Product Design9 min read

UX Laws & Principles – Part 2

Jarosław Buczkowski

UX/UI Designer

We aim as product designers to make our designs successful, memorable, and pleasurable.

We aim as product designers to make our designs successful, memorable, and pleasurable.


Certain standards have been developed in the design business to assist creatives in making better product decisions. Welcome to the second installment of the UX Laws and Principles series. If you landed here for the first time, be sure to check also the 1st part of UX Laws & Principles, where I’m describing 5 rules that enhance product design as a whole, and help in the decision making process.

Peak-End Rule

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.”

The peak-end hypothesis is a psychological guideline that states that an event is judged and remembered depending on its peak (most intense) moment and/or its end. It appears that our memory of events is highly influenced by our perception of events rather than the experience as a whole.

According to a 2009 study, there are experience gaps for both joyful and negative emotions. It was discovered that the gaps were larger for negative feelings. People remembered being more furious and unhappy than they indicated on actual experience measurements.

Because humans have limits on how much we can comprehend and recall, our brains do not function like computer operating systems. Our minds create strategies to categorize and analyze incoming information more efficiently.

Let’s jump to a quick example based on a language learning app which is… Duolingo, an educational app that makes learning a foreign language fun. Its colorful and conversational design encourages users throughout its interactive courses, adding to a pleasant first impression. Duolingo increases the activity’s natural appeal. The software validates those accomplishments, heightening the sense of achievement that comes from successfully answering questions.

So, what is the takeaway? If you want to create memorable digital products, design them with attention to detail around the key points of the client journey, with a focus on the last step.

How to apply this rule to design:

  • Pay particular attention to the most intense aspects of the user experience, as well as the concluding moments at the end of the user journey.
  • Determine the points at which your product is most useful, valuable, or amusing, and designed to pleasure the end user.
  • Keep in mind that people remember unpleasant events more vividly than happy ones.
Serial Position Effect

Serial Position Effect

“Users have a tendency to best remember the first and last items in a series.”

The serial position effect refers to the ability to recall the first and last elements on a list more easily than the middle ones. During his studies, Hermann Ebbinghaus discovered that the position of an item on a list affected his capacity to recall it.

We have to remember information that is provided to us in a sequence on a regular basis. Examples include remembering a grocery list, a phone number, and following directions. Because we want to remember significant information, we must understand how our memory works in order to increase recall.

Assume you’ve been handed a list of random words and have two minutes to try to memorize them. When asked to recall the things in any order afterwards, you would most likely begin by listing the items that were last on the list, a phenomenon known as the recency effect. The following items on your list will most likely be the first few items on the list, a phenomenon known as the primacy effect.

We regularly come across a great amount of information that we are required to retain when we utilize the internet or apps. This can involve activities such as video gaming and online shopping. Because of this impact, we should design and structure interfaces in a way that people will remember. This includes limiting the quantity of information displayed to users through the use of guides and filters, as well as presenting the most information at the beginning and end of the experience.

How to apply this rule to design:

  • The least important things should be put in the center of lists since they are not as well recalled as the front and end parts.
  • Memorization can be improved by placing critical activities on the far left and right interface side such as web navigation.
Pareto Principle

Pareto Principle

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

The Pareto principle, sometimes known as the 80/20 rule, is one of the most helpful ideas today. It has shown to be successful, time-saving, and just plain practical in anything from real-world scenarios to enormous software systems. We’ll look at how the 80/20 rule applies to UX design and how we can start using it.

A surprisingly wide range of contexts have demonstrated this 80/20 imbalance:

20% of websites capture 80% of web traffic.

20% of customers generate 80% of a company’s revenue.

20% of possible openings are used in 80% of chess games.

And so on..

UX teams typically have limited resources, little time, and the requirement to show business value to the enterprise. A UX team may quickly gain various benefits by exploiting the Pareto principle’s scaling impact, such as examining existing analytics data, reducing the scope of research and execution to persuade stakeholders of the possible return on investment of a UX project or produce significant outcomes in a timely manner.

Despite the fact that analytics systems capture vast amounts of behavioral data from your website or app, not all aspects of the user experience can be interpreted directly. Apply the Pareto principle first by evaluating your organization’s goals, metrics for monitoring them, and user data that supports those goals.

Even little modifications in these important areas can have an outsized impact.

How to apply this rule to design:

  • Focus the majority of your efforts on the areas that will provide the most advantages to the greatest number of people.
  • Apply the Pareto principle first by evaluating your organization’s goals, metrics for monitoring them, and user data that supports those goals.
Doherty Threshold

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.”

We’ve all been there: you’re on a website, you click a button, but the browser doesn’t respond. Is this a bug? or is your device stuck? Maybe your internet went down? So you start rage-clicking, and you can feel your irritation increase. This experience could make the user quit your website instantly and never come back because of this bad event.

So… How can we improve the experience on the example of a website? We can assist decrease user annoyance by keeping system response times under 400ms, which contributes to users productivity and focus. When a computer and its users communicate at that rate we can be sure that neither needs to wait on the other.

Fast websites are enjoyable to use. Websites with delayed or poor response times are terrible. The longer it takes your website to react to a request, the longer it takes your user to decide what to do next. If you keep your visitors waiting, they will go to another website to find what they are searching for. As a general guideline, you should respond to a user’s request within 400 ms to hold their attention.

How to apply this rule to design:

  • Provide system response within 400 ms to hold users’ attention and enhance productivity.
  • Introduce animations to visually engage users while loading or processing is taking place in the background.
  • Regardless of accuracy, progress bars help make wait periods tolerable.
Aesthetic-Usability Effect

Aesthetic-Usability Effect

“Users often perceive aesthetically pleasing design as design that’s more usable.”>

The aesthetic-usability effect explains a phenomenon in which individuals consider more aesthetically pleasing designs to be simpler to use than less aesthetically pleasing ones. The impact has been demonstrated in various trials and has important consequences for a design’s acceptance, use, and performance.

Aside from having a strong UX, it is also critical to have a great interface design and supporting visuals.

Users’ subsequent interactions with the product are influenced by these views, which are frequently tough to modify. According to research, first perceptions of a product determine long-term opinions regarding its quality and use. It is usual for people to acquire sentiments toward designs that have created good attitudes, while it is uncommon for people to develop feelings toward designs that have encouraged negative views.

Such personal and good associations with a design elicit sentiments of compassion, loyalty, and patience — all of which are important components in a design’s long-term usability and overall success. Many people, for example, develop a strong attachment to their automobiles. Some people even name their automobiles and treat them like pets. They treat their dogs as if they were their kids even if they have imperfections.

These positive associations have an impact on the efficiency with which people interact with designs. Positive interactions help to aid in the stimulation of creative thinking and problem solving.

How to apply this rule to design:

  • People’s brains respond positively to aesthetically beautiful designs, leading them to assume the design truly functions better.
  • When a product or service’s design is visually beautiful, people are more forgiving of small usability flaws.
  • Visually appealing design can conceal usability concerns and keep them from being identified during usability testing.

Finishing up…

These UX rules, when applied together, may guide a digital designer toward creating the greatest design available for any particular product. In order to produce better products, UX designers need to be aware of the factors that support the rules of UX, even if they are not literal laws but rather tried and tested cause and effect links.

These rules are the result of extensive research by multiple experts, and we can now apply them to improve the user experience in the products we create.

Thank you for taking the time to read the second part of UX rules and principles! There will be more! Let’s get together soon for a fresh article on a few more rules and concepts!


Jarosław Buczkowski

UX/UI Designer

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