Donald Norman’s Principles for Product Design
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As a team, we have delved deep into the history of UI/UX and the principles of great product design. Our research has led us through different concepts and ideologies, from Vastu Shastra and Feng Shui, which focus on the optimal spatial arrangement of objects derived from both India and China, to Greek agriculture and the ergonomics of tools. During our research, we came across Donald Norman, a cognitive scientist who worked at Apple during the 90s and coined the term UI/UX design. We decided to read his book, The Design of Everyday Things, to bridge the gap between psychology, interaction, and product design. While we are still making our way through the book, we have distilled some key concepts that we found interesting regarding interactions and design, and how these ideas should be considered to make good design decisions.
Norman emphasised that, "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." He also broke down the fundamental principles of design into four key principles, which included affordances, signifiers, mappings, and feedback.
An affordance is not a characteristic of a product, but rather the relationship between a product and its user. It is a term coined by J. J. Gibson, an eminent psychologist who provided many advances to our understanding of human perception. Good affordance provides users with a clear understanding of the number of opportunities available to them and should not be confused with a signifier. Affordances take into account the properties of an object as well as the ability of the person using it.
In a YouTube video created by Norman many years back, he uses an example of a chair. A chair has four legs, a seat rest, and is shaped to fit the human body. In this example, the chair offers good affordance to its user as it gives the user a place to sit. If, however, the same chair was given to an elephant, a creature that is substantially heavier than a human, then the chair would simply break. Therefore, a standard chair should offer good affordance to a human but not an elephant.
Norman admits that his definition of the term in previous renditions of the book left him dissatisfied. He noticed that many people failed to grasp the true idea of what this term meant and often confused it with signifiers. He stated that, "Affordances determine what actions are possible. Signifiers communicate where the action should take place." He used this opportunity to also emphasise the importance of language, appropriate definitions, and their relationship with clear communication.
Signifiers are signals and can be represented in a range of different ways, from signs and labels to even the arrangement of certain elements. Good signifiers provide users with discrete instructions and clues on how to interact with a product, making the overall experience a pleasant one. Good signifiers minimise friction and frustration and also contribute to the overall functionality of the product. No one wants to read a 100-page user manual. With correct signifiers, the product becomes somewhat intuitive.
Mapping is a mathematical term that connects two elements together. In product design, mapping is extremely important as it allows the user to feel some sense of control while using a product. The example Norman gave when it comes to mapping is the steering of a car. When you turn the wheel to the left, the direction of your car changes. Similarly, when you press the accelerator or brake pedal, the speed of the car is manipulated. Effective mapping creates a user/product connection.
Feedback is communicating the results of an action. Without feedback, it’s hard for a user to know if they are using the product correctly. Norman emphasises that "Feedback must be immediate," and that "even a delay of a tenth of a second can be disconcerting." He also raised the point that too much feedback can cause confusion and can also become annoying. Medical machinery that uses audio to portray the health status of vital organs can become stressful and overwhelming to hospital staff if too many of these machines are operating simultaneously. Norman also gave the example of a dishwasher completing its wash cycle at 3am. Sure, it’s good to know that the cycle is complete, but is it worth the cost of being disturbed during your sleep? Feedback that is instant, clear, and unobtrusive allows for pleasant product experiences.
Norman’s work and its link between human psychology and objects reinforce the importance of intuitive, easy-to-understand products and their impact on user utility. If businesses want to create products that deliver great experiences, then these principles should be considered, especially during the strategic planning phases of the product design. Many of Norman’s principles hold true today, and it will be interesting to see how we can apply them to develop more pleasant, user-friendly experiences.
Source: The Design Of Everyday Things, Donald Norman
