INF385P – Software Usability EngineeringI’m gonna go fast because . . .Chapter 1Good DesignNatural SignalsMappingSlide 7“First Principles”AffordanceComplex WorldPrinciples of DesignPrinciples of Design (cont’d.)Slide 13The Paradox of TechnologyChapter 2 -- Psy of Everyday ActionsModelsModels (cont’d.)BlameExplanation7 Stages of Action7 Stages (cont’d.)Slide 22Gulfs . . .DesigningDesigning (cont’d.)Chapter 3 - Knowledge in the Head and in the WorldKnowledgeBehaviorIn the worldKnowledge OF and Knowledge HOWConstraintsMemoryMemory StructureMemory Structure (cont’d.)3 Categories of things remembered3 Categories of things remembered (cont’d.)Slide 37Memory . . .RemindingIn the WorldNatural Mappings . . .Tradeoff . . .Ch. 4 -- Knowing what to doDesignConstraints - 4 ClassesPhysical ConstraintsSemantic ConstraintsCultural ConstraintsLogical ConstraintsThe Problem with DoorsThe Problem with SwitchesThe Problem with Switches (cont’d.)Visibility and FeedbackUsing Sound for VisibilityCh. 5 - To err is humanIn terms of the 7 stages of action . . .SlipsTypes of SlipsModesSlide 60MistakesThree Models of Human CognitionThird Approach -- ConnectionistTasksTasks (cont’d.)Conscious and Subconscious BehaviorConscious ThoughtDesigning for ErrorCh. 6 -- The Design ChallengeTypewriter - Case HistoryPitfallsComplexity of the Design ProcessFinally . . .Ch. 7 - UCDPrinciple 1Principle 23, 4, 56 and 7Etc.Next . . . your homeworkNow . . .Next weekR. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] – Software Usability EngineeringWeek 2 – Norman’s book and mental modelsR. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected]’m gonna go fast because . . .•It ain’t rocket science.•You’ve already read the book.•I’d rather make you scramble to keep up than bore you.•I have 80 slides I’m gonna do in 60 minutes (yeah, right!).–While I’m presenting this, see if you can characterize your good and bad designs that you’ve discovered this week in Norman’s terms.R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] 1•The PsychoPATHOLOGY of everyday things•Assumption: We blame ourselves for errors, but the real culprit is faulty design.•Assumption: There’s nothing special about computers. They have the same sorts of design problems as simpler, everyday things.R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] Design•Well designed objects . . .–are easy for the mind to understand–contain visible cues to their operation•Poorly designed objects . . .–provide no clues, or–provide false clues.R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] Signals•Natural signals lead to natural design.•A metal plate “naturally” is to be pushed.•Visible hinges “naturally” indicate attachment, and that the other side swings open. (And swings open TOWARD me?)R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected]•Mapping is a relationship between two things (e.g., between what you want to do and what appears possible).•Good design allows for a clear (visible) mapping between . . .–intended actions and–actual operations.•Now -- think of what this might mean in a web site.R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] Design•Principles of good design–the importance of visibility–appropriate clues–feedback of ones actions.•Just so you’ll know -- others have proposed OTHER principles of good design. Go check out the web site of Bruce Tognazzini:http://www.asktog.com/basics/firstPrinciples.htmlR. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected]“First Principles”“The following principles are fundamental to the design and implementation of effective interfaces, whether for traditional GUI environments or the web.”•Anticipation•Autonomy•Color Blindness•Consistency•Defaults•Efficiency of the user•Explorable Interfaces•Fitts’s Law•Human-Interface Objects•Latency Reduction•Learnability•Metaphors, Use of•Protect Users’ Work•Readability•Track State•Visible InterfacesR. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected]•Affordance is the perceived and actual properties of a thing.–Primarily those fundamental properties that determine how a thing could possibly be used.–“Affords” means, basically, “is for.”–A chair affords support, therefore affords sitting.•Affordances provide strong clues to things’ operations.•When affordances are taken advantage of, the user knows what to do just by looking.–No label, picture, or instruction (“Push”) is required.•- When simple things need pictures, labels, or instructions, the design has failed.R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] World•30,000 readily discriminable objects. How do we deal with all of them?–Partly, the way the mind works.–Partly, the information available from the appearance of objects.–Partly, the ability of the designer to:•make the operation clear, •project a good image of the operation, and •take advantage of the other things people might know.•Here is where the designer’s knowledge of the psychology of people coupled with the knowledge of how things work becomes crucial.R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] of Design•Four principles of Design for Understandability and Usability.1. Provide a good conceptual model.–A good conceptual model allows us to predict the effects of our actions.–Simply knowing the relationship between the controls and the outcomes.R. G. Bias | School of Information | SZB 562BB | Phone: 512 471 7046 | [email protected] of Design (cont’d.)2. Make things visible.3. The principle of mapping.–Natural mapping (taking advantage of physical analogies and cultural standards) leads to immediate understanding.–Move the control up, the sound gets