REQUIRMENTS GATHERING: knowledge of user interface and design

Contents: 1.Introduction: The two types of knowledge needed for user interface design 2.Four psychological principles 3.Three principles from experience: Visibility, affordance, and feedback 4.Design principles and design rules: knowledge for user interface design

1 - Introduction: The two types of knowledge needed for user interface design  “Design principles” are abstract, high- level guidelines – difficult to apply  “Design rules” are low-level, highly specific instructions

2 - Four psychological principles  Users see what they expect to see  Example: OK vs. Cancel  Example:  The principle of consistency  The principle of exploiting prior knowledge

2 - Four psychological principles  Users have difficulty focusing on more than one activity at a time  Multitasking  Cocktail party phenomenon  The principle of perceptual organization  The principle of importance

2 - Four psychological principles  It is easier to perceive a structured layout  The law of proximity - we group things that are close together  The law of similarity - shape, color, or format  The law of closure - we tend to fill in the gaps  The law of continuity - we look for patterns  The law of symmetry - we look for symmetrical borders  Figure-ground segregation

2 - Four psychological principles  It is easier to recognize something than to recall it  Example: grocery list  Knowledge in the head and in the world  Principle of recognition

3 - Three Principles From Experience: Visibility, Affordance, and Feedback  The principle of visibility: it should be obvious what a control is used for

3 - Three Principles From Experience: Visibility, Affordance, and Feedback  The principle of affordance: it should be obvious how a control is used

3 - Three Principles From Experience: Visibility, Affordance, and Feedback  The principle of feedback: it should be obvious when a control has been used

4 - Design Principles and Design Rules: Knowledge for User Interface Design  Design principles  Visibility, affordance, feedback  Design rules  Exercise 5.3 – look for standardization in the Microsoft Office XP software suite  Commercial style guides

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