Principle of Least Surprise
Updated 2026-08-05
INTRODUCTION
English translation pending.
CORE DEFINITION
The Principle of Least Surprise, also called the Principle of Least Astonishment, holds that the behavior of a system or a person should match what most users reasonably expect. If a user finds it strange, the design is wrong. The key condition is alignment with the audience's established mental models and conventions rather than the designer's cleverness; unexpected brilliance usually produces misuse.
SCAFFOLDING EFFECT
Reduce cognitive load
- Expectation test: check each interface against what users already assume it will do. - Convention first: follow familiar patterns and reserve novelty for where it earns its surprise. - Visible deviation: when intuition must be broken, state it openly instead of hiding it.
Anchor fast decisions
The principle works through expectation consistency: users carry mental models built from prior experience, and behavior that matches those models requires no relearning. When a system outsmarts expectations, attention shifts from the task to the tool, and errors follow.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
account_treeGenealogyexpand_more
menu_bookReferencesexpand_more
Source support: Explicit
- en.wikipedia.orghttps://en.wikipedia.org/wiki/Principle_of_least_astonishmentverified
PRIVATE NOTES · Only visible to you
SAVED Q&A
ENTRY Q&A · Private saving available
Ask with a clear boundary
thinkingmodels answers from published entry context only.
Your question is sent to thinkingmodels. The answer uses public entry context only.
RELATED MODELS