Notes

Outline

Preliminaries CS5540 HCI by Rich Riesenfeld 27 Aug 2001

What is the HCI Issue? Is the interface the concern? Is the matter of accomplishing some work, some set of tasks, the issue? Are we emphasizing the wrong thing?

Doing Work View Computer is simply the medium Interface focus can distracting Need to understand the characteristics of the computer/interface Need to understand the user and human behavior

What do we already know as good interface principles? Interesting, pleasing, attractive Effective to use Intuitive Alan Kay’s children Organized, hierarchically structured

What do we know as good interface principles?  (cont) Help functions, Search, etc Consistent form (aka design integrity) Automatic assistance Completions Spelling

What do we know as good interface principles?  (cont) Lead the user Prompts Indicate nature of any problem Specific communication

What do we know as good interface principles?  (cont) Meaningful error msgs Don’t send you elsewhere Give useful number Area of inadequate traditions

What do we know as good interface principles?  (cont) Multiple paths to a function Keep it simple Gain user’s trust. Bottom up is probably most acceptable Simple tasks should be simple

Our history hurts us… Developed some poor communications habits Resources were scare Other priorities, historically

Our history hurts us… Early computing: “Compiler error” Systems error: EM732851 Small road signs Confusing directions

Our history hurts us… Early computing: “Compiler error” Systems error: EM732851 Small road signs Confusing directions

Our history hurts us…

Our history hurts us… Korean Airlines Flight 007, with its 269 passengers and crew, had strayed off course over a Soviet missile installation in the far Pacific and was shot out of the sky Pilot had to key in the numerical coordinates by hand corresponding to flight plan!

Our history hurts us… How about an automatic download? How about picking from a menu? How about symbolic names

Our history hurts us… Audi Cars took off from a standing position Driver error, claimed Audi… Whose error was it?

Our history hurts us… NASA Lost a major mission over mistake in units One group worked in SI units One group worked in English units Combining the results let to bad numbers

Culture

Culture

Critical Interfaces Nuclear power plants Interface had better be clear Airplane cockpit controls Computer graphics has simplified

Effect of function: Examples Water faucets in a sink Manual gear shift Chords on a guitar Interface is dictated (confused) by needed effect

Other historical examples Books are essentially linear Stories or communications needs might not be Hyper-text breaks the bound with linear text

HCI is a “design problem” Design is old subject Well studied topic Apply design methodologies to build better interfaces We will look at this viewpoint

Important operational issues Reliability Availability Security Data integrity

Important Basics Standardization across app’s Apple first did this Integration of packages and tools Unix does this well Consistency in actions, design style, terms, menus, color, fonts, etc, etc Portability across platforms Less true than advertised (Quicken, eg)

Palm Desktop Calendar

Palm Handheld Calendar

Important stats Time to learn Speed of performance How much coffee can one drink? Rate of errors by users “The user is always right!”

Important stats (cont) Retention over time Do you have to start at square 1? Subjective satisfaction Do you like it (no explanation needed!) Can you develop an attachment for it?

Dramatically different needs Life-critical systems Air traffic; nuclear reactors; cockpits; power utilities; emergency, military, medical, operations Commercial Banks, resv’s, inventory, point-of-sales (Hertz, Fedex,..), registration,..

Different needs (cont) Home, office, entertainment Obvious needs Exploratory, creative, cooperative systems Bad interface (computer or otherwise) can destroy the process

Human Diversity Ergonomics, anthropometry Anyone here “average?” Physical consideration Height, stiffness, posture, shapeness, size of working area IPD, headsize, light sensitivity

Cognitive processes (from Engineering Abstracts) Short-term memory Long-term memory (Over 40 users…) Problem solving Decision making

Cognitive processes  (from Engineering Abstracts) (cont) Attention and set (scope of concern) ADHD, Ritalin population (5%)… Search and scanning Time perception

Perceptual and Motor Performance Factors (ibid) Arousal and vigilance Fatigue Perceptual (mental) load Knowledge of results Monotony and boredom

Perceptual and Motor Performance Factors (ibid) Sensory deprivation Sleep deprivation Anxiety and fear Isolation

Perceptual and Motor Performance Factors (ibid) Aging Drugs and alcohol Circadian rhythms

Gender Differences Males and Females are different! Much has been observed Firm principles are scarce

Carl Jung’s Personality differences Extrovert v Introvert Extroverts like action Sensing v Intuition Routine v discovering new

Carl Jung’s Personality differences (cont) Perceptive v judging New situations v planning Feeling v thinking Sensitive v logical

Recent study result … Multi-tasking does not work. Ergo, one should not: Drive a car Talk on a mobile phone Q: Is driving a car a single task??

Cultural and International Diversity Characters, numerals, special characters, diacriticals Left-to-right v right-to-left v vertical and reading Date and time formats Numeric and currency formats

Cultural and International Diversity (cont) Weights and measures Telephones and addresses Names and titles Mr., Ms., Mme, M., Dr. SSNs, national Ids, Capitalization and punctuation

Cultural and International Diversity (cont) Sorting sequences Icons, buttons, colors Pluralization, grammar, spelling Etiquette, policies, tone, formality, metaphors.

Users with Disabilities Can truly open doors Man with ALS who uses head to type Doing it well requires good client model Designer challenges

Evaluating interfaces Understanding of a practical problem Lucid statement of a testable hypothesis Manipulation of small number of independent variables Measurement of specific dependent variables

Evaluating interfaces (cont) Careful selection and assignment of subjects Control for bias in subjects, procedures, and materials Application of statistical tests Interpretation of results, refinement of theory, and guidance for experimenters

Possible research directions Reduced anxiety of computers Graceful evolution of systems Specification and implementation of interaction Direct manipulation

Possible research directions (cont) Input devices Online assistance Information exploration

End of Chapter 1