UX Glossary · M
Miller's Law
Also: The magical number seven
Working memory holds about seven items, plus or minus two, and the figure is routinely misapplied.
George A. Miller published “The Magical Number Seven, Plus or Minus Two” in 1956, observing that people could hold roughly seven items in immediate memory across several kinds of task.
It is probably the most misquoted finding in design.
What it actually said
Miller was writing about immediate memory for unrelated items, such as digits read aloud. He was not writing about navigation menus, and he explicitly discussed chunking: grouping items into meaningful units expands what can be held, which is why a phone number in three groups is easier than eleven loose digits.
Later research suggests the practical limit for genuinely unrelated items is closer to four, following Nelson Cowan’s work.
Why “seven menu items” is wrong
A menu is visible. Nothing is being held in memory, so the constraint does not apply. Trying to force navigation into seven items regularly produces worse structures than a well-organised list of fifteen, because the labels get vaguer to accommodate the limit.
Where it genuinely applies
Anything requiring the user to carry information across a boundary: a verification code between two screens, a reference number from an email to a form, values to compare across pages that cannot be seen together.
In practice
The design instruction is not “seven things”. It is to avoid making people remember, by keeping what they need visible.