J E N N I F E R W O N G

CHAPTER 7: USER – CENTERED DESIGN

• The point of the book was to advocate a user-centered design which is a philosophy that things should be designed with the needs & interests of the user in mind, making products that are easy to use & understand.

THE DESIGN SHOULD

1. Make it easy to determine what actions are possible at any moment.

2. Make things visible, including the conceptual model of the system, the alternative actions, & the results of actions.

3. Make it easy to evaluate the current state of the system.

4. Follow natural mappings between intentions & the required actions; between actions & the resulting effect; between the information that is visible & the interpretation of the system state.

Basically we should be able to (1) figure out what to do (2) tell what is going on

7 PRINCIPLES FOR MAKING DIFFICULT TASKS INTO SIMPLE ONES

1. Use knowledge in the world & knowledge in the head.

2. Simplify the structure of tasks.3. Make things visible: bridge the gulfs of

Execution & Evaluation.4. Get the mappings right.5. Exploit the power of constraints, both

natural & artificial.6. Design for error.7. When all else fails, standardize.

3 ASPECTS OF MENTAL MODELS

• The design model (the conceptualization the designer had in mind)• The user’s model (what the user develops to

explain the operation of the system)• And the system’s image (the system’s

appearance, operation, way it responds, manuals/instructions included with it)

• Ideally, the design model & user model are the same. The designer must ensure that the system image is consistent with & operates according to the proper conceptual model.

WAYS TO SIMPLIFY THESTRUCTURE OF TASKS

• Keep the task much the same, but provide mental aids (simple mental aids provides cues about what we should do)• Use technology to make visible what would

otherwise be invisible (improves feedback & the ability to keep control & hide stuff that is irrelevant to completing the task)• Automate, but keep the task much the same

(remove unnecessary steps of a task)• Change the nature of the task (use technology to

simplify)

MAKE THINGS VISIBLE: BRIDGE THE GULFS OF EXECUTION & EVALUATION

• Make things visible so users know what actions are possible.• Make things visible so people can see the

results of their actions.• The system should have actions that match

the users’ intentions.

GET THE MAPPINGS RIGHT

• Make sure the user can determine the relationships:

• Between intentions & possible actions• Between actions & their effects on the

system• Between actual system state & what is

perceivable by sight, sound, or feel• Between the perceived system state & the

needs, intentions, & expectations of the user

EXPLOIT THE POWER OF CONSTRAINTS, BOTH NATURAL & ARTIFICIAL

• Use constraints so the user feels as if there is only one possible thing to do – the right thing.• Ex: Ch. 4 - Lego toy motorcycle

DESIGN FOR ERROR

• Assume that any error that can be made will be made.• Make it so mistakes aren’t too critical,

undoable, etc.

MAKING THINGS DIFFICULT

• Sometimes a difficult design is good – it forces us to deliberately focus on what we’re doing (focus on it)• Good for :• dangerous equipment &

operations• Doors• Security systems

MAKING THINGS EASY TO USE

• To make something easy to use, match the number of controls to the number of functions & organize the panels according to function.• To make something look easy, minimize the

number of controls.

Remember, tools not only control WHAT we do, but HOW we do it & the way we VIEW ourselves, society & the world! Our design can change a task, a society, & the world.

SOURCES

• I created the PowerPoint.• I didn’t write the information on this PowerPoint.• I used the information from: http

://www.sharritt.com/CISHCIExam/norman.html#7• Norman, Don. "Chapter 7: The Design Challenge."

The Design Of Everyday Things. Print.