I'm reading Apple's Human Interface Guidelines about Mental models and I can't understand what is the difference between Mental and Conceptual models.

I prefer a short answer if possible :)

3 Answers 3


"A mental model is the representation that a person has in his mind about the object he is interacting with. A conceptual model is the actual model that is given to the person through the design and interface of the actual product." (Susan M. Weinschenk. 2011. 100 Things Every Designer Needs to Know About People)

So a mental model is the way the person thinks about what it is they are doing. For example, when getting a book out of the library, they form a mental model of the things they have to do to achieve this.

A conceptual model for an online library is the interface the person interacts with as a represented concept of a library.

  • 3
    No, the 'actual model' (interface of the product) is called the System Image. (See my original Norman reference below)
    – PhillipW
    Commented Jul 29, 2011 at 14:00
  • 2
    The person who asked the question requested a short answer. I simplified it. In relation to the Apple Human Interface Guidelines the purpose of having these models is so the designers design (the conceptual model) takes into consideration and matches how the user thinks (the mental model).
    – Katie C
    Commented Jul 29, 2011 at 18:41
  • Conceptual model: the mental representation of the design.

  • Mental model: the mental representation of the way the system works that emerges from its use.

They are not the same (nor it is mandatory to be the same). The important thing is they are aligned (there are not inconsistencies between them).

For example, the accelerator pedal in a car is perceived by the designers as a means to inject more fuel to the car engine. However, the driver perceives it as a means to go faster (ignoring the mechanical implications). Both visions are different but consistent.


They are, effectively, the same thing in the context of technology which interfaces with users.

Apple is using the two terms rather loosely and interchangeably in the Interface Guidelines.

Don Norman explains the original Designer's Model / System Image / Users Model distinction next to the graphic about 'Conceptual Models' as part of this jnd.org article on `Design as Communication'.

Don originally made the destinction about conceptual models (of how technology works) being just one type of mental model.

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    Thanks for the link. In that article, Norman wrote that conceptual and mental models ideally should coincide, but I don't think he meant that they're the same thing. Commented Jul 29, 2011 at 12:37
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    He did when he published it originally (1986). He's muddled the terminology in the more recent article by changing 'Designers Model' to 'Designers Conceptual Model' See page 16 of the Psychology of Everyday Things (1989) for the original.
    – PhillipW
    Commented Jul 29, 2011 at 13:58
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    "The design model is the designer's conceptual model. The user's model is the mental model developed through interaction within the system." Commented Jul 29, 2011 at 16:51
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    Agreed. Though I think its clearer to use the terminology Designer's Model / User's Model. A Conceptual Model is A TYPE of Mental model, where users have to figure out how some bit of technology works. In a broader context, people have mental models about all sorts of non-technological things.
    – PhillipW
    Commented Jul 29, 2011 at 21:43

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