Understanding and applying principles of psychology is crucial in UX design. Concepts like Hick's law, Gestalt principles, and the psychology of persuasion help designers create interfaces that are intuitive, visually appealing, and persuasive. By considering these psychological principles, UX designers can enhance user experiences and effectively engage users.

“A designer who doesn’t understand human psychologies is going to be no more successful than an architect who doesn’t understand physics”, says Joe Leech, author of the book Psychology of Designers.

Human psychology and UX design are intricately linked. When designing for people, stepping into their shoes and understanding their behavior is fundamental. Only by knowing how human brains work can a satisfactory user experience be created.

Delving into human psychology and the application of psychological principles in UX design enables designers to create best designs meeting user needs. In this article, we look at 15 laws that can help UX designers create compelling designs.

Top psychological principles for impactful UX

1. Hick’s law

Hick’s law explores the relationship between the time taken by users to make a decision and the number of choices. According to Hick’s law, increasing the number of choices increases the time taken to come to a decision. Think about how it's easier to choose between 2 flavors of icecream compared to 10 flavors – that’s Hick’s law in action!

a girl thinking about some creative idea

When people are given several options of equal importance, they get overwhelmed. Rather than taking the effort to figure out the complexity and make a choice, most people get confused and leave without making a decision. UX designers can create encouraging designs by applying Hick’s law in various parts of the design process.

  • While creating information architecture, apply Hick’s law to design navigation in the simplest way. Break down the navigation options into categories and subcategories and disclose to users as per need rather than displaying all navigation options at the same time.
  • Mandatory processes like checkout and form filling can be divided into smaller steps with minimum fields to be filled at a time. It makes the processes seem easy to comprehend, complete and motivates users to act.
  • Whenever users have to choose from long lists, make their decision easier by reducing the number of options displayed at a time and optimizing the list for scannability..

Certain aspects of the UX design process, such as navigation menu design and filter UI design can be greatly enhanced using Hick’s law. Wherever users need to be presented with a number of choices, the best practice is to prioritize information, break them into steps and validate through usability tests.

2. Gestalt principles

Human brains have a tendency to organize and group things together. That helps the brain process information in a predictable and easy manner. Gestalt principles define how the brains interpret and process information through six laws.

  • Law of symmetry : The law talks about the human tendency to find symmetry aesthetically appealing. When people look at things, they unconsciously look for a symmetry in them. Such symmetrical designs are better identified and remembered.
    Eg: Logo of McDonalds
  • Law of proximity : According to the law of proximity, elements placed closer together are perceived as a group even if they are not enclosed by visible borders. Because of the proximity, the brain infers distinct elements with different properties as a unit.
    Eg: Logo of Unilever
  • Law of similarity : This law states that in a group of elements, the brain identifies similar objects as a group. That is, based on a common factor (like color or size), the brain creates subgroups within groups.
  • Law of closure : Human brain has the ability to fill in missing information and perceive incomplete objects as whole. The gaps between shapes or letters are filled by the brain automatically to make the objects legible.
    Eg: Logo of IBM
  • Law of continuity : This law states that our eyes tend to follow lines and thus travel from one element to another. The lines act as visual cues and can be deliberately used to direct user attention to important elements of design. This law is often used in the design of DeFi platforms, healthcare apps, ecommerce sites and other digital mediums to attract users towards particular products or actions.
  • Figure and ground : Law of figure and ground describes how people subconsciously separate elements on different planes of focus. Humans can differentiate between an object (figure) and its surroundings (ground) and switch between them to perceive different images.

3. Psychology of persuasion

Persuasive design compels users to take actions. Different elements can be used to convince the users and the psychology of persuasion discusses how to do it.

  • Offer value : Offering something of value to users encourages them to take action. Platforms that offer free pdf on signup and stores providing discounts on a minimum purchase use this psychological principle in their designs.
  • Establish authority : Establishing authority helps to gain people’s trust and eliminate any friction they may have on associating with the product.
  • Show scarcity : Using scarcity to generate demand is a common tactic used in sales. People tend to give more value to things when the availability is limited. It creates FOMO (Fear of missing out) in them and encourages them to take action. Booking apps and ecommerce platforms make use of this principle extensively.
  • Showcase social proof : Positive words about a product or service from existing customers create a positive perception of it in people’s mind and act as a wonderful persuasion tool. In fact, people tend to trust genuine social proof more than a company’s marketing strategies.
  • Use familiar faces : Using familiar faces in designs increases users memory and influences them subtly. When a favorite celebrity or a close family member talks positively about something, people subconsciously feel a liking towards it.

4. Mental models

an illustration about ux psychology

Human beings understand the world through mental models. Mental models are a set of beliefs that people form based on their experiences, which guides their thoughts and actions. When people interact with digital interfaces, they have a mental model of how the experience should be. These are formed from their previous interactions and creates an expectation in their minds. When designs are aligned with users’ mental models, they find them easier to understand and use.

Mental models are the reason designers are advised to stick with conventions wherever possible. When designs disrupt conventions, it breaks mental models, making the interface difficult to use. For example, the different gestures used in smartwatch design have corresponding actions associated with them. A pinch gesture is matched with a zoom option. If a designer were to experiment with it and associate some other action with pinch, users would be confused.

4. Cognitive load

Designs must always keep the users’ cognitive load in mind to create a pleasant experience. Cognitive load refers to the amount of mental effort that users have to exert to operate an interface. If presented with too much information at a time, people feel overwhelmed as the working memory capacity and processing power of the human brain gets challenged.

To reduce cognitive overload, designers must take care to eliminate visual clutter, adhere to existing mental models and use easily graspable copy. Keeping in mind the human working memory capacity and designing with the principle “recognition over recall” helps to minimize cognitive overload.

6. Color psychology

Colors dont just add visual appeal to interfaces, they also influence the user behavior. Human brain associates different colors with different emotions and the right color can help to elicit the required reactions. Color psychology delves into the feelings associated with each color and the ways color can be used to improve the efficiency of designs. For example, the color red conveys excitement and energy while blue induces a feeling of trustworthiness and calm. .

Along with creating an emotional connection with users, colors can also be used to communicate states, urgency and attract attention. The color gray is used to indicate a state of inactivity while colors are used to show active states. And for buttons or other CTA elements, using colors that stand out from the background design grabs attention.

7. Von restorff effect

The Von Restorff effect or Isolation effect states that in a group of similar objects, the one that is different from the rest would be remembered by users. This psychological principle is the reason why important elements are presented visually distinctly in most designs. For example, in presenting subscription packages, it can be noticed that one package is highlighted compared to the others. Often users tend to choose the highlighted package as it attracts maximum attention and users feel it's the most viable option. Similarly, making the primary CTA elements standout by making them distinct is another application of the Von Restorff effect.

8. Dual coding theory

According to dual coding theory, memory is influenced by the relationship between verbal information and non-verbal information. When verbal information (text) is paired with non-verbal information (images), it improves the probability of information recall. Associating words with images makes information easier to understand and remember. Applying this psychological principle in UX design can really help to enhance the ease of learning and improve communication with users.

some examples of icon in  ux

9. Fitts’s law

Fitts’s law states that the time taken to acquire a target is a function of the size of the target and the distance to it. If a target is farther away from the user and is small in size, the user will take a longer time to reach it. Fitts’s law suggests placing targets closer to the user's control and making them larger to increase the number of interactions.

Some applications of this psychological principle in UX design of web and mobile interfaces are:

  • Locating the CTA button for an action close to the active elements
  • Presenting the important information in slightly larger size so that they are easier to click
  • Placing the primary CTA in the shortest user path
  • Making the target size smaller and farther away for undesired actions like Delete, Remove.

10. Jakob’s law

Jakob’s law states that users prefer familiar experiences and expect an interface to work similar to the ones they already know. The feeling of familiarity and comfort make them feel at ease. An innovative design approach may make the users feel challenged and create friction. Because they can’t intuitively figure out how it works, they may choose to not engage with the interface.

Although Jakob’s law advocates for familiarity, it doesn’t endorse sameness. The idea is not to copy the popular sites in a domain but rather to study them and figure out the common structure that users are accustomed to.

11. Miller’s law

Another useful psychological principle in UX design, Miller’s law addresses the memory limitation of the human brain. It states that humans can only keep upto 7 items in their working memory at a time. Any information beyond that will be difficult for the brain to recall. This law can be especially useful for designs that are content rich.

Presenting large volumes of information to users may result in cognitive overload. Splitting them into chunks as suggested by Miller’s law helps to improve the user experience. When content is presented in blocks of 6 or 7, it is easier for users to remember. One application of Miller’s law is in ecommerce UX design where users are presented with upto 7 products at a time.

12. Peak-end rule

Peak end rule states that people remember an experience based on how they felt at its climax and the end rather than considering the average of all moments. That is, the overall impression is based on some of the strong moments, be it pleasant or unpleasant. It is a cognitive bias that defines how people recall past events.

To apply the peak end rule in UX, designers should focus on creating positive peaks and making the final impression lasting. It may be unrealistic to expect that negative peaks be completely avoided. A practical approach is to make the negative peaks less impactful through helpful design.

13. The aesthetic usability effect

The aesthetic usability effect says that people believe interfaces that look better will work better. Users perceive aesthetic products as more usable and even tend to overlook the usability issues if the design looks appealing. It creates a positive response in the human brain and leads them to be more tolerant with inefficient designs.

While the aesthetic usability effect can mask minor usability issues, it has certain limits. In the long run, a stunning UI may tend to lose its charm and the usability problems will ruin the user experience.

14. Serial position effect

The serial position effect states that users tend to remember the first and last items of a series with greater accuracy than the items in the middle. There are two concepts involved here – primacy effect and recency effect. Primacy effect says that items at the beginning of a list are recalled with more accuracy than those in the middle while recency effect says that items at the end of a list are recalled with more accuracy than those in the middle.

This psychological principle informs UX designers to emphasize important information at the beginning and end to make it memorable. The serial position effect can be seen in action in several website landing pages where the most important information is presented in the first and last sequence while the middle sequence contains less important information. Ecommerce sites also make use of this effect by showcasing best selling items in the beginning and end of product lists.

15. The principle of least effort

A foundational law in UX design, the principle of least effort says that in doing any action, people choose the path of least effort to complete it. Even though humans are capable of handling complexities, the path with the least resistance is always prioritized. So, if there are several ways to perform an action, people choose the way that requires the least effort. The effort can either be the thought to be expended, the energy or time.

Using icons over text to showcase features, social signup option and guest checkout are some of the applications of this psychological principle in UX design.

Wrapping up

Human brain works in complex ways. Psychologists have been studying human behavior persistently for years and as a result it is possible to analyze human actions and identify the reasoning behind them. UX design being a domain where in-depth understanding of users is necessary, knowing the psychological principles is beneficial. The principles discussed in this article provide a solid foundation for designers in a UI UX design agency to create interfaces that will satisfy inherent expectations of users and engage them naturally.


Fazmeena is a UX enthusiast who loves learning about user-centric designs. She channels her passion for UX into every piece she writes, offering readers valuable insights into the domain of UX design. Connect with Fazmeena via www.linkedin.com/in/fazmeena-faisal/

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