A mental model is a person’s internal understanding of how something works, built from experience and used to predict what will happen next.
Overview
Everyone carries a mental model of the things they use. You expect a light switch to turn on a light, a trash icon to delete something, and an online cart to hold items until checkout. These models are rarely accurate in technical detail, but they do not need to be. They only need to be good enough to predict what will happen.[1][2]
Mental models are built from everything a person has experienced before: other software, paper processes, previous versions of the tool, colleagues’ explanations, and assumptions. People bring those models to every new product, which is why familiar patterns feel intuitive and unfamiliar ones feel confusing.
A mental model is the user’s side of the relationship. The designer’s side is the Conceptual Model: the explanation the product communicates about itself. Good design brings the two into alignment.
Why it matters
When a product works the way people expect, it feels easy. When it contradicts their model, people make confident mistakes, misread information, or lose trust. Mismatched mental models are behind many costly errors, such as believing a record was submitted when it was only saved, or that a change applies to one item when it applies to all.
Mental models are also hard to change. Retraining people’s expectations takes time and effort, so it is usually cheaper to design for the model people already have than to force a new one.
Key takeaways
- People’s models come from elsewhere. Most of what users know about your product, they learned from other products (see Jakob’s Law).
- Users do not share the team’s model. The people who built a system understand it in ways users never will.
- Research reveals models. Interviews, contextual inquiry, and card sorting show how people actually think about their work.
- Design for existing models where possible. Match familiar terms, structures, and patterns.
- When a new model is necessary, teach it through the design. Clear labels, consistent behavior, and good feedback help people build accurate models faster than documentation can.
- Different groups hold different models. Experts, newcomers, internal staff, and external partners may understand the same system in very different ways.
In practice
Common patterns in business applications, portals, and internal tools:
Designs that work with it | Designs that work against it |
|---|---|
Terms and categories come from the language users actually use. | Labels based on internal system names or org-chart structure. |
A new system keeps familiar concepts from the process it replaces where they make sense. | Discarding all familiar concepts, forcing everyone to relearn. |
The interface makes consequences clear (“This will update all 12 locations”). | Actions whose scope people have to guess. |
Research with each user group to understand their perspective. | Assuming that one group’s model represents everyone. |
Onboarding explains the few concepts that differ from people’s expectations. | Lengthy training on things that should be self-evident. |
Questions to ask in a design review
- How do people think about this task today, before using our product?
- Where does our design depart from what they expect, and is that departure necessary?
- Do different user groups think about this differently?
- When people make mistakes, what belief led them there?
Origin
Scottish psychologist Kenneth Craik proposed in The Nature of Explanation (1943) that the mind builds “small-scale models” of reality to reason about and anticipate events.[3][4]
The concept became central to cognitive science in 1983, with Philip Johnson-Laird’s book Mental Models and an influential collection edited by Dedre Gentner and Albert Stevens that included Don Norman’s observations on how people form models of technology.[4] Indi Young’s Mental Models (2008) adapted the idea into a practical design research method.[5]
Related concepts
- Conceptual Model — the model a product communicates to its users
- Jakob’s Law — people expect new products to work like familiar ones
- Card Sorting — reveals how people organize information mentally
- Contextual Inquiry — shows how people understand their real work
- Cognitive Dissonance — the tension when experience contradicts a model
- Mapping — how controls align with expectations
References and further reading
- Nielsen Norman Group. Mental Models and User Experience Design. https://www.nngroup.com/articles/mental-models/
- Yablonski, J. Mental Model. Laws of UX. https://lawsofux.com/mental-model/
- Wikipedia. Kenneth Craik. https://en.wikipedia.org/wiki/Kenneth_Craik
- Wikipedia. Mental Model. https://en.wikipedia.org/wiki/Mental_model
- Young, I. (2008). Mental Models: Aligning Design Strategy with Human Behavior. Rosenfeld Media. https://rosenfeldmedia.com/books/mental-models/
- Norman, D. A. (2013). The Design of Everyday Things: Revised and Expanded Edition. Basic Books. https://en.wikipedia.org/wiki/The_Design_of_Everyday_Things
- Yablonski, J. Laws of UX (format inspiration for this series). https://lawsofux.com/