Human-Computer Interaction IS 588 Spring 2007 Week 4 Dr. 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 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 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