Class 6 LBSC 690 Information Technology Human Computer Interaction and Usability

Agenda Questions Human computer interaction Mental models and user models Input/Output/Interactivity Visualization Usability/evaluation

Human-Computer Communications Humans are slow but versatile devices – words per minute –Multiple rich analog channels Computers are fast but limited –Around 1 billion words per minute –Single digital channel for each task The computer must slow down for us and we must sacrifice fidelity for the computer

Styles of Interaction Command-based GUIs/WIMP non-WIMP / SILK Passive Pervasive

Input Devices Keyboard Pointing device (mouse, trackball,...) Joystick Touch Panel, writing tablet Speech recognition Data-glove, head tracker, eye tracker, etc. Video camera (lip-reading, gestures, etc.)

Output Devices Displays (CRT, flat panel, stereo, etc.) Speakers, headphones, etc. Printer (dot matrix, ink jet, laser, etc.) Plotters, microfiche printers, etc. Speech synthesizers Full immersion (orientation, vibration, etc.)

Mental Models and User Models Task System Mental ModelsSight Sound Hands Voice TaskUser User (Software) Models Keyboard Mouse Display Speaker Human Computer

Mental Models The expectations the person has about how things work In particular: –how the computer and its software work –the information resources

User Models What the computer knows about the user –demographics age, gender, nationality –technology capabilities network, multimedia, CPU cycles –stable individual characteristics height, languages understood, hometown, knowledge/beliefs –transitory state of the individual last book read, type of car, how hungry

Using User Models A user model is not just data but ways of using those data (e.g., making predictions about a person). Ethical and legal issues about collecting personal information Anticipating the user vs. giving the user power tools Student models

Agents

Direct Manipulation “Directly manipulate” conceptual objects –Windows file manager, Windows 95 Explorer Compare this to DOS commands –Excel Compare this to Java Often done with icons –But icon interpretation can be difficult Too small, no good metaphor, cultural differences

Language-Based Interfaces Alternative to direct manipulation –Compact, flexible representation –Can be hard to use What can be done may not be apparent Interpretation requires conceptual effort Examples –Text retrieval interfaces –Programming languages

Menu Design Conserve screen space by hiding functions –Menu appears only when selected Can be logically grouped into several levels –But by who’s logic? Recognition (menus) vs. Recall Tradeoff between breadth and depth –Too broad and direct manipulation is better –Too deep and it can become hard to find things

Information Visualization Using pictorial (spatial) relationships to show relationships in attributes Some basic visualization techniques –Lenses and filters –Context and hierarchies –Coordinated windows Example - real-estate browser

Evaluation/Usability Design interacts with usability Expert reviews Feedback from real users is helpful –Across a variety of realistic tasks –Across a realistic user sample of users Examine many aspects of the interaction –e.g., training, error messages, response time

Simulation and Virtual Reality

HCI Summary HCI design starts with user needs + abilities –Users have a wide range of both Users must understand their tools –And these tools can learn about their user! Many techniques are available –Direct manipulation, languages, menus, etc. –Choosing the right technique is important This is the central focus of LBSC 795