Designing for fluency – Part 1 (by Mischa Weiss-Lijn)

From the new psychology of Fluency to usability, beauty and beyond

Having had a background in (proper) psychology, before emerging as a designer, I’ve often been dubious about the value of this fascinating ‘science of the mind’ for the practice of design.  Every now and then, you’ll hear some strained reference to Fitt’s law from a recent MSc. graduate; but let’s face it, in our day to day, very little psychology is actually brought to bear.

So, it came as a surprise to find a treasure trove of design insights, when reading the excellent “Thinking fast and slow” by the Nobel prize winning psychologist Daniel Kahneman.  Let me be clear; it’s not a book about design, it’s a pretty hardcore psychology book.  It’s about how we think and reason; not how we would like to think we think, but how we actually think.  Warts and all.  My hunch is that really understanding that, and the warts especially, could be a valuable tool for designers.


One example I’d like to pick out, is Kahneman’s treatment of a phenomenon generally termed ‘Processing fluency, which he calls ‘Cognitive Ease’.  Like it or not, and more ‘usability’ minded designers may well not, the perception of usability, trustworthiness, beauty is partially dependent on the myriad of superficially unrelated factors that drive the fluency of cognitive processing (don’t worry I’m about to explain).

Yes that’s right.  You can do things to make people think a design is more, trustworthy or beautiful, without actually making it more trustworthy or beautiful.  At all.

So let me explain.

As Kahneman explains it; our brain has a number of built-in dials (you could think of them as a bunch of sixth senses), that are constantly, effortlessly and unconsciously, updating us on (evolutionarily) important aspects of our environment.  So, for example: “What’s the current threat level?”, “Is anything new going on?”.  One of these is, Processing Fluency, which is basically a measure of how hard your poor brain is being asked to work.  It’s basic raison-d’etre, is to let you know when you need to redirect attention or make more effort.  However, interestingly for us designers, it ends up having a much broader impact on the way we evaluate things and make decisions.   Anything that increases fluency (and there are lots of things that do) will bias many types of (and perhaps all) judgements positively.

This is a, somewhat scarily, broad phenomenon.  Who would have thought that:

Rhyming statements seem truer than equivalent non-rhyming ones

Shares with more easily pronounced names outperform on the stock market

Text written with simpler words, are judged to have been written by a more intelligent author

To usability, beauty and beyond

But let’s focus on how this relates to design.

It turns out that anything that increases fluency, will positively effect many aspects of the way people perceive, judge, and presumably experience, something.  Fluency will make people trust something more, make it feel more familiar, more effortless, more aesthetically pleasing, more valuable; fluency will even make people feel more confident in their own ability to engage with the experience.  And these effects can all potentially be brought to bear independently, and on top of, the actual content of the experience.

What’s powerful here is that there are lots of ways in which you can increase the fluency of your experience; ‘manipulations’ in the parlance of psychologists.  I’ve tried to summarise what I’ve been able to glean from the psychology literature around this in the infographic below.  The thing to remember is that any of these manipulations will positively impact people’s perceptions of your experience.

You can make your copy more fluent, your visual design more fluent, and your flows more fluent.

Making your copy more fluent

Let’s start with copy.  A bunch of the things we normally think of as best practice, such as using simple straightforward language and uncomplicated syntax, increase fluency.  It’s interesting to realise that such simple things could end up impacting how much people will trust the experience!

Looking at copy from the perspective of fluency gives weight to more flippant techniques, such as the use of rhyme, alliteration.  It guides us to think carefully about how easy copy is to say out loud.  All these things improve what is called ‘Phonological Fluency’ i.e. how easy something is to say; how easily it rolls off the tongue.  If it’s easier to say, it’s easier to think.

Then, consider ‘Orthographic Fluency’ i.e. how easy one can translate written text into spoken words and meaning.  This guides us to avoid creative spellings (e.g. “Tumblr 4ever”).  It gives a clear rationale for always using the most direct, succinct and approachable notation available (e.g. “1” not “one”, “%” not “percent”).

Making your visual designs more fluent

Font designers will be happy to hear that there have been lots (and lots) of experiments that show the impact of the clarity and readability font on fluency, with all the many fold benefits this brings.  Readability is not just about readability – it’s about fluency.

Font selection is one thing that contributes towards ‘Physical Perceptual Fluency’, and psychologists have shown that having a good level of contrast does too (for fonts in particular, but presumably it will be just as important for UI elements).  Of course that’s not where it ends, even if psychologists haven’t really looked much deeper, much of the principles behind good, functional, visual design, such as leveraging Gestalt grouping principles, must surely drive this Physical Perceptual Fluency.

There’s also been a bunch of work looking at how the length of time people have to see and absorb a display impacts fluency; they call it Temporal Perceptual Fluency.  The less time, the less fluent.  This probably doesn’t have too much impact on most design applications unless you are presenting stuff for less than 1 second.  But my hunch is that judicious use of motion design will also contribute to this type fluency.

Make your flows more fluent

There has been a bunch of work looking at the role memory plays in fluency.

Most obviously using common UI patterns will create a more fluent experience by virtue of their familiarity.  Similarly when experiences are designed to be easier to learn and remember they are going to be more fluent. But you could have guessed that.

Something you might not have guessed is that you can use ‘Priming’ to make an experience more fluent.  Priming is a psychological technique that basically boils to exposing people to related stimuli before showing them the experience you’re interested in.  This activates the relevant areas of your brain making it easier to process the experience once it comes along.  Is this something we could use as designers?  Perhaps we can.  For example, we could sequence content and interactions to prime parts of the experience that we expect to be challenging.

What else?

While psychologists have already discovered lots of ways to manipulate fluency, I’d guess that there are many more waiting to be discovered.  Psychologists, haven’t been thinking about design, so they’ve not really been looking in all the right places.  In fact, i’ve taken a couple of liberties to add some obvious candidates to my graphic which are not (yet) grounded in empirical evidence (motion design and visual hierarchy). One area that doesn’t seem to have been explored at all is how to make interactions more fluent.  And there is surely much more we can do to create fluency in user journeys and IA. Perhaps someone should look into it!

And so… what?

Is this just dressing up our time honoured notions of usability in fancy new scientific jargon?   Or does it give us a genuinely new and useful conceptual tool for creating better experiences? After all we’ve had related concepts before, for example Cooper’s ‘Cognitive friction’ in his classic Inmates are running the asylum book.  Making experiences as easy and frictionless as possible is at the heart of all good digital design techniques.

To be honest, I’ve only just started thinking about this, and so haven’t yet been able to put it into practice.  But my hunch is that there are a couple of key things that the concept of fluency offers which are interesting, and potentially useful.  Firstly, there is the evidence of there being a broader set of qualities that go into making an experience frictionless or fluent, then we’ve traditionally allowed for.  Secondly, and more importantly, there is the discovery that any and all of these, impact on the full range of people’s perception and memory of an experience. We want to create experiences that people feel good about.  Depending on the experience, we want our users to come away persuaded, happy and confident.  An understanding of how to create fluency, gives us a new way of thinking about how to get the design outcomes we’re after.

Further reading for the curious

Part 2 of this fine blog: Fluency, cognitive choreography and designing better workflows, which looks at how we should be using our grip on Fluency to help users think in the right way, depending on the experiences they are engaged in.

Alter, Adam L, and Daniel M Oppenheimer. “Uniting the tribes of fluency to form a metacognitive nation” Personality and Social Psychology Review 13.3 (2009): 219-235.

Daniel Kahneman “Thinking, Fast and Slow” 2011