April 2nd, 2005
Do you believe in Mental Models?
by Joshua Porter | 
2 Comments | shortlink: http://bokardo.com/p/64
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?
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Comments
1. bill h-d 11:08am, Sun 3rd, 2005
I don’t want to beat a dead horse with my responses inspired by Activity Theory, but your question here is worth taking a shot at. Plus there is a dash of Suchman in this one…
I believe that users’ mental models, at the operational level which you discuss above and which techniques like GOMS render in detail, are “real” but not at all useful for design purposes. The simple reason is that these models, such as they are, are composed improvisationally…in response to situational variables that run the gamut from low-level physical conditions (like a mouse clicking) to very high-level somatic and affective conditions (like the user being jacked on too many espressos).
The level at which mental models correspond to design is not the immediate operational level, but the motivational level, the level where explcit goals can be matched to end-states that are desirable. Not “boy I’d like to click three times to confirm my order” but “boy, I sure hope Josh’s birthday present gets there on time.”
Designers would do well, in many cases, to ask not what users want to do…but rather who they want to be or become. Sounds odd, eh? Well, the *only* reasons I subject myself to the torturous, multi-level UI of my cell phone (handset, modal UI, network carrier, calling plan…) is that, in the end, it lets me “be” a better person – a more caring spouse, and here lately, a more attentive father.
If Nokia could design with those goals in mind…then we might have something…
2. Wolfgang 11:09am, Thu 1st, 2005
Your discussion appears to me as a more theoretical one. While it is quite difficult to grasp the idea of a mental model and its inherent qualities and structures, the practical side is simply: Uselabs show the importance of mental models. Maybe the desciption is better coined buy: the building of a hypothesis. Any perception during the orientation phase entering a website which may lead the user to a wrong hypothesis of what this is all about can damage all IA intentions badly.
I remember the uselab situation when two dynamic news items and two navigation elements concerning trainings on the homepage lead the user to the powerful hypothesis that this site is all about trainings. The many other elements (about 90% of all content elements) contradictory to this hypothesis were not any more relevant during the tasks that were to be completed afterwards. About five seconds for building a mental model of the site in comparison to ten minutes of trying to complete a given task – without further changes of the mental model. This gives some evidence about the power of a mental model, once it is formed.
The IA task seems to be to assure that all content elements work together smoothly for building a more appropriate hypothesis or mental model. In this case the dynamic news items had to be reduced to maximum one for every theme or content area.
But we have to admit nevertheless: It seems to be impossible to ensure appropriate mental models because they are not independent to preconceived notions, expectations, asscociative thinking etc. which is almost completely out of our reach.