Perception & Gestalt
Von Restorff Effect
When several similar items are present, the one that differs from the rest is the one most likely to be remembered.
Mechanism
Why it happens
Attention and memory are drawn disproportionately to whatever breaks a pattern, since novelty is processed as potentially important.
Impact
Why it matters
- Distinctiveness is a scarce resource. It only works if it's rare
- A row of identical buttons gives the eye no signal about which one matters
- Reserved for the right moment, one visual break does the job of ten labels
Example
Without vs. with
A row of five identically-styled buttons gives no indication of which is primary.
One filled, larger primary button sits among four smaller, outlined secondary buttons.
Checklist
How to apply it
Make the single primary action visually distinct from every secondary action in the same view
Limit distinctiveness to one element per view, or nothing stands out
Use size, colour, and weight to highlight what matters, not decoration
Reserve strong visual breaks for genuinely important state, like errors or new items
Where it shows up