User Experience

February 6, 2014

Design for Persuasion, Emotion & Trust

By Ben No comments

Years ago (but not so long ago), designing a website was all about delivering a beautiful product, that would make it stand out the masses.

Then UX (User Experience) came into play; as sites became more and more complicated, agencies and brands adopted a UX team to make sure their creations delivered a first class experience, putting their new heroes, the users, where they belong, in the centre of the story.

The next level is to make a usable website engaging. PET is essentially a psychological layer that supports users on their journey and meets them at an emotional level. To sum it up; “Usability allows users to do things. PET encourages users to do things.” PET compliments user experience best practises perfectly and I will be highlighting some of them in this article.


According to the Merriam-Webster definition, persuasion is the act of causing people to do or believe something: the act or activity of persuading people.

Persuasion design isn’t something new. Psychologist John B. Watson used his knowledge of human behaviourism to optimise advertising for several products back in the 1920s to drive more sales.

By understanding which triggers create emotion, reinforce trust, and persuade a user to perform a task, a layer of pleasurability can be added and complete the usability facet of a design.

There are many persuasion principles, but 6 of them often stand out:


Using a figure of authority drives trust. A credible testimony is more likely to persuade someone to act.

Example: is a website that features cover versions of any song submitted by anyone from the public. Covr approached Moby to ask his fans to make a cover of his music to be included on the website. In a single tweet he asked anyone if they wanted to cover one his songs, many of his fans obliged by covering his songs and there is a special feature section dedicated to Moby within the site.


“Give me something and I’ll give you something in return.”

It’s easier to get something from users if you give them a reward in return. This can be a free sample or demo, a free accessory related to a particular purchase, or even a free service.

Example: is a free language learning service for anyone to use, whilst at the same time providing translated content for websites. Users begin learning a new language by translating snippets of text from the web. Anyone, with any level of language skills can become a valuable translator. Quickly Duolingo builds up a the best translations of website texts from around the web, so helping companies have the best translations of their content for a global audience. It’s a win-win situation.

Social Validation

If users see that other people are happy about something, they will be more inclined to use/purchase something. Social validation can be used in different ways:

  • show share counts on a page and users will think “Ok, this page must be relevant and I can trust its content”
  • show customer reviews on a product page, it will reassure the user and may persuade them to make a purchase
  • add a message “Customers who bought this item also bought…”. This can push users to engage and allows companies to cross/up sell.


Scarcity is used to inform users that what they want is about to run out, or in a limited edition. The fear of missing an opportunity creates an urge to take action. Companies must sell with integrity otherwise you will lose the users trust.

Example: Threadless is a company known for selling t-shirts and other products designed by artists. Every batch of a particular design is printed in a limited amount of units. When stocks run low, they display how many items are left, urging users to purchase one before it’s too late.


Personalising content helps users might feel more comfortable, they feel you understand what they want and what you are interested in. “So I know you like Star Wars and LEGO, have you seen this amazing set yet?”

By offering users tailored content specific to them, in relation with their implicit or explicit behaviour on a website, there is better a chance they will interact more.


Framing the information can make it more appealing, or less scary. For example, asking for £60 a month for a service can feel like a lot. But if you tell the users that £60 is the equivalent of one coffee per day, the cost will suddenly look more affordable.

Example: Oxfam is an aid and development charity, they frame donation amounts with clear information around how far your donation goes.

“Give £39 today” becomes “By donating £39, you help us repair a water pump and helps an entire village to get fresh water”

With this perspective, we fell more inclined to make a donation if it potentially helps an entire village.


Like anything that surrounds us, websites can trigger emotions. These emotions can be: interest, frustration, joy, nervousness, surprise, pleasure, disruption, excitement, hope, fear, satisfaction… and more.

Back in the 1990s, websites used a very formal tone of voice, to look and sound professional. This is how you gained trust; by being serious, and pretty much emotionless.

Nowadays, the web has changed, we share, shop, and are more social online. We tend to address users in more human way. We know that engaging with their emotions will make their experience more enjoyable.

A great example is Photojojo. They sell photography related accessories and gadgets. They added a nice little device on the page; a lever next to the image with a label reading “DO NOT PULL”. Human nature dictates us to pull it of course, and a hand drops down from the top of the screen, grabs the page, and pulls you down to the product description. Unnecessary, you might say, but it brings an element of fun to the experience, you’ll find yourself scrolling back to try it again. You are more inclined to make a purchase with a smile on your face, and Photojojo got it just right. Triggering emotions in this way will make your usable website that little bit more pleasurable.

Visceral processing

According to Don Norman, there are three main levels of cognitive processing: visceral and behavioural and reflective processing. The human cognitive process is how our brain processes sensorial information and reacts to something presented to it. Which is why in UX, we’re very interested in understanding how this works.

Visceral design, and another technique called aesthetic usability, are based on sensory impressions, mostly visual; aesthetics of a website for example. A good and beautiful design will make a good first impression, and engage a user to give it a try. On the contrary, a poor design will probably not be as effective, even if it’s functionally ok. Ultimately what we are looking for, is to give a boost to the good usability of a site by increasing users’ willingness to use it.

A simple example is, their website makes use of a nice mix of colours, shapes and lines that invite users to scroll down. The use of parallax in the design makes the will to scroll even stronger. As the bottom of the website approaches, you find yourself back at the top of the site! People’s feedback was positive, they felt they ‘went for a ride.’ They found themselves scrolling through the site several times because it was pleasing, surprising, and fun!

Behavioural processing

Behavioural processing is all about use. When designing for behaviour, function is the main concern. Understanding how users will use the design is key. If a user starts using a design to perform a task and this task isn’t easy (or worse is impossible) to complete, it will lead to a strong feeling of frustration.

There are two main methods of behavioural design:

  • Innovation: this is probably the most difficult one because we want to design something for needs and behaviours that may not exist yet. Think of the behaviour design behind the first touch devices: how do you design an interface for a behaviour that is still mostly unknown? Iterating designs with user testing is the only answer. Guess, then watch, learn, correct.
  • Enhancement: this is about taking something that works and improving it. A product might pass the first behavioural test, but not have the best design.

Reflective processing:

Reflective processing happens after visceral and behavioural processing occurred. It’s about what a product, its image, means to you. How does the usage of a product impact on your image. This affects the users decision on whether to use a product or its competitor. When choice is offered, and all options pass the behavioural test (they all perform the task they’re built for), users will think about what image they will send to others when using a product, and they will tend to choose the one that sends the best image.

If your brand can build a positive image of it’s product, users will tend to use it. Apple is a clear champion for that: phones, laptops, mp3 players, most people would rather be seen with a well designed device, made with premium components that will make everyone envious.

Reflective design is usually part of a long-term relationship with a brand, and as Don Norman says: “Branding is pure reflection”


Without trust, your website can be beautiful, usable and pleasurable, but it won’t convert users into customers. If you can’t be trusted, you won’t be able to drive commitment.

Trust can be built using various methods, here are some typical ones:

  • Display clear and correct information in your “About us” page. An easy way to make sure everything is present on the page is to answer the 5 W’s (who, what, when, where, how).
  • Display any partnerships, the logos of big and well-known companies that work with you or use your product.
  • Show user reviews, testimonials, real stories. These will provide a feeling of confidence and trust to users.
  • Security; e-commerce websites strengthen trust by displaying security messages and reassuring visuals.
  • Show any awards, the recognition from industry peers gives confidence to your users.

  • Keep the information on your website up-to-date. A site lacking any attention to your content sends out the wrong message to your users or customers.
  • Technology, use the latest tech available.

As the Nielsen Norman Group says:

“Trust is essential to the user’s willingness to risk time, money, and personal data on a website. If you lose trust, you lose the sale and you may lose the customer as well.”

Using PET principles for designing a website is becoming more and more prevalent. It will improve the experience of users, but use these techniques carefully and with integrity, otherwise you will loose the trust from your loyal users. Keep asking yourself: Is helping the user to make the best choice here the right thing to do? This question will be easy to answer most of the time, if not, you can always run a quick usability test.


Aaron Walter: Emotional interface design: the gateway to passionate users

Nielsen Norman Group article

Human Factors articles

Barry Briggs (@quiffboy): PET: Designing for Persuasion Emotion, and Trust

UX White Paper by Howard Kiewe