Closure
The eye completes incomplete shapes, which is why a partially visible item signals that there is more.
Definition
A Gestalt principle describing the tendency to perceive incomplete figures as whole. The visual system fills gaps to produce a recognisable form.
Established research. Originates in published research and has been replicated. The effect is real. Its size in your product still needs measuring.
Interface uses
- Cutting off a card at the edge of a horizontal scroller signals that the row continues. A row that ends flush at the viewport edge reads as complete, and users do not scroll it.
- Truncated text with a fade or ellipsis implies continuation, though an explicit control is more reliable.
- Loading skeletons work partly through closure: the shapes imply the content that will fill them.
- Logos and icons can omit strokes and still read, which is what allows simplification at small sizes.
In practice
Peeking cards in a carousel
Mobile listingsShowing a sliver of the next card raises horizontal scroll engagement substantially compared with a row that ends at the viewport edge.
Sources
Where a source establishes something narrower than the popular reading of it, the note says so.
Principles of Gestalt Psychology
K. Koffka, Harcourt Brace, 1935
Continue from here
Each link says what the connection is, so you can tell a principle from an alternative from a thing people mix this up with.
Applied through
Where this shows up as a concrete interface decision.
- CarouselComponent
- Skeleton ScreensPattern
Principles behind this
The reasoning this solution is an application of.
- Law of PrägnanzLaw
- DiscoverabilityPrinciple
Related concept
Connected closely enough to change how you apply this.
- ContinuityUI foundation
- IconographyUI foundation