Design Of Interactive Systems

OVERHEADS I: DESIGN OF INTERACTIVE SYSTEMS

by MURRAY TUROFF

DEPARTMENT OF COMPUTER AND INFORMATION SCIENCE

NEW JERSEY INSTITUTE OF TECHNOLOGY

NEWARK NJ, 07102

TEL: 201 596 3399

© Copyright 1991 Murray Turoff

DESIGN METHODS

COMPARISON / DIFFERENTIATING

DESIGNING / REQUIREMENTS

TASK UNDERSTANDING / MACRO

COGNITIVE UNDERSTANDING / MICRO

GROUP UNDERSTANDING / MICRO & MACRO

ENHANCEMENTS / EVOLUTION

VISIONING / NORMATIVE

SOCIAL ENGINEERING

GOAL SETTING

ATMOSPHERE

HUMAN COMPUTER

SLOW RAPID

SLOPPY RIGOROUS

FORGETFUL PRECISE

BRILLIANT STUPID

HOW TO DESIGN A COMMUNICATION BETWEEN THE TWO?

WHY INTERACTIVE

ITERATIVE PROBLEM SOLVING

UNPREDICTABLE SEQUENCES

TOOL FLEXIBILITY

IMPOSSIBLE MANUALLY

COLLABORATION

ENHANCEMENT (SAVE TIME, EFFORT)

SPEED, QUANTITY, MEMORY

ENJOYMENT

SUBLIMATING AND BEING BUSY

DESIGN ATMOSPHERE

PERSONAL WORKSTATIONS

MEGABYTES OF CORE

OPTICAL DISKS

MANY MIPS

BROAD BAND COMMUNICATIONS

USERS

HIGH COGNITIVE VARIABILITY

MANAGERIAL

PROBLEM SOLVERS

SCIENTIFIC AND ENGINEERING

CREATIVE

VIEWS OF THE WORLD

REAL WORLD

OUTCOMES: VALIDATION

REQUIREMENTS MODEL

SYSTEMS ANALYSIS: EVALUATION

IMPLEMENTATION MODEL

SYSTEM DESIGN: TESTING

INTERFACE MODEL

METAPHOR: SYSTEM OPACITY

MENTAL MODEL

EXPERIENCE: FUNCTIONAL OPACITY

USER TYPES & MODES

NOVICE, CASUAL, INTERMEDIARIES

EXPERIENCED

ROUTINE

FREQUENT

OPERATORS

PROBLEM SOLVERS

POWER

RESULTS:

DIFFERENT ROLES IN ONE SYSTEM

MULTIPLE INTERFACE METHODS

DIMENSIONS OF INTERFACE DESIGN

© copyright 1991 Murray Turoff

CRITERIA FOR FACTOR DIMENSIONS

CAN IT BE PERCEIVED

CAN IT BE MEASURED

REPRODUCIBLE

RELIABLE

ORTHOGONAL

CAN IT GUIDE DESIGN

RELATE TO INTERFACE METHODS

CAN IT EVALUATE DESIGN

CAN IT SENSITIZE

FOUNDATION FACTORS

UNDERSTANDING & EASE OF LEARNING

SENSE OF CONTROL

EFFECTIVENESS

PSYCHOLOGICAL & SOCIOLOGICAL

ADMINISTRATIVE

FOUNDATION FACTORS

TIMELINESS

RESPONSIVENESS

RELIABILITY

ACCESSIBILITY / CONVINCE

EFFICIENCY / LEAST EFFORT

SECURITY

ACCURACY

PROTECTION / BULLET-PROOFING

UNDERSTANDING / EASE OF LEARNING

GUIDANCE

INFORMATIVENESS

CONCISENESS / BREVITY

CLARITY / SIMPLICITY

COMPREHENSION

SEGMENTATION / DECOMPOSITION

CONSISTENCY

RETENTION

SPECIFICITY

FAMILIARITY

SENSE OF CONTROL I

LEVERAGE / MODIFIABILITY

MANIPULABILITY

CLOSURE / CONFIRMATION / NOTIFICATION

FEEDBACK

SENSE OF CAUSALITY

MULTI-TASKING

PROCESS CONTROL / ESCAPE / INTERRUPT

SENSE OF CONTROL II

FORGIVENESS

TRANSPARENCY

FLEXIBILITY / COGNITIVE ADOPTION

PREDICTABILITY / REGULARITY

CONTEXTUAL VISIBILITY

TRACKING

BACKTRACKING / AUDITING

FORECASTING / ANTICIPATING

BACKUP / UNDO

EFFECTIVENESS I

TASK FUNCTIONALITY

GENERALITY

MATCHING

COMPLETENESS

ROBUSTNESS

ABSTRACTION

ADAPTABILITY

EFFECTIVENESS II

INTEGRATION / CONNECTIVITY

RESILIENCY / ROBUSTNESS / RICHNESS

RELEVANCE

PRECISION

PSYCHOLOGICAL & SOCIOLOGICAL I

ETHICAL / HONESTY

AESTHETIC / PLEASING / ARTFUL

INTERESTING / CHALLENGING / FUN

SELF IMAGE ENHANCEMENT

EXPECTATIONS / MOTIVATION

PEER RELATIONS / STATUS

SENSE OF COMMUNITY

HUMANIZATION / POLITE

PSYCHOLOGICAL & SOCIOLOGICAL II

SATISFACTION

SYSTEM

GROUP

TASK

MOTIVATION

EXPECTATIONS

PERCEIVED UTILITY

FEELING OF PARTICIPATION

ADMINISTRATIVE

TRAINING / DOCUMENTATION

MAINTENANCE

JOB ENHANCEMENT

HUMAN HELP

ORGANIZATION RELATIONSHIPS

SYSTEM EVOLUTION / MODIFIABILITY

EVALUATION / FEEDBACK

CHARGING POLICIES

CONFIDENCE

CONFLICTS AND TRADEOFFS: EXAMPLES

COMPREHENSION SEGMENTATION

CONSISTENCY EFFICIENCY

CONSISTENCY COGNITIVE ADOPTION

CONCISENESS INFORMATIVE

CONCISENESS CLOSURE

RESILIENCY EASE OF LEARNING

TASK GENERALITY TASK MATCHING

SPECIFICITY FAMILIARITY

LEVERAGE MANIPULABILITY

BASIC PROBLEM

PROPER LEVEL OF TOOLS

TOO PRIMITIVE:

DIFFICULT TO WORK WITH

TOO MACRO:

INFLEXIBLE

GULF OF EXECUTION

GOALS, INTENTIONS, TO ACTIONS

GULF OF EVALUATION

DISPLAY, INTERPRETATION, TO EVALUATION

CONTROL SYSTEM VIEW

INPUT - CONTROL

OUTPUT - RESULT

SYSTEM - BLACK BOX

OBJECTIVE - COMPARATOR

LAW OF REQUISITE VARIETY

EVALUATION OF INTERFACES

INDUSTRIAL ENGINEERING - HUMAN FACTORS

PSYCHOLOGICAL AND SOCIOLOGICAL

PROTOCOL ANALYSIS

CONTROLLED EXPERIMENTS

FIELD TRIALS

INTERVIEWS

SURVEYS

LONGITUDINAL STUDIES

EVALUATION OF INTERFACES I

MANAGEMENT SCIENCES - PERCEPTIONS

SYSTEM MONITORING

USER SATISFACTION

COST - BENEFITS / PRODUCTIVITY

EFFICIENCY

QUALITY

OPPORTUNITIES

INDUSTRIAL ENGINEERING

HUMAN FACTORS

EVALUATION OF INTERFACES II

PSYCHOLOGICAL

COGNITIVE PROCESSES

HUMAN PROBLEM SOLVING

SOCIOLOGICAL

GROUP PROCESSES

ENVIRONMENTAL INTERACTION

EVALUATION OF INTERFACES III

ANTHROPOLOGICAL

METAPHORS

PARTICIPANT OBSERVATION

ARCHAEOLOGICAL

ARTIFACTS

PHILOSOPHICAL

VIRTUAL REALITY

APPROACHES TO UNDERSTANDING

EXPERIMENTAL

FEATURES RELATIONSHIPS

COGNITIVE PSYCHOLOGY FACTORS

MODELS OF TOTAL SYSTEMS

HUMAN

TASKS

COMPUTERS

FIELD TRIALS AND PROTOTYPING

ARTIFACTS AND METAPHORS

SOCIAL ENGINEERING

EXPERIMENTS

FIXED MESSAGE FORMAT VS. USER DESIGNED

LESS NOTE TAKING

GREATER COMPREHENSION

DUAL MODE EDITOR

AFTER 16-20 HOURS USERS SWITCHED TO COMMANDS

USED HELP MORE IN COMMAND MODE

MORE ERRORS

MENU CRITERIA

TIME TO CREATE MENU < CHOICE TIME

MENU EXTENSIBLE BY USER

THEN BETTER THAN COMMANDS EVEN FOR EXPERTS

SPECIFIC DESIGN FAULTS I

POOR INTERACTIVE DIALOGUE

LONGER TO DO THAN MANUALLY

NO TOLERANCE FOR HUMAN ERRORS

NO FLEXIBLE PARSING (RIGIDITY)

WRONG FUNCTIONALITY

START-STOP HASSLE

POOR DOCUMENTATION AND HELP

INCONSISTENT METAPHORS

SPECIFIC DESIGN FAULTS II

MOST COMMON PROBLEM: FLEXIBILITY

APPLICABILITY TO BROAD RANGE OF TASKS

MULTIPLE APPROACHES TO A GIVEN TASK

MULTIPLE WAYS OF INVOKING

ADAPT TO DIFFERENT

USER STYLES

USER TYPES

GREATER FLEXIBILITY IMPLIES MORE COMPLEX SYSTEM

PSYCHOLOGICAL IMPACTS

FISHBOWL

BULLY

PEEPHOLE

CONCRETE

CLUTTER

PEOPLE ANGST

COMPUTER ANGST

RORSCHACH BLOT

PHASES OF USER EVOLUTION

UNCERTAINTY

INSIGHT

INCORPORATION

SATURATION

PSYCHOLOGICAL ROLES

EVALUATOR MAGICIAN

HELPER ENTERTAINER

COMPANION CHALLENGER

FOE MENTOR

ACCOMPLICE PRODUCER

OVERSEER DICTATOR

PRIEST SERVANT

PICKY PARENT GOD

DESIGN INTRODUCTION

CONTROL FUNCTION EXAMPLES

GO BACK (HOW FAR)

GO FORWARD (HOW FAR)

GO ELSEWHERE (HOW FAR)

PRINT/FILE (HOW MUCH)

OBJECT, SCREEN, HALF SCREEN, PAGE, LIST

INTERACTION STATE, TASK, FUNCTION, PROCESS, TRANSFER, UP/DOWN LOAD

CONFIRM, QUIT, HELP, UNDO, ESCAPE, FINISH, INTERRUPT, CONTINUE, TRANSFER, QUIT, SAVE, EXECUTE, OPEN, CLOSE, TRANSFER, COPY, MOVE

INTERACTION METHODS

MENUS, COMMANDS

LISTS, FORMS, DIALOGUE

WINDOWS, ICONS, GUI

DIRECT MANIPULATION

MIMICKING / RECORDING

ANIMATION AND MODELS

LANGUAGES

SCRIPTING

VIRTUAL REALITIES

AI AND EXPERT SYSTEMS

DESIGN COMPONENTS I

GOALS AND OBJECTIVES

TASKS

SYSTEM METAPHOR

SYSTEM ARTIFACTS

OBJECTS / SUB-OBJECTS

OBJECT PARTS

SHORTEST, ABSTRACT, CONTENT

FUNCTIONS ON OBJECTS

GENERIC AND EXPLICIT

STRATEGIC CHOICE SETS

REACTIVE CHOICE SETS

CONTROLS

DESIGN COMPONENTS II

MODIFIERS AND STATUS STATES

SUBSETS, TRACKING

LATERAL LINKAGES

SHARED PROCESSES

LIST PROCESSING

SEARCHING

FORMATS

SCREEN LAYOUTS

WORKSPACE, STATUS AREAS

CONTROL AREA, MESSAGE AREA

DESIGN COMPONENTS III

USER INTERACTION STATES

INTERACTION PROCESSES

USER OBJECT LISTS

USER TASKS

ALTERNATIVE SETS

PROCESSES AND CLOSURE

ERROR CONDITIONS

SYSTEM MESSAGES

MODEL RELATIONSHIPS

MENTAL MODEL TO REAL WORLD: EXPERIENCE

REQUIREMENTS MODEL TO IMPLEMENTATION MODEL: TESTING

REAL WORLD TO IMPLEMENTATION MODEL: VALIDATION

MENTAL MODEL TO IMPLEMENTATION MODEL: EVALUATION

MENTAL MODEL TO INTERFACE MODEL: LEARNING AND TRAINING

MODELS

COGNITIVE DISSONANCE:

MENTAL MODEL TO INTERFACE MODEL:

FUNCTIONAL OPACITY

IMPLEMENTATION MODEL TO INTERFACE MODEL:

SYSTEM OPACITY

INFORMATION DOMAINS OF USERS I

COMMON IS SUPPORT LEVELS

SINGLE FUNCTION TASKS:

SIMPLE INQUIRY / CALCULATIONS / MESSAGING

STRUCTURING:

ORGANIZING / FILTERING / SUMMARIZING

STATUS BRIEFING / REPORT GENERATION

TRACKING / MONITORING

INFORMATION DOMAINS OF USERS II

CURRENT INDIVIDUAL CHALLENGES

EXCEPTION REPORTING

CREATION TASKS

MODELING / STRUCTURING

DIAGNOSIS

DISCOVERY

HYPOTHESIS TESTING AND ANALYSIS

CURRENT GROUP CHALLENGES

PLANNING AND DECISION ANALYSIS

DECISION IMPLEMENTATION

COMMAND AND CONTROL

FOLKLORE OF INTERACTIVE SYSTEMS

FOLKLORE OF INTERACTIVE SYSTEMS I

USERS:

FAILURE TO NOTICE EXPLICIT INSTRUCTIONS

DO THE UNANTICIPATED AND THE FORBIDDEN

FORMULATE OPINION ON LITTLE KNOWLEDGE

MISINTERPRET MEANINGS

WILL NOT ASK FOR HELP

WILL NOT REPORT BUGS

FOLKLORE OF INTERACTIVE SYSTEMS II

USERS:

WILL NOT APPRECIATE IMPLEMENTATION EFFORT

ONLY APPRECIATE UTILITY TO THEM

WILL FALL INTO HABITS

WILL NOT READ MANUALS

NOT UNDERSTAND DOCUMENTATION

FOLKLORE OF INTERACTIVE SYSTEMS III

DESIGNERS:

EXPECT USERS TO LEARN WHOLE SYSTEM

TO UNDERSTAND WHOLE SYSTEM

WILL RE-INVENT THE WHEEL

TREAT ALL USERS THE SAME

WILL NOT TAKE CRITICISM WELL

WILL NOT EXPLAIN THEIR DESIGN

CANNOT TEACH USERS

FOLKLORE OF INTERACTIVE SYSTEMS IV

GENERAL I:

BEST WAY OF USING COMPUTER NOT EVIDENT TO USER

WRONG TO AUTOMATE, BUT EASY TO SELL

DESCRIPTIVE DESIGNS CAN BE PRESCRIPTIVE

USER BEHAVIOUR WILL CHANGE AND EVOLVE

DESIGNER HAS LINE OF CREDIT

FOLKLORE OF INTERACTIVE SYSTEMS V

GENERAL II:

DESIGNER KNOWLEDGE OF TASK CRITICAL

TWO OR MORE SHOULD DESIGN

ROLE FOR OMBUDSMAN

MULTIPLE DESIGN ITERATIONS DESIRABLE

ALLOW USER TO "CHUNK" PROBLEMS

USER FRIENDLY - EXPERIENCED HOSTILE

FOLKLORE OF INTERACTIVE SYSTEMS VI

GENERAL III:

VALUE WILL OVERCOME POOR INTERFACE

BEST SYSTEM IS THE FIRST LEARNED

EFFICIENT COMPUTER DATA STRUCTURE MAY BE INEFFICIENT FOR THE USER

FOLKLORE OF INTERACTIVE SYSTEMS VII

GENERAL IV:

USERS LEARN BEST BY TRAIL AND ERROR

EFFICIENT USE OF MACHINE MAY EQUAL INEFFICIENT USE OF PEOPLE

EXPERIMENT LEADS THEORY

DESIGNERS SHOULD KNOW APPLICATION AREA

REMEMBER THE MAGIC NUMBER 7 +- 2

A SYSTEM EVOLVES OR DIES

FOLKLORE OF INTERACTIVE SYSTEMS VIII

GENERAL V:

EVALUATING THE USER NOT A SYSTEM TASK

USERS WANT TO IGNORE SYSTEM

INVOLVE THE USER IN THE DESIGN PROCESS

ERROR DETECTION AS SOON AS POSSIBLE

USERS SHOULD HAVE CONTROL

USER ROLES AND TYPES

NOVICE, CASUAL, ROUTINE

INTERMEDIARY

FREQUENT

OPERATOR

EXPERIENCED

PROBLEM SOLVER

POWER

RESULTS:

DIFFERENT ROLES IN ONE SYSTEM

MULTIPLE INTERFACE METHODS

USER RESPONSE TO INADEQUATE SYSTEM

DIS-USE: TURN TO OTHER SOURCES

MIS-USE: USING INAPPROPRIATE WAYS

PARTIAL USE: USE OF WRONG SUBSET

DISTANT USE: USE OF INTERMEDIARY

MODIFICATION OF TASK: CHANGE TASK TO FIT SYSTEM

COMPENSATORY ACTIVITY: USER HAS TO DO MORE

DIRECT PROGRAMMING: USER MODIFIES SYSTEM

NON-USE: AVOIDING THE SYSTEM

PROTOCOL ANALYSIS

PROTOCOL ANALYSIS I

OBJECTIVE: TO DISCOVER THE PROCESS A PERSON GOES THROUGH IN SOLVING A PROBLEM

USES: LEARNING COGNITIVE PROCESSES, DEVELOPING EXPERT SYSTEM MATERIAL, EVALUATING INTERFACES

PROTOCOL ANALYSIS II

ASSUMPTION: COGNITIVE PROCESSES THAT GENERATE VERBALIZATION ARE A SUBSET OF THOSE THAT GENERATE BEHAVIOUR

EXAMPLE: "LISA LEARNING," BY CARROLL AND MAZUR, IEEE COMPUTER, NOVEMBER 1986.

PROTOCOL ANALYSIS III

INVERSE RELATIONSHIP BETWEEN THE AMOUNT OF TRUST AND HOW MUCH NEEDS TO BE REPORTED VERBALLY.

1. DO YOU KNOW THE CAPITAL OF SWEDEN?

2. WHICH OF THE THREE: OSLO, STOCKHOLM, OR COPENHAGEN IS THE CAPITAL?

3. NAME THE CAPITAL OF SWEDEN.

RETROSPECT TO 1: TELL WHAT YOU WERE THINKING

PROTOCOL ANALYSIS IV

TALK ALOUD, THINK ALOUD MODE: WHILE INFORMATION IS ATTENDED.

CONCURRENT PROBING MODE: WHILE IN SHORT-TERM MEMORY.

RETROSPECTIVE PROBING MODE: AFTER COMPLETION OF TASK

PROTOCOL ANALYSIS V CONDITIONS

SUBJECT ASKED TO VERBALIZE WHAT THEY ARE THINKING

SUBJECT IS NOT BEING EVALUATED

OBSERVER MUST NOT PARTICIPATE IN PROCESS OR AID SUBJECT

SUBJECT PROVIDING KNOWLEDGE OF HOW THEY SOLVE A PROBLEM OR HOW THEY LEARN A SYSTEM

PROTOCOL ANALYSIS VI CODING

NEED A CODING SCHEME FOR VERBALIZATIONS

EXAMPLE I:

INTENTIONS: GOALS, SHALL, WILL, MUST, HAVE TO

COGNITIONS: CURRENT ATTENTION SITUATION

PLANNING: IF X THAN Y

EVALUATION: YES, NO, DAMIT, FINE

PROTOCOL ANALYSIS VII CODING

EXAMPLE II:

SURVEYING GIVEN INFORMATION

GENERATING NEW INFORMATION

DEVELOPING A HYPOTHESIS

UNSUCCESSFUL SOLUTIONS

CHANGING CONDITIONS OF THE PROBLEM

SELF REFERENCE OR CRITICISM

SILENCE

PROTOCOL ANALYSIS VIII

EXPERTS ON A PROBLEM VERBALIZE A LOT MORE THAN NON EXPERTS (DOUBLE).

VERBALIZATION OCCURS ONLY 30% TO 50% OF THE TIME

PEOPLE CANNOT VERBALIZE WHEN:

READING TEXT

DOING INTENSE COGNITIVE ACTIVITY

MAKING CHOICES

PEOPLE HAVE TO SLOW DOWN TO VERBALIZE

PROTOCOL ANALYSIS IX

HOW TO INCREASE VERBALIZATION

1. HOLD BACK STIMULUS OR ENCOURAGE SLOWNESS

2. SEGMENT STIMULUS

3. INTERRUPT WITH PRE-ARRANGED SIGNAL OR SET POINT

PROTOCOL ANALYSIS X OBJECTIVES

OBJECTIVES FOR INTERACTIVE SYSTEMS:

DETERMINE THEIR UNDERSTANDINGS OF TERMS IN THE INTERFACE

UNDERSTAND THE CAUSE OF ERRORS OR MISINTERPRETATIONS

DETERMINING MISSING FUNCTIONALITY OR USER REQUIREMENTS

DETERMINING THE UTILITY OF THE METAPHOR FOR LEARNING

DETERMINING THE UTILITY OF HELP AND GUIDANCE

PROTOCOL ANALYSIS XI APPROACH 1

ASK THE USER TO DESCRIBE WHAT HE OR SHE IS DOING OUTLOUD

TO GO THROUGH THE TERMS ON THE SCREEN AND EXPLAIN WHAT THEY THINK THEY MEAN

TO TRY TO FORECAST WHAT A COMMAND CHOICE WILL DO

CAN RECORD, TAPE, AND/OR MAKE NOTES

PROTOCOL ANALYSIS XII APPROACH 2

EXPLAIN IT IS SYSTEM BEING EVALUATED, NOT USER

THERE TO OBSERVE ONLY, CANNOT HELP USER

ONLY ASK USER TO VERBALIZE IF IT IS UNCLEAR AS TO WHAT THEY ARE DOING

PROTOCOL ANALYSIS XIII APPROACH 3

ASK TO EXPLAIN:

1. WHAT THEY ARE TRYING TO DO

2. WHAT CONFUSION OR CONCERNS THEY HAVE

3. WHAT THEY EXPECT TO HAPPEN NEXT

4. WHAT THEY DON'T KNOW THE MEANING OF

PROTOCOL ANALYSIS XIV APPROACH 4

GIVE HELP ONLY IF USER IS AT A DEAD END

USERS DO NOT ALWAYS KNOW WHY THEY DO THINGS

SAVE RETROSPECTIVE QUESTIONS FOR END

PROTOCOL ANALYSIS XV ADVANTAGES

A LOT LESS EFFORT THAN OTHER APPROACHES

CAN BE DONE ON PROTOTYPE OR MOCKUP

LEARNING HOW USER APPROACHES TASK

CAN LEARN ATTITUDE

RAPID FEEDBACK FROM SMALL SAMPLES

PROTOCOL ANALYSIS XVI REQUIREMENTS

REQUIREMENTS:

SUBJECTS MUST BE REPRESENTATIVE

INSTRUCTIONS SIMPLE

YOU MUST BE OBSERVER ONLY

PROTOCOL ANALYSIS XVII QUESTIONS

CAN ASK:

WHAT ARE YOU THINKING?

WHAT DOES THAT TERM MEAN?

SHOULD NOT ASK:

WHY DID YOU DO THAT!

WHAT DOES A MESSAGE DO?

PROTOCOL ANALYSIS XVIII HOW TO 1

A ONE PAGE EXPLANATION TO THE SUBJECT

A SET OF WRITTEN TASKS IN USER TERMS

SUBJECT SHOULD SPEND ABOUT ONE HOUR

A CATEGORISATION SCHEME FOR RECORDING

TAPE RECORD THEIR VERBALIZATIONS

PROTOCOL ANALYSIS XIX HOW TO 2

RETROSPECTIVE QUESTIONNAIRE FOR END

RETENTION OF MAJOR CONCEPTS

PERCEIVED UTILITY OF FEATURES

DO NOT TRY TO TEST EVERYTHING

AT LEAST THREE SUBJECTS ON SAME TASKS

BE SPECIFIC ABOUT USER EXPLAINING CHOICE THEY ARE ABOUT TO MAKE

GUIDELINES

MODELS I

COGNITIVE MODEL

DESCRIPTION OF MENTAL PROCESS BY WHICH HUMAN PERFORMS A TASK

USER CONCEPTUAL/MENTAL MODEL

DESCRIPTION OF THE MODEL OF THE SYSTEM THAT THE USER UNDERSTANDS

SYSTEM METAPHOR

DESIGNERS MODEL OF THE SYSTEM INTENDED TO BE THE ONE THE USER UNDERSTANDS

MODELS II

IMPLEMENTATION MODEL

MODEL USED TO DESCRIBE THE INTERNAL SYSTEM

REQUIREMENTS MODEL

MODEL DEVELOPED THROUGH SYSTEMS ANALYSIS PROCESS

REAL WORLD MODEL

WHAT OCCURS IN THE PHYSICAL WORLD

GUIDELINES I

HIGHLIGHTING

COLOR, SOUND, REVERSE VIDEO, FLASHING, SIZE, FONTS, BOXING, WINDOWING

PURPOSE: ATTENTION GETTING AND FEEDBACK

SCREEN LAYOUT

STATUS, WORK, CONTROL, ERROR, HELP

GUIDELINES II

TELL USER WHAT HE/SHE IS WORKING ON

HIGHLIGHT WHAT USER HAS SELECTED

PUT DATA IN SOME ORDER

LONG STRINGS/NUMBERS BROKEN UP INTO MEANINGFUL CHUNKS

106677471812 1066-742-1812

SCREEN DENSITY 25% TO 50%, 30% USUALLY IDEAL

GUIDELINES III

ORDER/GROUP MATERIAL: SEQUENTIAL, CLASSIFIED, HIERARCHICAL

MENU CHOICES: 5 TO 9 (7+-2)

GROUP MENU ITEMS:

CHANGE / NO CHANGE

TWO DIMENSIONAL ( 5 X 5 = 25 )

GUIDELINES IV

MENU TYPES

STRATEGIC MENUS / CONTROL PANELS

MENU TREES / OUTLINES

POPUP/PULLDOWN MENUS

LISTS (MULTIPLE CHOICES)

OBJECT MENUS (ICONS)

ACTION MENUS

MODIFIER MENUS

GUIDELINES V

CHOICE SELECTION

CURSOR KEYS / MOUSE

SELECTION BAR

NUMBERS

LETTERS

ABBREVIATION

IMPORTANT FACTORS

FREQUENCY OF USE

GROUPINGS OF COMMANDS

HABIT & ERROR AVOIDANCE

CONTROLS

GUIDELINES VI

SEPARATE PARAGRAPHS BY BLANK LINES

USER STANDARD REPRESENTATIONS: HH:MM:SS

USE COMPLETE WORDS

AVOID HYPHENATION

USE VERTICALLY ALIGNED LISTS

USE OUTLINES AND BULLETS

MOST SIGNIFICANT WORDS FIRST

MINIMIZE PUNCTUATION: CPU

GUIDELINES VII

LABELING

LABEL OR IDENTIFICATION FOR AN OBJECT

DESCRIPTIVE TITLE, PHRASE

SPEED SCAN OF SHORT VERSION OF OBJECT

FULL STATUS DESCRIPTION OF AN OBJECT

APPLIES TO CONTENT OBJECTS, MENUS, SCREENS, STATES

GUIDELINES VIII

USER SHOULD BE ABLE TO CONTROL AMOUNT OF INFORMATION

ALL MEANINGFUL ALTERNATIVES IN ONE SCREEN

CONSISTENCY IN USE OF TERMS

SPECIFICITY OF TERMS DESIRABLE

FAMILIARITY OF TERMS DESIRABLE

GUIDELINES IXX

ALLOW SYNONYMS WHERE POSSIBLE

ALWAYS CONFIRM CRITICAL ACTIONS (E.G. DELETE)

MINIMIZE NUMBER OF MODES OF INTERACTION (E.G. EDIT MODE)

DISPLAY ACTION TAKING PLACE (E.G. STATUS)

MINIMIZE SUPERFLUOUS TASKS (E.G. LOGON)

GUIDELINES XX

PROMPTS AS SOON AS POSSIBLE AFTER ERRORS

USER GIVEN IMMEDIATE CHANCE TO CORRECT

IDENTIFY ERRORS SPECIFICALLY

PROVIDE RECOVERY INFORMATION

+UNDO OR +OOPS

SHOULD EXPLAIN WHY WHEN SOMETHING CAN NOT BE DONE

GUIDELINES XXI

ALLOW USER TO STAY IN ONE MODE OF ENTRY AS LONG AS POSSIBLE

ALLOW ENTRY STACKING OR ANSWER AHEADS

USE LOWER AND UPPER CASE

INDEXING

INDEXING I

HIERARCHICAL

SINGLE LOCATION IN TREE

PRECISE DEFINITIONS

E.G. 1. 1.1 1.2 1.1.1

E.G. OUTLINES, MS/DOS FILES

RIGID, DIFFICULT TO ADAPT

INDEXING II

NETWORK (LATERAL LINKS)

SINGLE LOCATION IN NETWORK

PRECISE RELATIONSHIPS

E.G. BOOK INDEX, CITATION INDEX

E.G. HYPERTEXT

LACK OF GLOBAL VIEW

INDEXING III

SUBJECT HEADINGS

MULTIPLE SUBJECT HEADINGS

FIXED CATEGORIES, NO STRUCTURE

PRECISE DEFINITIONS

E.G. COMPUTERS IN CHEMISTRY AND INTEGRAL EQUATIONS

INDEXING IV

KEY WORD AND COORDINATE SYSTEMS

FIXED KEY WORDS

FREE KEY WORDS

MULTIPLE KEYS

COORDINATES FOR PROPERTIES E.G. TALL, MEDIUM, SHORT

INDEXING V

SYNTACTIC LANGUAGES 1

TAGGED DESCRIPTORS

QUALIFIED KEYS

E.G. TANK.WEAPON, TANK.PETROLEUM

INDEXING VI

SYNTACTIC LANGUAGES 2

FACETED INDEX

SEPARATE DIMENSIONS

E.G., QUANTITY, STYLE, COLOR

E.G., FOR LEATHER, WINE, METAL ALLOYS

E.G., AUTHOR, TITLE, SOURCE

E.G., STEEL, COMPONENT, INDUSTRY

MIXED INDEXES

UNIVERSAL DECIMAL CLASSIFICATION

INDEXING VII

UNIVERSAL DECIMAL CLASSIFICATION

341.67:623.454.8(094.2)

341.67: DISARMAMENT, LIMITATION AND CONTROL OF WEAPONS OF MASS DESTRUCTION

623.45: AMMUNITION, PYROTECHNIC DEVICES, WEAPONS OF MASS DESTRUCTION

623.454.8: ACTIVE RAYS, ATOMIC NUCLEAR (THERMO) WEAPONS

094.2: HISTORICAL SOURCES (09), INTERNATIONAL TREATIES

INDEXING VIII

PHRASES

SHORT PHRASES, TITLES

E.G. KWIC INDEX

E.G. CHAPTER HEADINGS

NATURAL LANGUAGE

E.G. ABSTRACTS

INDEXING EFFECTIVENESS IX

RELEVANT NON-RELEVANT

RETRIEVED A B

NOT RETRIEVED C D

PRECISION = A / (A+B)

RECALL = A / (A+C)

SPECIFICITY = D / (B+D)

SEARCH EFFICIENCY = (RECALL)(SPECIFICITY)

INDEXING EFFECTIVENESS X

TIMELINESS (UPDATING)

ACCURACY

COMPLETENESS (ALL IN DATABASE)

FORM OF DATA (E.G. SUMMARY, RAW DATA)

SUBJECTIVE / OBJECTIVE

ADOPTION

HISTORICAL RELEVANCE

INDEXING XI

INDEX TYPE

AMBIGUITY EXPRESSIVE CONCISE

HIERARCHICAL

LOW LOW HIGH

NETWORK

SUBJECTS

FIXED KEYS

FREE KEYS

TAGGED DESCRIPTORS

FACETED INDEXES

PHRASES

NATURAL LANGUAGE

HIGH HIGH LOW

INDEXING XII

INDEX TYPE

RETRIEVAL SELECTION ADOPTION

EFFORT EFFORT EFFORT

HIERARCHICAL

LOW HIGH HIGH

NETWORK

SUBJECTS

FIXED KEYS

FREE KEYS LOW

TAGGED DESCRIPTORS

FACETED INDEXES

PHRASES

NATURAL LANGUAGE

HIGH LOW HIGH

INDEXING XIII

INDEX TYPE IDEAL USE

HIERARCHICAL

MACRO, WELL STRUCTURED

NETWORK

MICRO, STRUCTURED RELATIONSHIPS

SUBJECTS

MACRO, STRUCTURED CONCEPTS

FIXED KEYS

FREE KEYS

MICRO, UNSTRUCTURED

INDEXING XIV

TAGGED DESCRIPTORS

FACETED INDEXES

MICRO, STRUCTURED FACTORS

PHRASES

MACRO, SEMI STRUCTURED

NATURAL LANGUAGE

MACRO, UNSTRUCTURED

INDEXING XV

ZIPF'S LAW

LOG FREQUENCY OF TERMS IN THE ENGLISH LANGUAGE ARE LINEAR WITH LOG OF RANK ORDER

USED TO DETERMINE INDEX TERMS

HIGH FREQUENCY USELESS

LOW FREQUENCY USELESS FOR KEYS LEFT

TERMS DIFFERENT FROM NORMAL ENGLISH

LEADS TO PRINCIPLE OF LEAST HUMAN EFFORT

USER & TASK PROPERTIES

USERS AND TASKS

INDIVIDUAL DIFFERENCES

ABILITIES, SKILLS, BACKGROUNDS COGNITIVE STYLE

DATA DIFFICULT TO USE BY DESIGNERS

IS USED IN SELECTION OF JOBS

OFTEN TIED TO TASK WHICH IS EASIER TO DEAL WITH

VERY USEFUL TO HAVE TASK TAXONOMY

DESIGNERS FAMILIAR WITH TASK DOMAIN USUALLY DO BETTER JOB

ERROR ANALYSIS

ERROR FREQUENCY ANALYSIS CAN BE VERY INDICATIVE OF DESIGN PROBLEMS

SINGLE MOST IMPORTANT MONITORING FUNCTION

SYNTACTIC ERRORS CAN BE USED TO TRIGGER LEARNING AIDS

CONCEPTUAL ERRORS WHERE THE CURRENT CHALLENGE IS

USER TASKS

TRAP OF DESIGNING A SYSTEM WHICH REINFORCES CURRENT USER BEHAVIOUR

MICRO AND MACRO UNDERSTANDING OF TASK

MICRO = COGNITIVE LEVEL

MACRO = FUNCTIONAL LEVEL

PREDICTING WHAT HAS NOT BEEN POSSIBLE

EXAMPLE: CLASSIFYING COMMUNICATIONS OF A MANAGER

USER TASKS

PAPER SIMULATION

USER OBSERVATION

PARTICIPANT OBSERVATION

PROTOCOL ANALYSIS APPLIED TO TASK

PROTOTYPING ALTERNATIVES

MOCK UPS (DEMO2)

TASK MODEL APPROACHES I

CONTROL SYSTEM MODELS

PHYSIOLOGICAL

SPEED/ERROR ASSESSMENT

NETWORK MODELS

STATISTICAL

BEHAVIOUR PATTERNS

DECISION THEORY MODELS

TASK STRATEGIES

E.G., SEARCHES

INFORMATION PROCESSING MODELS

MEMORY, ATTENTION

RECOGNITION

TASK MODEL APPROACHES II

PROBLEM SOLVING MODELS

MACRO BEHAVIOUR

GOALS, OBJECTIVES

COGNITIVE MODELS

MICRO BEHAVIOUR

SCANNING, SPECIFICITY, ETC.

MENTAL (METAPHOR) MODELS

LEARNING

COMPREHENSION

PROBLEM OF TASK ALLOCATION:

WHAT TO GIVE TO THE USER AND WHAT TO GIVE TO THE COMPUTER TO DO

CHOOSING PROBLEM SOLVING AIDS

NOT UNITARY, NOT ONE AID FOR EACH SITUATION

BOTH TASK AND USER EXPERIENCE INVOLVED

PROBLEM SOLVING SUBTASKS

PROBLEM RECOGNITION

PROBLEM DEFINITION

GOAL DEFINITION

STRATEGY SELECTION

ALTERNATIVE GENERATION

ALTERNATIVE EVALUATION

ASPECTS OF A TASK

1. GOALS AND INTENTIONS

2. SPECIFICATION OF ACTIONS

3. MAPPING FROM GOALS TO ACTIONS

4. TRANSLATION: COGNITIVE TO PHYSICAL

5. PHYSICAL STATE OF THE SYSTEM

6. CONTROL MECHANISMS

7. MAPPING PHYSICAL TO CONTROL

8. INTERPRETATION OF SYSTEM STATE

9. EVALUATING OUTCOMES

USER ACTIVITIES

ESTABLISHING GOAL

FORMING INTENTION

SPECIFYING ACTION SEQUENCE

EXECUTING THE ACTION

PERCEIVING SYSTEM STATE

INTERPRETING THE STATE

EVALUATING RELATIONSHIPS

BEHAVIOUR DIMENSIONS

ABSTRACTION NO ABSTRACTION

SEARCH NO SEARCH

DATA DRIVEN CONCEPTUALLY DRIVEN

ABSTRACTION: DEAL WITH STRATEGY

NO ABSTRACTION: GENERATE ALTERNATIVES

SEARCH: NEW STRATEGIES

NO SEARCH: USING ESTABLISHED STRATEGIES

DATA DRIVEN: EVALUATION BY DATA

CONCEPTUALLY DRIVEN: EVALUATION BY CONCEPT

METHODS OF PROBLEM SOLVING I

ALTERNATIVE EVALUATION: SEARCH, NO ABSTRACTION

ALTERNATIVE GENERATION: SEARCH, NO ABSTRACTION, CONCEPTUALLY DRIVEN

BACKTRACKING: NO ABSTRACTIONS, SEARCH

IMPROVING DATA: DATA DRIVEN

CHANGE PROBLEM REPRESENTATION: ABSTRACTION

CONSISTENCY CHECKING: DATA DRIVEN

STRATEGY IMPROVEMENT: ABSTRACTION, CONCEPTUALLY DRIVEN

METHODS OF PROBLEM SOLVING II

DECOMPOSITION AND RECOMBINATION: ABSTRACTION, CONCEPTUALLY DRIVEN

EXTENDED MEMORY: NO ABSTRACTION, SEARCH, NO SEARCH, DATA DRIVEN, CONCEPTUALLY DRIVEN

RAPID TRIAL AND ERROR: NO ABSTRACTION, SEARCH, DATA DRIVEN

STRATEGY CAPTURE (RULE SYSTEMS): DATA DRIVEN

DIALOGUE PROPERTIES

INITIATIVE: COMPUTER OR USER INITIATIVE

FLEXIBILITY: NUMBER OF WAYS A USER CAN ACCOMPLISH A GIVEN TASK

POWER: AMOUNT OF WORK DONE BY THE SYSTEM IN RESPONSE TO A SINGLE USER ACTION

INFORMATION LOAD: DEGREE TO WHICH THE INTERACTION ABSORBS MEMORY AND PROCESSING RESOURCES OF USER

GUIDELINES

INTERFACE BUGS

OUTRIGHT FAILURE

DOING SOMETHING THE WRONG WAY

NOT ALLOWING SOMETHING TO BE DONE

STRUCTURAL: USER CAN DO X Y BUT NOT Y X

DESIGN PRINCIPLES

MAKE EXPLANATIONS BRIEF

ESSENTIAL PART OF DESIGNING USER INTERFACES IS TO EXPLAIN THEM

A STRUCTURE MODEL IS KEY TO UNDERSTANDING

MENDELEEV'S PERIODIC TABLE AND IMPACT ON CHEMISTRY

JOSS DESIGN PRINCIPLES I

EXECUTION STEPS ARE ALWAYS COMPLETED

INTERRUPT CAUSES NO STATE CHANGE

SINGLE MODE

COMMAND CAUSING AN ERROR HAS NO IMPACT

JOSS AND USER PERCEIVE SAME INTERNAL STATE

JOSS DESIGN PRINCIPLES II

JOSS INSISTED ON LETTER PERFECT INPUT/OUTPUT

USER / COMPUTER CONTROL BY LOCKED KEYBOARD -NEVER ANY DOUBT

ANYTHING INPUTTED COULD BE STORED

INCREMENTAL AND BATCH THE SAME

USER MENTAL MODELS

USER MODEL IS RARELY VERBALIZED

A USER MODEL IS GENERALLY AS SIMPLE AS POSSIBLE

THE USER MODEL OFTEN CHANGES AS HE OR SHE ACQUIRES MORE KNOWLEDGE ABOUT THE SYSTEM

USER MODELS SHOULD CONFORM TO PSYCHOLOGICAL REQUIREMENTS

TASK MODEL OF WRITING I EXPLORE

I. EXPLORE

GATHER RAW MATERIALS

EXPLORE (BROWSE) MATERIALS

PLAY WITH DIFFERENT CLUSTERS OF IDEAS AND

RELATIONSHIPS

LET IDEAS HAPPEN

MECHANICS

JOT AND POSTING, OUTLINE, DIAGRAMS, FILL IN HOLES, BOTTOM UP, TOP DOWN

OBJECTIVE: MAP CONCEPTUAL SPACE

WRITING II ANALYSES 1

II. ANALYZE READERS

IDENTIFY READERSHIP

RANK THEM

ESTIMATE WHAT THEY KNOW ABOUT SUBJECT

DETERMINE WHAT YOU HAVE TO TELL THEM

SET GOALS ON HOW MUCH YOU WANT TO CHANGE THEM

WRITING III ANALYSES 2

CHANGE KNOWLEDGE, CHANGE ATTITUDE

METHODS

ESTIMATE DISTANCE FROM YOU

MATRIX OF CONCEPTS BY READER TYPES

WRITING IV FOCUS 1

III. FOCUS

DECIDE ON THE DOCUMENT YOU WILL WRITE OUT OF ALL POSSIBLE

WHAT IS OVER RIDING POINT

MOST IMPORTANT READERS

CHANGE TO MAKE IN READERS

HOW TO SOUND (IMAGE)

WRITING V FOCUS 2

ORGANIZE TOP-DOWN HIERARCHICAL STRUCTURE

HEADINGS ARE CUES TO READER ON CONCEPTS

BOTTOM LEVEL:

PARAGRAPH FOR WHAT YOU DO NOT KNOW WELL

PAGE OR MORE FOR MATERIAL YOU KNOW WELL

WRITING VI WRITING 1

IV. WRITE

PRODUCE USABLE DRAFT FOR LATER REVISION

DO NOT REVISE AS YOU GO

ALTERNATIVE WAYS

START TO FINISH

TOP-DOWN: INTRODUCTION AND SUMMARY

RANDOM ORDER

BOTTOM UP: DETAILS FOR EACH SECTION

WRITING VII WRITING 2

PROBLEMS IN WRITING

WITH WORDING

MARK FOR LATER

3 STRIKES YOUR OUT,

KEEP WRITING

WITH STRUCTURE

MINOR - KEEP WRITING

MAJOR - RETHINK STRUCTURE

THINK STRATEGICALLY: TO PERSUADE, TO INFORM, SIGNAL HIERARCHY

WRITING VIII FINAL STAGES

V. VERIFY AND REVISE

GOAL: TO TURN DRAFT INTO FINISHED PRODUCT

SET PRIORITY AND EFFORT

SYNTACTIC: GRAMMAR, WORD CHOICE, SPELLING

SEMANTIC: OBJECTIVES, STRUCTURE, PARAGRAPHS

VI. REVIEW

VII. FORMAT

VIII. COLLABORATIVE DOCUMENT

WRITING IX STRUCTURE

RELATION WRITERS READERS

NETWORK EXPLORING REMEMBERING

HIERARCHY ORGANIZING COMPREHENDING

SEQUENCE ENCODING DECODING

DOCUMENT SHOULD SIGNAL STRUCTURE: HEADINGS

PARAGRAPH IS A SINGLE THOUGHT

HYPERTEXT AN APPROACH TO NETWORKS LEVEL

WRITING AND READING X

HIGHLIGHT WHAT THEY WANT: IMPOSE VALUE

ANNOTATE, MARGINAL NOTES

FLIP PAGES BACK AND FORTH

SEEK REFERENCES, INDEX, GLOSSARY, TEXT TO FIGURE, EARLIER ITEMS

MARKING TRIALS

BOOKMARKS FOR INTERRUPTIONS

COPYING NOTES

AGENDA FOR FURTHER WORK

MENTAL MODEL GUIDELINES 1

FORM DATA CHUNKS THAT ARE USED THROUGHOUT THE APPLICATION

VERBAL MEDIATION: WITHIN SYSTEM IMPORTANT WORDS SHOULD TAKE ON SPECIALIZED MEANINGS

MODEL PROCESSES IN THE INTERFACE TO THE LEVEL OF DETAIL WHICH THE USER CAN AFFECT, BUT NO MORE

MENTAL MODEL GUIDELINES 2

PROCESSES SHOULD BE GROUP TOGETHER TO HIGHER LEVEL: E.G., ALL UPDATING TASKS

LOWER LEVEL PROCESSES SHOULD BE THE SAME WHERE EVER THEY ARE (SEARCH).

MENTAL MODELS I INTERACTING OBJECTS & EVENTS

CASUAL COMMONSENSE

TEXT OBJECT AND MEMBER OBJECT

CHAIN OF EVENTS

SET OF SYSTEM STATES

MORE AMBIGUOUS AND FUZZY

WORK ON OBJECTS

USERS SELECT OBJECT FIRST

AUTOMATIC PROCESSING

PARALLEL PROCESSING

EVENT DRIVEN

MENTAL MODELS II VARIABLES AND RULES

DETERMINISTIC REASONING

MEASURE BY OBSERVED VARIABLES

MEASURED BY RULES BETWEEN VARIABLES

WORK ON ACTIONS

COMMANDS CHOSEN FIRST

CONSCIOUS PROCESSING

SERIAL PROCESSING

MENTAL MODELS III

USERS WANT TO SUBDIVIDE AND CLASSIFY (ENCODE) SYSTEM

LOW LEVEL OF SYSTEM TO DEAL WITH EVENT DRIVEN PROCESSES (REACTIVE)

HIGHER LEVEL DRIVEN BY GOALS AND MOTIVES (STRATEGIC)

MENTAL MODELS IV

PROBLEM IS POSSIBLE LATERAL PROCESSING BETWEEN BOTTOM LEVEL NODES

BOTTOM LEVEL

DATA DOMAIN FOR ASSOCIATION, RECOGNITION, AND MATCHING

FUNCTIONAL DOMAIN FOR ABDUCTION, DEDUCTION, AND INDUCTION

MENTAL MODELS V

IF SYSTEM STATE IS NOT OBVIOUS USERS WILL ENCODE IT THEIR OWN WAY

PEOPLE DO NOT MIND DEALING WITH COMPLEXITY IF THEY CAN CONTROL IT

BOTH DATA DRIVEN AND HYPOTHESIS DRIVEN MODES SHOULD BE CATERED TO

MENTAL MODELS VI

USERS SHOULD UNDERSTAND ANY INFERENCE PROCESS

STRUCTURE OF GROUPED DATA SHOULD BE EVIDENT

DATA MANIPULATION SHOULD EXHIBIT RESULTS RATHER THAN INFORM IT IS DONE

ONLY ONE EXIT AND ONE ENTRY TO A PROCESS SHOULD BE USED

MENTAL MODELS VII

T(TASK) = T(ACQUIRE) + T(EXECUTE)

ACQUISITION IS MAIN PROBLEM IN REDUCTION OF TIME

USE USERS COGNITIVE MODEL

MATCHING MECHANISMS:

SYNTACTIC (GRAMMAR)

PARAMETRIC (FORM, COLOR, SHAPE)

SEMANTIC (TEXT)

ICONIC (VISUAL PATTERN)

MENTAL MODELS VIII

TASK KNOWING: GOAL AND SUBTASKS TO BE ACCOMPLISHED

INTERFACE KNOWING: MECHANICS OF ACCOMPLISHING TASK

SYSTEM ARCHITECTURE KNOWING: HOW SYSTEM WORKS

DESCRIPTIVE REPRESENTATIONS: WHAT USER CURRENTLY KNOWS

PRESCRIPTIVE REPRESENTATIONS: WHAT USER SHOULD KNOW

MENTAL MODELS IX GOMS

GOMS: GOALS, OPERATORS, METHODS, AND SELECTION RULES

GOALS, SUBGOALS

RULES TO CHOOSE METHODS

SEQUENCE OF OPERATORS TO DO A METHOD

MENTAL MODELS X GOMS

EXAMPLE: SEVERAL WAYS TO FIND FIRST PLACE TO EDIT:

SEARCH, PAGE SCANNING, CURSOR KEYS

MODELS OF PROCESSING TIME BASED UPON KEYSTROKING VERY ACCURATE

MENTAL MODELS: IF I DO THIS, THIS WILL HAPPEN

MENTAL MODELS XI MODEL TYPES 1

SURROGATES: PERFECTLY MIMICS TARGETS, NO CORRESPONDENCE (SPREADSHEETS)

METAPHORS: DIRECT COMPARISON BETWEEN TARGET SYSTEM AND SOMETHING KNOWN TO USER (DESKTOP)

GLASS BOX: ATTEMPTS TO REPRESENT INTERNAL SUBSYSTEMS (STORAGE FILE CABINETS)

MENTAL MODELS XII MODEL TYPES 2

NETWORK: SYSTEM STATES, USER STATES, AND TRANSITION CONDITIONS

PROBLEM: A FLOW CHART IS LIKE A PIPELINE (GAS/WATER/USER KNOWLEDGE)

MENTAL MODELS XIII INFERENCES

GOMS (SEQUENCE/METHOD) APPROACHES CAN PREDICT EFFORT BUT NOT ERRORS. CAN PREDICT USE OF KNOWLEDGE

MENTAL MODELS EXPLAIN ERRORS AND BEHAVIOUR IN NOVEL SITUATIONS

LEARNING INVOLVES: INTERNALIZATION, ELABORATION, AND CONSTRUCTION

EXPLANATIONS OF CALCULATORS VARY WIDELY EVEN BY PEOPLE WHO USE THEM.

MENTAL MODELS XIV INFERENCES

UNIX: 20 OF 400 COMMANDS ACCOUNT FOR 70% OF USAGE (LOCAL TASK VIEWS)

EXTENSIVE USAGE DOES NOT LEAD TO POWER USE OF SYSTEM (WITHOUT METAPHOR?)

MENTAL MODELS XV LEARNING

IF DESIGN IS BASED UPON A MODEL THEN USER CAN BE TRAINED BY TEACHING THE MODEL

TEACHING A CALCULATOR BY EXPLAINING INTERNAL MODEL

SAME ON STANDARD TASKS

BETTER FOR NOVEL TASKS

SOME INDICATION BETTER LEARNING IF METAPHOR FORCES ACTIVE LEARNING

READING UNDERSTOOD BETTER IF GOALS PRIOR TO DETAILS IN STORIES

MENTAL MODELS XVI METAPHOR EXAMPLES 1

TYPEWRITER (WORDPROCESSING)

DOCUMENT (GML, PAGEMAKER)

OUTLINE (THINKTANK)

CHALKBOARD

NOTECARDS (HYPERTEXT)

DESKTOP (STAR, LISA, ETC.)

DESKTOP TOOLS (SIDEKICK)

DASHBOARD

BUSINESS FORMS

MENTAL MODELS XVII METAPHOR EXAMPLES 2

TABLES OF DATA

SPREADSHEETS

BUILDINGS

THEATRE

ROADMAP

LETTERS

POST OFFICE

SPACES

TOOLS

MENTAL MODELS XVIII PROBLEMS 1

METAPHORS OFTEN INCOMPLETE ANALOGY

MISMATCHES PROVIDE PROBLEMS (DESTRUCTIVE BACKSPACE)

PAPER FORM ON SCREEN MAY RESTRICT INPUT TO FIELDS, NO MARKING

HOWEVER, CAN VERIFY DATA

MENTAL MODELS XIX PROBLEMS 2

METAPHORS OFTEN APPLIED UNEVENLY

METAPHORS CAN BE MORE THAN PHYSICAL WORLD (GAMES)

METAPHORS CAN BE MISLEADING

STRUCTURE OF ATOM = STRUCTURE OF SOLAR SYSTEM

MENTAL MODELS XX COGNITIVE STATES

COGNITIVE STATES OF METAPHOR USE

INSTANTIATION: AUTOMATIC ACTIVATION PROCESS, USUALLY BASED UPON SIMILARITY

MISMATCHES STIR ELABORATION

ELABORATION: MAPPING STRUCTURE BY GOAL MATCHING AND CHECKING INFERENCES

CONFIRMATION OF INFERENCES LEAD TO CONSOLIDATION

CONSOLIDATION: CREATION OF MODEL, CONDENSING INTO SINGLE REPRESENTATION

MENTAL MODELS XXI PROPERTIES

PROPERTIES OF METAPHORS

BASE SPECIFICITY: DEGREE TO WHICH IT SPECIFIES THE TARGET

CLARITY: DEGREE OF ONE TO ONE CORRESPONDENCE

ABSTRACTION: DEGREE OF GENERALITY

RICHNESS: EXPANDABILITY

BASE EXHAUSTIVENESS: COVERS WHOLE OF TARGET

MENTAL MODELS XXII DESIGNING METAPHORS

IDENTIFY CANDIDATE METAPHORS

DETAIL METAPHOR / SOFTWARE MATCH

USE REPRESENTATIVE USER SCENARIOS

IDENTIFY MISMATCHES

IDENTIFY DESIGN STRATEGIES TO HELP USERS

MANAGE MISMATCHES

TO DESCRIBE METAPHOR:

TASKS: WHAT PEOPLE DO

METHODS: OBJECTS, ACTIONS

APPEARANCE: LOOK AND FEEL

MENTAL MODELS XXIII EXAMPLE 1

SCENARIO:

METAPHOR: REMOVE DOCUMENT FROM A FOLDER TO VIEW

TARGET: REMOVE FILE FROM A FILE DIRECTORY TO VIEW

METHODS:

METAPHOR: OPEN FOLDER BY PULLING BACK FOLDER COVER

TARGET: OPEN FOLDER BY DOUBLE CLICKING FOLDER ICON

MENTAL MODELS XXIV EXAMPLE 2

APPEARANCE:

METAPHOR: 3-D PAPER FOLDER THAT UNFOLDS

TARGET: 2-D ICON THAT EXPANDS INTO 2-D WINDOW

MENTAL MODELS XXV LEARNING MODEL 1

COGNITIVE APPRENTICESHIP THEORY

I. BEGIN WITH TASK EMBEDDED IN FAMILIAR ACTIVITY (BY EXAMPLE)

PROVIDES SCAFFOLDING FOR UNFAMILIAR TASK

II. POINT TO DIFFERENT DECOMPOSITIONS

STRESSES HEURISTICS ARE NOT ABSOLUTE

MENTAL MODELS XXVI LEARNING MODEL 2

III. ALLOW LEARNER TO GENERATE THEIR OWN PATHS

ENCULTURATING/SITUATED COGNITION

MENTAL MODEL XXVII DOCUMENTATION

MINIMAL MANUAL

FOCUS ON REAL TASKS NOT OVERVIEWS

DON'T EXPLAIN MENU BUT SHOW HOW TO CREATE A MESSAGE

EXPLAIN PRINCIPLE ERRORS USERS MAKE AS DETERMINED BY PROTOCOL ANALYSIS

COORDINATE WRITING WITH THE USE OF THE SCREENS

"CAN YOU FIND THIS PROMPT ON THE SCREEN?"

MENTAL MODELS XXVIII COGNITIVE 1

DIFFICULT CONSTRUCTING COMMANDS THAT ARE "NATURAL"

NATURAL IMPLIES EXISTENCE OF GOAL-ACTION ASSOCIATION

COMMAND HIERARCHY IS ONE APPROACH

GET.LIST

GET.SCAN

GET.VIEW

MENTAL MODELS XXIX COGNITIVE 2

NUMBER OF RULES TO DECOMPOSE A GOAL INTO SUBGOALS AND TO EXECUTE THE SEQUENCE OF ACTIONS PREDICTS LEARNING TIME

LEARNING PROGRAM LANGUAGE = 200-500 HOURS

NUMBER OF THOUGHTS TO CONSTRUCT NEXT ACTION PREDICTS DELAY

AMOUNT NEEDED IN SHORT TERM MEMORY PREDICTS ERRORS

MENTAL MODELS XXX COGNITIVE 3

VISUAL LAYOUT FOUND TO BE VERY IMPORTANT AND NOT PREDICTED BY GRAMMAR RULES

REDUCE NUMBER OF RULES NEED IS AN OBJECTIVE

DELETING SENTENCE SAME RULE AS DELETING PARAGRAPH

TRAINING WHEELS: INTRODUCE ONLY SUBSET OF SYSTEM

MENTAL MODELS XXXI COGNITIVE 4

METAPHORS SHOULD NOT BE MECHANISTIC

WHETHER OR NOT SYSTEM USES METAPHOR IN THE DESIGN THE USER WILL FORMULATE ONE

MAIL METAPHOR AN EXAMPLE OF LIMITING THE UNDERSTANDING OF WHAT IS POSSIBLE

MENTAL MODELS XXXII OBSERVATION

"METAPHORS ARE NOT JUST GOOD OR BAD DESCRIPTIONS OF THEIR TARGETS, RATHER THEY ARE STIMULATING OR UNSTIMULATING INVITATIONS TO SEE TARGET DOMAIN IN A NEW LIGHT." CARROL

COGNITIVE PROPERTIES

THE MAGIC NUMBER 7+-2

MILLER (1956)

CHUNKING

1776149219181941

LIMITED CHANNEL CAPACITY

SHORT TERM MEMORY

INFORMATION THEORY

LEARNING STRATEGIES

PEOPLE REORGANIZE INFORMATION TO OVERCOME LIMITATIONS

THE MAGIC NUMBER 7+-2

EXAMPLES

THE SEVEN SEAS

THE SEVEN WONDERS OF THE WORLD

THE SEVEN SINS

RECIPROCAL RELATIONSHIP

COGNITIVE PSYCHOLOGY

INFORMATION PROCESSING

MEMORY MODELS

LEARNING THEORIES

LANGUAGE PROCESSING

IMAGE PROCESSING

ORGANIZATION AND CLUSTERING

LEVELS OF MEMORY

HUMAN FACTORS AND ENGINEERING

STIMULUS RESPONSE MODELS

PERCEPTION PROCESSING

SIGNAL/NOISE RELATIONSHIPS

PHYSIOLOGICAL RESPONSES

SIGNAL DETECTION THEORY

CHOICE REACTION TIME

DECISION PERFORMANCE

STRESS REACTIONS

FILTERING

MAN-MACHINE SYSTEMS

COMMUNICATIONS AND INFORMATION THEORY

COMMUNICATION CHANNELS

CAPACITY

CODING

SERIAL AND PARALLEL PROCESSING

UNCERTAINTY AND AMBIGUITY

SUBJECTIVE INFORMATION MEASURES

MORSE CODE CODING

LETTER CODE PROBABILITY

E * .131

T - .105

A *- .082

X *-** .0012

Z **** .0008

THE THIRD METAPHOR COMPUTER ANALOGY TO THINKING

GENERALITY OF PURPOSE

ALGORITHMS, SUBROUTINES AND COMPILERS

CONDITIONAL INSTRUCTIONS AND DECISION MAKING

SIMULATION

STRUCTURAL THEORY

SYMBOL MANIPULATION

LEVELS OF ABSTRACTION

PROGRAMS AND INTERNAL STORAGE

THEORIES OF LANGUAGE AND KNOWLEDGE

AN INFORMATION PROCESSING SYSTEM

ENVIRONMENT

RECEPTORS, EFFECTORS, PROCESSOR, MEMORY

SYMBOLS

STRUCTURE

SET OF RELATIONSHIPS

REFERENCES OBJECT

PROGRAM OR INTERPRETER

MEMORY

RETAINS SYMBOL STRUCTURES

REPRESENTATION

SYSTEM CONCEPTS

INFORMATION FLOW

DECOUPLING

HIERARCHICAL STRUCTURE

NETWORKING STRUCTURE

ASSOCIATIVE STRUCTURE

CHOICE REACTION TIME (CRT) SERIAL PROCESSING MODE

STIMULUS PREPROCESSED

STIMULUS COMPARED UNTIL CATEGORIZED

CATEGORISATION IS BASIS FOR RESPONSE SELECTION

SUBJECT PROGRAMS HIS RESPONSE EXECUTION

PROPORTIONAL TO LOG OF CHOICES

CONSISTENT WITH INFORMATION THEORY

40 MSEC PER ITEM, 400 MSEC INITIAL SETUP

SERIAL AND PARALLEL PROCESSING

CRT SERIAL

TYPING AND PHONE NUMBERS PARALLEL

SCANNING FOR:

(K, Z), OR (K, O), OR (O, C)

K OR (K,Z) SAME TIME

(K, O) DOUBLE TIME

PREPROCESSORS FOR SENSES

PEOPLE SCANNING NEWSPAPERS

SPEED INDEPENDENT OF NUMBER OF CLIENTS

SPEED-ACCURACY TRADE-OFF

EXTREME ACCURACY EMPHASIS

SLOW, MAXIMUM ACCURACY

EXTREME SPEED EMPHASIS

FAST, VERY LOW ACCURACY

HUMANS CAN CHOOSE TRADEOFF POINT

SIGNAL DETECTION THEORY

SIGNAL DETECTION THEORY I

HUMAN SETS:

UPPER THRESHOLD

FAST POSITIVE RESPONSE

SMALL NUMBER OF FALSE ALARMS

LOWER THRESHOLD

FAST NEGATIVE RESPONSE

SMALL NUMBER OF MISSES

SIGNAL DETECTION THEORY II

BETWEEN THRESHOLDS

MEMORY SEARCH YIELDING

SLOWER POSITIVE AND NEGATIVE RESPONSES

FAMILIARITY IS THE X AXIS

LEARNING EFFECTS

RECOGNITION DECISION FLOW

STIMULUS PRESENTED

ENCODING AND ACCESS TO

FAMILIARITY VALUE

RESPOND IMMEDIATELY

NO: EXHAUSTIVE SEARCH

YES: ACTIVATE RESPONSE

RESPONSE OUTPUT

HUMAN PERFORMANCE CAN BE INFLUENCED

Design Of Interactive Systems

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