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Many of us spend hours filling out forms on computers--forms that require names, dates, addresses, telephone numbers, monetary sums, and other information in a fixed, rigid format. Worse, often we are not even told the correct format until we get it wrong. Why not figure out the variety of ways a person might fill out a form and accommodate all of them? Some companies have done excellent jobs at this, so let us celebrate their actions. Cons..
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Donald A. Norman |
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d5b881b
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Forcing functions are a form of physical constraint: situations in which the actions are constrained so that failure at one stage prevents the next step from happening. Starting a car has a forcing function associated with it--the driver must have some physical object that signifies permission to use the car. In
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Donald A. Norman |
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interlocks as forcing functions to prevent people from opening the door of the oven or disassembling the devices without first turning off the electric power: the interlock disconnects the power the instant the door is opened or the back is removed. In automobiles with automatic transmissions, an interlock prevents the transmission from leaving the Park position unless the car's brake pedal is depressed.
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Donald A. Norman |
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d3e8602
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Subconscious thought is biased toward regularity and structure, and it is limited in formal power. It may not be capable of symbolic manipulation, of careful reasoning through a sequence of steps. Conscious thought is quite different. It is slow and labored. Here is where we slowly ponder decisions, think through alternatives, compare different choices. Conscious thought considers first this approach, then that--comparing, rationalizing, fi..
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Donald A. Norman |
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Affordances, signifiers, mappings, and constraints can simplify our encounters with everyday objects. Failure to properly deploy these cues leads to problems.
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Donald A. Norman |
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Most expert, skilled behavior works this way, whether it is playing tennis or a musical instrument, or doing mathematics and science. Experts minimize the need for conscious reasoning. Philosopher
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Donald A. Norman |
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b926481
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A usable design starts with careful observations of how the tasks being supported are actually performed, followed by a design process that results in a good fit to the actual ways the tasks get performed. The technical name for this method is task analysis. The name for the entire process is human-centered design (HCD), discussed
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Donald A. Norman |
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Unless it is your ambition to become a nightclub performer and amaze people with great skills of memory, here is a simpler way to dramatically enhance both memory and accuracy: write things down. Writing is a powerful technology: why not use it? Use a pad of paper, or the back of your hand. Write it or type it. Use a phone or a computer. Dictate it. This is what technology is for. The unaided mind is surprisingly limited. It is things that ..
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Donald A. Norman |
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Cultural constraints are likely to change with time.
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Donald A. Norman |
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7114453
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We only need to remember sufficient knowledge to let us get our tasks done. Because so much knowledge is available in the environment, it is surprising how little we need to learn. This is one reason people can function well in their environment and still be unable to describe what they do.
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Donald A. Norman |
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Procedural knowledge is difficult or impossible to write down and difficult to teach. It is best taught by demonstration and best learned through practice.
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Donald A. Norman |
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Procedural knowledge is largely subconscious, residing at the behavioral level of processing.
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Donald A. Norman |
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The study of slips is the study of the psychology of everyday errors--what Freud called "the psychopathology of everyday life." Freud believed that slips have hidden, dark meanings, but most are accounted for by rather simple mental mechanisms."
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Donald A. Norman |
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An interesting property of slips is that, paradoxically, they tend to occur more frequently to skilled people than to novices. Why? Because slips often result from a lack of attention to the task. Skilled people--experts--tend to perform tasks automatically, under subconscious control. Novices have to pay considerable conscious attention, resulting in a relatively low occurrence of slips.
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Donald A. Norman |
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825f688
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Emotion interacts with cognition biochemically, bathing the brain with hormones, transmitted either through the bloodstream or through ducts in the brain, modifying the behavior of brain cells. Hormones exert powerful biases on brain operation. Thus, in tense, threatening situations, the emotional system triggers the release of hormones that bias the brain to focus upon relevant parts of the environment. The muscles tense in preparation for..
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Donald A. Norman |
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b9169e6
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Designers should strive to minimize the chance of inappropriate actions in the first place by using affordances, signifiers, good mapping, and constraints to guide the actions. If a person performs an inappropriate action, the design should maximize the chance that this can be discovered and then rectified. This requires good, intelligible feedback coupled with a simple, clear conceptual model. When people understand what has happened, what..
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Donald A. Norman |
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Recognize that most of our interactions with products are actually interactions with a complex system: good design requires consideration of the entire system to ensure that the requirements, intentions, and desires at each stage are faithfully understood and respected at all the other stages.
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Donald A. Norman |
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Standardization is indeed the fundamental principle of desperation: when no other solution appears possible, simply design everything the same way, so people only have to learn once. If
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Donald A. Norman |
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Knowledge in the world includes perceived affordances and signifiers, the mappings between the parts that appear to be controls or places to manipulate and the resulting actions, and the physical constraints that limit what can be done. Knowledge
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Donald A. Norman |
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Knowledge in the head includes conceptual models; cultural, semantic, and logical constraints on behavior; and analogies between the current situation and previous experiences with other situations.
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Donald A. Norman |
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Constraints are powerful clues, limiting the set of possible actions. The thoughtful use of constraints in design lets people readily determine the proper course of action, even in a novel situation.
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Donald A. Norman |
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In the absence of external information, people can let their imagination run free as long as the conceptual models they develop account for the facts as they perceive them. As
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Donald A. Norman |
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It is when the disciplines operate independently of one another that major clashes and deficiencies occur.
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Donald A. Norman |
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Blaming a person is seldom appropriate or useful, a
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Donald A. Norman |
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Violation of cultural conventions can completely disrupt an interaction.
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Donald A. Norman |
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Cognition attempts to make sense of the world: emotion assigns value. It
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Donald A. Norman |
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A positive emotional state is ideal for creative thought, but it is not very well suited for getting things done. Too much, and we call the person scatterbrained, flitting from one topic to another, unable to finish one thought before another comes to mind. A brain in a negative emotional state provides focus: precisely what is needed to maintain attention on a task and finish it. Too much, however, and we get tunnel vision, where people ar..
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Donald A. Norman |
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To understand products, it is not enough to understand design or technology: it is critical to understand business.
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Donald A. Norman |
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Three Levels of Processing: Visceral, Behavioral, and Reflective. Visceral and behavioral levels are subconscious and the home of basic emotions. The reflective level is where conscious thought and decision-making reside, as well as the highest level of emotions.
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Donald A. Norman |
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1bb4d37
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Herbert Read thought we would need a mystical theory to connect beauty and function. Well, it took one hundred years, but today we have that theory, one based in biology, neuroscience, and psychology, not mysticism.
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Donald A. Norman |
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6b86a86
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Design is concerned with how things work, how they are controlled, and the nature of the interaction between people and technology.
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Donald A. Norman |
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Radical innovation is what many people seek, for it is the big, spectacular form of change. But most radical ideas fail, and even those that succeed can take decades and, as this chapter has already illustrated, they may take centuries to succeed.
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Donald A. Norman |
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Even systems that do not use menus need to provide some structure: appropriate constraints and forcing functions, natural good mapping, and all the tools of feedforward and feedback. The most effective way of helping people remember is to make it unnecessary.
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Donald A. Norman |
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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.
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Donald A. Norman |
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the first edition of this book, then called POET, The Psychology of Everyday Things, I started with these lines: "This is the book I always wanted to write, except I didn't know it." Today I do know it, so I simply say, "This is the book I always wanted to write."
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Donald A. Norman |
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Question everything. I am particularly fond of "stupid" questions. A stupid question asks about things so fundamental that everyone assumes the answer is obvious."
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Donald A. Norman |
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Ask "Why?" as many times as may be necessary to get to the root cause of the problem and then fix it so it can never occur again."
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Donald A. Norman |
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What are the design implications? Don't count on much being retained in STM. Computer systems often enhance people's frustration when things go wrong by presenting critical information in a message that then disappears from the display just when the person wishes to make use of the information. So how can people remember the critical information? I am not surprised when people hit, kick, or otherwise attack their computers.
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Donald A. Norman |
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Danger awaits those who deliberately violate the frames of a culture.
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Donald A. Norman |
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Beauty comes from the reflective level. Beauty looks below the surface. Beauty comes from conscious reflection and experience. It is influenced by knowledge, learning, and culture. Objects that are unattractive on the surface can give pleasure. Discordant music, for example, can be beautiful. Ugly art can be beautiful.
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Donald A. Norman |
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b79e822
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Whenever you see hand-lettered signs pasted on doors, switches, or products, trying to explain how to work them, what to do and what not to do, you are also looking at poor design.
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Donald A. Norman |
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a75041a
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When I used to work for the local government organisation we HAD TO change our Passwords every three months. To ensure I could remember it, I used to write it on a Post-It note and stick it above my desk.
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Donald A. Norman |
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A brain in a negative emotional state provides focus: precisely what is needed to maintain attention on a task and finish it.
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Donald A. Norman |
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I have long held the belief--and encouraged it in my students and employees--that failures are an essential part of exploration and creativity. If designers and researchers do not sometimes fail, it is a sign that they are not trying hard enough--they are not thinking the great creative thoughts that will provide breakthroughs in how we do things. It is possible to avoid failure, to always be safe. But that is also the route to a dull, unin..
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Donald A. Norman |