Human Computer Interaction and Usability

1. Human Computer Interaction and Usability Class 6 LBSC 690 Information Technology

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

3. Human-Computer Communications • Humans are slow but versatile devices • 120-300 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

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

5. 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.)

6. 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.)

7. Mental Models and User Models Human Mental Models Sight Sound System Task Hands Voice Keyboard Mouse User (Software) Models Task User Display Speaker Computer

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

9. 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

10. 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

11. Agents

12. 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

13. 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

14. 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

15. 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

16. 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

17. Simulation and Virtual Reality

18. 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