The use of users’ mental models in information design is essential to develop effective outputs. However, there is confusion surrounding the concept of mental models and how to use knowledge of users’ mental models in the design process. Some information designers tend to use “mental models” to refer to a whole range of concepts, even when they don’t know if that’s what they need or why they are helpful. Other information designers use the term in incoherent ways while some don’t really understand what mental models are and how they differ from other terms of similar meaning like schemas and frames.

This poor understanding of key concepts appears to be the result of lack of communication between communities—information design, human factors, computer scientists, human-computer interaction, ergonomics and psychologists. Same terminology has very different meanings for members from different disciplines, so unless each person knows the meaning that the other is referring to, there is a high risk of misunderstanding. As information designers increasingly work in interdisciplinary teams, addressing this issue is particularly essential to foster successful collaboration.

Continuum: From schemas to mental models

Mental models, schemas and frames are theories of knowledge representation that indicate people’s understanding of reality. That is, these are subjective representations of external reality based on what people have learned and experienced since they were born. These theories originated in different domains and areas of knowledge. Schemas (or schemata) were introduced by British psychologist Frederic Bartlett in the 1930s, the mental model term was originated in 1943 by Scottish psychologist Kenneth Craik, and American computer scientist Marvin Minsky coined the term frames in the 1970s as an extension of Bartlett’s schema concept to represent the development of machines with human-like abilities. Human factors and human computer interaction communities brought the mental model concept to the design context, becoming commonplace in the 70s, as a way to help designers create computer systems and tools in line with users’ needs.

I will focus on mental models and schemas only as they are the most used and confused terms in design. Before diving into their use in design, let’s review what these concepts mean:

• Schemas represent stored knowledge (concepts, experiences) that we use to give meaning to what we see. These are general and can evolve as we learn more things. They provide a psychological explanation of the world; we use schemas in perception, memory, comprehension, and other sensory activities to make sense of reality.
• Mental models are representations formed by a user of a system and/or task, based on a stored schema (previous experience) as well as new observation, which provides most (if not all) of their subsequent system understanding and thus guides how they perform a task. Mental models represent people’s understanding of the specific actual environment they are interacting with. These broad conceptual structures represent some aspect of the environment, of how something works, explaining cause and effect, and how changes in one object or situation can trigger changes in another.

Mental models are considered creations of the moment, and although the same mental model may be reconstructed many times, schemas are the ones which are stored and activated. Furthermore, schemas are seen as data structures in memory, which can be activated, but mental models are seen as the utilization of such information in a computationally dynamic manner. This is why the relation between schemas and mental models is better represented as a continuum, rather than as a rigid distinction.

Why mental models matter for information design

Understanding the meaning that a new design solution—new system, tool, map, signage, interface—could have for your audience and how they would interact with it should be the governing logic to make any design decisions. One way to represent this understanding is by representing your audience’s mental models.

There are various research techniques that you can use to guide your audience to articulate or outline mental models relevant for your project. For example, when working on wayfinding projects, it is common to ask people during interviews to draw a map of the area under investigation or to draw how would they navigate a space to get from A to B. The resulting drawings are their mental models, that you can use to highlight common routes, determine where to place signs or identify core milestones for commuters. Similarly, when working on an interaction design project, use a contextual inquiry or usability study to observe how they interact with a design. Pay attention to the sequence of actions they perform to complete a task, identify any unclear areas and notice what actions seem easier and harder. These insights can help you reconstruct their mental models for this design. Further design decisions should respond to and support this sequence of thinking and acting to avoid users feeling frustrated when interacting with the new design.

Working with mental models

Now that you have a better understanding of mental models and their role in the design process is clearer, here are two key points to keep in mind to avoid misunderstandings and help align the team while working in an information design project with mental models:

Who you are talking with. Remember that people with different background can use same terms with different meaning. For example, psychologists and human factors experts use mental models to describe different things. In general words, while in psychology the term is used to describe mental processes, in human factors it is used to describe the product of such processes. Always seek clarification.

Whose mental models you are working with. Make sure you clarify what mental models you are referring to. You could refer to the users’ mental models of a system or tool that you are creating, or the models that you, as a designer, would develop of the user. To avoid confusion and expanding on Don Norman’s framework, you could have:

• Mental models to describe the user’s way of understanding a design (e.g. system) based on their expectations and experience and on their current perception of the design, which provides a basis of their understanding
• Conceptual model to describe your way (the designer) of understanding the design
• Your (the designer) model of the user’s mental model, which represents your assumptions of how the user may understand and interact with the design

When these three models get mixed up, the result is unsuccessful solutions as the design has been created using a “blueprint” that was unfamiliar to the user.

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Craik, K. J. W. (1943). The nature of explanation. Cambridge, England: Cambridge University Press.
Norman, D. (1981) Some observations on Mental models
Wilson, J.R. and Rutherford, A. (1989) Mental Models: Theory and Application in Human Factors. Human Factors, 31(6),617-634