And it seems to me you lived your life
Like a candle in the wind
Never knowing who to cling to
When the rain set in
And I would have liked to have known you 
But I was just a kid
Your candle burned out long before
Your legend ever did

(Elton John, Candle in the wind – on the right a 1961 portrait of Marylin Monroe by Henry Cartier Bresson)

You may have recognized from these few verses the famous song that Elton John dedicated to Marylin Monroe’s memory. Assuming you know the song, let’s do an experiment.

First, just read the world without the music; then read the words while humming the music in your mind. In which conditions do you feel these words sound truer and more meaningful?  If the theory of fluency is correct, the answer is with the music.

Why the words in a song we find so poignant are even more meaningful when accompanied by the music than without? Because the music we love facilitates fluent information processing. The same reason can be offered to explain why rhyming verses are believed to be more true than non-rhyming[1]or why we perceive as more true a statement presented on a high contrast display[2]. Maybe this is also why ancient poems were performed accompanied by music and why traditional poetry has a rhythmic structure (metrics).

What is information processing fluency and why does it matter for designers?

According to this theory[3], our aesthetic experience is influenced by how easily we process the information associated with an aesthetic stimulus. Fluency can be perceptual, i.e. associated to the physical aspects of an object, or conceptual, i.e. relative to the cognitive operations and knowledge structures that are necessary to make sense of the stimulus.

One of the key intuitions behind the theory is that fluency is determined by our expectations: we are more likely to experience fluency when its source is unknown, and its experience comes as a surprise. Let’s see some practical implications of the theory of fluency to product and experience design.

  1. Aesthetic pleasure. High fluency feels good. High level of fluency in a design can elicit positive emotions because fluent information processing is associated with the understanding of how a product works.
  2. Non obvious simplicity. High fluency does not equate to bare simplicity. While attributes like ease of use and straightforward usefulness are always appreciated, products that are too simple are not able to excite us because the source of fluency is too obvious. The source of fluency should instead work in the background in a way that is transparent to the user, very much like the music does by providing the right emotional setting for the message contained in the lyrics.
  3. Predictable surprise. Fluency combines uniformity and variety, simplicity and complexity. A design exhibiting simple and complex characteristics, familiar and novel features, expected and unexpected attributes can create a surprise effect but in a known context. A surprise is by definition unsettling, it raises a question. A fluent interface swiftly provides the answer and the peace of mind associated with getting the problem solved.
  4. Beauty as interaction. Fluency cannot be achieved without interacting with a design. A design that does not invite to such interaction has lost the opportunity to gain our interest from the very beginning. Fluency theory is based on an interactionist view of beauty: beauty does not reside in the object and is not purely subjective either. Rather beauty emerges from the ways we relate to a design.

You can use all of the above for a test of good design. Let’s take as an example the iconic coffee maker designed by Bialetti in 1930. 

  • Aesthetic pleasure: the coffeemaker elicits positive emotions and therefore because of its sleek and proportionate design. Its overall configuration comes in a double-S, symmetric and anthropomorphic shape that slims at the “waist”. Its aluminium body makes it shiny and light. The juxtaposition between the curvy handle and the triangular spout gives the coffee maker a familiar jug shape.
  • Non obvious simplicity: still today, if you have never used this coffee-maker, you might wonder how it works. The answer comes easily, yet it is not obvious: coffee is filtered in an original way, by the force of a steam jet that comes from the bottom and that squeezes the aroma out of the coffee powder into the upper carafe
  • Predictable surprise: the espresso effect is new and original, but it is an incremental innovation over the more traditional coffee percolators. It’s a kind of accelerated percolation. The lack of visual indicators signalling when the coffee is ready is compensated by the gargling noise produced when the last drops of water have moved from the boiler to the carafe.
  • Beauty as interaction: Alessi coffee maker is inviting us to use it. It can be easily disassembled into only three pieces. The funnel-like shape of the filter is waiting to be filled with coffee and it also works as a scoop to measure the right amount of coffee. The upper and lower parts are made to be grabbed with one hand and joined together with a rotatory movement of both hands in opposite directions, which seals the machine and gives the right amount of compression to the coffee powder.

This simple yet ingenious design does not require instructions. The invitation is issued, now it is up to us to engage. Interacting with this product is easy and rewarding. It makes making coffee a little daily ritual in which we know our skills can make the difference: how much water, how much coffee, which coffee type and grind, how much fire. The coffee maker guides us gently in any of these choices but leaves to us the final decision, and finally rewards us with the comforting noise, the great smell that is diffused through the V-shaped carafe, and the great taste that we eventually enjoy.

[1]McGlone,M. S.,& Tofighbakhsh,J.(2000).Birds of a feather flock conjointly: Rhyme as reason in aphorisms. Psychological Science, 1, 424-428.

[2]Reber,R.,& Schwarz,N.(1999).Effects of perceptual fluency on judgments of truth. Consciousness and Cognition, 8, 338-342. 

[3]Reber, R., Schwarz, N., & Winkielman, P. (2004). Processing fluency and aesthetic pleasure: Is beauty in the perceiver’s processing experience?. Personality and Social psychology Review8(4), 364-382.

[4]Coates, D. (2003). Watches tell more than time: Product design, information, and the quest for elegance. London: McGraw-Hill.

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