Human computer interaction

1. Human computer interaction EurIngRoger Fairhead BSc CEng MIET MAPM MICG With thanks to:

2. Content • What is the human-computer interface? • The human • The computer • Interaction • User interfaces • Interface design

3. What is HCI? HCI is the study of people, computer technology and the ways these influence each other HCI adds design principles for computer screens and the human computer dialogue

4. Goals of HCI The goals of HCI are to produce systems which are: • usable • safe • functional • effective • efficient

5. Why is HCI important? A lack of a good user interface will often mean that software is often difficult and tedious to use. A good interface will help to achieve • higher productivity • increased safety

6. Who contributes to HCI? Research into HCI combines expertise from many areas • computer science • psychology (cognitive and social) • ergonomics • linguistics • artificial intelligence • engineering and design

7. The human (1) Input provides a human with information that can be used to comprehend its surroundings Output allows a human to interact with and influence its surroundings

8. The human (2) Memory is a human with information that can be used to comprehend its surroundings Three types of human memory • sensory • short-term • long-term

9. sensory short term long term The human (3) Input Attention Recall Rehearsal

10. The computer Input provides the computer with information that its program needs to ‘solve’ a problem Output allows the computer to communicate the results of its processing to the user

11. Interaction Interaction can be achieved using a number of styles • command entry • menus and navigation • forms and spreadsheets • question and answer dialogue • natural language dialogue • WIMP • direct manipulation

12. User interfaces An interface can refer to the physical connection between two pieces of hardware. A user interface refers to: the way people (users) interact with a computer: how they tell it what to do, and how the computer communicates a response or result

13. Interfaces types (1) • Command line interface • type in commands • need to know syntax and command names • Natural language processing • type in commands in user’s natural format • sentences, abbreviations used

14. Interfaces types (2) • Menu-driven interface • learning time reduced • option is chosen and computer carries out appropriate sequence of commands • Graphical user interface (GUI) • command/menu approaches are text based • GUIs use icons as well as text • pointing device used

15. Interface design (1) Interface design is not independent of program design. Need a model of the user, which requires understanding of: • types of users • user’s requirements • user’s level of ability

16. Interface design (2) Considered along with the model of the user: • screen design • controls • user guidance • error messages • response time

17. Usability Three categories of principles to determine usability of an interface • learnability • flexibility • robustness

18. Web Design Principles (WAI) • Accessibility The Web Accessibility Initiative (WAI) develops strategies, guidelines, and resources to help make the Web accessible to people with disabilities

19. Web Design Principles (WAI) The power of the Web is in its universality.Access by everyone regardless of disability is an essential aspect. Tim Berners-Lee, W3C Director and inventor of the World Wide Web

20. Web Design - Accessibility The needs that Web accessibility aims to address include: • Visual • Motor/Mobility • Auditory • Seizures • Cognitive/Intellectual http://en.wikipedia.org/wiki/Web_accessibility

21. Web Design - Accessibility • Visual impairments including blindness, various common types of low vision and poor eyesight, various types of color blindness;

22. Web Design - Accessibility • Motor/Mobility: e.g. difficulty or inability to use the hands, including tremors, muscle slowness, loss of fine muscle control, etc., due to conditions such as Parkinson's Disease, muscular dystrophy, cerebral palsy, stroke;

23. Web Design - Accessibility • Auditory: Deafness or hearing impairments, including individuals who are hard of hearing;

24. Web Design - Accessibility • Seizures: Photoepileptic seizures caused by visual strobe or flashing effects.

25. Web Design - Accessibility • Cognitive/Intellectual: Developmental disabilities, learning disabilities (dyslexia, dyscalculia, etc.), and cognitive disabilities of various origins, affecting memory, attention, developmental "maturity," problem-solving and logic skills, etc.;

26. Principles of effective Web design • Don’t make users think • Don’t squander users’ patience • Manage to focus users’ attention • Strive for feature exposure • Make use of effective writing http://www.smashingmagazine.com/2008/01/31/10-principles-of-effective-web-design/

27. Principles of effective Web design • Strive for simplicity • Don’t be afraid of the white space • Communicate effectively with a “visible language” • Conventions are our friends • Test early, test often http://www.smashingmagazine.com/2008/01/31/10-principles-of-effective-web-design/

28. Some links • Web page accessibility checker • http://www.webpagesthatsuck.com/ • http://www.rnib.org.uk/professionals/webaccessibility/Pages/web_accessibility.aspx