Systematic Modeling
Thesis Abstract
My thesis develops systematic methods in interaction design using three case studies. I am focusing on two systematic models: the conceptual model and the mental model.
A conceptual model is a model that is given to the user through the interface of the product. It is the model in the designer’s mind.
A mental model is a model that a user develops in his or her mind from the interface of the product. It is a model in the user’s mind.
My thesis relates and combines these two models in the design process, exploring three questions: How can we designers find the right way and the most efficient way to find out a user’s mental model? How can we represent these models? How can we use these models in the design process?
Why am I interested in this topic?
I was amazed by the idea of discussing the interactions without talking about the interfaces but instead discussing the logic and the skeleton behind the interfaces.
When I was working as an interaction designer in Huawei, I spent a lot of time on drawing wireframes and rarely thought about the logic behind them. I felt it is not the right way to design the interfaces especially when I was designing the whole interaction system of the Telematics (an automobile software system). Some functions overlapped with other functions, and some functions had multiple accesses. Sometimes I felt confused by some of the complex functions. How can users use the product if the designer doesn’t have a clear map in mind?
When Hugh Dubberly introduced the conceptual model, I felt excited about it. I think it, or something close to it is the missing bridge between research and design.
Hugh Dubberly is the master of systematic thinking in the design world. He introduced the conceptual model to me in a system’s course. He has a new way of representing the conceptual model by using the concept map method (introduced by Joseph D. Novak and D.Bob Gowin in the book Learning How to Learn). He is the co-founder of Dubberly Design Office. At Apple Computer in the late 80s and early 90s, he managed cross-functional design teams and later managed creative services for the entire company.
Modeling is a way to convey what is in a user’s mind to other team members. It is also the abstraction of interfaces to help designers understand the logic and concepts behind the interfaces. Models can help designers focus on the functionality needed by the user in carrying out all the tasks from the task domain.
It can help developers understand the whole picture of the application in the early stages of design so that conflicts between designers and developers can be decreased. It is the “boundary object” to let researchers, designers, and developers consent on what the application means to the end users.
Shoulders of Giants
The ideas of the conceptual model and the mental model are not totally new, and the terms of these two models have been defined differently by several different people. These “giants” influenced my thoughts.
My Interventions
What are my interventions?
In their book Conceptual Models, Core to Good Design, Jeff Johnson and Austin Henderson talk about what the elements of a conceptual model are and how to “make” a conceptual model. However, their representation of the conceptual model is just a list of words, which does not communicate well and hard to understand.
Hugh Dubberly has his own way of representing the conceptual model, which is very inspiring. However, there is no clear clue of where the conceptual model comes from and how designers can use it.
Susan Weinschenk has a very interesting point of view: one of the most important things for designers is to nd the mismatches between users’ mental models and designers’ conceptual models. However, how can we nd the mismatches? How can we express or communicate the mismatches? How can we utilize the mismatches?
Right now, each of the conceptual and mental model theories stands quite alone. One is from the product’s side, the other is from user’s side, but how can we combine them together?
Thus, my interventions hope to shed light on these three questions:
1. How can we designers find the right way and the most efficient way to find out what is in a user’s mind?
2. How can we represent these models?
3. How can we use these models in the design process?
The Three Projects
I explored my thesis by these three case-study projects. At the same time, I explored and developed the methodology.
The Three Models
There are three kinds of models in my theory of systematic modeling – a mental model, a conceptual model, and an implementation model.
A researcher’s main job is to discover what is in a user’s mind and communicate the findings with other team members. Part of the findings can be extracted into mental models. Ideally, a designer’s conceptual model is derived from the user’s mental model. Mental models are often partial and personal, but conceptual models are more complete and accurate. The conceptual model is also like a bridge between the mental model and the implementation model. The implementation model is how a product is really constructed. It is the model in a developer’s mind. Ideally, it is transferred from a designer’s conceptual model.
These three models all have a connection with users. The mental model is from the user’s mind. The conceptual model is a designer’s assumption of a user’s mental model. The implementation model constructs the product which creates a user’s mental model.
Conceptual Model
A conceptual model is a model with which users interact. Ideally, it is the designer’s assumption of the user’s mental model.
Here is Susan Weischenk’s definition: “A conceptual model is an actual model that is given to the user through the interface of the product.”
The diagram below is from Tim Sheiner and Hugh Dubberly. Users have goals or tasks in mind when they are using an app. An app has input and output, and users input data and see the output. The input and output connect with each other by logic, and there is also a storage below the logic. In Tim Sheiner’s perspective, the user’s conceptual model contains Object Model (the elements and their relationships), and Data Model (how to manage different states). After all, there is the designer’s assumption of all the things described above, and he called it designer’s conceptual model.
I do not completely agree with the diagram, but this diagram is the starting point of my thesis. Tim Sheiner and Hugh Dubberly name the model in user’s mind “user’s conceptual model,” and name the model in designer’s mind “designer’s conceptual model.” However, throughout my researches and interviews, I found the models in users’ mind are just snippets that to some extent reflect their mental models. In my perspective, the terminology of “user’s conceptual model” is very confusing and misleading. I will call the models in users mind “mental models.” However, it is very important to determine what are the components of the conceptual model in this diagram and thinking about what should be included in the conceptual model.
Let’s think about a simple digital alarm clock on your phone. When a designer is designing an alarm clock, he intentionally or unintentionally creates concepts for users – “current time,” “alarm time,” etc.
Mental Model
A mental is a model in a user’s mind. The model develops when people interact with the world. Here is the definition from Susan Carey’s 1986 journal article, “Cognitive science and science education”:
A mental model represents a person’s thought process for how something works (i.e., a person’s understanding of the surrounding world). Mental models are based on incomplete facts, past experiences, and even intuitive perceptions. They help shape actions and behavior, influence what people pay attention to in complicated situations and define how people approach and solve problems.
Jeff Johnson and Austin Henderson said “To use an application, a user have some understanding of it. Such an understanding is called a ‘mental model’ because it is in the user’s mind… … Therefore, mental models are personal, partial, uncertain and dynamic.”
Mental models are what we can get from user research – interviews, observations, user testing, etc.
Implementation Model
The implementation model is the model of how the tool is actually built. It is used for developers and engineers to build the tool. For example, the structure of WordPress is an implementation model. It tells developers how to understand the architectural structure of WordPress.
Differences and relationships between the mental model and the conceptual model
A researcher’s main job is to discover what is in a user’s mind and communicate the findings with other team members. Part of the findings can be extracted into mental models. Ideally, a designer’s conceptual model is derived from the user’s mental model. Mental models are often partial and personal, but conceptual models are more complete and accurate. The conceptual model is also like a bridge between the mental model and the implementation model. The implementation model is how a product is really constructed. It is the model in a developer’s mind. Ideally, it is transferred from a designer’s conceptual model.
One of the most important jobs for designers is to find the mismatches between the user’s mental model and the designer’s conceptual model.
How to use the models in the interaction design process?
Although this topic is not completed developed, there are still some ways to utilize these methods in the design process. This may not be a perfect methodology yet, but I want to introduce some of my conclusions.
There are five modules in this methodology: map out the conceptual model; redesign mental models; compare the two models; redesign the conceptual model; redesign the product. The order of these modules can be changed to better fit your project. But the order I introduced is the most ideal one.
Conclusion
The conceptual model is a designer’s assumption of users’ mental models. The mental model is users’ understanding of how a product works. The conceptual model should be within task domains. Designers should engage users when designing the conceptual model. These two kinds of models are the main components of the systematic modeling design methods. It is a methodology that focuses on what a product really means to users.
However, there are still questions that need further interventions: Is there a universal visual language of the conceptual model that can be used in all kinds of products? What is the best way to translate models into representations? How do we connect the conceptual model with the implementation model?
I hope to work on this topic in my further explorations. I’d love to discuss it with anyone who is also interested.
Email me if you are interested in this topic: lindaliangying@163.com
