6 Cognitive Psychology Theories to Improve UX Design

UX, or interaction experience, encompasses the perception and emotion that a software product or service evokes. UX is characterised by ease of use, accessibility, and usability. UX is more commonly spoken of in the context of electronic devices, smartphones, computers, software or websites. But such a concept is not new; it is something that is rapidly changing under the influence of technological progress, new types of interactions and consumer trends.

Users are looking for lightning-fast solutions to problems, so UX is critical. Make sure the site is clear and easy for users to understand. These cognitive principles may help you with that.


1. Fitts law

Fitts's Law is named after Paul Fitts who derived this law. Paul Fitts was the first head of the psychological department of the US Air Force Aerodynamics Laboratory.

Fitts's law determines the speed of user interaction with interface elements.

In simple terms, the larger the object is, the less time it will take to click on it. In other words, the larger the button, the easier it is to click on.

This law has an interesting feature - if we use the corner of the screen, then, in fact, it is very easy for us to get there: to hover the cursor if we are talking about a desktop. This is much easier than aiming at a specific area of the screen.

The first conclusion that we can draw from this law is that there is no need to save space and make objects small - it will be more difficult for the user to find them with the cursor.

And the second conclusion - the angle or border of the screen gives a phenomenal speed of interaction if you are designing an interface, for example, for a desktop.


2. Hicks law

The more objects in front of us, the more time it takes to choose. This is how Hick's Law is presented in a simplified form. Formulated in the middle of the 19th century, dependence was experimentally confirmed only in 1952 by psychologists William Hick (Great Britain) and Ray Hyman (USA).

Scientists have developed a formula that describes the logarithmic relationship between reaction time and the number of objects from which to choose.

T = a + b * log2 (n + 1)

T -  is the total reaction time,

a and b - are constants that describe individual characteristics of perception, such as the delay before completing a task and the individual coefficient of the speed of decision-making,

n -is the number of equivalent alternatives to choose from.

When designing interfaces, Hick's Law helps to determine the optimal number of objects in a homogeneous array, for example, in a menu. It is usually used in conjunction with Fitts's Law.


3. Parett’s rule

If you have a large number of elements, it is best to select 20% of the most important ones, and hide the remaining 80% in "More details". This is the essence of this rule.

The fact is that our brain cannot adequately perceive too much information. It is much easier for it (the brain) to perceive a small amount of data. So we are better guided in information and better assimilate it.

To demonstrate the Parett Rule "in action", just look at an element such as "Filter", which is often used in online stores.


4. The Restorff effect

The Restorff effect (or the isolation effect) is a feature of memory when an object that stands out from a series of homogeneous objects is remembered better than others. Named after the German psychiatrist and pediatrician Hedwiga Restorff, who discovered it experimentally in 1933: during the experiment, the participants were presented with a list of homogeneous words, among which there was one that was very different. The results showed that it was this word that the subjects remembered best in the end.

This is a general pattern. We will better remember a word or object if it will differ from the others, for example, in size, shape, colour.


5. Gestalt principles

Gestalt (form, image) - the combination of things (sounds, visual elements, feelings) into a single whole.

Along with systems such as modular grid, golden ratio and colour theory, gestalt theory is the principles by which professional designers build visual communication.

The designer's job is made easier by the fact that the viewer is actually looking for some kind of organisation, something that connects the various elements. We don't want to see unrelated chaos. The designer creates specific trigger clues that help the viewer find a coherent context and unity. If the viewer does not find the template by which he decrypts the message, the image is ignored.


6. The Psychology of Persuasion

The next step in UX design is an aspiration to evoke persuasion, emotion and trust in your customers. If you understand how the human mind works, it is easier for you to attract people's attention, it is easier to get them to perform the desired actions (for example, subscription or purchase). But, the most important thing is to gain trust.

For example, if you want customers to have confidence in your company and the people who work in it, try to present the company and employees to customers in the right way. Let the audience meet you. For this, use good quality corporate headshots or interesting video presentation. There is no one right answer. Be creative!



User time is precious! Time = Life. Nobody is obligated to stay or use your product. (especially when there are alternatives).

Get to know the user, interact with him. Guide the user towards their goal by highlighting the options they care about in that context. This will optimise the decision-making process and speed up the task. In the end, both sides will be happy.