Read The Design of Everyday Things Online
Authors: Don Norman
The Design of Everyday Things (21 page)
REMINDING: PROSPECTIVE MEMORY
The phrases
prospective memory
or
memory for the future
might sound counterintuitive, or perhaps like the title of a science-fiction novel, but to memory researchers, the first phrase simply denotes the task of remembering to do some activity at a future time. The second phrase denotes planning abilities, the ability to imagine future scenarios. Both are closely related.
Consider reminding. Suppose you have promised to meet some friends at a local café on Wednesday at three thirty in the afternoon. The knowledge is in your head, but how are you going to remember it at the proper time? You need to be reminded. This is a clear instance of prospective memory, but your ability to provide the required cues involves some aspect of memory for the future as well. Where will you be Wednesday just before the planned meeting? What can you think of now that will help you remember then?
There are many strategies for reminding. One is simply to keep the knowledge in your head, trusting yourself to recall it at the
critical time. If the event is important enough, you will have no problem remembering it. It would be quite strange to have to set a calendar alert to remind yourself, “Getting married at 3 PM.”
Relying upon memory in the head is not a good technique for commonplace events. Ever forget a meeting with friends? It happens a lot. Not only that, but even if you might remember the appointment, will you remember all the details, such as that you intended to loan a book to one of them? Going shopping, you may remember to stop at the store on the way home, but will you remember all the items you were supposed to buy?
If the event is not personally important and several days away, it is wise to transfer some of the burden to the world: notes, calendar reminders, special cell phone or computer reminding services. You can ask friends to remind you. Those of us with assistants put the burden on them. They, in turn, write notes, enter events on calendars, or set alarms on their computer systems.
Why burden other people when we can put the burden on the thing itself? Do I want to remember to take a book to a colleague? I put the book someplace where I cannot fail to see it when I leave the house. A good spot is against the front door so that I can't leave without tripping over it. Or I can put my car keys on it, so when I leave, I am reminded. Even if I forget, I can't drive away without the keys. (Better yet, put the keys under the book, else I might still forget the book.)
There are two different aspects to a reminder: the signal and the message. Just as in doing an action we can distinguish between knowing
what
can be done and knowing
how
to do it, in reminding we must distinguish between the
signal
âknowing that something is to be remembered, and the
message
âremembering the information itself. Most popular reminding methods typically provide only one or the other of these two critical aspects. The famous “tie a string around your finger” reminder provides only the signal. It gives no hint of what is to be remembered. Writing a note to yourself provides only the message; it doesn't remind you ever to look at it. The ideal reminder has to have both components: the signal that something is to be remembered, and then the message of what it is.
The signal that something is to be remembered can be a sufficient memory cue if it occurs at the correct time and place. Being reminded too early or too late is just as useless as having no reminder. But if the reminder comes at the correct time or location, the environmental cue can suffice to provide enough knowledge to aid retrieval of the to-be-remembered item. Time-based reminders can be effective: the
bing
of my cell phone reminds me of the next appointment. Location-based reminders can be effective in giving the cue at the precise place where it will be needed. All the knowledge needed can reside in the world, in our technology.
The need for timely reminders has created loads of products that make it easier to put the knowledge in the worldâtimers, diaries, calendars. The need for electronic reminders is well known, as the proliferation of apps for smart phones, tablets, and other portable devices attests. Yet surprisingly in this era of screen-based devices, paper tools are still enormously popular and effective, as the number of paper-based diaries and reminders indicates.
The sheer number of different reminder methods also indicates that there is indeed a great need for assistance in remembering, but that none of the many schemes and devices is completely satisfactory. After all, if any one of them was, then we wouldn't need so many. The less effective ones would disappear and new schemes would not continually be invented.
The Tradeoff Between Knowledge in the World and in the Head
Knowledge in the world and knowledge in the head are both essential in our daily functioning. But to some extent we can choose to lean more heavily on one or the other. That choice requires a tradeoffâgaining the advantages of knowledge in the world means losing the advantages of knowledge in the head (
Table 3.1
).
Knowledge in the world acts as its own reminder. It can help us recover structures that we otherwise would forget. Knowledge in the head is efficient: no search and interpretation of the environment is required. The tradeoff is that to use our knowledge in the head, we have to be able to store and retrieve it, which might
require considerable amounts of learning. Knowledge in the world requires no learning, but can be more difficult to use. And it relies heavily upon the continued physical presence of the knowledge; change the environment and the knowledge might be lost. Performance relies upon the physical stability of the task environment.
TABLE 3.1. | |
Knowledge in the World | Knowledge in the Head |
Information is readily and easily available whenever perceivable. | Material in working memory is readily available. Otherwise considerable search and effort may be required. |
Interpretation substitutes for learning. How easy it is to interpret knowledge in the world depends upon the skill of the designer. | Requires learning, which can be considerable. Learning is made easier if there is meaning or structure to the material or if there is a good conceptual model. |
Slowed by the need to find and interpret the knowledge. | Can be efficient, especially if so well-learned that it is automated. |
Ease of use at first encounter is high. | Ease of use at first encounter is low. |
Can be ugly and inelegant, especially if there is a need to maintain a lot of knowledge. This can lead to clutter. Here is where the skills of the graphics and industrial designer play major roles. | Nothing needs to be visible, which gives more freedom to the designer. This leads to cleaner, more pleasing appearanceâat the cost of ease of use at first encounter, learning, and remembering. |
As we just discussed, reminders provide a good example of the relative tradeoffs between knowledge in the world versus in the head. Knowledge in the world is accessible. It is self-reminding. It is always there, waiting to be seen, waiting to be used. That is why we structure our offices and our places of work so carefully. We put piles of papers where they can be seen, or if we like a clean desk, we put them in standardized locations and teach ourselves (knowledge in the head) to look in these standard places routinely. We use clocks and calendars and notes. Knowledge in the mind
is ephemeral: here now, gone later. We can't count on something being present in mind at any particular time, unless it is triggered by some external event or unless we deliberately keep it in mind through constant repetition (which then prevents us from having other conscious thoughts). Out of sight, out of mind.
As we move away from many physical aids, such as printed books and magazines, paper notes, and calendars, much of what we use today as knowledge in the world will become invisible. Yes, it will all be available on display screens, but unless the screens always show this material, we will have added to the burden of memory in the head. We may not have to remember all the details of the information stored away for us, but we will have to remember that it is there, that it needs to be redisplayed at the appropriate time for use or for reminding.
Memory in Multiple Heads, Multiple Devices
If knowledge and structure in the world can combine with knowledge in the head to enhance memory performance, why not use the knowledge in multiple heads, or in multiple devices?
Most of us have experienced the power of multiple minds in remembering things. You are with a group of friends trying to remember the name of a movie, or perhaps a restaurant, and failing. But others try to help. The conversation goes something like this:
“That new place where they grill meat”
“Oh, the Korean barbecue on Fifth Street?”
“No, not Korean, South American, um,“
“Oh, yeah, Brazilian, it's what's its name?”
“Yes, that's the one!”
“Pampas something.”
“Yes, Pampas Chewy. Um, Churry, um,”
“Churrascaria. Pampas Churrascaria.”
How many people are involved? It could be any number, but the point is that each adds their bit of knowledge, slowly constraining the choices, recalling something that no single one of them could
have done alone. Daniel Wegner, a Harvard professor of psychology, has called this
“transactive memory.”
Of course, we often turn to technological aids to answer our questions, reaching for our smart devices to search our electronic resources and the Internet. When we expand from seeking aids from other people to seeking aids from our technologies, which Wegner labels as “cybermind,” the principle is basically the same. The cybermind doesn't always produce the answer, but it can produce sufficient clues so that we can generate the answer. Even where the technology produces the answer, it is often buried in a list of potential answers, so we have to use our own knowledgeâ or the knowledge of our friendsâto determine which of the potential items is the correct one.
What happens when we rely too much upon external knowledge, be it knowledge in the world, knowledge of friends, or knowledge provided by our technology? On the one hand, there no such thing as “too much.” The more we learn to use these resources, the better our performance. External knowledge is a powerful tool for enhanced intelligence. On the other hand, external knowledge is often erroneous: witness the difficulties of trusting online sources and the controversies that arise over Wikipedia entries. It doesn't matter where our knowledge comes from. What matters is the quality of the end result.
In an earlier book,
Things That Make Us Smart
, I argued that it is this combination of technology and people that creates super-powerful beings. Technology does not make us smarter. People do not make technology smart. It is the combination of the two, the person plus the artifact, that is smart. Together, with our tools, we are a powerful combination. On the other hand, if we are suddenly without these external devices, then we don't do very well. In many ways, we do become less smart.
Take away their calculator, and many people cannot do arithmetic. Take away a navigation system, and people can no longer get around, even in their own cities. Take away a phone's or computer's address book, and people can no longer reach their friends (in my case, I can no longer remember my own phone number).
Without a keyboard, I can't write. Without a spelling corrector, I can't spell.
What does all of this mean? Is this bad or good? It is not a new phenomenon. Take away our gas supply and electrical service and we might starve. Take away our housing and clothes and we might freeze. We rely on commercial stores, transportation, and government services to provide us with the essentials for living. Is this bad?
The partnership of technology and people makes us smarter, stronger, and better able to live in the modern world. We have become reliant on the technology and we can no longer function without it. The dependence is even stronger today than ever before, including mechanical, physical things such as housing, clothing, heating, food preparation and storage, and transportation. Now this range of dependencies is extended to information services as well: communication, news, entertainment, education, and social interaction. When things work, we are informed, comfortable, and effective. When things break, we may no longer be able to function. This dependence upon technology is very old, but every decade, the impact covers more and more activities.