Human-Computer Interaction

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					Human-Computer Interaction
Introduction to HCI

Alexiei Dingli

What is HCI?

   The study of how people interact with
  computers and to what extent computers
   are or are not developed for successful
       interaction with human beings.

What is HCI?

  “Human-computer interaction is a discipline
   concerned with the design, evaluation and
   implementation of interactive computing
 systems for human use and with the study of
      major phenomena surrounding them”

      (ACM SIGCHI definition of HCI).

Creating usable systems (1)

• HCI investigates interaction between
  • Human (1 user, a group, sequence of users)
  • Computer (any computer big or small, process
    control, embedded, etc)

• used to perform various tasks

• in particular environments.

Creating usable systems (2)
• The human factors …

  • different users
  • different conceptions or mental models about
    their interactions
  • different ways of learning, keeping knowledge
    and skills
  • cultural and national differences
  • user preferences change as they gradually
    master new interfaces

Creating usable systems (3)
• The computer factor …

  • different devices
     • Smart phones, Touch Screen Kiosks, …
  • different capabilities and limitations
     • Computing power, Input/output devices, …
  • different operating systems
  • user interface technology is changing rapidly
  • it offers new interaction possibilities to which
    previous research findings may not apply
     • Visual, Tactile, Gesture based, …
Creating usable systems (4)
• What about the interaction?

  • Communication between user and computer

  • Direct interaction
     • Dialogue with feedback
     • Control throughout performance of the task

  • Indirect interaction
     • Batch processing
     • Intelligent sensors controlling the environment

Creating usable systems (5)

•    It aims to achieve

    1.   Usability (Useful, Usable, Used)
    2.   Safe
    3.   Effective
    4.   Efficient
    5.   Enjoyable system

Creating usable systems (6)
•   User compatibility      •   WYSIWYG
•   Product compatibility   •   Flexibility
•   Task compatibility      •   Responsiveness
•   Work flow               •   Invisible
    compatibility               Technology
•   Consistency             •   Robustness
•   Familiarity             •   Protection
•   Simplicity              •   Ease of Learning
•   Control                     and Use

Creating usable systems (7)
•   HCI focuses on user needs by assessing
    interface design & implementation
    according to usability criteria.

•   Makes use of new, novel techniques &

•   It applies usability design principles to
    achieve more productive & usable systems
    and more satisfied users.
Creating usable systems (8)
• EC Directive 90/270/EEC

• Requires employers to ensure the following
  when designing, selecting, commissioning or
  modifying software:

  • suitable for the task
  • easy to use
  • where appropriate, adaptable to user’s knowledge
    & experiences

Creating usable systems (9)
 • provides feedback on performance
 • displays information in a format & at a pace that is
   adapted to the user
 • It must conform to the principles of software
 •   (Ergonomics is the science that deals with the interaction between
     people/work/environment/psychology. It considers the functions of the human body in the
     design of tools, equipment, etc.)

 • Designers & employers can no longer afford to
   ignore the user!!

Question …
• Have you ever used a system that exhibit good
  HCI with the users?
• Give a few examples …

• What systems have you used that exhibit bad
  HCI with the users?
• Name a few … and why do you think they were

Historical basis of HCI (1)
 • Second World War …
   • Study of interaction between
     humans & machines in order to
     produce more effective weapons
     (Bletchley Park, Enigma,

 • Ergonomic Research Society
   formed (1949)

 • Research in Man-Machine
   Interaction began to spread
Historical basis of HCI (2)

Historical basis of HCI (3)

Historical basis of HCI (4)

Basic Interaction (1)
• Graphical Objects
  • 1963 (MIT)
    • Graphical Objects manipulated by a pointing device (light
    • Objects could be selected, moved, resized, etc.
  • 1966 (Imperial College, London)
    • Icons, Gesture Recognition, Dynamic Menus, etc.
  • 1970 (XEROX PARC)
    • Object selection and manipulation

Basic Interaction (2)
• Mouse
  • 1965 (Stanford Research Lab [SRI])
    • Created to be a cheap replacement for light pens
  • 1970
    • Adopted at Xerox PARC

  • First appeared commercially as part of
    • The Xerox Star (1981),
    • The Apple Lisa (1982),
    • The Apple Macintosh (1984).

Basic Interaction (3)
• Windows
  • 1968 (Stanford Research Lab [SRI])
  • 1969 - 1974 (Xerox PARC)
     • Smalltalk System
  • 1974 (MIT)
     • EMACS Text Editor
  • 1981 (Xerox PARC)
     • The Cedar Window Manager
  • 1981 Xerox Star
  • 1982 Apple Lisa
  • 1983 (Carnegie Mellon University funded by IBM))
     • Andrew window manager
  • 1984 Apple Macintosh

  • The early versions of the Star and Microsoft
    Windows were tiled, but eventually they supported
    overlapping windows like the Lisa and Macintosh.

Applications (1)
• Drawing programs
  • uses a mouse for graphics (1965)
  • uses a tablet (1971)
  • handling of lines and curves (1975)
• Text Editing
  • first word processor with automatic word wrap, search &
    replace, user-definable macros, scrolling text, & commands
    to move, copy, and delete characters, words, or blocks of
    text (1962)
  • screen editing & formatting of arbitrary-sized strings with a
    lightpen (1967)
  • mouse-based editing (1968)
  • first WYSIWYG editor-formatter (1974)
Applications (2)
• Spreadsheets
  • initial spreadsheet was VisiCalc (1977-8) for the Apple II
• HyperText
  • the idea where documents are linked to related documents
  • Ted Nelson coined the term "hypertext" (1965)
  • NLS system was one of the first on-line journals, and it
    included full linking of articles (1970)
  • HyperCard from Apple (1988) significantly helped to bring
    the idea to a wide audience
  • Tim Berners-Lee used the hypertext idea to create the
    World Wide Web in 1990 at the government-funded
    European Particle Physics Laboratory (CERN)
  • Mosaic, the first popular hypertext browser for the World-
    Wide Web

Eg: Cosmic Book

Applications (3)
• Computer Aided Design (CAD)
  • first CAD systems similar to drawing programs (1963)
  • pioneering work on interactive 3D CAD system (1963)
  • first CAD/CAM (manufacture) system in industry was
    probably General Motor's DAC-1 (about 1963)

• Video Games
  •   first graphical video game was probably SpaceWar (1962)
  •   the first computer joysticks (1962)
  •   early computer adventure game was created (1966)
  •   first popular commercial game was Pong (about 1976).

Up & Coming Areas (1)
• Gesture Recognition
  • first pen-based input device used light-pen gestures (1963)
  • first trainable gesture recognizer (1964)
  • a gesture-based text editor using proof-reading symbols
  • gesture recognition has been used in commercial CAD
    systems since the 1970s
  • came to universal notice with the Apple Newton (1992)
• Multi-Media
  • multiple windows with integrated text and graphics (1968)
  • Interactive Graphical Documents project was the first
    hypermedia system which used raster graphics and text
  • Diamond project explored combining multimedia (text,
    spreadsheets, graphics, speech) (1982)

Up & Coming Areas (2)
• 3-D
  • first system 3-D CAD system (1963)
  • first interactive 3-D system used for molecular modelling
  • the late 60's and early 70's saw the flowering of 3D raster
    graphics funded by the government
  • the military-industrial flight simulation work of the 60's - 70's
    led the way to making 3-D real-time
• Virtual Reality
  • original work on VR funded by Air Force (1965-1968)
  • study of force feedback, early research on head-mounted
    displays and on the DataGlove (1971)

Up & Coming Areas (3)
• Computer Supported Cooperative Work
  • remote participation of multiple people at various
    sites (1968)
  • Electronic mail, still the most widespread multi-user
    software, was enabled by the ARPAnet (1969)
  • and by the Ethernet from Xerox PARC (1973)
  • an early computer conferencing system (1975)
• Natural language and speech
  • Speech synthesis
  • Speech recognition

HCI as a business necessity
• Can the users be ignored? (Linux, Windows,…)
• NO
  • HCI + Usability engineering are a crucial business
  • Good Interface & Interaction Design should not
     • Be added after system is built
  • Supporting users is an integral part of the design.
    To do this one must consider …
     • International Standards in HCI and Ergonomics
     • User population is growing (size, diversity, etc.)
     • Expanding awareness amongst users of what can be

Case Study (1)
• A mechanical syringe was once being
  developed. An input device had to be created in
  order to enter the injected dose.

• Design such a device …

Case Study (2)
• A prototype was developed by the
  manufacturing company and demonstrated to
  the hospital staff. Happily they quickly noticed
  the potentially fatal flaw in its interface.

Case Study (3)
• The doses were entered by a numeric keypad:
  an accidental keypress and the dose could be
  out by a factor of 10! The production version
  had individual increment/decrement buttons for
  each digit .

Safety-critical systems (1)
• Poor designs
  • Very common in
    • Safety
    • Life-critical
  • Which all depend on computer-control
  • We need to understand why
    • Disasters
    • Accidents
    • Frustrations
  • happen?
  • Can you mention some examples?
Safety-critical systems (2)
•   Computer failure hits post office Lancashire, UK - Sep 5, 2006
    A VILLAGE post office has been struck by a technical glitch, leaving customers unable to pay bills and collect benefits.
    Edgworth ...

•   999 Ambulance Computer Failure Putting Lives at Risk International News Service, Australia - Aug 23, 2006
    LIVES are being put at risk because of a crisis with London Ambulance Service's computer-controlled 999 system. ...

•   US Department of Energy sponsors storage research CTR, CA - 20 hours ago
    ... The data storage institute will focus its efforts in three areas: collecting field data about computer failure rates and
    application behaviors, disseminating ...

•   Temporary failure hits Houston 911 center, TX - Sep 8, 2006
    ... system. This past July, the Houston Emergency Center experienced a computer failure which knocked out the automated
    dispatch system. ...

•   Warning on need for super reserves The Australian, Australia - Sep 10, 2006
    ... must maintain 4 per cent of assets in liquid form to meet any immediate needs, arising from banking and operational risks,
    such as computer failure or staff ...

•   Book on IT debacles urges caution, New Zealand - Aug 27, 2006
    ... That is the central theme of Dangerous Enthusiasms – E-Government, Computer Failure and Information System
    Development, a 160-page book just published by ...

•   Search is on for escaped McMinn inmates Chattanooga Times Free Press, USA - Sep 8, 2006
    A computer failure that left 225 inmates under supervision of just four corrections officers may have contributed to the ...

•   4:59 pm | Computers delay Charlotte flights Charlotte Observer, NC - Sep 6, 2006
    ... two dozen US Airways Express flights going in and out of Charlotte were canceled Wednesday after a thunderstorm in Ohio
    led to a computer failure that affected ...
    Homes facing night without water BBC News, UK - Aug 20, 2006
    ... and Powys. The Pant storage tank ran dry after the water firm was not alerted to the problem because of a computer failure.
    She ...

Safety-critical systems (3)
• Air-traffic control
  • Aircraft crash due to problems pilot had to interpret
    information on cockpit display

• Manned spacecraft
  • On June 4, 1996, the maiden flight of the European
    Ariane 5 launcher crashed about 40 seconds after
    takeoff. Media reports indicated that the amount lost
    was half a billion dollars. The error came from a
    piece of the software that was not needed during
    the crash!!
Safety-critical systems (4)
• Nuclear power plant (The Meltdown at Three
  Mile Island 1979)
  • “As alarms rang and warning lights flashed, the
    operators did not realize that the plant was
    experiencing a loss-of-coolant accident. They took
    a series of actions that made conditions worse by
    simply reducing the flow of coolant through the
• Medical Institutions
  • Break down in the scheduling system led to delays
    in reaching seriously ill patients. (UK)

Disaster examples
• 1988
• USS Vincennes shot down an Iran Air A300 Airbus
  with 290 people aboard
• Aegis weapon system had
  • Sophisticated software to identify potential threats
  • Was unable to provide up-to-date altitude information on
    its large display (this could be read from other screens)
• In the confusion, the Airbus which leveled off at
  12,500 feet was taken to be an F-14 fighter
  descending to attack!

‘User Hostile’ example
• Poor HCI can lead to User Hostile systems rather
  than User Friendly ones …

  • John has a stereo system with a matched set of
    components made by the same manufacturer: a receiver,
    a CD player, and a cassette deck, stacked in that order.
    They all have the on/off button on the left side. Every time
    John goes to turn off all three components, he presses
    the top left button on the receiver, which turns it off; then
    he presses the top left button on the CD player, which
    turns it off; then, naturally, he presses the top left button
    on the cassette deck -- which pops open the cassette

It’s obvious …
• It seems "obvious" that the manufacturer could
  have improved the interface
   • putting all three buttons in the same location

• But it clearly wasn't obvious to the system's

• Most actions used to accomplish tasks with an
  interface are quite obvious to people who know
  them, including, of course, the software designer.
  But the actions are often not obvious to the first-
  time user.

Another example …
•   Imagine a first-time user of a computer
    1. he has been shown how to login to the system
    2. has done some work
    3. is now finished with the computer for the day

•   Experienced computer users will find it obvious that a logout
    command is needed.

•   But it may not occur to first-time users that a special action is
    required to end the session.
    •   People don't "log out" of typewriters or televisions or video games, so
        why should they log out of computers?

•   Learning to predict problems like these by taking the user's
    point of view is a skill that requires practice.

Who studies HCI? (1)
• Multi-discipline field …
 Psychology +            Knowledge of user’s
 Cognitive Science       perceptual, cognitive &
                         problem-solving skills

 Sociology               Understand Interaction

 Computer Science +      Build the necessary
 Engineering             technology

 Business                Market the product
Who studies HCI? (2)
Ergonomics          User’s physical capabilities

Graphic Design      Produce effective interaction

Technical Writing   Produce the manuals and

Conclusion (1)
• HCI studies

  • Interaction between users & computer systems

  • In order to build systems which are:
    •   Usable
    •   Safe
    •   Efficient
    •   Effective
    •   Enjoyable

Conclusion (2)
•    Important points to keep in mind …

    1.   You need a lot of common sense
    2.   You must be ready to accept criticism
    3.   Think ‘user’
    4.   Try it out (They know what they want!)
    5.   Involve the users
    6.   Iterate

• If we take a toaster ...
• Describe:
  • the users the machine seems to be designed for;
  • the tasks and subtasks the machine was evidently
    designed to support;
  • the "interface" part of the machine;
  • the part of the machine that is NOT the interface.

• What about an electric drill ...

Suggested readings for next week
• Introduction to Dix et al.
• Chapter 1 of Dix et al.

• HCI History
  • http://www-


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