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10 Main Laws for UX Designers

10 Main Laws for UX Designers

Design Process
8 min read

Designers’ work is often associated with unbounded creativity aimed to give birth to something beautiful. But not many know that aesthetic design doesn’t automatically mean usability. 

In the Arounda team, designers often rely on psychological laws to adjust a website, mobile app, or SaaS to human needs. This article explains the ten rules that we use most often throughout our 5-year experience designing digital products and conducting UI/UX audits. So let’s come straight to UX laws with examples. 

1. The Aesthetic-Usability Effect

Have you ever wondered why Apple is so popular, although its products are more expensive than standard PCs or cell phones with similar characteristics? Most likely, that’s because Apple’s computers and iPhones follow common laws of UX examples.

In 1995, the researchers of the Hitachi Design Center tested 26 variations of the automated teller machine interface with 252 participants. As a result, they realized that users rate aesthetic UI higher than more convenient button layouts that look awry. 

Similarly, a website or an app with a beautiful color scheme and professional photos will gain positive feedback even if users face difficulties finding information, purchasing, or completing other tasks.  

People tend to perceive attractive products as more usable. That’s because they believe things that look better will also function better. But in fact, they might be less efficient.

Takeaway: Users are more tolerant of an aesthetically pleasing interface. Appealing design can counterbalance the UI problems to some extent.  

2. False-Consensus Effect

Psychologists have noticed that we often unconsciously project our beliefs onto others and assume they will think and behave the way we would. This mispersuasion is called the false-consensus effect. And it turns into one of the most precious laws UX.

Designers might expect users to react to their work just like they do. But people using the product will perceive it differently because their tastes, backgrounds, and goals vary. 

Takeaway: Test your design and its usability on real people as often as possible to get the actual feedback. Use prototypes, A/B tests, and surveys to stay in touch with your audience.    

3. Pareto Principle

Vilfredo Pareto, an Italian sociologist, economist, and political scientist noticed that 80% of the wealth in Italy belongs to around 20% of the population. Similarly, salespeople might observe that 20% of accounts bring 80% profit. Moreover, marketers would agree that 20% of campaigns generate 80% of leads.

Paleto principle states that 20% of effort applied at the right point results in 80% of the outcome. Meanwhile, the rest 80% of actions will add only 20% to your result. 

Takeaway: Focus on designing aspects that deliver the most significant benefit to your users. When dealing with a complex website or app, study your users. Thus, you can learn which pages, features, and services evoke the main interest and prioritize them.  

4. Doherty Threshold

In 1982, IBM Systems Journal published the research of Walter J. Doherty, which set the limit of 400 milliseconds for the computer response time. The investigation showed that this delay feels natural when people interact with computers.

Four hindred milliseconds is a standard limit for the computer response time called the Doherty Threshold.  

Takeaway: If the loading process takes longer than 400 milliseconds, use progress bars or animations to engage users while waiting. 

5. Fitt's Law

It would likely be riskier for Wilhelm Tell to hit the apple on his son's head from 20 feet than from the 10 feet distance. And shooting a watermelon, in this case, would be much easier. The law of psychologist Paul Fitts says that the accuracy of hitting the target depends on the distance and the size of the target proportionally. It’s also true for cursor movements. 

Firstly, smaller buttons are more difficult and time-consuming to click. Secondly, the distance between an eye-catching area and a related button should be as small as possible. 

Takeaway: Fitt’s UX design law means that interactive elements must be big enough to click or tap easily. And it’s wrong to place them where the cursor can reach fast.  

6. Hick's Law

If you remember shopping at Amazon recently, you will likely agree that choosing among multiple products is puzzling. 

Hick’s law states that the more choices or stimuli you suggest to an individual, the longer it will take to make a decision.

Takeaway: If you have many options to present to users, try not to display them all at once. You may categorize choices, break longer processes into stages, and reveal related information gradually.    

7. Weber's Law of Just Noticeable Differences

An anatomist Ernst Heinrich Weber carried out several experiments examining the human ability to distinguish the increase in lifted weights. For example, if you lift a 2-pound weight and then hold the 2.2-pound weight of the same shape, you will hardly notice the difference or experience an additional muscular strain. But if the weight changes from 2 to 2.5 pounds, you will feel the task's more complex. 

Weber's Law from the UX design perspective states that users dislike a dramatic change in products they use, despite the benefits they eventually get. 

Takeaway: If you conduct a massive redesign, implement it in small iterations over a long period. Small and subtle changes won’t scare your users away. 

8. The rule of the first impression

The well-being of a person often depends on their skill to determine whether to trust a stranger. Mother nature gave us the ability to judge others by face, voice, and posture within a tenth of a second. And the experiments by Princeton psychologists reveal that further consideration doesn’t change the first impression significantly. 

First impressions of a digital product last for a long time and are hard to change.    

Takeaway: Similar to the first and the sixth laws of UX design, this rule tells us to invest time and thought into a pleasing design. This approach will ensure an immediate positive emotional reaction. So it’s worth creating mood boards and gathering reference feedback beforehand.   

9. Von Restorff Effect (or Isolation Effect)

In 1933, German psychiatrist Hedwig von Restorff published a study about memory peculiarities. She discovered that people better remember the items somewhat differently or isolated from the others on the list. So, for example, if one of the items on a shopping list is highlighted or written in bold, you will certainly hold it in your mind. 

So when you present chunks of content on the site or an app, users will remember the one that differs from others.

Takeaway: Make sure essential information like CTAs or “Buy” buttons are visually distinctive through size, shape, color, spacing, and animation. 

10. Peak-End Rule

In 1993, four investigators suggested to participants two types of unpleasant experiences. In the first trial, they had to hold a hand in cold water for a minute. In the second go, they had 30 more seconds when the water temperature was raised by one degree. 

When the participants had to choose which of those two experiences to repeat, most preferred the longer trial with cold water. That’s because people liked the final memory of it a bit more.  

We mostly judge an experience by emotions at the peak and the end of the outliving. The duration and the average impression influence the final attitude less than peaks. 

Takeaway: Deliver the best possible impressions in the most intense points and the end moments of the user journey.


Good UX design is rooted in human psychology and aims to eliminate any discomfort while using the product. UX laws and principles ensure that designers understand the nature of the users well. 

Arounda has completed over 130 projects dealing with web design, UI/UX audit & redesign, brand identity, and product strategy. We know from practice that UX laws work well in fintech, e-commerce, and NFT cases. And we share these core principles with confidence. 

If you are looking for UI/UX specialists with solid expertise, we are here for you!


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FAQ on UI/UX design services

How many laws are there in UX design?

Different sources name from ten to twenty laws of UX design. We have picked up the most efficient ones for this article. There is more to discover in the collection of Jon Yablonski in the Laws of UX resource.

What is Weber's Law in UX?

Weber's research shows that people accept small changes more willingly than massive ones. For a UX specialist, it means that customers may dislike significant redesign even if it’s beneficial for them. So instead, it’s wiser to make changes gradually over long periods.

What is Parkinson's law in UX?

According to Parkinson's law, if people have a preset time interval to complete a task, they will eventually use all of it. As a UX designer, you can help them move faster through the sales funnel if you autofill some registration data.

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