Transcript No Slide Title

Chp.1: What is HCI?
Spring 2002
• study of interaction between humans & computer
• a methodology for:
– modeling the human (e.g., perception, behavior)
– examining usability of computer programs,
devices, techniques (in general doesn’t have to
be just computers, applies to anything man-made
that humans use, e.g., cars, light switches,
kettles, etc.)
• most imporantly: HCI leads to DESIGN of interface
• past contributions: physical devices (mouse, HMD),
code (GUI toolkits, window managers)
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Chp.1: What is HCI?
Spring 2002
• All about design - in the context of Computer Science, design of
interface to “back-end” program
• Interface:
– graphical (GUI)
– command-line (CLI)
– web-based
– VR, etc.
• “Back-end”:
– word processor
– Operating System (O/S)
– air traffic control display
– dB
– flight simulator
– web site
– nuclear plant
– spreadsheet
– automobile displays
– calculator
– etc.
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Chp.1: What is HCI?
Spring 2002
• Computer interaction
– almost ubiquitous (everywhere); chances are in whatever
device you use, there’s a chip in there
– e.g., typical day:
• get up, press “snooze” on alarm clock (what’s the
interface on the clock?)
• drive to work (car interface)
• stop by ATM (ATM screen)
• after work, shopping (scanners at store)
• at home, eat dinner (microwave, stove)
• watch TV/DVD/VCR (various ent. devices)
• Interface design applies to all these; computer interface is more
obvious in some than in other examples
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Chp.1: What is HCI?
Spring 2002
• Why bother with interface design?
– increasing productivity
• e.g., in the workforce: employees with a better word
processor will be more productive
– safety: critical systems with poor interface may endanger
lives
• e.g., ATC, operating room, nuclear plant
– commerce: a good interface may sell a product
• e.g., today’s “hot items”: MP3 players, digital cameras,
DVD players, etc.
• Key point: users shouldn’t have to think (much) about
intricacies of interface to use the tool (INTUITIVE INTERFACE)
– e.g., ATM: walk up to it, withdraw cash (fairly easy to use)
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Chp.1: What is HCI?
Spring 2002
• Key principles of interface design:
– visibility: controls should be visible (e.g., volume
control on an MP3 player)
– affordance: controls should map to their function,
I.e., it should be obvious what each control
(button, slider, etc.) does.
• controls should be intuitive, e.g., volume
control: use a vertical slider (up = loud)
– feedback: device should give user indication of its
state (e.g., phone: dial tone [ready], busy signal,
flashing light [message or on hold])
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Chp.1: What is HCI?
Spring 2002
• Examples of design, visibility, affordance, feedback
Fig.1: salt / pepper shakers: which is which?
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Chp.1: What is HCI?
Spring 2002
• Examples of design, visibility, affordance, feedback
Fig.2: which knob controls which burner?
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Chp.1: What is HCI?
Spring 2002
• Examples of design, visibility, affordance, feedback
Fig.3: can I set the freezer / fridge temperature independently?
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Chp.1: What is HCI?
Spring 2002
• When designing a computer program:
– think what capabilities program should have
– how is a user going to access those functions
• More formally,
– HCI 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
• NOT just the creation of “user-friendly” programs
• Need to understand human processes (cognition,
perception) and interaction protocol between human
and computer
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Chp.1: What is HCI?
Spring 2002
• HCI challenges:
– continuous technological development, e.g.:
• better / faster machines
• new languages, applications (web, internet,
VR, multimedia, imaging, graphics, etc.)
– two concerns:
• keep abrest of technology (e.g., SIGCHI)
• marry good HCI with effective use of
technology (I.e., make sure both are good: the
“back-end” program works and the interface is
good)
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Chp.1: What is HCI?
Spring 2002
• HCI Goals:
– production of usable, safe, and functional systems
– development or improvement of systems (including
computing systems), with respect to:
• safety
• utility (functionality, what system does)
• effectiveness (is it good at what it does)
• efficiency (in case of programming, speed, memory
utlization, etc.)
• usability (key concept in HCI: make system easy to learn
and use)
– system: consider complete environment, not just hardware
or software, but people
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Chp.1: What is HCI?
Spring 2002
• Examples of not very usable systems:
– complicated telephones
• do you use all the features (e.g., multi-party
conf. calls, call forwarding, call-waiting, etc.)?
– wristwatch
• how often do you use its “extended” features
(time zone, stopwatch, alarm, countdown timer,
etc.)
• Examples of very usable systems:
– scissors
• intuitive how to use, mainly because it mostly
has just one application
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Chp.1: What is HCI?
Spring 2002
• Underlying HCI belief: people come first; a computer
is just a tool, a means to accomplish some task, e.g.,
– writing a paper
– communicating with friends
– designing a landscape
– preparing income taxes
– cataloging, organizaing, printing pictures
– desinging roads, bridges, airplanes, cars, etc.
• For good design, need knowledge of humans and
technology
– often need multi-disciplinary teams (e.g., Comp.
Sci, Psychology, IE, Arts, etc.)
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Chp.1: What is HCI?
Spring 2002
• Evolution of HCI
– 70s--80s: psychologists interested in informationprocessing aspects of computer as analogy to
mental processes (e.g., modeling brain as a
computer, connectionist network, associative
memory, etc.)
• various HCI studies: testing menus (depth vs.
breadth), usability of single-user computer
– 80s--90s: examining more powerful PCs,
workstations, communication (e.g. email),
multimedia (e.g., imaging, visualization, “data
mining”), VR (“presence”), group work (CSCW)
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Chp.1: What is HCI?
Evolution of HCI: three landmark systems
Spring 2002
1. Dynabook
• Alan Kay, Xerox Parc
• one of first laptops (book-sized PC)
2. Star
• Xerox Parc
• desk-sized system
• high-res display, graphics, icons
• mouse mapped to 2D “desktop” on screen
3. Apple Lisa
• based to some extent on Dynabook & Star
• precursor to Macintosh
• WIMP: Windows, Icons, Menus, Pointer
• introduction of desktop metaphor
• GUI, WYSIWYG word processor
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Chp.1: What is HCI?
Evolution of HCI: Main considerations
Spring 2002
• All HCI takes place in social & organizational context
• Application design is geared towards specific purposes,
dividing tasks between human and machine
• To adapt application to human, need to know something about
human psychological and physiological abilities and limitations
– human info processing: limited attention, memory
– language: linguistics, verbal comm.
– communication: methods of, body language, emoticons, etc.
– interaction: human-to-human, e.g., turn-taking
– ergonomics: carple-tunnel syndrome, eye strain, fatigue, …
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Chp.1: What is HCI?
Evolution of HCI: Main considerations
Spring 2002
• To create successful computer application, need to
know something about capabilities and limitations of
computer
– input: devices, e.g., keyboard, mouse, camera,
microphone, sensors, etc.
– output: displays, graphics, sound, etc.
– dialogue techniques, genre, style: what & how to
communicate to user, e.g., state of system, output
(visualizations, charts, numbers, etc.), what colors
to use, animation speed, etc…
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Chp.1: What is HCI?
Discussion
Spring 2002
• Can you think of examples of:
– very usable systems
– not so usable systems (are there any devices that
appear to be confusing to people)? How can they
be improved?
• Can you think of examples of:
– very usable computer programs
– not so usable computer applications? How can
they be improved?
• ASSIGNMENT 1: collect at least 3 examples
(pictures) of not so usable “systems”, e.g., door,
whatever, doesn’t have to be computer program
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Chp1: Goals of System Engineering
Spring 2002
• Functionality
• Reliability, availability, security, data integrity
• Standardization
– common UI features (e.g., WIMP)
• Integration
– of multiple components/modules (libs)
• Consistency
– common action sequences (e.g., File->Open)
• Portability
– e.g., Mac OS X, Linux, Windows
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Chp.1: Goals of UI Design
Spring 2002
• Human factors central to evaluation:
– Learnability (time to learn)
– Performance
– Human error (rate of errors by users)
– Retention (easy to use?)
– Satisfaction (subjective)
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Chp.1: Human Modeling
Spring 2002
• Human cognitive and perceptual abilities
– Short-term memory
– Long-term memory and learning
– Decision making
– Attention and set (scope of concern)
– Search and scanning
– Time perception
• Personality differences
• Cultural diversity
• Universal accesibilty (users with disabilities)
• Elderly users
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