Quotes from Donald A. Norman

Perceived affordances help people figure out what actions are possible without the need for labels or instructions.

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.

How does the product manager keep the entire team on schedule despite the apparent random and divergent methods of designers? Encourage their free exploration, but hold them to the schedule (and budget) constraints. There is nothing like a firm deadline to get creative minds to reach convergence.

When people err, change the system so that type of error will be reduced or eliminated. When complete elimination is not possible, redesign to reduce the impact.

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

It is possible to avoid failure, to always be safe. But that is also the route to a dull, uninteresting life.

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.

Design is concerned with how things work, how they are controlled, and the nature of the interaction between people and technology. When done well, the results are brilliant, pleasurable products. When done badly, the products are unusable, leading to great frustration and irritation. Or they might be usable, but force us to behave the way the product wishes rather than as we wish.

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.

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

the proper natural mapping requires no diagrams, no labels, and no instructions.

Los errores deben ser fáciles de detectar, deben tener unas consecuencias mínimas y, de ser posible, sus efectos deben ser reversibles.

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. Just

If the system lets you make the error, it is badly designed. And if the system induces you to make the error, then it is really badly designed.

Even if the first versions of a product are well done, human-centered, and focused upon real needs, it is the rare organization that is content to let a good product stay untouched.

Customer research is a tradeoff: deep insights on real needs from a tiny set of people, versus broad, reliable purchasing data from a wide range and large number of people. We need both. Designers understand what people really need. Marketing understands what people actually buy. These are not the same things, which is why both approaches are required: marketing and design researchers should work together in complementary teams.

You build up expectations of behavior based upon prior experience, and if the items with which you interact fail to live up to expectations, that is a violation of trust, for which you assign blame, which can soon lead to anger.

Two of the most important characteristics of good design are discoverability and understanding. Discoverability: Is it possible to even figure out what actions are possible and where and how to perform them? Understanding: What does it all mean? How is the product supposed to be used? What do all the different controls and settings mean?

Why do people err? Because the designs focus upon the requirements of the system and the machines, and not upon the requirements of people.

Attractive things certainly should be preferred over ugly ones, but why would they work better? Yet in the early 1990s, two Japanese researchers, Masaaki Kurosu and Kaori Kashimura, claimed just that.

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.

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.

Emotions, we now know, change the way the human mind solves problems—the emotional system changes how the cognitive system operates. So, if aesthetics would change our emotional state, that would explain the mystery.

After all, these systems do not do a very good job of gathering trust. They lose files and they crash, oftentimes for no apparent reason. Moreover, they express no shame, no blame. They don't apologize or say they are sorry. Worse, they appear to blame us, the poor unwitting users. Who is "they"? Why does it matter? We are angered, and appropriately so.