Laws of UX

Jakob's Law

  • Users will transfer expectations they have built around one familiar product to another that appears similar.
  • By leveraging existing mental models, we can create superior user experiences in which the users can focus on their tasks rather than on learning new models.
  • When making changes, minimize discord by empowering users to continue using a familiar version for a limited time.

Fitts’s Law

  • Touch targets should be large enough for users to accurately select them.
  • Touch targets should have ample spacing between them.
  • Touch targets should be placed in areas of an interface that allow them to be easily acquired.

Hick’s Law

  • Minimize choices when response times are critical to increase decision time.
  • Break complex tasks into smaller steps in order to decrease cognitive load.
  • Avoid overwhelming users by highlighting recommended options.
  • Use progressive onboarding to minimize cognitive load for new users.
  • Be careful not to simplify to the point of abstraction.

Miller’s Law

  • Don’t use the “magical number seven” to justify unnecessary design limitations.
  • Organize content into smaller chunks to help users process, understand, and memorize easily.
  • Remember that short-term memory capacity will vary per individual, based on their prior knowledge and situational context.

Postel’s Law

  • Be empathetic to, flexible about, and tolerant of any of the various actions the user could take or any input they might provide.
  • Anticipate virtually anything in terms of input, access, and capability while providing a reliable and accessible interface.
  • The more we can anticipate and plan for in design, the more resilient the design will be.
  • Accept variable input from users, translating that input to meet your requirements, defining boundaries for input, and providing clear feedback to the user.

Peak–End Rule

  • Pay close attention to the most intense points and the final moments (the “end”) of the user journey.
  • Identify the moments when your product is most helpful, valuable, or entertaining and design to delight the end user.
  • Remember that people recall negative experiences more vividly than positive ones.

Aesthetic–Usability Effect

  • An aesthetically pleasing design creates a positive response in people’s brains and leads them to believe the design actually works better.
  • People are more tolerant of minor usability issues when the design of a product or service is aesthetically pleasing.
  • Visually pleasing design can mask usability problems and prevent issues from being discovered during usability testing.

von Restorff Effect

  • Make important information or key actions visually distinctive.
  • Use restraint when placing emphasis on visual elements to avoid them competing with one another and to ensure salient items don’t get mistakenly identified as ads.
  • Don’t exclude those with a color vision deficiency or low vision by relying exclusively on color to communicate contrast.
  • Carefully consider users with motion sensitivity when using motion to communicate contrast.

Tesler’s Law

  • All processes have a core of complexity that cannot be designed away and therefore must be assumed by either the system or the user.
  • Ensure as much as possible of the  burden is lifted from users by dealing with inherent complexity during design and development.
  • Take care not to simplify interfaces to the point of abstraction.

Doherty Threshold

  • Provide system feedback within 400 ms in order to keep users’ attention and increase productivity.
  • Use perceived performance to improve response time and reduce the perception of waiting.
  • Animation is one way to visually engage people while loading or processing is happening in the background.
  • Progress bars help make wait times tolerable, regardless of their accuracy.
  • Purposefully adding a delay to a process can actually increase its perceived value and instill a sense of trust, even when the process itself actually takes much less time.