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Ch. 3: InteractionCh. 3: Interaction

Introduction – 3.1 (Reading Introduction – 3.1 (Reading Assignment – RA)Assignment – RA)

Models – 3.2, 3.3 (RA)Models – 3.2, 3.3 (RA) Ergonomics or Human Factors – 3.4 Ergonomics or Human Factors – 3.4

(RA)(RA) Interaction Styles – 3.5,3.6,3.7,3.8Interaction Styles – 3.5,3.6,3.7,3.8 Context – 3.9 (RA)Context – 3.9 (RA) Conclusion – 3.10 (RA)Conclusion – 3.10 (RA)

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Interaction ModelsInteraction Models Why use modelsWhy use models

Models and frameworks provide a Models and frameworks provide a theoretical basis for design, analysis and theoretical basis for design, analysis and evaluationevaluation

We will discuss two modelsWe will discuss two models

Some terminologySome terminology Domain, tasks, goals, intentions, actionsDomain, tasks, goals, intentions, actions System and user: state and languageSystem and user: state and language

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Norman’s ModelNorman’s Model Execution-evaluation cycleExecution-evaluation cycle

ExecutionExecution Establishing a goalEstablishing a goal Formulating intentionsFormulating intentions Specifying actionsSpecifying actions Executing actionsExecuting actions

EvaluationEvaluation Perceiving the system statePerceiving the system state Interpreting the system stateInterpreting the system state Evaluating the system stateEvaluating the system state

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Two GulfsTwo Gulfs Gulf of executionGulf of execution

Difference between actions formulated by the user Difference between actions formulated by the user and actions allowed by the system. The lesser this and actions allowed by the system. The lesser this difference, the more effective the interaction.difference, the more effective the interaction.

Gulf of evaluationGulf of evaluation Difference between user’s expectation of state Difference between user’s expectation of state

changes and the system’s presentation of its changes and the system’s presentation of its changed state. The more effort user has to expend changed state. The more effort user has to expend to interpret this presentation, the less effective to interpret this presentation, the less effective the interaction.the interaction.

Very important when designing error messages.Very important when designing error messages.

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Good DesignGood Design

Minimize both gulfsMinimize both gulfs

Thinking assignment: come up with Thinking assignment: come up with examples of each gulf from any examples of each gulf from any interactive system that you are interactive system that you are familiar with, and explain the gulfsfamiliar with, and explain the gulfs

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The Interaction The Interaction FrameworkFramework

S U

I

OPresentation Observation

ArticulationPerformance

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The Interaction The Interaction FrameworkFramework

Interaction requires translation between the Interaction requires translation between the 4 languages of user, input, system and 4 languages of user, input, system and outputoutput Language of thought: intentions, comprehensionLanguage of thought: intentions, comprehension System’s interface command languageSystem’s interface command language System’s underlying computationsSystem’s underlying computations System’s interface presentation languageSystem’s interface presentation language Articulation: intentions > commandsArticulation: intentions > commands Performance: syntax > executionPerformance: syntax > execution Presentation: execution > presentationPresentation: execution > presentation Observation: presentation > comprehensionObservation: presentation > comprehension

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The Interaction The Interaction FrameworkFramework

ArticulationArticulation Larger the gulf of execution, the more Larger the gulf of execution, the more

difficulty user will face in translating difficulty user will face in translating intentions to actionsintentions to actions

Conversely, if articulation is easy, gulf of Conversely, if articulation is easy, gulf of execution will be smallexecution will be small

Example: GUIs vs. Command-line Example: GUIs vs. Command-line interfaces for file operationsinterfaces for file operations

PerformancePerformance A system design issue: implementation costA system design issue: implementation cost Example: immersive VR vs. Command-lineExample: immersive VR vs. Command-line

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The Interaction The Interaction FrameworkFramework

PresentationPresentation An interface design issue: interface must An interface design issue: interface must

be sufficiently expressive to show all be sufficiently expressive to show all relevant system changesrelevant system changes

Important in minimizing the gulf of Important in minimizing the gulf of evaluationevaluation

ObservationObservation Problems: incompleteness of the Problems: incompleteness of the

presentation and misinterpretation by userpresentation and misinterpretation by user Examples: stove controls, progress metersExamples: stove controls, progress meters

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The Interaction The Interaction FrameworkFramework

Interaction difficulties arise when Interaction difficulties arise when presentation, observation and/or articulation presentation, observation and/or articulation are incomplete or difficult to accomplish.are incomplete or difficult to accomplish.

System inefficiencies arise when performance System inefficiencies arise when performance and presentation are poorly designed.and presentation are poorly designed.

Thinking assignments:Thinking assignments: Come up with examples of articulation and Come up with examples of articulation and

observation problems from any interactive system observation problems from any interactive system that you are familiar with.that you are familiar with.

Understand how these two models are related. Understand how these two models are related.

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Human FactorsHuman Factors Study of the physical characteristics of interactionStudy of the physical characteristics of interaction Issues:Issues:

Physical layout of controls and displaysPhysical layout of controls and displays Design of work environmentDesign of work environment Health issuesHealth issues Aspects of presentations: color, sound etcAspects of presentations: color, sound etc

Reading assignment: 3.4, especially the design Reading assignment: 3.4, especially the design focus, p.112focus, p.112

If you are interested in pursuing a HF topic for the If you are interested in pursuing a HF topic for the report/presentation project, see proceedings of the report/presentation project, see proceedings of the annual meetings of human factors and ergonomics annual meetings of human factors and ergonomics society and the journal Human Factors.society and the journal Human Factors.

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Next TopicNext Topic Interaction Objects & StylesInteraction Objects & Styles Read 3.5 and 3.6 from the text Read 3.5 and 3.6 from the text

AND AND All of Ch. 3 in Reference All of Ch. 3 in Reference