• Doherty Threshold

    Productivity soars when a computer and its users interact at a pace (<400ms) that ensures that neither has to wait on the other.

    Principle
  • Fitts’s Law

    The time to acquire a target is a function of the distance to and size of the target.

    Heuristic
  • Hick’s Law

    The time it takes to make a decision increases with the number and complexity of choices.

    Heuristic
  • Jakob’s Law

    Users spend most of their time on other sites. This means that users prefer your site to work the same way as all the other sites they already know.

    Heuristic
  • Law of Common Region

    Elements tend to be perceived into groups if they are sharing an area with a clearly defined boundary.

    Gestalt
  • Law of Proximity

    Objects that are near, or proximate to each other, tend to be grouped together.

    Gestalt
  • Law of Prägnanz

    People will perceive and interpret ambiguous or complex images as the simplest form possible, because it is the interpretation that requires the least cognitive effort of us.

    Gestalt
  • Law of Similarity

    The human eye tends to perceive similar elements in a design as a complete picture, shape, or group, even if those elements are separated.

    Gestalt
  • Miller’s Law

    The average person can only keep 7 (plus or minus 2) items in their working memory.

    Heuristic
  • Occam’s Razor

    Among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected.

    Principle
  • Pareto Principle

    The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes.

    Principle
  • Parkinson’s Law

    Any task will inflate until all of the available time is spent.

    Heuristic
  • Peak-End Rule

    People judge an experience largely based on how they felt at its peak and at its end, rather than the total sum or average of every moment of the experience.

    Cognitive Bias
  • Postel’s Law

    Be liberal in what you accept, and conservative in what you send.

    Principle
  • Serial Position Effect

    Users have a propensity to best remember the first and last items in a series.

    Cognitive Bias
  • Tesler’s Law

    Tesler's Law, also known as The Law of Conservation of Complexity, states that for any system there is a certain amount of complexity which cannot be reduced.

    Principle
  • Von Restorff Effect

    The Von Restorff effect, also known as The Isolation Effect, predicts that when multiple similar objects are present, the one that differs from the rest is most likely to be remembered.

    Cognitive Bias
  • Zeigarnik Effect

    People remember uncompleted or interrupted tasks better than completed tasks.

    Cognitive Bias