Psychology in Design

Aymen Rebouh
Dec 9, 2019 · 6 min read

This article is for the 9th date of the Eureka Advent Calendar.

Who I am?

I am Aymen and I am from Marseille, France, working in Tokyo, Japan.

I joined Eureka in June 2018 as an iOS Engineer. It’s a company developing the dating application Pairs, which help people find their life partners 🌸 and Pairs Engage which is a digital and affordable Marriage Matchmaking Agency helping people to marry as soon as possible.

Why I am talking about this topic

One of my goal recently was to be able to help my team with not only my iOS development skills, but also helping with UI/UX if possible.

So I tried to think about an interesting issue we found out that was happening in our product and that I could try to resolve: Some users think that Pairs Engage is like an Online Dating app ( but it’s not, it’s a digital Marriage Matchmaking service )

So I researched about how to change people image/vision about a product and make users feels like this is a digital Marriage Matchmaking service and not only an Online Dating service.

And while I was doing research about how to do that, I found an interesting website called Laws Of UX.

Laws of UX

Jon Yablonski created a list of what he calls UX Laws about User Experience and he believes that by knowing them, you will be able to create more intuitive design.

Why? Because those rules are based on general scientific understanding on how the mind works and so focus on the psychology part of design

So I want to dive in through some of those UX Laws, understand them, and see how it can happens with both physical and digital products.

Aesthetically pleasing effect Law

Did you ever wonder why cheap wine tastes better in fancy glasses? I did. And that’s kind of what is it about.

Researchers Masaaki Kurosu and Kaori Kashimura from the Hitachi Design Center tested 26 variations of an ATM UI and found out that users are strongly influenced by the look and feel of interfaces.

Basically, It means that nice design can make users more tolerant of minor usability issues and prevent issues from being discovered during usability testing.

To have a better understanding of this, if we take a look at the screenshot below:

Source: Pinterest images

That would mean that most of the users preferred the screen at the left over the one at the right because of the “better UI”, its look and feel.

When looking more closely, we can see that actually the screen at the left has some issues, such as not being able to correct, erase nor validate manually the pin code like we find in nowadays ATM UI ( right screen ).

Peak End Rule Law

The Peak End Rule says that we don’t remember experiences accurately.
Rather, we tend to recall the highlights and how the experience end ( good or bad end )


A good example is people waiting in a queue for an attraction:


Attractions Parcs like Disney Land have tons and tons of amazing attractions. And so long queues where people wait to be able to do them. After waiting, here we go, it’s time for the fun. It’s usually a short time of fun, excitement, and pleasure in comparison to the waiting queue.

When asking “how was the attraction?” to some peoples, many people may omit the annoying waiting queue in their discussion and just talk about how the attraction was, meaning good or bad.

That shows that how an experience ends is important and that’s what some people may remember the most from an experience.

How does it apply to digital products?

Many things can annoy users when using digital products: a survey, the reading of guidelines, a long and unterminable registration forms etc..

Does having a gift/surprise at the end as a “peak experience” can make the user forget about the boring but necessary survey/form? It can be a coupon, points or whatever makes the user feels like it was not worth nothing.

Hick’s Law

The time it takes to make a decision increases with the number and complexity of choices. Users bombarded with choices have to take time to interpret and decide, giving them work they don’t want.


What are the common points between those two images?

  • They both have many options
  • Some of them can be complex

For both examples, It can makes the user takes some time to do an action, or, for the case of Netflix, just giving up about watching something..

How to reduce the complexity of choices?

  1. One way is to focus on what is important
Apple Remote

This example shows how focusing on what is important can help reduce complexity.

For this second example, imagine having to look for a specific country among an unsorted and long list of all countries, compared to a sorted and group-by-continent list.. Using grouping of related informations can help reduce the complexity to find and achieve an action.

Miller’s Law

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

Which phone number is easier to remember? There is a big change that the second one may be easier, and here is why:

Every time your brain has to remember information, whether it’s a phone number, how to navigate through a website, etc, there is a mental effort.

The problem is that the space in your brain in which this information is processed and stored is limited. Your brain begins to slow down or even abandon the task at hand when it receives more information than it can handle.

This overload can be due to too many choices, too much thought required, or lack of clarity.

Regarding the phone number, chucking is one way of reducing the overload/mental effort. It’s about grouping the long phone number into small group of information easy to remember.

Conclusion may be a great resource for improving your design-making process and also your arguments during design review since it’s based not on your personal taste or thinking but on scientific studies that can be used to demonstrate and add more value to your arguments when doing design review.t

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Aymen Rebouh

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Eureka Engineering

Learn about Eureka’s engineering efforts, product developments and more.

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