Psychological principles to consider in UX design and user testing 2

Psychological principles to consider in UX design and user testing

When it comes to delivering a positive user experience, the importance of knowing your customer should never be underestimated. 

It is vital to identify ways to encourage the customer to share what they really want or need. You will then need to interpret and translate that feedback into digital propositions stakeholders will recognise as valuable and essential to the design process.

Learning about user motivations is important. The sooner you can extract and understand the user’s deeper needs, wants and concerns, the stronger your end prototype will be. This is only made possible through more considered research that leverages psychological principles to enable deeper understanding of the end-user.  

Psychology influences a user’s experience with a product or application, so it plays a key role in system design. It is also an important lens through which to view and interpret their feedback as this can greatly impact the ideas you eventually formulate based on this.

The impact of psychology on UX design can be transformative. However, it is important to keep in mind that the use of psychological theory and techniques in UI and UX is expansive and ever-evolving. The theories we are about to discuss offer just a snapshot of what might be considered when researching for design. 

Read on to learn more about the impact of psychology on UX design and user testing. 

Anchoring bias

As humans, we tend to refer to the first thing we see as an anchor. Consider that you are buying a new jewellery item, with a budget of £150. The first item that catches your eye costs £200. The next one you see is £175, which seems more reasonable, despite the fact it is still £25 over your budget. Compared with the first item, it seems like a better deal. Basically, the judgments that we make later down the line will be influenced by our thoughts on the original anchor. 

Anchoring bias is important when establishing a pricing strategy, as it affects how much the user is willing to pay in exchange for a product or service. It also affects how content is consumed, for instance in the case of a hero banner – since it is the first thing users will see, it will become anchored in their brain. After reading it, they will only need to scan through all of the other information, meaning it will be quicker for them to reach the end and begin using the product or solution. For product owners or proposition managers, it is a key principle to be aware of when framing and providing context for feedback as stakeholders may have their own ideas of what prices or information are most valuable.

Isolation effect

Sometimes known as the von Restorff effect, this concept predicts that when several similar objects are present, the odd one out is most likely to be remembered. This is why call to action buttons in many interfaces often have a different appearance to other action buttons. It is important that these look different so that the user knows the purpose of the CTA button and remembers it when looking through the rest of the form, app or website. 

Decoy effect

This refers to a situation when a user’s choice between two items changes when a third option is introduced. The third option is deliberately made easy to discard, to encourage users towards the target option. The decoy effect is not designed to restrict or manipulate the user; it is used to help them feel that they have independently made an informed decision. 

In one experiment by National Geographic, customers were inclined to choose small popcorn when they only had the choice of small ($3) and large ($7). A medium option was introduced as the decoy, priced at $6.50. Afterwards, the large popcorn started to sell out in huge quantities, meaning customers were led to buy a more expensive product then they normally would have. 

When developing digital propositions, this could affect your decision-making around the actual value of the product or service and how this is marketed to the consumer. Understanding this principle can help you decide what package or option you strategically target over others.

Serial position effect

This relates to a user’s tendency to best remember the first and final items in a series. This is one of the reasons that the hamburger menu has declined in popularity, with many UX designers opting for a bottom or top bar navigation pane. This enables them to put the most important user actions to the right or left-hand side. 

This can greatly impact the information hierarchy of your website or digital application and is therefore likely to play a key role in later stages during wireframing when decisions are made around how to organize the interface.

Curse of knowledge

This cognitive bias occurs when people fail to take into account that others do not have the same information or background knowledge as them. For example, a person that is knowledgeable in a certain field might find it difficult to explain a complicated concept to a beginner using layman’s terms. One way to tackle the curse of knowledge is to stick to factual statements and case study stories, instead of using vague or abstract statements. 

Product managers, in particular, may want to keep the curse of knowledge in mind when rolling out a new update or introducing a new product. Even though it can be difficult, it is vital to design with the user’s baseline knowledge in mind to ensure a positive user experience. To do so, try stepping into the shoes of a brand new user and pretend you are using it for the very first time. 

Recognition over recall

Answering a multiple-choice question is often much easier than answering an open-ended one. Similarly, when trying to remember a person you have met in the past, it is often easier to recognise them by looking at their picture than trying to recall memories of them. 

Put simply, it is easier for people to recognise something they have experienced previously than to conjure up a memory. When we recall from memory, there is an increase in cognitive load. As a UX designer, your goal is to minimize the need for the user to tap into their passive memory. 

For example, for someone who uses Uber to reach the office each morning at 7.30 am, Uber suggests the office locations as the destination. This reduces the mental effort required of the user to arrange the Uber. 

As a UX designer or product manager, if you want to take advantage of recognition over recall you should design products to complement existing ones. In most cases, there is no need to design a product from scratch. 


The key psychological principles outlined in this article have an impact on final design and can even be applied when conducting user testing. They are also important to keep front of mind throughout the entire design process as you develop and shape the digital propositions that will underpin your final product designs. Being aware of common cognitive biases means you will be able to allow for them when facilitating and interpreting user feedback, and understanding how to take this feedback forward into the design, development and testing phases.

Andy Curry
Andy Curry
Articles: 16

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