Comments on What's Your Idea of a Mental Model?

Muhammad Faizan Ali — Thu, 20 Dec 2007 09:33:31 GMT

i worked as developer at whizbang Solutions, but never heard about Mental models , although it is new to me but really has very importance for me , thanks for increasing knowledge

Muhammad Faizan Ali — Thu, 20 Dec 2007 09:31:43 GMT

i think after reading this aritcle, evelution of a system is made due two things, increasing requirements and customer mental models. IAs have to think at the level where coustomer does. right?

George Abraham — Fri, 12 Oct 2007 08:08:09 GMT

Oops! Not transposed, I meant to say overlaid.

George Abraham — Fri, 12 Oct 2007 08:04:17 GMT

I am assuming that this debate on mental models and conceptual models does not have an expiry date.

I consider mental models to be broader in scope than conceptual models. Hence, I would like to propose that conceptual models are mental models that are transposed on the system or interface. In other words, a mental model that is now bounded by what the system makes visible or implies in terms of tasks/goals that can be completed, and how to go about doing them.

I hope this explanation compliments the comment made just before this one.

Asli Adisen — Mon, 13 Aug 2007 11:16:54 GMT

Conceptual model is the model represented to the user, usually by a designer, researcher or trainer which is intended to convey the workings of the system in a manner that the user can understand.

Mental model is the model of the system that the user builds in his or her mind.The user’s mental model may be based on the conceptual model provided, but it is probably not identical to it.

Bob Baxley — Fri, 26 Jan 2007 14:51:02 GMT

It’s important to distinguish between the conceptual model – a description of what the application, site or service does – and a mental model – a description of how the application, site, or service is structured.

As the most abstract level of the interface, the purpose of the conceptual model is to leverage the user’s experience from the physical world to enable them to form accurate and useful expectations about what type of functionality or content is available. It helps them answer the question, “is this thing a store, a brochure, a newspaper, a reporting system, or what?”

Despite their abstract nature however, conceptual models invariably represent real world objects and experiences. For example, blogs are a like a diary, iTunes is like a jukebox, Microsoft Word is like a typewriter, and an ATM is like a bank teller. Although none of these models tell the user how something is likely to be organized or structured, they do tell them what types of transactions, features, objects, and capabilities are likely to be present.

By contrast, a mental model describes how a user expects a particular system or service to be organized. It helps them say, “Given that this thing is a store, I expect there to be a place dedicated to product X, a space for product Y, and a place to complete my transaction.” Of course, mental models are intensely individual things, varying from one user to the next. Therefore, a significant challenge is to discover the various mental models and then find consistent and predictable ways of reconciling and expressing them as a single, coherent information architecture.

Andrew — Fri, 26 Jan 2007 14:51:02 GMT

One of my big troubles (and I recall Peterme asking this question ages ago) is: what does a mental model look like? How is it physically drawn/written/articulated on paper so that people can grasp it? For content-heavy sites, I like the solution that Adaptive Path eventually came up with, a sort of heirarchical bar chart thing that is really pretty clear and easy to understand.

I’ve seen mental models drawn as overlapping circles, flowcharts, or other diagrams, and I’ve seen them written as text.

Does anyone have good examples or URLs to show?

Benjamin Listwon — Fri, 26 Jan 2007 14:51:02 GMT

I may be getting a little off-topic here, but I am having some trouble convincing myself that we do users justice by creating for them, or having them tell us about their mental models of a project.

In the original article, Scott writes:

“Because the databases do not have fields in common, the system needs a separate search page for each database. Users, however, will have trouble making this distinction and will expect to see only a single search page. The ideal solution to this problem is to restructure the databases so they can both be searched from the same search page.”

What I am having trouble getting my head around is what a concise, user-defined mental model should look like. From the statement above, it would appear that the assumptions about the product are still driving the mental model that we think the user possesses. Consider the fact that they should not, and in fact may not at all, think of their articles as being stored in databses at all.

The ideal solution may be more along the lines of allowing users to search all data transparently, and gracefully helping them to refine their searches for criteria that are either not present, or not relevant. The user’s mental model is probably more along the lines of a library catalog, where every book, journal, periodical and whatever else, is searchable on a few common attributes, regardless of whether it is oversized, stored on microfiche or whatever.

So, I guess I am left with some questions. How do we know when we have accurately portrayed a mental model? Is one model really all there is, or are there so many potential models with equally applicable ideas that it is difficult to select a forerunner or two?

Just my $.02, and I hope it is not too far off the mental model track.

—Ben

Scott McDaniel — Fri, 26 Jan 2007 14:51:02 GMT

About how to get at the mental model—One of the defining principles of user-centered design is that you base design decisions based on observed behavior, not stated opinion. I think Jenny is right that you can’t just ask a person what their mental model is or ask 2-3 “right” questions to fully reveal it. I’ve seen usability tests reveal mental models well, particularly when everyone makes the same mistake at the same place. Contextual inquiry can also get at mental models well. I’d also say it’s impossible to fully document a complete mental model—we’re just interested in those parts of it that lead people to make assumptions and behave in certain ways.

About expectations—“Mental model” and “conceptual model” are certainly jargon terms, and we need them for our own discussions. I’d also agree that we don’t need to expose everyone to them, and I like “expectations” as a close way to convey what we mean. To switch back to jargon for a moment, though, I think that the mental model is the thing that produces the expectation, not the expectation itself. Users might expect a UI to work a certain way, but the mental model explains why.

Perhaps a better way to think about this “target mental model” is not so much something that we want to bring the user into compliance with, but rather the standard set of assumptions, terms, visual representations, and processes that we will use in the software. Ideally, we will base this on the users’ actual mental models, but sometimes we won’t be able to do that. In such cases, we will know where the users’ mental model differs from what we’ve set down as the UI’s standard model. An understanding of that difference will help us better target the training, documentation, tutorials, instructions, and error messages.

Joe — Fri, 26 Jan 2007 14:51:01 GMT

My first exposure to these terms was through Donald Norman’s “The Design of Everyday Things.” I understand (and still do) the distinction between mental and conceptual models to be point of origin: a mental model is the perception a user brings to an application, and a conceptual model is the background, overarching idea of how to realize a thing best to match this user’s mental model. So, in short: users have mental models, software designers have conceptual models.

Semiotics speaks to me when trying to understand this…kind of a sign/signifier/signified thing. True, it is jargon—but it’s important jargon within our community, I think. I’d expose this jargon less frequently outside of UX professional circles, probably.

jess — Fri, 26 Jan 2007 14:51:01 GMT

I’ve felt for some time that “mental model” and “conceptual model” are largely terms used by the industry in an exclusive, jargonerific way.

What is the difference between a “mental model” and an “expectation”? I see very little, and have replaced my references to mental models with “expectations” when I’m talking with managers, developers, or clients.

As to where expectations come from, in rough order:

- past experience (skill level, use of similar systems, use of different systems, use of this system)
- environment (social & physical)
- the cues presented by the system

Scott McD. — Fri, 26 Jan 2007 14:51:01 GMT

Karl asked about the difference between mental and conceptual models. I tend to use “conceptual model” to mean the high-level definition of a user interface. Used this way, a UI’s conceptual model includes:

1) Architectural diagram of the UI, showing major screens and their relationships.

2) Screen layouts for key screens.

3) Target mental models of the UI or the major objects (from the user’s perspective) in the UI.

4) Graphic design for the UI.

Mental models, then, are one aspect of a larger conceptual design that also shows how those models are to be implemented in the UI.

Andrei questioned the idea of trying to document a designer’s mental model and then figure out how to transition the user’s mental model to it. I guess it depends on what we mean by “designer’s model.” A system designer’s model of the objects in the backend (execution threads, databases, etc.) is different from a UI designer’s model of the objects in a UI that a user should perceive. That model, which I’m calling the target mental model, will reflect the actual users’ models in a best case scenario. That’s not always possible, though, and understanding where the models differ can help mitigate usability problems.

In one of the projects on which I based the example mental models, we had a technical constraint that meant we had to have two different search screens, one for a document’s meta data and one for its full text. Since we couldn’t create a single search page, we were able to put instructions and a link on the meta-data search page to point people to the full text search page. A before and after usability test showed that the instruction and link was partially successful, but not completely. People still started down the wrong path, but then usually saw the note and got back on track. The real solution is to combine the search pages, but given the scope and schedule of the project it wasn’t practical. In that case, considering the mental models did help some.

Andrei — Fri, 26 Jan 2007 14:51:01 GMT

Not sure that getting a mental model down on paper in this fashion is very helpful from the point of view of trying to get users to “transition” over to a target mental model.

I’ve never encountered a user that would switch their mental model when told what to do, or “adopt” a different mental model than what they already have when they use a product. They just do what they want, think what they want, and that’s usually all there is.

Their mental model of the product is far different than mine would ever be, and there’s not much I’m going to be able to do to change that, and one could argue I should NOT attempt to change it. (What right do we have to try and get people to think differently? Just a thought.)

However, I do agee that understanding their mental model is useful in that I can try to bridge the gap to keep what I know to be true in the product, but make it *appear* like something they can relate with in their mental model.

Bridging the gap to give users something to hang their hat on is what mental models are for imho. Transitioning them over to a new one sounds like a task where I want to pound my head agaisnt a wall.

Consider one case in point: the whole desktop metaphor for the OS. The original UI designers from XeroxPARC and Apple created icons to represent folders to give users a bridge into what a hard disk and file system does. Do the users of computers REALLY understand what is happening at the OS level with the file system, how the code saves files, where it points, how it store the data, etc? No. But they can relate to folders because it fits their mental model of how they work in the office.

This is a case where you as the designer bridge the gap. Maybe its semantics, but I don’t think you ever want to try and bring people over to your target mental model. But you do want to find way to brdige the gap between what you know is going on in the product at the engine level to something the user can relate to in their own mental model of what is going on.

Andrei

Karl Fast — Fri, 26 Jan 2007 14:51:01 GMT

How would you make the distinction between ‘mental models’ and ‘conceptual models?’

This question comes up now and then and I think it arises from our loose usage of these two phrases. How would you make the distinction?