The open tab in my browser reminded me that I’d intended to follow up on this interview with Indi Young on the subject of Mental Models.
In this context, a “Mental Model” is a diagram that expresses the goals and needs of your intended audience, and pairs them up with the support structure in place that helps the audience fulfill those needs. It’s a strategic document — you do some research and synthesize it into the diagram. If there are gaps in the support structure, that’s a need that’s going unmet, or is being met poorly.
Or, to put it another way, it’s a business opportunity.
So, the mental model is a sense-making tool, which can be used to translate design thinking into actionable strategic recommendations.
A mental model is a picture of how your end users are supported by what you are creating. We draw mental models by audience segment — mostly a behavioral audience segment. If you are a non-profit organization and are trying to make sure that information about diabetes gets out to third world countries, then you’ve got a certain audience. You draw a picture of how they behave and how they find out information about diabetes and then you show how you support them. You understand if their motivation is to help a relative who has diabetes, then you support that motivation as opposed to approaching it from a different direction. You’re trying to approach it from the understanding of the end user and the world that they live in.

Here, we’ve got an example model, which describes a common activity: Learn More about a Film. We’re all pretty familiar with why and how we do that.
The activity is broken down into the different stereotypical behaviors that support that activity, shown as stacks, or towers, across the top. This is a pretty simple activity, so the towers are short and simple, but a more diverse or complex model might have stacks of different, related tasks which fit into the same “tower.” These “towers” are called “Mental Spaces.”
Below each mental space is a stack of ways in which the users are supported in their tasks. The mental spaces, those clusters of towers I was talking about, map in a real way the structure; how you want to support the user. For example, if we were talking about a diabetes website, you might have sections in that application or product that correspond to the mental spaces of how a user takes care of their disease.
Check out the interview, but I found Jared Spool’s recent podcast conversation with Indi Young on mental models to be most helpful. It’s a good commute-time listen if you’re interested in the subject.