A conceptual model is the mental model that people carry of how something should be done. Conceptual modelling can be carried out at a very early point in the design cycle so that there is a basic understanding of how users conceive tasks and this can then be brought to bear on UI design. The ability to sketch conceptual models quickly and easily can save large amounts of time in UI design and help deliver more intuitive applications.
We build mental models of concepts without thinking about it; it helps us categorize things in our lives easily and simply. So for example, when we think about appointment setting our mental model is probably a diary or a calendar – not a piece of software.
This is true even though we probably use software for setting most of our appointments. It’s also the reason that most appointment setting software will make reference to diaries/calendars; the conceptual model of the software matches the mental model of the user.
Conceptual models are designed to help us communicate the underlying intention of our application design. The better the conceptual model relates to users’ existing mental models – the easier it is to use the conceptual model to explain what we intend to do with our application.
Conceptual Modelling Comes Before UI Design
Author/Copyright holder: Rick Sandusky and Mikel D. Petty . Copyright terms and licence: Public Domain
The conceptual model for any design should be constructed right at the beginning of your design cycle. Not only will it reflect the concepts that you intend to bring to life within your mobile app but it will also explore relationships that exist between the concepts.
In essence, the conceptual model can inform the UI design for your team. It can also help shine light on areas where you want to examine the user’s existing mental model.
Why Conceptual Modelling is a Good Idea
It provides a high-level understanding of how your mobile application will work
It allows you to try to match the way your mobile application works with the mental models of your users. This in turn should make the application more usable and intuitive.
It allows you to see how well your conceptual model matches different mental models. New scheduling software may need to take into account the traditional diary/calendar approach (for those with no experience of using software tools) but also other software such as Outlook or Google’s calendar functionality.
It allows you to examine when a mental model is not aligned with the conceptual model and to decide whether you are going to shift the conceptual model or to try and shift the user’s mental model. Someone who has never used scheduling software has probably never received an automate reminder of a meeting – how will you help the user model that idea mentally?
Alien Concepts can Cause Cognitive Friction
If your conceptual model breaks the user’s mental model – it is likely that your mobile app is going to create a certain level of cognitive friction for a user. Even the relabelling of one simple item may make your app more complex to use. For example, the floppy disc save icon is a mental model – it’s an outdated model now, very few people still use floppy discs, there’s a generation of users who have possibly never even seen a floppy disc… but creating a new save icon is still likely to make life harder for the user who wants to save their data. The floppy disc icon is how we model saving things on any application and that hasn’t changed even when you can’t put a floppy disc into a smartphone.
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Conversely, if you’re trying to do something new – something the user has no current mental model for – it will be much easier to create an alien concept because there is no cognitive friction to overcome.
What Goes Into a Conceptual Model?
Tasks – your conceptual model should take into account the task models that you build. It should explain tasks in the language of the user and wherever possible try to avoid introducing alien concepts.
Objects – what are the physical objects that a user relates to? A calendar is an object. You should be looking to identify these objects and map the relationships between them.
Actions and attributes should be assigned to your objects. What will your users be able to do with these objects? Set an appointment? If so, how? What do you need to set a specific appointment? What attributes will that have? (E.g. start date, end date, time, contact, etc.). You can then look at the relationships between objects and see which actions and attributes belong to a wider subset of objects and carry them across easily.
Terminology Definitions – standard terminology across the product will make it easier for you to help your user understand what an action is all about. If you book an appointment on one page of the mobile app – it should not be renamed as booking a meeting elsewhere. A single conceptual model helps you streamline the language of your app early to better support a consistent user experience.
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What Else Can a Conceptual Model Help With?
Your development team can use the conceptual model (and your task models) to generate use cases for the system and model how the user will interact with the application itself.
The UI team can use the conceptual model to determine the best approach to UI design.
The conceptual model provides both teams with the understanding of:
What tasks the users will be able to conduct with the mobile app
The objects that they will work with within the app
The relationships that those objects have to each other
The actions that users can take using the objects
The attributes associated with each object
The language used to describe objects, attributes, etc.
The Take Away
Conceptual models make it easier to stand in the user’s shoes and make sure your products are intuitive and usable. They also allow the development team to create use cases more easily and the UI design team to create UI that takes into account the user’s mental models. They are an extension of task modelling and should be done during the early phase of design to bring the biggest value to the project.
Dr. Susan Wenschenk reflects on mental and conceptual models here.
Abhijit Raweel Principal Product Developer at Oracle shares his thoughts here.
Hero Image: Author/Copyright holder: Ana Zdravic. Copyright terms and licence: All Rights Reserved.