Human Computer Interaction: Part 2

1. Human ComputerInteraction: Part 2 Rebecca W. Boren, Ph.D. Introduction to Human Factors & Ergonomics Engineering IEE 437/547 November 7, 2011

2. In the future, Human Factors specialists will be primarily involved in designing computer hardware and software.

3. The Trouble with Computers and Software Design • Computers are relatively new tools. • They change rapidly. • Computer software is sometimes poorly designed causing a number of negative consequences.

4. User performance suffers. • Users think of computers as “difficult to use.”

5. Increased Productivity? • Between 1980 and 1989, investment in technology in the service sector increased by 116% per worker. • Productivity increased only 2.2% per worker. • Increased computer technology does not guarantee increased productivity. • Poorly designed software has been implicated in disasters and accidents.

6. Design Criteria for Usable Software • Efficiency • Accuracy • Learnability • Memorability • Satisfaction

7. Efficiency • Ability to accomplish a job with a minimum expenditure of time and effort. • The ratio of the output to the input of any system. • The production of the desired effects or results with minimum waste of time, effort, or skill.

8. Accuracy • Freedom from error. • Precision or exactness. • Capability of recovery from errors (confirmation, undo or recycle bin).

9. Learnability • Measure of the degree to which a user interface can be learned quickly and effectively. • Learning time is the typical measure. User interfaces are typically easier to learn when they are designed to be easy to use based on core human factors principles, and when they are familiar.

10. Learnability • Familiarity may come from the fact that it follows standards or that the design follows a metaphor from people's real world experience.

11. The Problem with Metaphors • Over reliance on a physical metaphor can cause users to overlook powerful capabilities available in the computer because they do not exist in the real world. • The typewriter metaphor causes 20 to 60% of novice errors on a word processor.

12. Memorability • Easily remembered. • Concept of memorability is that a user can leave a program and, when he or she returns to it, remember how to do things in it.

13. Satisfaction • Confident acceptance of something as satisfactory, dependable, true, etc. • Is it user-friendly?

14. Software Design Cycle • Similar to the design process described in chapter 3. • Three major phases • Understand the User • Design • Evaluate • The design process is iterative.

15. Understand the User The first step in the design cycle. User Needs

16. Knowledge Level of the User • Novice or first-time users • Knowledgeable intermittent users • Expert frequent users

17. Novice or first-time users • Focus on ease of learning and low reliance on memory. • Vocabulary is highly restricted. • Tasks are easy to carry out. • Error messages are constructive and specific. • Rely on GUI interfaces.

18. Novice or first-time users - Examples • Airport check-in. • ATM bank machines. • Any “walk up and use” systems.

19. Knowledgeable intermittent users • Reducing the load on memory is critical for intermittent users. • One size (interface design) does not fit all. • Offer several ways of doing tasks. • Pull-down menus • Keyboard shortcuts • Clicking on icons

20. Expert frequent users: • The interface should provide information and input mechanisms that map onto the task. • If the task is complex, then learning will probably take a period of time. • For life-critical systems or hazardous equipment, designers may perceive that error rates are by far the most important of the five criteria.

21. Understand System and Users Characteristics • Software can perform simple tasks such as arithmetic or complex functions, such as control of a chemical processing plant. • Functionality refers to the number and complexity of things the computer can do.

22. Creeping Featurism • Microsoft WORD has over 1000 commands. • In 1992, it had 311. • A few of the commands are important to any one user. • The rest complicate the system.

23. Cognitive - Implications for Design • Minimize burden on memory • Flashing elements tax sensory memory • Use lists of choices rather than relying on memory • Recognition is preferred to recall • Provide cues

24. Cognitive - Implications for Design • Mental Models include our understanding of • System components • How the system works • How to use it • Mental models generate a set of expectancies about how a system works • Conform to the conventional

25. Support Mental Models • Make invisible parts and processes visible to the user. • Example: clicking an icon that depicts a file and dragging it to a trash can. • Provide feedback • Consistency builds conceptual models

26. Design is an Iterative Process User Needs Interface Design Refine Evaluation

27. Evaluate the Interface • Usability Heuristics • Chapters 3 (Design), 8 (Displays), and 9 (Controls). • Two to four experts should evaluate separately. • Least expensive method of evaluation.

28. Usability Tests • Prototypes with storyboards, index cards, sticky notes, paper and pen drawings • The designs are evaluated and refined before being programmed.

29. Usability Testing – the Lab

30. Usability Testing – the Users Graph shows that 80% of usability problems can be determined by about 4 to 5 users. Fifteen users can find 100% of the problems.

31. Usability Testing • Best to use 5-6 people to identify problems. • Make changes (refine the interface). • The maximum benefit/cost ratio occurs with approximately 5 evaluation and redesign cycles. • Even as many as 60 cycles can produce a benefit/cost ratio greater than one. • Have programmers observe the users.

32. Dr. Boren’s Usability Testing Laboratory Subject is seated in the subject testing area. Cards are used to present problems. The subject tries to locate the target by pressing keys on the telephone key pad. This telephone is connected to the simulator which offers options in a human voice. The simulator keeps track of the key presses, response time, and type of errors. The simulator is pictured to the left. The subject is on the other side of the back screen. The simulator is a DOS-based software program with a hardware card. The script is digitally recorded human voice so it has a natural quality. The computer keeps track of the response time, key presses, number and type of errors.

33. We have covered personal computers and the Internet. The future of computing is just around the corner. What will it bring?

34. Ubiquitous Computing • What is it?

35. Physicist and futurist Michio Kaku describes Ubiquitous Computing as "an invisible intelligent network hidden in our walls, our furniture, even our clothing”.

36. The UP wrist device tracks our health information.

37. The Internet makes Ubiquitous Computing possible.

39. Era 1: Mainframe Computers

40. Era 2: Personal Computers Commodore 64 IBM XT

41. APPS

42. Wearable Computers The M-Dress is an elegant silk jersey dress that is also a functional soft electronics mobile phone. The M-Dress accepts a standard SIM card and allows the wearer to receive and make calls without carrying a cellular phone in their pocket or purse. The wearer inserts their usual SIM card in the small slot underneath the label and the dress is ready to be used, having the same phone number as your usual phone. When the dress rings, the simple gesture of bringing your hand to the ear will allow the sensor to open the call and when done talking the gesture of releasing the hand downwards will close the call. CuteCircuit introduced special gesture recognition software to allow the M-Dress to work in an easy and intuitive way.

43. Japanese Engineers Build GPS Into Glasses

44. Sixth Sense

45. Other Issues Related to Human-Computer Interaction

46. Users don’t care about the web design. • They just want to get things done and get out • People usually spend no more than 2–3 minutes on a website • The average page visit lasts about 30 seconds. • The more experienced the users are, the less time they allocate to each Web page.

47. How to be Smart about Email. • Email trust • Identifiable “From” line • Explicit subject line • Be brief • Avoid • Opening attachments unless you are certain who sent them. • Do not reply by clicking on an embedded link.

48. Email • Banks or credit card companies • A logo can easily be copied into an email to make the email look legitimate. • Do not send emails asking for information, such as account number and password. • Do not be intimidated by threats to close your account if you do not immediately reply. • Consider having multiple email addresses. • Be suspicious!

49. E-merchants • Does the website have all the elements to lend credibility? • Consider using Google checkout or PayPal. • Use bizrate.com to investigate the online company’s reputation. • Do not click on pop-up ads. Use a pop-up blocker. • Consumer Report sponsors WebWatch.

50. My Favorite Websites • Amazon.com • eBay.com • Zappos.com • Improvementdirect.com/