1. Part 1: The Psychopathology of Everyday Things
Unit 3
The Design of Everyday Things
Part 1: The Psychopathology of Everyday Things

2. Do you need an Engineering Degree to Figure this out?
Well-designed objects
Are easy to interpret
Contain visible clues to their operation
Poorly-designed objects
Difficult and frustrating to use
Provide no clues, or sometimes false clues
Poor design Predominates

3. The Frustration of Everyday Things
Visibility problems:
No visual operational cues
“Norman doors”
Inability to see cues during operation
No visual outcome of the operation
Too many visual cues (clutter and confusion)
Norman quote: “It is frequently a lack of visibility that makes so many computer-controlled devices so difficult to operate. And it is an excess of visibility that makes many types of modern gadget ridden equipment so intimidating.”

4. Push? Or Pull?

5. How about now?

6. Major Areas of Design (Norman, p. 5)
Industrial Design: The professional service of creating and developing concepts and specifications that optimize the function, value, and appearance of products and systems for the mutual benefit of both users and manufacturer.
Interaction Design: The focus is on how people interact with technology. The goal is go enhance people’s understanding of what can be done, what is happening, and what has just occurred. Interaction design draws on principles of psychology, design, art, and emotion to ensure a positive, enjoyable experience.
Experience Design: The practice of designing products, processes, services, events, and environments with a focus placed on the quality and enjoyment of the total experience.

7. Human-Machine Interaction: Why are there so many problems?
Limitations of technology
Self-imposed restrictions on designers (cost!)
Lack of understanding of the design principles necessary for effective human-machine interaction.
Most design is done by engineers who are experts in technology, but not in their understanding of people.
Engineers are taught to think logically—when instead we should accept human behavior the way it is, not the way we wish it to be (e.g., ”… if only people would read the instructions ... Everything would be alright.”)
Three Mile Island plant’s control rooms were so poorly designed that error was inevitable; design was at fault, not the operators (Norman, p. 7)

8. Human-Centered Design
Approach that puts human needs, capabilities, limitations and behavior first, then designs to accommodate these.
Requires good communication, especially from machine to person, indicating possible actions, what’s happening, and what’s about to happen.
Designers should focus on cases where things go wrong (concept of reasonably foreseeable use/misuse).
When this happens, but the machine highlights the problems, then the person understands the issue, takes the proper actions, and the problem is solved.
Steps in the process: Observe, rapid prototype, test, iterate …

9. Human-Centered Design Principles
Discoverability: Is it possible to 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?
Relevant components must be visible and must communicate the correct message.
With doors, the designer must provide signals that naturally indicate where to push (e.g., vertical panel; make supporting pillars visible).
With complex devices, discoverability and understanding require manuals or personal instruction.
Products must satisfy engineering, manufacturing and ergonomic requirements, but also the aesthetics of form and the quality of interaction.

10. Fundamental Principles of Interaction
When interacting with a product, we need to figure out how to work it (discoverability).
Discoverability relies on appropriate application of five psychological concepts
Affordances
Signifiers
Constraints (we’ll deal with this a bit later).
Mappings
Feedback

11. Affordances
Refers to the relationship between the properties of an object and the capabilities of the agent (person) that determine just how the object could possibly be used. Affordances are relationships, not properties.
They are clues to the operation of things.
A chair affords (“is for”) sitting.
A flat plate mounted on a door affords pushing.
Slots are for inserting things into; knobs for turning, pushing and pulling.
Glass affords seeing through and support, but not the passage of air or most physical objects.
To be effective, affordances (and anti-affordances) have to be discoverable (perceivable).

12. Signifiers (are not Affordances)
Whereas affordances determine what actions are possible, signifiers communicate where the action should take place.
A signifier is any mark or sound, any perceivable indicator that communicates appropriate behavior to a person. Signifiers communicate the purpose, structure, and operation of a device to the people who use it.
The word PUSH on a door.
A visible trail through a field or over a snow-covered terrain to determine the best path.
Presence of absence of people at a train station to determine whether we missed the train.
A flag is an indicator of wind direction.

13. The Sink That Would Not Drain: Where Signifiers Fail
I washed my hands in my hotel sink in London, but then, as shown in Photo A, was left with the question of how to empty the sink of the dirty water. I searched all over for a control: none. I tried prying open the sink stopper with a spoon (Photo B): failure. I finally left my hotel room and went to the front desk to ask for instructions (Yes, I actually did). “Push down on the stopper,” I was told. Yes, it worked (Photos C and D). But how was anyone to ever discover this? And why should I have to put my clean hands back into the dirty water to empty the sink? The problem here is not just the lack of signifier, it is the faulty decision to produce a stopper that requires people to dirty their clean hands to use it (Norman, p. 17)

14. Affordances and Signifiers: A Summary
Affordances are the possible interactions between people and the environment. Some affordances are perceivable, others are not.
Perceived affordances often act as signifiers, but they can be ambiguous (and even misleading).
Signifiers signal things, in particular what actions are possible and how they should be done. Signifiers must be perceivable, else they fail to function.
In design, signifiers are more important than affordances because they communicate how to use the design.
A signifier can be words, a graphical illustration, or a device whose perceived affordances are unambiguous.

15. Mapping
Term indicating the relationship between elements of two sets of things.
Example: the “mapping” between the lighting in a classroom and the rows of light switches on the wall at the front of the room.
Mapping is important when considering the design and layout of controls and displays.
In steering a car, rotating the steering wheel clockwise causes the car to turn right. (In early cars other devices were used: tillers, handlebars, reins).
The relationship between a control and its results is easiest to learn when there is an understandable mapping between the controls, the actions, and the intended result.

16. Natural Mapping
Taking advantage of spatial analogies leads to immediate understanding
Examples: to move an object up, move the control up; arrange a bank of light switches in the same pattern as the lights.
Gestalt principles can be very helpful.
Related controls should be grouped together
Controls should be close to the item being controlled

17. Natural Mapping: Car seat adjustment control
The control is in the shape of the seat itself: the mapping is straightforward. To move the front edge of the seat higher, lift upon the front part of the button. To make the seat back recline, move the button back. (Norman, p. 22).

18. Feedback (communicating the results of an action)
Even simple tasks (e.g., picking up a glass) require feedback to aim the hand, grasp the glass, and lift it.
A misplaced hand will spill the drink, too hard a grip will break the glass, too weak a grip will allow it to fall.
Some requirements. Feedback must be:
Immediate
Informative
Not too much, but not too little.
Properly designed
Unobtrusive/non-annoying
Prioritized
Consistent with human cognitive capabilities/limitations

19. Conceptual Models
A conceptual model is an explanation, usually simplified, of how something works.
Example: The files, folders and icons displayed on a computer screen help people create the conceptual model of documents and folders inside the computer or of applications residing on the screen.
Mental models: conceptual models in people’s minds that represent their understanding of how things work.
People may hold different mental models of the same item.
A person may hold multiple models of the same item that deal with different aspects of its operation.
Valuable for predicting how things will behave, and figuring out what to do when things don’t go as planned. Without them, we rely on trial and error.

20. Inadequate Conceptual Models
Example: A common two-compartment refrigerator: fresh foods and freezer.
Two controls; one for the freezer and one for the refrigerator fresh food (see next slide).
What’s the problem? The two controls are not independent (see the following slide).
The controls suggest a false conceptual model (see Figure 1.10A).
There is actually only one thermostat and only one cooling mechanism (see 1.10B).
One control adjusts the thermostat setting, the other the relative proportion of cold air sent to each of the two compartments of the refrigerator.

23. System Image: Pity the poor design engineer!
Manufacturers want something that can be produced economically.
Stores want something that will be attractive to customers.
The purchasers focus on price and appearance, as well as functionality and usability.
Repair Service want the device to be easy to take apart, diagnose, and service.
The Design Challenge: Design requires the cooperative efforts of multiple disciplines. The number of different disciplines required to produce a successful product is staggering!

24. The 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. c

25. Key Concepts
Affordance: refers to the relationship between the properties of an object and the capabilities of the agent (person) that determine just how the object could possibly be used. Affordances are relationships, not properties
Constraints: limit choices, and restrict undesired operations
Conceptual Models: mental idea of the device and its operation
Discoverability: Is it possible to figure out what actions are possible and where and how to perform them.
Feedback: sending back to the user information about what action has actually been done and what result has been accomplished.
Human Centered Design: The approach that puts human needs, capabilities, limitations and behavior first, then designs to accommodate these. It requires good communication, especially from machine to person, indicating possible actions, what’s happening, and what’s about to happen.

26. Key Concepts
Mapping: The relationship between elements of two sets of things (e.g., the relationship between a control and its results is easiest to learn when there is an understandable mapping between the controls, the actions, and the intended result).
Natural signals: allow the design to be interpreted without any need to be conscious of them.
Signifier: any mark or sound, any perceivable indicator that communicates appropriate behavior to a person. Signifiers communicate the purpose, structure, and operation of a device to the people who use it.
System image: results from the physical structure that has been built (including documentation, instructions, and labels).
Understanding: What does it all mean? How is the product supposed to be used? What do all the different controls and settings mean?
User’s model: the mental model developed through interaction with the system.