Author: Donald A. Norman
Publisher: Basic Books, 2002
(first published in 1988 as The Psychology of Everyday Things)
Looking at the cover image of Norman's famous book, and now almost a classic, one cannot help get curious about all the odd and quirky things that we often encounter in our daily lives. A teapot with a nice handle and a spout looks hardly interesting until you notice that the handle cannot serve its purpose well. You can use it to lift but not pour. If you are looking for one clear example of design gone wrong, this would be it.
Why is it that sometimes we have trouble opening doors? Do we push or pull? Why does a housewife have trouble remembering which knob connects to which stove on a kitchen hob? Why is it that we always have to do trial-and-error experiments to figure out the light switches in a room? Why are some websites so difficult to navigate? In all these cases, engineers focused on getting things working. They ignored the usability aspect of design.
After many years in academia, first as an electrical engineer and later as a psychologist, Norman realized that there are many things wrong with the way we design things. He joined the industry to champion the cause of design with the user in mind. Even the term user-centered design owes a lot to Norman for its popularity. Back in late 1990s he even predicted that PCs were simply unusable and would one day bite the dust. This has largely come to pass as most users have now switched to PDAs (early 2000s), mobiles and tablets. If PCs are still around today, it's only because they have become easier to use: touchscreens, faster boot-up, automatic updates, plug-n-play solutions, cost, longer battery life, smaller form factor.
One may wonder what does psychology have anything to do with design. This is actually the reason why Norman succeeds. He does not simply point out bad designs. He tries to rationalize why and how design could be better based on how humans learn and use technology. There is certainly a lot of theory in this book but with clear everyday examples, he makes this an interesting read.
For example, we often delete important files from our computer systems only to realize later that we should not have done it. This happens even when the system asks for our confirmation. The problem is that as users we often focus on the wrong part of the process: deletion rather than importance of the file. We don't realize our mistake until it is too late. Certainly, to err is human but designs have to built with error tolerance and constraints.
A good example is the insertion of a SIM card into a mobile. There is a physical constraint which ensures that it cannot be inserted the wrong way. Another great example is the "undo" command found in most software applications. This command is perhaps the most important one from a usability perspective. Without it, computers would never have become as successful as they are today. On the other hand, there are equal number of cases where forgiveness is not built into the design. There are doors that can be locked without keys. If you have locked yourself out of your own house, you will know exactly what I am talking about.
Disasters are often blamed on human operators but Norman points the finger at poor design. Mistakes happen for many reasons: too many features, too many functions controlled by too few buttons, incoherent mapping between functions and controls, similar descriptions for different actions. An electronic watch with just two buttons can be a frustrating experience for many of us because setting the time, date, alarm or starting a countdown timer, all have to be done with just two buttons.
With human to human interactions, there is always some form of feedback. Use of technology is often difficult and frustrating if feedback is not built into it. You press a button in an elevator but the button doesn't light up. You therefore end up pressing it a dozen times to make sure it stops on your floor. The humble telephone is a classic case of good feedback. When you pick up a landline handset, a dialtone comes on. This is an indication that the line is ready for an outgoing call. Mobile phones don't have this requirement but the feedback principle is just as valid. In mobiles, feedback comes on the display screens, through audible beeps and ringing tones.
We use technology based on some conceptual models that take shape from our prior experiences of the world. Norman gives the example of controlling the temperature in a refrigerator. With two separate controls, one for the freezer and one for the vegetable section, we may form a mental model that these two parts are controlled independently. When the actual engineering model of the refrigerator is quite different, users face frustration. Their refrigerator is not behaving the way they expected it to. Design therefore has to be so clear that users cannot form wrong conceptual models.
One of the interesting terms that Norman introduces is that of affordance, the intrinsic property of an object or material. For example, vandals don't usually cover glass surfaces with graffiti. They would rather break them. Graffiti is reserved for surfaces of wood or concrete. Designers can benefit from affordance. Knobs are for turning. A door knob that's meant to be pushed is bad design. Horizontal bars on doors are for pushing. Slots are for inserting coins. Chains are for pulling. A small button is for pushing, such as on an electronic door bell. Designs that follow this principle rarely require manuals or accompanying instructions.
In the end, this is a wonderful and engaging book. After reading it, you are guaranteed to look at the world differently. Design is a complex subject involving many factors. Perhaps it's best to conclude with a quote directly from book's preface:
All great designs have an appropriate balance and harmony of aesthetic beauty, reliability and safety, usability, cost, and functionality.