals inaccuracies and omissions that are crucial for deep understanding and application of course material, thus informing improvements in course design.

Some of the characteristics of mental models are:

• They are incomplete and constantly evolving
• They are usually not accurate representations of a phenomenon; they typically contain errors and contradictions
• They are parsimonious and provide simplified explanations of complex phenomena
• They often contain measures of uncertainty about their validity that allow them to used even if incorrect
• They can be represented by sets of condition-action rules. 

The study of mental models has involved the detailed analysis of small knowledge domains (e.g., motion, ocean navigation, electricity, calculators) and the development of computer representations (see Gentner & Stevens, 1983). For example, DeKleer & Brown (1981) describe how the mental model of a doorbell is formed and how the model is useful in solving problems for mechanical devices. Kieras & Bovair (1984) discuss the role of mental models in understanding electronics. Mental models have been applied extensively in the domain of troubleshooting (e.g., White & Frederiksen, 1985).

One interesting application of mental models to psychology is the Personal Construct Theory of George Kelley (1955). While the primary thrust of Kelly's work was therapy rather than education, it has seen much broader applications (see http://repgrid.com/pcp/) [Thanks to Richard Breen for bringing this to my attention]