Human-Computer InteractionIS 588 Spring 2007

Week 4Dr. Dania Bilal

Dr. Lorraine Normore

Overview

• Last week– Perception– Learning– Thinking and problem solving

• This week– Motor control– Collaboration and communication– Emotion

Display devices

• Commercial systems– CRT/VDT: desktop systems– LCD: laptops, PDAs

• Visibility issues– Contrast– Stable images– Resolution

• Pixel density between 72 and 96 dpi depending on the size of the monitor (contrast hi quality print 300-600 dpi)

Motor control

• Issue for input systems – Compare with sensory systems and displays

• Determining factors– Reaction time– Choice reaction time– Movement time

Reaction time

• Consider the pathway– Sensory input CNS Motor response

• “Simple reaction time” (RT)

• Choice reaction time– A function of simple RT and number of

choices

• Affected by physical state, attention, S-R compatibility, practice, familiarity

Movement time

• Two features– Duration– Accuracy

• Movement as ballistic, with correction

• Movement time, as measured by Fitts’ Law is a function of the distance to be moved and target size

Input systems

• Text entry– Key and inter-key size– Key shape and contour– Keyboard slant and contour

• Positioning, pointing and drawing devices– Separate input and output devices

• Mouse, stylus, trackball

– Integrated input and output devices• Touchscreens• Virtual reality/3D systems

Why do these things matter?

• Display design– Placement and size of controls– Task difficulty

• Interaction design and input devices– Health and safety– Universal accessibility

Activity: Thought experiments on input system alternatives

• Remote control surgery

• Cerebral palsy

• Automobile

• Simulated combat

• Office environment

Face-to-face communication

• Types– Personal space– Eye contact and gaze– Gesture and body language

• Common issues– Awareness of the other– Social status effects– Cultural differences– And conversational interactions!

Conversation and coordination

• A sequence of turn-takings between listener and speaker

• Verbal and non-verbal components• Back channels

– Convey information from listener to speaker below conversational turn-taking

– “Smooth” the turn-taking

• Use of artifacts/shared external representations

Theoretical frameworks

• Language/action framework– Winograd & Flores, 1986– Grounded in philosophy (“speech act theory”)– Analyze role & intent of communicative acts

• Distributed cognition– Hutchins, “Cognition in the wild”– Focus on interactions among people, with artefacts in

on-going behavior

• Other frameworks– Activity theory, ethnomethodology, situated action,

common ground theory

Analyzing conversations

• Uses– Way to analyze transcript– To guide decision decisions– To drive design: structure the system around

the theory

• Groupware– Computer-mediated communication– Meeting and decision support systems– Shared applications and artifacts

Computer-mediated communication

• Email and Bulletin Boards

• Structured message systems

• Informal, unstructured messaging

Meeting and decision support systems

• Video conferences

• Argumentation tools

• Meeting rooms

• Virtual collaborative environments

Shared systems

• PCs and window systems

• Work surfaces

• Editors

• Diaries/calendars

Groupware dimensionality: Time-space matrix

Same place

(co-located)

Different place

(remote)

Same time

(synchronous)

Different time

(asynchronous)

Activity

• Discuss location and time as variables for – Computer-mediated communication– Meeting and decision support systems– Shared applications and artifacts