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Copyright 2006 John Wiley & Sons, Inc 2 of 22
Metaphors
drawing on previous knowledge/models that are similar to current situation -describe metaphor verbally & explicitly allows one to function in new situation let’s us take knowledge of familiar items/situations
and apply them to novel or abstract things goes back to analogies
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[Verbal] Metaphors
we do this all the time arguments in terms of war
marshall your arguments attack their position win the argument
“Let’s take a look at metaphors” a seeing metaphor for an abstract process
computers my machine is acting irrational, crabby, stupid
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Creating metaphors
Two components are involved elements: the objects relationships between objects
Obviously, new situation (computer) won’t map entirely onto metaphor of person or similar machine seems metaphor enables dis-similarities to be identified
and incorporated into a new model (for the computer) Apple's User Interface Guidelines states, "Use
concrete metaphors and make them plain, so that users have a set of expectations to apply to computer environments."
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Creating metaphors
how to functional definition - understand how it works ID users problems - what is not clear to them? create the metaphor - generate many so can evaluate
and test them (come from first two steps) evaluate metaphor
if you use these, use them fully pay attention to the details - it’s all in the details
digressions tolerated if made obvious good reference:
http://www.firelily.com/opinions/metaphor.html (process for building them)
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Examples of metaphors
desktop book slide show museum mail calendar clipboard
how many things can you put on it?
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Examples of metaphors
Metaphor Attributesspreadsheet row, column, calculation, cell, scripts run on multiple cells,
graphical reports, templates, accounting, cost estimationroadmap roads, legend, exit, street names, landmarks, trip planner,
one- way streets, detours, tollswarehouse shelves, fork lift, part number, inventory, access method (fork lift
vs. roller skates), supplier, customercafeteria trays, stations, take-out, place where you get utensils, place
where you pay, automat, coffee refills, condiments
circus ringmaster, three rings, clowns, high wire, multiple simultaneous events, barkers, side show, animals, food vendors in the aisles, master of ceremonies
building windows, hallways, heating system, doorway, elevators, room numbers, addresses, organization by floors and corridors,
vending machines, electricity, power, distinctive interior decoration
movie script stage directions, setting, characters, lines, view, zoom, pan, montage, fade to black, dissolve, inset, script, props
train conductor, caboose, track, tickets, cars with special functions (such as diner, sleeper), stations to stop at, derailment
playground sandbox, teeter-totter, trash can, slide, benches, fence to enclose, curfew, attendants, caretakers, presence of peers
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Projecting the metaphor
Can encourage this on part of user by: in documentation, say “when drag file to another
folder, this is like putting your paper in a different file folder”
this fosters a mental model of a file system (but comes with a lot of baggage)
? when drag a file from My Documents to folder My Work, is file being moved to the new file?
Copyright 2006 John Wiley & Sons, Inc 9 of 22
Projecting the metaphor
Designer makes the object/relationships mimic the real world (ie. look like it, act like it, etc). idea is that user will recognize they are in
office environment at a desktop and will function accordingly
icons that look like real items they represent, etc. an electronic world created that represents
physical world (mental model and presentation/interface combined into one package)
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Evaluating metaphors
brings structure? if vague, doesn’t add much to have a metaphor
how applicable is it? Does it fit? how easily can it be represented in the interface? does it fit the target user group?
concept of pointers to non-programmers is it extendible? (brings a richer context) good metaphors - ubiquitous
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Problems with metaphors
how represent actions that go beyond or aren’t present in real world? cut and paste between apps ‘magical’ activities that extend beyond the metaphor
what about elements/relationships that don’t follow the metaphor? in verbal metaphor, person making the connections so
aware it won’t fit perfectly (not upset when doesn’t) here, designer presenting metaphor so user assumes it will
fit (non-fits are surprises) Problem example: desktop metaphor - and stack of
papers/windows
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Examples of poor metaphors
bad interface metaphor can suggest an incorrect model of a system – so can mislead users into believing that an event has occurred when it has not
Erickson (90) – voice mail system and utilization of ‘mailboxes in which
messages may be left’ suggests messages left here in real time directly in reality, can be substantial time delay as they are not ‘directly
deposited’ metaphor of an ‘answering service’ might be better
deleting files on a Mac humans don’t like false-negative decisions (decide not to
when could have) – better to err on the side of caution users ‘gut feelings’ (Roher)
Copyright 2006 John Wiley & Sons, Inc 13 of 22
Examples of poor metaphors
Interface Hall of Shame: Metaphors
http://homepage.mac.com/bradster/iarchitect/metaphor.htm report of the demise of “Clippie” is here
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Solution: composite metaphors
found that people are OK with mixtures of models that can explain discrepancies eg. windows, scroll bars in desktop model ? applications multitasking - what is model for this?
problems with models: users that work through weird exceptions (ah-hah) develop stronger models males vs. females on experimentation cost of experimentation by software
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Relation to conceptual/mental models
conceptual model made up of metaphors so important to impart this correctly to user
terms: design model (conceptual model) system image (how design model is related to
user user model (mental model)
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Relation to conceptual/mental models
goal of designer is to facilitate user development of a mental model of system that maps to their design model this allows user to access functionality that
designer intended/designed into system keep in mind mental models have problems
inaccurate firmly held - hard to change, will use wrong
one even if know it’s wrong so simplifying
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Development of mental models
How does user develop model of system? from the system image
physical interface (how looks, devices, etc) - elements
don’t’ forget motor memory behavior of system (relation between elements,
their functionality, responsiveness, error catching, feedback)
documentation (help systems, manuals, first time user guided tours of system)
Problem when gulf between user and design mental model of system
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Design Implications
Tog - idea that your system is the framework of a car - you are creating the skin that goes over that similar analogy - software wrappers
another interesting idea - test users, then ask what they remember - then fix this stuff again, if invisible (ubiquitous), then means it is
working
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Design Implications
consistency more important in interpretation of user
behavior than elements/objects follow published guidelines and standards don’t change something unless must
then make a big change - obvious add new skillsets rather than modify existing
can change look/feel if metaphor remains the same
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Ubiquitous vs. Direct Manipulation
Ubiquitous - Means technology is invisible and works without your direct attention intelligent badges so phone calls routed to your location person as a computer (shake hands, exchange data) -
anthropomorphic good: focus on task, decreases your conceptual load,
don’t have to worry about metaphor/interface (invisible) bad: loss of control, if problem occurs, don’t know how
to fix it, ascribe intelligence agent technology (Patti Maes and MIT) – unsupervised
intelligence Current example – Firefly at Amazon
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Ubiquitous vs. Direct Manipulation
Direct Manipulation: you directly make things happen (Ben Schneiderman, U of M) drag something over with mouse, etc. good: gives you control and sense of control bad: requires your time and attention,
repetitive tasks annoying, requires excellent interface
Current example: plug and play devices
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Anthropormorphism
a lot of research on social interaction between humans and computers (Reeves & Nass) basically thus far shown that users interact with computers in
same manner as with people definitely affects attention, evaluation of information (more
positive), perception, memory Expectations
Virgin Mobile 1-888-322-1122 Sam - http://www.meteosam.com/eng/index.php kismit -
http://www.ai.mit.edu/projects/sociable/movies/kismet-and-rich.mov