The Psychology of Everyday Things
Design is an act of communication and relies on an understanding of human behavior and cognition. Good design embodies the right amount of information to create a working conceptual model of the product in the mind of the person using it.
The Psychology Of Everyday Things by Donald A Norman
In The Design of Everyday Things Don Norman covers design principles, human behavior, and dissects mistakes in design and the actions that contributed to a variety of industrial and public accidents. For Norman, design fundamentally depends on good communication. If a person cannot understand what options are available from an object, system, or environment, they will be unable to use the product or service to meet their goals. The first goal for a designer is to communicate the available affordances. If there is limited or ambiguous feedback, the person will be unable to adjust their behavior to achieve their objectives. The complementary goal for the designer is include good feedback that informs the user as to whether or not they have met their goals.
A key theme in the book is an exposition of how humans think, process information, and act. Good designers understand how people will behave when initially encountering a product or environment and what actions they make take while interacting with it, especially if something goes wrong. Human centered design is designing for the way that humans perceive, act, decide, and respond.
Norman does not limit himself to technology or even physical objects. He discusses human environments such as building interiors and large-scale systems like air traffic control to illustrate good design, design mistakes. The book includes a inventory of common mental mistakes that people make, sometimes with disastrous results. Norman’s mini case studies illustrate the slips and errors that hint at human mental processes and highlight behaviors that must be taken into account when designing products, systems, and environments.
The fundamental principles of design
Norman breaks down human actions into a seven stage model which informs product design. The answers to each question are related to one or more of his seven fundamental principles of design:
|Taking Action||What do I want to accomplish?||Discoverability|
|Taking Action||What are the alternatives?||Constraints|
|Taking Action||What can I do?||Affordances|
|Taking Action||How do I do it?||Mappings|
|Feedback||What does it mean?||Conceptual model|
|Feedback||Is this OK? Have I accomplished my goal?||Feedback|
A common theme in Norman’s writing is the importance of communication in design. Discoverability, signifiers, feedback, and constraints help build the mappings and conceptual model that enable the person using the product to effectively take advantage of the affordances.
Knowledge in the head and in the world
Put the knowledge required to operate the technology in the world. Don’t require that all the knowledge must be in the head.
Some information about the product is held in the head of the person using and some information is incorporated in the product itself. The more information that is in the product (the world), the less the person using the object has to learn, remember, or bring to the interaction. The reason constraints are important is because they limit what must be remembered, thus simplifying the usage of the product. The more that must be remembered, the longer the learning curve and time to achieve goals. Knowledge embedded in the product can trigger memories and information to be retrieved.
Use the power of natural and artificial constraints: physical , logical, semantic, and cultural.
Constraints come in several varieties and serve to guide the users of a technology to the desired goal. Designers must be aware of cultural norms and constraints as well as those physically built into a product or environment. Norman points out that the design process essentially consists of applying constraints until a single viable solution is found.
The Gulf of Execution and the Gulf of Evaluation
Make it possible to determine the system’s status readily, easily, accurately, and in a form consistent with the person’s goals, plans, and expectations.
The Gulf of Execution represents the challenge that person has in determining what affordances a system or product has. The Gulf of Evaluation is effectively feedback–the way in which the system communicates is internal state the result of actions initiated by the user to the user. The designer’s goal is to ensure the conceptual model in the user’s mind is the same as the actual functional model of the system. Bridging both gaps is difficult for product teams because they know the product so well they often cannot perceive the gulfs. Testing with real users is the only way to find and resolve these gulfs. It’s tempting to dismiss user misunderstandings, but they are typically a direct indicator of product design failures.
…invariably, the problem I am asked to solve is not the real, fundamental, root problem.
Norman writes that “in the real world, the problems do not come in nice, neat packages.” Although business people and engineers are focused on solving problems that are presented to them, the problem as presented is often just a symptom. In contrast, the designer’s perspective is to generate new ideas, explore, and find the right problem. The book includes a section on the Five Whys, a method for finding root causes. Using these two perspectives, “finding the right problem and meeting human needs and capabilities”, Norman introduces divergent and convergent thinking. Divergent thinking generates many alternatives and explores the problem space while convergent thinking is execution focused and strives to narrow the options to a single optimal solution.
Note that traditional measures of people, such as age, education, and income, are not always important: what matters most are the activities to be performed.
Norman discusses several product development methods popularized after the book was written:”jobs to be done” and”getting outside the building“. He recommends identifying and finding the core need for a set of users by focusing on activities to be performed rather than using demographic or psychographic attributes. Norman also recommends visiting with real users in their natural environments as the best way to understand the people for whom you are designing.
The day a product development process starts, it is behind schedule and above budget.
Norman discusses many of the realities of product development in the book: external constraints, market pressures, and internal realities. To win in the complex and competitive environment with multiple conflicting requirements, Norman says “good design requires stepping back from competitive pressures and ensuring that the entire product be consistent, coherent, and understandable.” He identified two approaches for effective product development: Youngme Moon‘s strategy of focusing on strengths rather than bolstering weaknesses and Jeff Bezos’ customer obsession (focus on the customer and the rest will take care of itself).
Design is successful only if the final product is successful–if people buy it, use it, and enjoy it, thus spreading the word.