Blog · Series

Mental models in UX

Ideas borrowed from economics, psychology and science, and what each one changes in day-to-day design work. One idea per article.

Poster with the headline 'The number went up.' and a photograph of a speedboat towing a parasail across a bay.
Design - Mental Models
The number went up. Did the product get better?

Goodhart's law is usually read as a warning about people gaming metrics. In product design, a number can reward a worse product with nobody cheating.

20 October 2026
Poster with the headline 'First principles belong in the brief' and a photograph of a worn red brick.
Design - Mental Models
First principles thinking belongs in the brief

First principles thinking is wasted on a date picker. It pays one level up, in the brief, where real constraints and old habits both arrive as "we have to".

27 October 2026