Mental Model

What is a mental model?

A mental model is the picture in someone's head that explains how something works. It doesn't have to be technically accurate. It just has to make useful predictions in everyday life: click "Delete" and something disappears. Open a folder and you expect files inside.

The idea goes back to psychologist Kenneth Craik, who argued in 1943 that people build small internal models of the world to anticipate what will happen. These models grow out of experience, including every other app and online store someone has used before.

Why mental models matter

Problems show up whenever the model in a user's head doesn't match what the product actually does. Features feel illogical, people make mistakes, and trust erodes. Teams easily miss these gaps because they know their product from the inside. Once you understand what users expect, you can either shape the design around those expectations or explain clearly where the product deliberately works differently.

How to account for mental models in practice

• Ask about expectations: Before a click, have test participants describe what they think will happen next.
• Use your users' words: Internal jargon rarely fits how your audience thinks.
• Check your structure: Card sorting shows how people would group your content themselves.
• Respect conventions: Only break established patterns when you have a clear reason.
• Flag the differences: If something behaves differently than expected, say so right where it happens.

Example

In a SaaS newsletter tool, the "Save" button stores a campaign and schedules it for sending at the same time. Users, however, expect a draft they can review later. In testing, several participants accidentally send half-finished emails. The fix is two separate actions, "Save as draft" and "Schedule send", which match the way users already think about the task.