What is Laws of UX about?

Laws of UX is Jon Yablonski's collection of ten principles drawn from psychology and cognitive science that bear directly on user interface design. Originally a website (lawsofux.com) launched in 2018, the book version published by O'Reilly in 2020 expands each principle with context, examples, and design guidance. It is a short, dense book aimed at practitioners who want to ground their design decisions in human cognitive tendencies rather than taste or convention.

The principles Yablonski covers include Hick's Law (more choices mean slower decisions — relevant to navigation and feature design), Fitts's Law (targets should be sized and positioned proportionally to how often they're used), the Aesthetic-Usability Effect (attractive interfaces are perceived as more usable, sometimes falsely), the Peak-End Rule (users remember the peak moment and the final moment of an experience disproportionately), and the Von Restorff Effect (things that differ from their surroundings are remembered). None of these are original to Yablonski — they come from psychology research spanning decades — but his contribution is to apply them specifically to digital product design and to show, with concrete examples, how violation of each principle produces recognizable failures.

The book's ambition is explicitly ethical as well as practical. Yablonski is aware that the same principles used to make interfaces usable can be used to make them manipulative — dark patterns exploit cognitive tendencies just as surely as good design works with them. He dedicates a chapter to the ethics of design, arguing that practitioners have a professional obligation to understand the power they wield and to use it responsibly. This makes the book more honest than most UX writing, which tends to treat manipulation and design as entirely separate concerns.

The brevity is a feature, not a bug: each law is explained, illustrated, and reflected on within about twenty pages. Practitioners can absorb the full framework in an afternoon and return to individual sections when working on specific problems. The book's weakness is that the coverage is necessarily selective — there are many more psychological principles relevant to design than ten — and the depth of application is limited. Yablonski is clear that this is an introduction, not a comprehensive framework.