Do you believe in Mental Models?

Mental models are often used to express what’s going on inside the head of users. The question is, what do they look like? I think that, if anything, they would be task-oriented. What do you think?

Note: I updated this one after the initial post. I’m a bit under the weather…

Mental models is a term used to describe the represention of a web site in a user’s mind. It is often used in a context of information architecture: that good architecture will facilitate the right mental model in users.

Scott McDaniel’s piece on mental models is definitely worth a read. In it, he outlines a few key characteristics of mental models:

  • Mental models include what a person thinks is true, not necessarily what is actually true.
  • Mental models are similar in structure to the thing or concept they represent.
  • Mental models allow a person to predict the results of his actions.
  • Mental models are simpler than the thing or concept they represent. They include only enough information to allow accurate predictions.

What has always bothered me about mental models, however, is that we’re trying to make concrete decisions about something that by definition isn’t concrete. How do we know we are representing the user’s representation faithfully? Is there some way to test that? It would seem, just by observing how differently two people think, that almost everyone would have different mental models anyway. What ends up happening, though, is that those talking about them make them sound so formal, so structured, as if there was one and only one mental model that should guide our decision making.

I’m not so sure. In my experience watching users and dealing with learning systems, mental models, if they exist beyond what we call an “idea”, fall way short of any structure. They are much more task-oriented than structural, and because of that, each user has a different one (or ones), making them very hard to generalize for the purpose of design.

To borrow the example from McDaniel’s article, the mental model shown on the left is the user’s mental model of a document. On the right is the designer’s model of the document.

Perhaps I’m not like most people, but I sure that if I’ve ever had a mental model of a document, it’s not even close to the image on the left. For me, my mental activity is usually concerned with the task at hand: “what does this document do for me?” or “why do I need this document?” or “does this document solve my problem?” or “does this document tell me something I don’t already know?”. These are not structural questions, but task-oriented questions that focus on what’s in it for me.

Granted, McDaniel says that his formulation is just a start. To that end, I would propose that we take a more user-centered approach toward them. So, in addition to any mental model of a system that users make (in McDaniels article he talks about a user not knowing there are two databases behind the interface), I think it we also need to include the user’s mental model of themselves, and how they relate to whatever it is they’re doing with whatever it is they want to do. Users rarely care about a system beyond how it will help them achieve their goals. Perhaps a geek would, yes. But, well, that’s what makes them geeks. They love to know, and they love to let others know what they know. But as for regular folks, their concerns are more personal. What do you think?

Published: April 2nd, 2005

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