The Design of Everyday Things

by Donald A. Norman

The result: mathematics phobia—not because the material is difficult, but because it is taught so that difficulty in one stage hinders further progress.

The vicious cycle starts: if you fail at something, you think it is your fault. Therefore you think you can’t do that task. As a result, next time you have to do the task, you believe you can’t, so you don’t even try. The result is that you can’t, just as you thought. You’re trapped in a self-fulfilling prophecy.

to focus upon a positive psychology, a culture of positive thinking, of feeling good about oneself. In fact, the normal emotional state of most people is positive. When something doesn’t work, it can be considered an interesting challenge, or perhaps just a positive learning experience.

In using the keyboard to enter data, it was necessary to differentiate between the Return key and the Enter key. If the wrong key was pressed, the last few minutes’ work was irrevocably lost.

The designer’s first response was: “Why did you make that error? Didn’t you read the manual?” He proceeded to explain the different functions of the two keys.

“Yes, yes,” I explained, “I understand the two keys, I simply confuse them. They have similar functions, are located in similar locations on the keyboard, and as a skilled typist, I often hit Return automatically, without thought. Certainly others have had similar problems.”

“Nope,” said the designer. He claimed that I was the only person who had ever complained, and the company’s employees had been using the system for many months. I was skeptical, so we went together to some of the employees and asked them whether they had ever hit the Return key when...

Well, how come nobody ever said anything about it? After all, they were encouraged to report all problems with the system. The reason was simple: when the system stopped working or did something strange, they dutifully reported it as a problem. But when they made the Return versus Enter error, they blamed themselves. After all, they had been told what to do. They had simply erred.

The idea that a person is at fault when something goes wrong is deeply entrenched in society.

But in my experience, human error usually is a result of poor design: it should be called system error.

Many machines are programmed to be very fussy about the form of input they require, where the fussiness is not a requirement of

the machine but due to the lack of consideration for people in the design of the software. In other words: inappropriate programming. Consider these examples.

Consider Microsoft’s calendar program. Here, it is possible to specify dates any way you like: “November 23, 2015,” “23 Nov. 15,” or “11.23.15.” It even accepts phrases such as “a week from Thursday,” “tomorrow,” “a week from tomorrow,” or “yesterday.” Same with time. You can enter the time any way you want: “3:45 PM,” “15.35,” “an hour,” “two and one-half hours.” Same with telephone numbers: Want to start with a + sign (to indicate the code for international dialing)? No problem. Like to separate the

number fields with spaces, dashes, parentheses, slashes, periods? No problem. As long as the program can decipher the date, time, or telephone number into a legal format, it is accepted. I hope the team that worked on this got bonuses and promotions. Although I single out Microsoft for being the pioneer in accepting a wide variety of formats, it is now becoming standard practice. By the time you read this, I would hope that every program would permit any intelligible format for names, dates, phone numbers, street addresses, and so on, transforming whatever is entered into whatever form the internal programming needs.

But I predict that even in the twenty-second century, there will still be forms that require precise accurate (but arbitrary) formats for no reason except the laziness of the programming team. Perhaps in the years that pass between this book’s publication and when you are reading this, great improvements will have...

The Seven Stages of Action: Seven Fundamental Design Principles

The information that helps answer questions of execution (doing) is feedforward. The information that aids in understanding what has happened is feedback. Everyone knows what feedback is. It helps you know what happened. But how do you know what you can do? That’s the role of feedforward, a term borrowed from control theory.

The next time you can’t immediately figure out the shower control in a hotel room or have trouble using an unfamiliar television set or kitchen appliance, remember that the problem is in the design. Ask yourself where the problem lies. At which of the seven stages of action does it fail? Which design principles are deficient?

One of my self-imposed rules is, “Don’t criticize unless you can do better.”

A friend kindly let me borrow his car, an older, classic Saab. Just before I was about to leave, I found a note waiting for me: “I should have mentioned that to get the key out of the ignition, the car needs to be in reverse.” The car needs to be in reverse! If I hadn’t seen the note, I never could have figured that out. There was no visible cue in the car: the knowledge needed for this trick had to reside in the head. If the driver lacks that knowledge, the key stays in the ignition forever.

The psychologists Ray Nickerson and Marilyn Adams showed that people do not remember what common coins look like (Figure 3.1).

Knowledge of—what psychologists call declarative knowledge—includes the knowledge of facts and rules. “Stop at

the United States, when it introduced the Susan B. Anthony one-dollar coin; Great Britain, a one-pound coin (before the switch to decimal currency); and France, a ten-franc coin (before the conversion to the common European currency, the euro). The

PARIS With a good deal of fanfare, the French government released the new 10-franc coin (worth a little

more than $1.50) on Oct. 22 [1986]. The public looked at it, weighed it, and began confusing it so quickly with the half-franc coin (worth only 8 cents) that a crescendo of fury and ridicule fell on both the government and the coin.

In retrospect, the French decision seems so foolish that it is hard to fathom how it could have been made. After much study, designers came up with a silver-colored coin made of nickel and featuring a modernistic drawing by artist Joaquim Jimenez of a Gallic rooster on one side and of Marianne, the female symbol of the French republic, on the other. The coin was light, sported special ridges on its rim for easy reading by electronic vending machines and seemed tough to counterfeit. But the designers and bureaucrats were obviously so excited by their creation that they ignored or refused to accept the new coin’s similarity to the hundreds of millions of silver-colored, nickel-based half-franc coins in circulation [whose] size and weight were perilously similar. (Stanley Meisler. Copyright © 1986, Los Angeles Times. Reprinted with permission.)

pence coin, newcomers (and children) did not have the same confusion. This is because the long-term residents were working with their original set of descriptions, which did not easily accommodate the distinctions between these two coins.

In the United States, the Susan B. Anthony dollar coin never became popular and is no longer being made, so the equivalent observations cannot be made.

How do people memorize such voluminous amounts of material? Do some people have huge amounts of knowledge in their heads? Not really. It turns out that external constraints exert control over the permissible choice of words, thus dramatically reducing the memory load. One of the secrets comes from the powerful constraints of poetry.

In both examples, even though you might have found answers, they were not likely to be the same three that I had in mind. There simply are not enough constraints.

But suppose I now tell you that the words I seek are the same in both tasks: What is a word that means a mythical being and rhymes with “post”? What word is the name of a building material and rhymes with “eel”? And what word is a unit of time and rhymes with “ear”?

The classic study of memory for epic poetry was done by Albert Bates Lord.

In

the mid-1900s he traveled throughout the former Yugoslavia (now a number of separate, independent countries) and found people who still followed the oral tradition. He demonstrated that the “singer of tales,” the person who learns epic poems and goes from village to village reciting them, is really re-creating them, composing poetry on the fly in such a way that it obeys the rhythm, theme, story line, structure...

In fact, as Lord points out, the original and new recitations are not the same word for word, but both teller and listener perceive them as the same, even when the second version was twice as long as the first.

When he reached the entrance of the cavern, he pronounced the words, Open Simsim! The door immediately opened, and when he was in, closed on him. In examining the cave he was greatly astonished to find much more riches than he had expected from ‘Ali Baba’s relation.

He quickly laid at the door of the cavern as many bags of gold as his ten mules could carry, but his thoughts were now so full of the great riches he should possess, that he could not think of the necessary words to make the door open. Instead of Open Simsim! he said Open Barley! and was much amazed to find that the door remained shut. He named several sorts of grain, but still the door would not open. Kasim never expected such an incident, and was so alarmed at the danger he was in that the more he endeavoured to remember the word Simsim the more his memory was confounded, and he had as much forgotten it as if he had never heard it mentioned. Kasim never got out. The thieves returned, cut off Kasim’s head, and quartered his body. (From Colum’s 1953 edition of The Arabian Nights.)

How do most people cope? They use simple passwords. Studies show that five of the most common passwords are: “password,” “123456,” “12345678,” “qwerty,” and “abc123.”

The more complex the password requirements, the less secure the system. Why? Because people, unable to remember all these combinations, write them down. And then where do they store this private, valuable knowledge? In their wallet, or taped under the computer keyboard, or wherever it is easy to find, because it is so frequently needed. So a thief only has to steal the wallet or find the list and then all secrets are known. Most people are honest, concerned workers. And it is these individuals that complex security systems impede the most, preventing them from getting their work done. As a result, it is often the most dedicated employee who violates the security rules and weakens the overall system.

There is often a logic involved in the choice of unlikely places. For example, a friend of ours was required by her insurance company to acquire a safe if she wished to insure her valuable gems. Recognizing that she might forget the combination to the safe, she thought carefully about where to keep the combination. Her solution was to write it in her personal phone directory under the letter S next to “Mr. and Mrs. Safe,” as if it were a telephone number. There is a clear logic here: Store numerical information with other numerical information. She was appalled, however, when she heard a reformed burglar on a daytime television talk show say that upon encountering a safe, he always headed for the phone directory because many people keep the combination there. (From Winograd & Soloway, 1986, “On Forgetting the Locations of Things Stored in Special Places.” Reprinted with permission.)

Make something too secure, and it becomes less secure.

Don’t count on much being retained in STM.

have seen nurses write down critical medical information about their patients on their hands because the critical information would disappear if the nurse was distracted for a moment by someone asking a question. The electronic medical records systems automatically log out users when the system does not appear to be in use. Why the automatic logouts? To protect patient privacy. The cause may be well motivated, but the action poses severe challenges to nurses who are continually being interrupted in their work by physicians, co-workers, or patient requests. While they are attending to the interruption, the system logs them out, so they have to start over again. No wonder these nurses wrote down the knowledge, although this then negated much of the value of the computer system in minimizing handwriting errors. But what else were they to do? How else to get at the critical information? They couldn’t remember it all: that’s why they had computers.

Sleep seems to play an important role in strengthening the memories of each day’s experiences.

It is a profoundly erroneous truism, repeated by all copy-books and by eminent people when they are making speeches, that we should cultivate the habit of thinking of what we are doing. The precise opposite is the case. Civilization advances by extending the number of important operations which we can perform without thinking about them. (Alfred North Whitehead, 1911.)

Want a simpler way? Try this approximation—you can do it in your head, there is no need for paper or pencil: °C = (°F–30) / 2

1. They write down the critical information. 2. They enter it into their equipment as it is told to them, so minimal memory is required. 3. They remember some of it as meaningful phrases.

“Frasca 141” is the name of the airplane, announcing the intended recipient of these instructions. The first critical item to remember is to turn left to a compass direction of 090, then climb to an altitude of 2,000 feet. Write those two numbers down. Enter the radio frequency 124.3 into the radio as you hear it—but most of the time this frequency is known in advance, so the radio is probably already set to

and see that it is set properly. Similarly, setting the “squawk box to 5270” is the special code the airplane sends whenever it is hit by a radar signal, identifying the airplane to the air-traffic controllers. Write it down, or set it into the equipment as it is being said. As for the one remaining item, “Expect 3,000 10 minutes after departure,” nothing need be done. This is just reassurance that in ten minutes, Frasca 141 will probably be advised to climb to 3,000 feet, but if so, there will be a new command to do so.

Other aircraft will not hear the commands, which reduces pilot awareness of what all the airplanes in the vicinity are going to do. Researchers in air-traffic control and aviation safety are looking into these issues. Yes, it’s a design issue.