What Von Restorff Actually Found
In 1933, German psychiatrist Hedwig von Restorff published a study in Psychologische Forschung showing that when people are shown a list of similar items with one item that stands apart, they remember that one item far better than its neighbours - even though every item in the list was shown for exactly the same length of time. It's since become known as the isolation effect, and it's one of the more consistently reproducible findings in memory research.
It's Relative Distinctiveness, Not Raw Boldness
A 1995 re-examination of von Restorff's original work, published in Psychonomic Bulletin & Review, made an important correction to how the effect gets applied: isolation doesn't require visual loudness. What matters is the item's difference from its immediate surroundings. A plain white card in a row of colourful ones is exactly as isolated - and exactly as memorable - as a bright red button among grey ones. The effect is about contrast with context, not about how much attention any single element demands on its own.
Applications in UI Design
- Primary CTA: Give the main action a visual treatment nothing else on the screen shares - colour, weight, or shape. Everything else should read as subordinate by comparison.
- Pricing tables: A "Most popular" plan with a different background or border pulls attention by breaking the pattern the other columns establish.
- Critical alerts: Errors need to look nothing like regular content - colour and iconography that never appear elsewhere in the interface.
- Empty states: One illustration in an otherwise list-heavy product creates a moment that's disproportionately memorable relative to its size.
The Caveat: Overuse Cancels the Effect
Because isolation is relative, it collapses the moment everything is trying to stand out. Three bold buttons on one screen means none of them read as the priority. Audit for "highlight inflation" - too many primary-coloured elements, too many badges - the same way you'd audit for visual noise anywhere else.
