Dialog Design

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SCHOOL OF INTERACTIVE ARTS + TECHNOLOGY [SIAT] | WWW.SIAT.SFU.CA

Dialog Design

Categories of Dialogs

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Agendag Dialog design

– Command Language– WIMP - Window, Icon, Menu, Pointer– Direct manipulation– Speech/Natural language– Gesture, pen, multi-touch, VR…

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Dialog Designg How does a user interact with the

interface?

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Command Languagesg Earliest UI interaction paradigms

g Examples– MS-DOS shell– UNIX shell

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CL Attributesg Work primarily by recall, not

recognitiong Heavy memory loadg Little or nothing is visible

so…

g Poor choice for novicesbut...

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CL Attributesg Specify commands to operate on

current data collectiong User only controls initiationg Single thread of controlg Some other display area needed

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CL Advantagesg Advantages for experts

– Speed, conciseness• % ls <ret>

– Can express actions beyond a limited set• Flags, pipes

– Repetition, extensibility• Scripts, macros

– Easier implementation, less overhead– Power

• eg. Wild cards

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CL Dangersg With added power, comes added

responsibility and danger– UNIX

% rm -r *• Deletes every file that you have, and you

can’t get them back

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CL Reflectiong Command languages are often

maligned (for good reason)g But increased functionality can win

out over bad UI (e.g., LINUX)– Try to get both– Avoid excess functionality (comes at

cost)

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CL Design Goalsg Consistency

– Syntax, orderg Good naming and abbreviations

g Doing your homework in design can help alleviate some of the negatives

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Consistencyg Provide a consistent syntax

– In general: Have options and arguments expressed the same way everywhere

– UNIX fails here because commands were developed by lots of different people at different organizations• No guidelines provided

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Dialog Orderg English: SVO subject verb object

g CL: S assumed (you)Is VO or OV better? % rm file

% file rmg V dO iO vs. V iO dO

% print file thePrinter% lpr -PthePrinter file

Dialog Orderg Technical issues dictate the choice:g V iO dO

% lpr -PthePrinter fileg The command must parse the

arguments– So the command comes first

g Flags control how to act on the file– Want to parse all flags before checking

files– e.g. -o outputFileFeb 10, 2011 IAT 334 13

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Syntaxg Pick a consistent syntax strategy

– Simple command list• eg., vi minimize keystrokes

– Commands plus arguments• realistic, can provide keyword parameters• % cp from=foo to=bar

– Commands plus options plus arguments• what you usually see

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Terminologyg Keep terminology consistent

– Same concept expressed with same options

– Useful to provide symmetric (congruent) pairings• forward/backward• next/prev• control/meta

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Exampleg vi text editor

w - forward wordb - backward word

g Wouldn’t ‘f’ be better for forward?‘f’ already used

g How about ‘fw’ and ‘bw’?Extra keystrokes

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Orderingg Keep ordering consistent

– VO seems to be the most natural– Typically need to pick where options go

g Example– % ln -s file1 file2 (I can never

remember)– Think of % cp file1 file2

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Names and Abbreviationsg Specificity versus Generality

– General words• More familiar, easier to accept

– Specific (typically better)• More descriptive, meaningful, distinctive

– (Nonsense does surprisingly well in small set)

Abbreviations

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Abbreviationsg Abbrevs. allow for faster actions

– Expert performance begins to be dominated by motor times such as # of keystrokes

– Not good idea for novices– (Allow but don’t require)

• IBM CMS and DEC VMS had shortened commands- first unique characters were enough

• filelist -- f, fi, fil, file, filel, fileli, filelis, filelist

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Picking Good Abbrevs.g Strategies

– Simple truncation (works best, but conflicts)

– Vowel drop plus truncation (avoid conflicts)

– First and last letters– First letters of words in a phrase– Standard abbrev from other contexts

• qty, rm, bldg– Phonics

• xqt

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Abbrv Gdlnsg Use single primary rule (with single

fallback for conflicts)– Use fallback as little as possible– Mark use of fallback in documentation

g Let user know primary and secondary rulesg Truncation is good but generates conflictsg Fixed length is better than variable lengthg Don’t use abbrevs in system output

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WIMPg Focus: Menus, Buttons, Forms

g Predominant interface paradigm now (with some direct manipulation added)

g Advantages:– ?

Recognition g Recognition is easier than recall!

– Recall has one cue

– Recognition has the recall cue + the presence of the prompting word/icon

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Menusg Key advantages:

– 1 keystroke or mouse operation vs. many

– No memorization of commands– Limited input set

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Menusg Many different types

– pop-up– pull-down– radio buttons– pie buttons– hierarchies

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Menu Itemsg Organization strategies

– Create groups of logically similar items– Cover all possibilities– Ensure that items are non-overlapping– Keep wording concise, understandable

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Bad Exampleg Travel web page links:

– Flight page– 3 Best Itineraries– Flights & Prices– Timetables– Fares

g Which do you choose for reservations?

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Presentation Sequenceg Use natural if available

– Time• e.g. Breakfast, Lunch, Dinner

– Numeric ordering• e.g. Point sizes for font

– Size• Canada-> BC -> Surrey

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Presentation Sequenceg Choices

– Alphabetical– Group related items– Frequently used first– Most important first– Conventional order (MTWRF)

g Don’t change the order on the fly!

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Presentation Sequenceg User studies

– Novices: alpha > functional > random– Experts: categorization

g How would you do it in general?

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Presentation Sequenceg One possible methodology (first-

>last)– Natural order (if it exists)– Frequency of use– Order of use– Categorical– Alphabetical

g Don’t change dynamically!

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Direct Manipulationg Continuous visibility of the objects and

actions of interestg Rapid, incremental actionsg Reversibility of all actions to encourage

experimentationg Syntactic correctness of all actions—every

action is syntactically legalg Replacement of command language

syntax by direct manipulation of object of interest

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Direct Manipulationg Examples

– WYSIWYG editors and word processors– VISICALC - 1st electronic spreadsheet– CAD– Desktop metaphor– Video games

DM Syntaxg Typical DM syntax is postfixg DirectObjects first, Verb second

– In this case, the command completes the utterance

g Enables separate selection syntaxg Indirect objects typically specified

before direct objects– e.g. brush size before painting in

PhotoshopFeb 10, 2011 IAT 334 37

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DM Essenceg Representation of reality that can be

manipulated

g The user is able to apply intellect directly to the task

g Don’t have to name things, just touch them

g The tool itself seems to disappear

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DM Advantagesg Easier to learn & rememberg Direct WYSIWYGg Flexible, easily reversible actions

helps reduce anxiety in usersg Provides context & instant visual

feedbackg Exploits human use of visual spatial

cuesg Limits types of errors

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DM Problemsg Takes of screen spaceg Need to learn meaning of

components of visual representationg Visual representation must be

learnedg Mouse ops may be slower than

typingg Not self-explanatory (no prompts)

Direct Manipulation is Localityg DM Relies on a primary geometric

organizationg Items located nearby are frequently

edited together– The words in a sentence– A column of numbers in a spreadsheet

g Less related -> Less local -> Less DM!

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DM Problemsg Not good at

– Repetition

– History keeping (harder)– Certain tasks (Change all italics to bold)– Macros harder– Abstract elements (variables)

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What is Directness?g Related to three things:

– Physical Distance– “Gulfs” between user’s goals & system

image– Engagement

Hutchins, Hollan, Norman ‘86

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Distance: Two “Gulfs”g Gulf of execution

– Distance between user’s goals and means of achieving them in system• Does the system allow the user to do what the user

wants to do?

g Gulf of evaluation– Amount of effort person must expend to

interpret system state and judge if intention was achieved• Can user perceive if progressing favorably?

Goals System

Execution

Evaluation

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Directness and Distanceg Two types

– Semantic - Relation between what user wants to express and what is available in interface• Can I say what I want (concisely)?

– Articulatory - Relation between meanings of expressions and their physical form(s)• Is the way to perform an action expected

and clear (appropriate)?

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Engagementg Feeling that you are directly

manipulating the objects of interestg Promoted by

– Unobtrusive interface – Minimizing gulfs of execution and

evaluation– Appropriately responsive system

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Speech Inputg Speech synthesisg Speaker recognitiong Speech recognitiong Natural language understanding

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English Speechg Made up of 40 phonemes, 24

consonants and 16 vowels

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Speech Synthesisg Often hear robotic voice

g Store tones, then put them together– The transition is the difficult thing to do

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Speaker Recognitiong Tell which person it is (voice print)

g Could be important for monitoring meetings

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Speech Recognitiong Primarily identifying words

g Improving all the timeg Commercial systems:

– IBM/Nuance ViaVoice, Ford Sync ...

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Recognition Dimensionsg Speaker dependent/independent

– Parametric patterns are sensitive to speaker

– With training can get betterg Vocabulary

– Some are getting 50,000+ wordsg Isolated word vs. continuous speech

– Continuous: where words stop & begin– Typically a pattern match, no context

used

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Recognition Systemsg Typical system has 5

components:– Speech capture device - Has analog -> digital

converter– Digital Signal Processor - Gets word

boundaries, scales, filters, cuts out extra stuff– Preprocessed signal storage - Processed

speech buffered for recognition algorithm– Reference speech patterns - Stored templates

or generative speech models for comparisons– Pattern matching algorithm - Goodness of fit

from templates/model to user’s speech

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Errorsg Systems make four types of errors:

– Substitution – one word for another– Rejection - detected, but not recognized– Insertion – word added– Deletion – word not detected

g Which is more common, dangerous?

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Natural Language Understandingg Putting meaning to the words

g Input might be speech or could be typed

g Holy grail of Artificial Intelligence problems

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NL Factors/Termsg Syntactic

– Grammar or structureg Prosodic

– Inflection, stress, pitch, timingg Pragmatic

– Situated context of utterance, location, time

g Semantic– Meaning of words

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SR/NLU Advantagesg Easy to learn and rememberg Powerfulg Fast, efficient (not always)g Little screen real estate

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SR/NLU Disadvantagesg Doesn’t work well enough yetg Assumes knowledge of problem

domain– Not prompted, like menus

g Requires typing skill (if keyboard)g Enhancements are invisibleg Expensive to implement

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Good in Situationsg Hands busyg Mobility requiredg Eyes occupiedg Conditions preclude use of keyboardg Visual impairmentg Physical limitation

Documents

Dialog Design