Von Restorff effect

The von Restorff effect, also called the isolation effect, is the finding that an item that stands out from a group of similar items is remembered better than the others. It is named after the German psychiatrist and pediatrician Hedwig von Restorff, whose 1933 paper in Psychologische Forschung showed that when one item in a list is different from the rest, memory for that item improves. Studies since then have isolated items by changing their size, shape, color, spacing or underlining.

Why it matters

Interfaces are full of similar elements: rows in a list, cards in a grid, buttons in a toolbar, plans on a pricing page. Distinctiveness is how you tell people which one matters. Used well, it guides attention to the primary action or the most important warning. Used carelessly, everything competes and nothing stands out.

How to apply it

• Do make the primary action visually different from secondary ones, for example one filled button next to outlined ones.
• Do reserve a strong accent color or treatment for the few things that truly need attention, such as errors, unsaved changes or a recommended option.
• Do combine cues. Laws of UX advises not relying on color alone, because people with color vision deficiencies or low vision may miss it. Pair color with weight, an icon, a label or position.
• Do be careful with motion as a contrast cue, since it can be a problem for people with motion sensitivity. Respect reduced-motion settings.
• Don't highlight several items at once. If three cards are "featured", none of them is.
• Don't make important content look like an ad. Banner-style boxes and loud colors can push people to skip them.

Common mistakes

• Overusing emphasis. Bold, color, badges and animation lose their effect when they appear everywhere, and the page becomes noisy.
• Using the effect to mislead. Making the expensive option or the "accept all" button stand out while the alternative fades away is a deceptive pattern, not good emphasis.
• Highlighting the wrong thing. The effect works on whatever is distinctive, including a decorative element that pulls attention away from the task.
• Treating it as purely visual. Distinctiveness can come from wording or sound too, and an item stands out only relative to what surrounds it.
• Assuming it is only about surprise. Reed Hunt's 1995 paper What von Restorff really did revisits the original work, which found better recall for the isolated item regardless of where it appeared in the list. That is hard to explain as a simple violation of expectations, so the effect is less tidy than the one-line summary suggests.