CX Insights

3 Ways In Which Fluency Psychology Will Shake Up Usability Design

5 min read

As usability professionals, we love to understand what makes a website or interface ‘feel’ right. While usability testing remains an indispensable tool in ironing out our interface’s bottlenecks, new insights into the ways in which people process information are always welcome. What brain circuits are sparked when someone interacts with our work? And how do these processes guide further courses of action?

Currently, one of cognitive psychology’s most treasured topics is processing fluency. It’s a simple concept, yet amazingly powerful in creating interfaces that work. Let’s dig in.

So, what’s fluency and why does it matter?

In a nutshell, fluency refers to the ease with which a task or chunk of information is processed by the brain. Experiencing fluency puts the user in a positive mood and instills a sense of familiarity and effortlessness – even when an interface does contain difficult or unfamiliar elements.

Clear and crisp fonts are easy on the brain, while graceful swirly typography is not. Short words and paragraphs stimulate fluency as well, while sturdy walls of text do not. It’s all about the psychology of text. In similar vein, contrasting buttons aid fluent intuitive navigation, whereas an unsaturated mess does not. So far, nothing that the usability community isn’t already aware off. Indeed, high fluency automatically arises within a well-built usability environment.

Nonetheless, usability is always evolving. Just think back to what was deemed ‘usable’ ten years ago. It often takes a scientific breakthrough such as processing fluency to open up a shiny new toolkit filled with powerful UX techniques. At the time of writing this article, these tricks still linger in inception, but I’d expect their use to explode rapidly in the coming years.

I’m excited to share three of these fluency principles with you today.

1- The Power of Previews

Have you ever assembled a – presumably Swedish – piece of furniture yourself? If so, then you likely found the job to be a lot easier when you had the final result pictured in your mind from the start, even though each individual step is clearly explained in a neat booklet.

The reason lies in fluency: when you hold an overall expectation of what’s to come, any individual step is less taxing on your brain. This implies that, as usability professionals, our job is to build and reinforce a sense of structure throughout every step of our interface.

The ways in which this principle can be put into practice are amazingly versatile. Say, you are creating a multi-page product customizer; then you could show a thumbnail of the next page the moment a user’s mouse hovers over the next-button. This brief moment alone prompts the brain what to expect and makes the subsequent user experience more fluent. Currently, there are many tools to enhance links with realtime page previews.

Can you think of more ways to add fluency in usability by building on this principle? I’d love to read your ideas in the comments.

A mouse-over preview can provide a more fluent surfing experience

2- Copywriting Magic for Fluency

Yes, you’ve probably read it countless of times: use short, concrete words and sentences. While this old copywriting mantra is still very true today, the science of fluency now adds another factor to the mix: context.

Words are more than the sum of their parts. They influence one another and are influenced by their surrounding context. Some specific combinations are particularly well-liked by the brain. You should seek these out whenever possible.

– Images

Similar to the power of previews, images provide context in which words can be processed more effortlessly. This also applies to button icons (such as a basket icon on an add-to-cart-button).

– First-person button copy

Examples: “I want to check-out”, “Add to my cart”
Instead of telling people what to do, let your button copy reflect their actual thoughts. First person is often the most fluent mode of processing. But, as always, you should test that.

– Rhyme and Alliteration

Examples: “Choose your check-out method”, “Pick your packaging”
Rhyme and alliteration are very smooth to process and do a great job at garnering attention as well. It’s a powerful but underused method to craft compelling call-to-actions and button copy.

Call-to-action button copy written from a first-person perspective

3- This One Small Change Makes Tough Decisions Easy

A well-known method to making a choice more fluent is the so-called default choice. This refers to a specific option being preselected, which allows users to continue the choice process without depleting their brain’s battery too much. For instance, a check-out system often pre-selects the most preferred shipping and payment options.

However, in many cases preselecting is not an option – either by law or by the very nature of the question– and the choice is too complex to be made intuitively. Good news: decision science has uncovered a surefire method to make hard questions easy and even persuasive. It’s called Enhanced Active Choice.

An Enhanced Active Choice consists of two components. First, instead of ticking the regular single checkbox (e.g., “Check the box to add a 2-year warranty program to this product”), users now actively have to choose between a yes and no option (e.g., “Yes, I want a 2-year warranty” versus “No, I don’t want a 2-year warranty”).

Second – and here’s where the fluency comes in – each option explicitly states what the user either stands to gain or lose, thereby making one option clearly appear more attractive. In the current example, the options would be framed as “Yes, I want a 2-year warranty and have the certainty of all potential damage and defects being compensated at no added cost” versus “No, I don’t want a 2-year warranty, even if that means I have to pay for all potential damage and defects myself.”

By vividly highlighting the consequence of each choice, you make it easier for the user to make a choice that ‘feels right’ without complex thinking. This technique works especially well when there is one clearly desired yes or no option. But beware when there isn’t, as it could stifle users into overthinking-mode.

Both options of this yes-or-no question are presented with their associated gain or loss


Embed subtle cues that build a sense of structure throughout the entire UX
Ease reading-fluency with images, a first-person perspective and the occasional rhyme
Enhance decisions by providing two opposing alternatives and state each option with either a gain or a loss

Tom van Bommel
Psychologist, at work in marketing and user experience. Unearths powerful insights about what makes humans tick and click. Loves small changes that spark big differences. Founder of Studio ST&T, a Dutch marketing agency rooted in psychology.