UX Glossary · J
Jakob's Law
People spend most of their time on other sites, so they expect yours to work the same way.
Jakob’s Law, stated by Jakob Nielsen in 2000, holds that users spend most of their time on other people’s products, so they form expectations there and bring them to yours.
It is a statement about the distribution of a user’s attention. Your product might be excellent, but it occupies a small fraction of someone’s day, and the conventions they have internalised were learned elsewhere.
What it argues for
Conventional placement and behaviour for anything a user does not want to think about. A logo top-left linking home. A cart icon top-right. Underlined links. A search field that accepts Enter. Form fields that behave like form fields.
Novelty in these places costs the user attention and buys nothing, because nobody chose your product for its unusual navigation.
What it does not argue for
Never innovating. It argues for spending your novelty budget where it creates value, in the thing your product is actually for, and paying convention elsewhere.
It is also frequently misused to defend copying a competitor wholesale, including their mistakes. A convention is a pattern users have learned, not whatever the market leader shipped last quarter.
In practice
The question to ask of any unusual pattern is what the user gains from it. If the honest answer is that it looks distinctive, the law says it will cost more than it returns.