10 laws of UX

Using psychology to design better products & services

1. Jakob’s Law

One of the most common principles to be used as guidance for designing digital interfaces. It was created by Jakob Nielsen and according to him, the law can be defined as the following:

2. Fitts’ Law

Established back in 1954 by the American psychologist Paul Fitts as a model for understanding human movement in the physical. Today, it is regarded as one of the most successful and influential mathematical models of human motion, and it is widely used in ergonomics and human-computer interaction. Fitts’s Law is the following:

  1. Have ample space between them
  2. Be placed in areas of the interface that allow them to be easily acquired

3. Hick’s Law

A fundamental principle to decision-making and the complexity of choices available. The law originates from 1952 when William Edmund Hick and Ray Hyman set out to examine the relationship between the number of stimuli present and an individual’s reaction time to any given stimulus. The law that resulted from their studies is the following:

  1. Break tasks into smaller steps to decrease the cognitive load
  2. Simplifying an interface or process helps to reduce the cognitive load for users and increases the likelihood that they’ll complete their tasks and achieve their goals
  3. Be careful not to simplify to the point of abstraction. Make sure to add contextual clues to help users identify the options available and determine the relevance of the information available to the tasks they wish to perform

4. Miller’s Law

Originating from a paper published in 1956, which presented that, based on Miller’s observation, the memory span in young adults is approximately limited to 7 chunks of information. This led to the idea that bits, the basic unit of information, don’t affect memory span as much as the number of information chunks that are memorized.

  1. Remember that short-time memory will vary per individual, based on their prior knowledge and situational context

5. Postel’s Law

Jon Postel was an American computer scientist who made significant contributions to the underlying protocols that would come to form the internet. Some of his major contributions were in the early implementations of the Transmission Control Protocol (TCP), the foundation on which we send and receive data over the network.

  1. The more we can anticipate and plan for in the design, the more resilient the design will be
  2. Accept variable input from users, translating that input to meet your requirements, defining boundaries for input, and providing clear feedback to the user
  3. Be empathic to, flexible about, and tolerant of the various actions the user could take or any input they might provide

6. Peak-End Rule

An interesting thing happens when we recollect a past event: instead of considering the entire duration of the experience, we tend to focus on an emotional peak and on the end, regardless of whether those moments were positive or negative. This observation, known as the peak-end rule, strongly suggests we should pay close attention to these critical moments to ensure users evaluate an overall experience positively.

  1. Identify the moments when your product is most helpful, valuable, or entertaining and design to delight the end-user
  2. Remember that people recall negative experiences more vividly than positive ones

7. Aesthetic-Usability Effect

An aesthetically pleasing design can influence usability — it not only creates a positive emotional response, but also enhances our cognitive abilities, increases the perception of usability, and extends credibility. This phenomenon is known as the aesthetic-usability effect:

  1. People are more tolerant of minor usability issues when the design of a product or service is aesthetically pleasing
  2. Visually pleasing design can mask usability problems and prevent issues from being discovered during usability testing

8.von Restorff Effect

In our evolution, we as humans developed an incredibly sophisticated system of vision and cognitive processing. We can identify objects in a fraction of a second, have superior pattern processing capabilities, and have an innate ability to spot small differences in objects. These traits that were essential for our survival in the past, remained with us and are affecting the way we perceive the world around us. The goals we try to achieve are not the only thing directing our focus. It is also directed by these instinctual abilities.

  1. 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
  2. Don’t exclude those with a colour vision deficiency or low vision by relying exclusively on colour to communicate contrast
  3. Carefully consider users with motion sensitivity when using motion to communicate contrast

9. Tesler’s Law

A key objective for designers is to reduce complexity for the people that will use the products and services provided, yet there is some inherent complexity in every process. Inevitably, we reach a point at which complexity cannot be reduced any further but only transferred from one place to another. At this point, it finds its way either into the user interface or into the process and workflows of designers and developers.

  1. Ensure you lift as much of the burden as possible as much as possible from users by dealing with inherent complexity during design and development
  2. Take care not to simplify interfaces to the point of abstraction

10. Doherty Threshold

One of the features that is critical to a good user experience is performance. Emotions can quickly turn to frustration and leave a negative lasting impact when users who are trying to achieve a task are met with slow processing, lack of feedback, or excessive load times. Speed should be considered an essential design feature that is core to a good user experience.

  • It provides visual interest while waiting
  • It reduces the perception of waiting by shifting the focus to the animation of the progress bar instead of the actual process of waiting
  • it might be difficult for the user to comprehend what happened, since the speed of the change does not allow sufficient time for mental processing
  1. Use perceived performance to improve response time and reduce the perception of waiting
  2. Animation is one way to visually engage people while loading or processing is happening in the background
  3. Progress bars help make waiting more tolerable, regardless of their accuracy
  4. Purposely adding a delay to a process cab actually increase its perceived value and instil a sense of truth, even when the process itself actually takes much less time



User Experience Engineer that creates digital products 👩‍💻 with knowledge and passion💖 https://znap.link/andraardna

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Andra Cimpan

User Experience Engineer that creates digital products 👩‍💻 with knowledge and passion💖 https://znap.link/andraardna