I have observed that good design takes into consideration two important aspects of use:
- Failure Rate
- Recovery Rate
Well-designed products or software interfaces have low failure rates and low failure amounts. This is related to the concept of fault tolerance. A well-designed product or interface should not fail easily, and failure should not be complete.
“If its operating quality decreases at all, the decrease is proportional to the severity of the failure, as compared to a naively designed system in which even a small failure can cause total breakdown.”
A well-designed product or interface should also be easy to recover from failure.
I recently bought a set of headphones. These were good headphones in most respects…until they broke at the complicated juncture where the ear pieces rotate. Once these headphones broke, there was really nothing I could do to fix them. But I decided to try – using a special putty that dries and holds things into place.
It took a long time to figure out how to do this. When I finally repaired the broken part, I realized that the wires had been severed inside. There was no sound coming through. I had no choice but to put them into the garbage bin where they will contribute to the growing trash heap of humanity. Bad design is not just bad for consumers: it’s bad for the planet.
While most people (including myself) would claim that Audio Technica headphones are generally well-designed, we are usually not taking into account what happens when they break.
Sometimes the breakdown is cognitive in nature. There’s a Keurig coffee machine at work. It uses visual symbols to tell the user what to do.
As I have pointed out in another article, visual languages are only useful to the extent that the user knows the language. And designers who use visual language need to understand that natural language includes how something behaves, and shows its internal states, not just what kinds of icons is displays on its surface.
The Keurig coffee machine is a nice specimen in many respects. But I had discovered that if I apply the necessary actions in the wrong order, it fails. Namely: if I add the little coffee supply and press down the top part before the water has finished heating up, it doesn’t allow me to brew the coffee.
So…after the water finished heating up, I saw the buttons light up. “Cool” – I said.
But nothing happened when I pressed a button to dispense the coffee. “WTF” – I said. Then I decided to open up the lid and close it again. That did the trick. The lights started blinking. But I was not satisfied with the solution. The discoverability of this bit of behavioral body language ranks low on my list.
Hint: “Blinking Lights” Means “You Can Press a Button”
I have to say, though: I have experienced worse examples of undiscoverability with appliances – especially appliances that are so simple, sleek, and elegant that they have no body language to speak of. This infuriates me to no end. It is not unlike the people I meet on occasion who exhibit almost no body language. It makes me squirm. I want to run away.
Now, thanks to YouTube and the interwebs in general, there are plenty of people who can help us get around these problems…such as this guy who has a solution to a related blinking light problem:
I realize there are not many people who are bringing up this seemingly small problem. But I bring it up because it is just one of many examples of poor affordance in industrial design that are so small as to be imperceptible to the average user. However, the aggregate of these small imperceptible stumbles that occur throughout our lives constitutes a lowering of the quality of life. And they dull our sense of what good design should be about.
Tiny Rapid Failures and Tiny Rapid Recoveries
Now consider what happens when you ride a bicycle. When riding a bike, you may occasionally lose balance. But that balance can easily be recovered my shifting your weight, turning the wheel, or several other actions – many of which are unconscious to you.
Think of riding a bike as a high-rate of tiny failures with a high-rate of tiny recoveries.
Taken to the extreme: a bird who is standing on one leg has neuromuscular controls that are correcting the balance of the bird’s center of gravity at such a high rate and in such tiny amounts, that we don’t even notice it (and neither does the bird).
Natural Affordance: Perceived Signifiers
User interfaces (in computer software as well as in appliances) should use natural affordances whenever possible so that users can make a good guess as to whether something is about to fail, whether it is failing, how much it is failing, and how to recover.
The best design allows for rapid, and often unconscious correction while using the product. Good design is invisible!
Donald Norman brought some of these ideas to the fore when he wrote the Design of Everyday Things. We still have a lot to learn from his teachings.
Design is a way of life. If you design your life with resilience in mind – with the ability to recognize failures before they happen, and with the ability to recover from those failures, you will live a better life. The same goes for designing the technology that increasingly fills our lives.