Good design starts with an understanding of psychology and technology. Good design requires good communication, especially from machine to person, indicating what actions are possible, what is happening, and what is about to happen. Communication is especially important when things go wrong. It is relatively easy to design things what work smoothly and harmoniously as long as things go right. But as soon as there is a problem or a misunderstanding, the problem arise. This is where good design is essential. Designers need to focus their attention on the cases where things go wrong, not just on when things work as planned. Actually, this is where the most satisfaction can arise: when something goes wrong but the machine highlights the problems, then the person understands the issue, takes the proper actions, and the problem is solved. When this happens smoothly, the collaboration of person and device feels wonderful.
Affordances determine what actions are possible. Signifiers communicate where the action should take place.
When the mapping uses spatial correspondence between the layout of the controls and the devices being controlled, it is easy to determine how to use them.
It seems natural for people to blame their own misfortunes on the environment. It seems equally natural to blame other people’s misfortunes on their personalities. Just the opposite attribution, by the way, is made when things go well. When things go right, people credit their own abilities and intelligence. The onlookers do the reverse. When they see things go well for someone else, they sometimes credit the environment, or luck.
The phenomenon called learned helplessness might help explain the self-blame. It refers to the situation in which people experience repeated failure at a task. As a result, they decide that the task cannot be done, at least not by them: they are helpless. They stop trying. If this feeling covers a group of tasks, the result can be severe difficulties coping with life. In the extreme case, such learned helplessness leads to depression and to a belief that the individuals cannot cope with everyday life at all. Sometimes al lit takes to get such a feeling of helplessness are a few experiences that accidentally turn out bad. The phenomenon has been most frequently studied as a precursor to the clinical problem of depression, but I have seen it happen after a few bad experiences with everyday objects.
When people have trouble using technology, especially when the perceive (usually incorrectly) that nobody else is having the same problems, they tend to blame themselves. Worse, the more they have trouble, the more helpless they may feel, believing that they must be technically or mechanically inept. This is just the opposite of the more normal situation where people blame their own difficulties on the environment. This false blame is especially ironic because the culprit here is usually the poor design of the technology, so blaming the environment (the technology) would be completely appropriate.
Constraints simplify memory.
Before widespread literacy, and especially before the advent of sound recording devices, performers traveled from village to village, reciting epic poems thousands of lines long. This tradition still exists in some societies. How do people memorize such voluminous amounts of materials? 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.
Consider the constraints of rhyming. If you wish to rhyme one word with another, there are usually a lot of alternatives. But if you must have a word with a particular meaning to rhyme with another, the joint constraints of meaning and rhyme can cause a dramatic reduction in the number of possible candidates, sometimes reducing a large set to a single choice.
It is a profoundly erroneous truism, repeated by all copy-books and 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.
One way to simplify thought is to use simplified models, approximations to the true underlying state of affairs. Science deals in truth, practice deals with approximations. Practitioners don’t need truth: they need results relatively quickly that, although inaccurate, are “good enough” for the purpose to which they will be applied.
It is relatively easy to design for the situation where everything goes well, where people use the device in the way that was intended, and no unforeseen events occur. The tricky part is to design for when things go wrong.
Consider a conversation between two people. Are errors made? Yes, but they are not treated as such. If a person says something that is not understandable, we ask for clarification. If a person says something that we believe to be false, we question and debate. We don’t issue a warning signal. We don’t beep. We don’t give error messages. We ask for more information and engage in mutual dialogue to reach an understanding. In normal conversations between two friends, misstatements are taken as normal, as approximations to what was really meant. Grammatical errors, self-corrections, and restarted phrases are ignored. In fact, they are usually not even detected because we concentrate upon the intended meaning, not the surface features.
One of my rules in consulting is simple: never solve the problem I am asked to solve. Why such a counterintuitive rule? Because, invariably, the problem I am asked to solve is not the real, fundamental, root problem. It is usually a symptom. In design, the secret to success is to understand what the real problem is.
Engineers and business people are trained to solve problems. “Where do you think the problems come from?” I ask. The real world is not like the university. In the university, professors make up artificial problems. In the real world, the problems do not come in nice, neat packages. They have to be discovered. It is all too easy to see only the surface problems and never dig deeper to address the real issues.
The power of the unaided mind is highly overrated. Without external aids, deep, sustained reasoning is difficult. Unaided memory, though, and reasoning are all limited in power. Human intelligence is highly flexible and adaptive, superb at inventing procedures and objects that overcome its own limits. The real powers come from devising external aids that enhance cognitive abilities. How have we increased memory, thought and reasoning? By the invention of external aids: it is the things that make us smart. Some assistance comes through cooperative, social behavior: some arises through exploitation of the information present in the environment; and some comes through the development of tools of thought — cognitive artifacts — that complement abilities and strengthen mental powers.