Human Factors in HCI Design
Human Factors in HCI Design
Human Factors in HCI Design
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<strong>Human</strong> <strong>Factors</strong> <strong>in</strong> <strong>HCI</strong> <strong>Design</strong><br />
Cham, Tat-Jen Tat Jen<br />
Associate Professor / SMA-CS SMA CS Fellow<br />
School of Computer Eng<strong>in</strong>eer<strong>in</strong>g<br />
Nanyang Technological University<br />
http://www.ntu.edu.sg/home/astjcham
Pervasive Comput<strong>in</strong>g:<br />
Technology-Centric Technology Centric View<br />
Python-GTK<br />
3G<br />
Wi-Fi<br />
iPAQs /<br />
handhelds<br />
Glade<br />
Mixed-reality<br />
systems<br />
Bluetooth<br />
seamless<br />
handover<br />
L<strong>in</strong>ux<br />
Projection /<br />
OLED<br />
displays<br />
Grid comput<strong>in</strong>g<br />
Security /<br />
data protection<br />
SMA5508 /<br />
MIT6.893<br />
Student<br />
Bayesian<br />
networks<br />
Intelligent<br />
agents<br />
Smart<br />
rooms<br />
Speech recognition<br />
[speaker (<strong>in</strong>)dependent,<br />
isolated vs cont<strong>in</strong>uous speech,<br />
HMMs]<br />
Haptic Interfaces<br />
[force-feedback mechanisms]<br />
Computer vision<br />
[which really has noth<strong>in</strong>g to do<br />
with user’s visual system]
Pervasive Comput<strong>in</strong>g:<br />
<strong>Human</strong>-Centric <strong>Human</strong> Centric View<br />
Isn’t that football<br />
game on now? I’d<br />
love to watch it<br />
I’d really like to have a<br />
face-to-face conversation<br />
with Sarah <strong>in</strong> Europe, now<br />
When is my next<br />
appo<strong>in</strong>tment with John?<br />
Smith /<br />
Lim<br />
What’s the fastest way<br />
home to get out of this<br />
traffic jam?<br />
What are recent statistics of<br />
patients with the symptoms<br />
of Bob here?<br />
Heck, the pilot’s down with<br />
food poison<strong>in</strong>g. How can I<br />
land this plane?!
<strong>Human</strong>-Computer <strong>Human</strong> Computer Interfac<strong>in</strong>g<br />
Semantic Interface<br />
dataflow, scientific visualization, f<strong>in</strong>ancial<br />
account<strong>in</strong>g, remote communication<br />
Syntactic Interface<br />
shell commands + arguments, menus, icons,<br />
keyboard shortcuts, drag-n-drop, speech,<br />
gestures, handwrit<strong>in</strong>g<br />
Physical Interface<br />
keyboards, mice, display, stylus,<br />
device form factors, microphone
History of Computers<br />
Not the usual stuff<br />
Number of transistors<br />
Faster speeds<br />
Smaller sizes<br />
Power efficiency<br />
What about the user <strong>in</strong>terfaces…<br />
<strong>in</strong>terfaces
History: Physical Interfac<strong>in</strong>g 1<br />
Abacus – 3000 BC<br />
Pascalene – 1642<br />
Babbage Difference Eng<strong>in</strong>e – 1832
History: Physical Interfac<strong>in</strong>g 2<br />
ENIAC – 1946<br />
IBM 650 – 1953<br />
DEC PDP-1 – 1960
History: Physical Interfac<strong>in</strong>g 3<br />
Engelbart’s Workstation – 1966<br />
TRS-80 / Apple II– 1978<br />
IBM PC – 1981<br />
Xerox Star -- 1979<br />
Mac<strong>in</strong>tosh – 1985<br />
New iMac – 2001
History: Syntactic Interfac<strong>in</strong>g 1
History: Syntactic Interfac<strong>in</strong>g 2
History: Semantic Interfac<strong>in</strong>g<br />
VisiCalc MS Excel<br />
Quicken<br />
Matlab
The Attention Divide<br />
Early Era<br />
Mid Era<br />
Late Era<br />
Future?<br />
Mach<strong>in</strong>e Operation<br />
Software Manipulation<br />
Task Completion<br />
Mach<strong>in</strong>e Operation<br />
Software Manipulation<br />
Task Completion<br />
Mach<strong>in</strong>e Operation<br />
Software Manipulation<br />
Task Completion<br />
Mach<strong>in</strong>e Operation<br />
Software Manipulation<br />
Task Completion<br />
Enjoy<strong>in</strong>g Life
<strong>HCI</strong> <strong>Design</strong> – Involv<strong>in</strong>g the User<br />
Difficult to def<strong>in</strong>e <strong>HCI</strong> requirements specifications<br />
before-hand<br />
before hand<br />
Even harder <strong>in</strong> the pervasive comput<strong>in</strong>g era<br />
Iterative rather than open-loop open loop development<br />
process<br />
e.g. Star Model (Hartson ( Hartson & Hix, Hix,<br />
1989) c.f. Waterfall Model<br />
Prototyp<strong>in</strong>g<br />
Prototyp<strong>in</strong>g<br />
Implementation<br />
Implementation<br />
Evaluation<br />
Evaluation<br />
Conceptual<br />
Conceptual<br />
/<br />
/<br />
formal<br />
formal<br />
design<br />
design<br />
Task<br />
Task<br />
/<br />
/<br />
functional<br />
functional<br />
analysis<br />
analysis<br />
Requirements<br />
Requirements<br />
specification<br />
specification
<strong>HCI</strong> <strong>Design</strong> Guidel<strong>in</strong>es<br />
Reflexive (Motor-Sensory)<br />
(Motor Sensory)<br />
M<strong>in</strong>imize bra<strong>in</strong> cycles needed to use the<br />
<strong>in</strong>terface (“muscle ( muscle memory”)<br />
memory<br />
Cognitive<br />
Allows users to harness <strong>in</strong>tuitive,<br />
problem-solv<strong>in</strong>g problem solv<strong>in</strong>g skills<br />
Social / Organizational<br />
Meet requirements for multi-person<br />
multi person<br />
<strong>in</strong>teraction
Reflexive Considerations<br />
Intuition versus learn<strong>in</strong>g<br />
simplicity versus completeness<br />
/ efficiency?<br />
Accuracy-speed Accuracy speed tradeoff<br />
ROC curve<br />
User feedback<br />
visual, aural, tactile<br />
Motor-sensory Motor sensory channel<br />
separation<br />
e.g. is gaze cursor control a<br />
good <strong>in</strong>terface?<br />
Ergonomics<br />
M<strong>in</strong>imize physical stra<strong>in</strong> on<br />
users<br />
www.5dt.com<br />
Twiddler<br />
HP Tablet PC<br />
www.eyegaze.com
Reflexive Performance Studies:<br />
Evaluation and Model<strong>in</strong>g<br />
Evaluations are typically based on tim<strong>in</strong>g<br />
experiments<br />
Keystroke-Level Keystroke Level Model<br />
Card, Moran & Newell 1980<br />
Task time = Σ (unit tasks time)<br />
Unit tasks: Keystrok<strong>in</strong>g, Keystrok<strong>in</strong>g,<br />
Po<strong>in</strong>t<strong>in</strong>g,<br />
Hom<strong>in</strong>g, Draw<strong>in</strong>g, Mental, Response<br />
Modified Fitts’ Fitts Law<br />
Applicable to po<strong>in</strong>t<strong>in</strong>g tasks<br />
movement ⎛ distance ⎞<br />
⎜<br />
⎟<br />
time<br />
= a + b log2<br />
+ 1<br />
⎝ target width<br />
⎠<br />
Steer<strong>in</strong>g Law (Accot Accot & Zhai 1997) 1997<br />
Navigation of menus<br />
Images from Buxton 2003
Cognitive Considerations<br />
Metaphors<br />
Info visualization<br />
Visual programm<strong>in</strong>g<br />
Anthropomorphism<br />
Cognitive load<br />
Fatigue, stress of task<br />
automation vs user choice<br />
Focus of attention<br />
multi-task<strong>in</strong>g<br />
multi task<strong>in</strong>g<br />
how easy is it to return to<br />
a suspended task?<br />
User Model<strong>in</strong>g<br />
Interfaces tailored to<br />
<strong>in</strong>dividuals<br />
Khoros – Cantata<br />
MSR data mounta<strong>in</strong><br />
HP CRL –<br />
Smart Kiosk
Social and Organizational<br />
Considerations<br />
Synchronized experience<br />
Massive multiplayer games<br />
‘<strong>in</strong>stant <strong>in</strong>stant’ messag<strong>in</strong>g, but typ<strong>in</strong>g<br />
latency?<br />
Organizational order<br />
Onl<strong>in</strong>e roles and process flow<br />
e.g. teach<strong>in</strong>g groupware have<br />
onl<strong>in</strong>e roles for <strong>in</strong>structors, TAs<br />
and students<br />
Social norms<br />
privacy<br />
<strong>in</strong>stant messag<strong>in</strong>g – should onl<strong>in</strong>e<br />
state be revealed?<br />
what should default umasks be?<br />
etiquette<br />
tak<strong>in</strong>g turns dur<strong>in</strong>g tele-<br />
collaboration<br />
smileys – better or worse?<br />
America’s Army
Prototyp<strong>in</strong>g and Evaluation<br />
Wizard of Oz Prototyp<strong>in</strong>g<br />
<strong>Human</strong> `wizard’ `wizard to simulate<br />
mach<strong>in</strong>e <strong>in</strong>teraction<br />
Faster prototyp<strong>in</strong>g<br />
elim<strong>in</strong>ates programm<strong>in</strong>g<br />
overhead<br />
Usability Studies<br />
Task completion time, # errors / task,<br />
learn<strong>in</strong>g curve, function frequency<br />
distribution<br />
User satisfaction and feedback<br />
Physiological measurements?
Future Challenges<br />
As computers and comput<strong>in</strong>g<br />
become pervasive…<br />
pervasive<br />
what are the best <strong>in</strong>terfaces?<br />
how do we effectively move beyond<br />
keyboards, mice, screens, WIMP?<br />
Should we?<br />
Interfaces that<br />
comb<strong>in</strong>e cool technology, and<br />
satisfy human-centric human centric demands
References<br />
Bill Buxton, Less is More (More or Less), Less) , 2001<br />
http://www.billbuxton.com/LessIsMore.html<br />
J. Preece, Preece,<br />
Y. Rogers, H. Sharp, D. Benyon, Benyon,<br />
S.<br />
Holland, T. Carey, <strong>Human</strong>-Computer <strong>Human</strong> Computer Interaction,<br />
Interaction,<br />
Addison-Wesley, Addison Wesley, 1994<br />
Marc Rettig, Rettig,<br />
Interaction <strong>Design</strong> History <strong>in</strong> a Teeny<br />
Little Nutshell, Nutshell,<br />
2003<br />
http://www.marcrettig.com/writ<strong>in</strong>gs/rettig.<strong>in</strong>teractionDe<br />
signHistory.2.03.pdf<br />
CHI – ACM SIGCHI Conference on <strong>Human</strong> <strong>Factors</strong><br />
<strong>in</strong> Comput<strong>in</strong>g Systems
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