Open any suggested reading list for designers and you’ll come across The Design of Everyday Things. It’s packed with insights and aha-moments for product designers. This year, I finally got around to picking up a copy, and over the next few months I’ll be summarising the key insights I took from each chapter.
The Design of Everyday Things- Chapter 1: The Psychopathology of Everyday Things
Human Centred Design
Why do products fail?
In Chapter 1 of The Design of Everyday Things, Don Norman invites us to view failure with a fresh perspective- it is rarely user error that causes products to fail, but instead, it’s poor design. Products should be built with a focus on the user – meaning that the function of a product should be clear. The user should be able to discover how it works before it fails.
In this chapter, Don lays out his model for discoverability in hopes that designers can use it to make more intuitive products. The hope is that human-centred design will help create products that enhance lives and add to pleasure and enjoyment.
Push or Pull? A lack of Discoverability and Understanding
When was the last time you pushed on a pull door, or vice versa?
Don Norman introduces Chapter One with a universally relatable design failure. While a handle or a push plate can indicate the desired action for interaction with a door, the door’s aesthetic is often given more priority than its function. The design’s first priority needs to be function: doors should be easy for users to open.
So now the question: When a user pushes on a pull door, is this a user error or a design error?
Don Norman argues that this is a design error. There is no product manual for a door; you should intuitively know where to push or pull on it. Even if every door came with a manual, could a product designer reasonably expect the user to read it? In the case of more complex appliances where the user may read the manual (ex: blenders, chainsaws, cars or airplanes), will the reader digest and remember all of the information in the manual? In most cases, the answer is no.
So if a product designer can’t expect the user to read or retain all of the information in the instruction manual, what can they do to ensure the user can still use their product?
A good product designer should design with user empathy, and build their product with enough discoverability.
Discoverability
Put simply, discoverability is how we figure out how to use a product. It shows us how a product works and what operations are possible.
In my opinion, the bulk of the insight from Chapter One is Don Norman’s 5 Fundamental Principles of Interaction– which show you the discoverability of products and how to improve this.
Affordances
This is not a queue that tells us what we can do with an object, but rather the relationship between the user and the object’s properties. A chair offers support, therefor it affords us the ability to sit. Chairs also afford the ability to be lifted or moved.
To be effective, affordances need to be discoverable. Glass affords transparency and also affords the prevention of objects from passing through. However, because of the lack of discoverability of the latter, millions of birds crash into glass windows every year.
Affordances are key to how products function, but how can users find them?
Signifiers
These relate to affordances: they are signals that tell us what affordances an object provides or what actions are possible.
If a button on a touch screen affords pressing, a designer may make it red to signal that it is a button. If a door affords pushing, a designer may put a panel on it to signal that the user should push. Signifiers can also be labels, drawings, or anything that provides the user more information about the tasks they can perform.
Don also warns of the existence of accidental signifiers. A flat surface affords placing an object on it. When someone places their trash on the flat surface, it signifies that trash can be left there. This will lead more users to discover this affordance and leave their trash on the flat surface.
Mapping
Mapping is the relationship between sets of things. Think about the light switches corresponding to the different lights in your home. The switch for the bedroom light is probably in the bedroom. The switch for the bathroom light is probably in the bathroom. If there is a light in each half of the dining room, the switches are probably next to each other. The switch for each half of the room is likely on the same side as its corresponding light.
In another example, Don talks about steering a car- when we turn the wheel to the right, the car should steer to the right. The user doesn’t need to know the mechanisms of the device. The relationship between the action and the result is understandably mapped.
Using familiar patterns and arrangements will make mappings clearer and more intuitive. Turning a dial clockwise will almost always result in moving an increment (like volume) up. Keep in mind, however, that different cultures may anticipate different mappings.
Feedback
Feedback is what an object gives back to you to let you know the system has processed your request. A backlight behind an elevator button to show that you have requested the 8th floor is a great example of feedback. The button is not lit, you press it, and it illuminates to let you know you can stop pressing it.
Feedback can also be more innate. When you pick up a glass of water, the firmness of the surface tells you that your grip is substantial. Too soft of a grip and the glass will slip from your hand. Too firm of a grip (if you’re strong enough) will shatter the glass.
In the book, the requirements for good feedback are outlined.
- Immediate– The user must know immediately that their input was received. Even a delay of 1/10th of a second can be unsettling.
- Informative– If the feedback is too simple, it can leave the user confused and anxious. Think about a subtle beep when you press a button. Did you miss the beep? Was that the noise that corresponded to your button?
- Not too much– If the user is notified too often, it can become an annoyance and cause the user to ignore all the feedback.
- Well designed– while a single colour light or a single tone beep may reduce costs, the difference between a long beep, double beep, and a short beep may not be perceived, causing confusion and frustration. Likewise, a cluttered dashboard of lights is difficult to read, making interpreting feedback difficult.
All actions should be confirmed, but unobtrusively and understandably. Feedback should be planned, and different types of feedback should be prioritised to allow users to concentrate on completing their task.
Conceptual models
This is a model of how something works. It doesn’t need to be complete or accurate as long as it’s useful. For example, there are no actual folders in a computer (mostly cables, drives, 1s, and 0s), but the computer folder on my desktop tells me how the system works.
The conceptual model for scissors is quite simple. The logical affordance of the holes is that you can put your fingers in them. The easiest way to do this is to put your thumb in the small hole, and other fingers in the large hole. From here, the concept of using the scissors is quite clear.
With more complex devices, simple conceptual models are tricky to create. On a digital watch, the function of every button is not usually obvious, and you will likely need to read the instruction manual to understand how it works.
On a stovetop, you can use dials ranging from 0-9 to configure the temperature of different hubs. This is a relatively effective conceptual model.
- The temperature only needs to be accurate between off, hot, and hotter.
- The temperature of one hub will not affect the other.
- The feedback from an adjustment is quick to immediate.
However, in a refrigerator, the conceptual model for similar dials is much more confusing:
- The scale of temperature is not accurate enough. How many degrees is a 5 on the dial?
- The relationship between the dials is not always clear. Does a colder fridge mean diverted cooling from the freezer?
- It will take some time to allow your fridge to give you feedback on new settings. When you change the settings from a 5 to an 8 the cooling can take several hours.
In the case of the stovetop, the dials work as a simplified but accurate enough conceptual model. In the case of the refrigerator, a more complete conceptual model is needed.
Wrap Up- Using Discoverability & The Paradox of Technology
Because designers cannot communicate directly with users, they need to use the concepts above to help users to discover how a product functions. As technology expands, life becomes simpler, but features and tech can also make life more complicated. This is Don’s Paradox of Technology.
“The same technology that simplifies life by providing more functions in each device also complicates life by making the device harder to learn, harder to use.”
A designer’s job is to make the usage and functions of a product clear by devoting focus to the discoverability of their product. This can be more than just paying attention to the “happy path” of their user. Designers should pay close attention to all ways users can misunderstand their product, and it can fail.
Ultimately, considering the discoverability of a product by reviewing the 5 Fundamental Principles of Interaction will make it more useable and successful.
Posted 31/08/2022
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