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
(c) Copyright 1991 Murray Turoff

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CONTENTS

  1. Background
  2. Dimensions of Design
  3. Evaluation
  4. Design Guidelines
  5. Folklore
  6. Protocol Analysis
  7. Guidelines
  8. Indexing
  9. User & Task Properties
  10. User Mental Models
  11. Cognitive Properties

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

GO TO START


DIMENSIONS OF INTERFACE DESIGN

* (c) copyright 1991 Murray Turoff

DIMENSIONS OF INTERFACE DESIGN

* 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

DIMENSIONS OF INTERFACE DESIGN

* FOUNDATION FACTORS
* UNDERSTANDING & EASE OF LEARNING
* SENSE OF CONTROL
* EFFECTIVENESS
* PSYCHOLOGICAL & SOCIOLOGICAL
* ADMINISTRATIVE

DIMENSIONS OF INTERFACE DESIGN

* FOUNDATION FACTORS

* TIMELINESS
* RESPONSIVENESS
* RELIABILITY
* ACCESSIBILITY / CONVINCE
* EFFICIENCY / LEAST EFFORT
* SECURITY
* ACCURACY
* PROTECTION / BULLET-PROOFING

DIMENSIONS OF INTERFACE DESIGN

* UNDERSTANDING / EASE OF LEARNING

* GUIDANCE
* INFORMATIVENESS
* CONCISENESS / BREVITY
* CLARITY / SIMPLICITY
* COMPREHENSION
* SEGMENTATION / DECOMPOSITION
* CONSISTENCY
* RETENTION
* SPECIFICITY
* FAMILIARITY

DIMENSIONS OF INTERFACE DESIGN

* SENSE OF CONTROL I

* LEVERAGE / MODIFIABILITY
* MANIPULABILITY
* CLOSURE / CONFIRMATION / NOTIFICATION
* FEEDBACK
* SENSE OF CAUSALITY
* MULTI-TASKING
* PROCESS CONTROL / ESCAPE / INTERRUPT

DIMENSIONS OF INTERFACE DESIGN

* SENSE OF CONTROL II

* FORGIVENESS
* TRANSPARENCY
* FLEXIBILITY / COGNITIVE ADOPTION
* PREDICTABILITY / REGULARITY
* CONTEXTUAL VISIBILITY
* TRACKING

* BACKTRACKING / AUDITING
* FORECASTING / ANTICIPATING
* BACKUP / UNDO

DIMENSIONS OF INTERFACE DESIGN

* EFFECTIVENESS I

* TASK FUNCTIONALITY

* GENERALITY
* MATCHING
* COMPLETENESS
* ROBUSTNESS
* ABSTRACTION
* ADAPTABILITY

DIMENSIONS OF INTERFACE DESIGN

* EFFECTIVENESS II

* INTEGRATION / CONNECTIVITY
* RESILIENCY / ROBUSTNESS / RICHNESS
* RELEVANCE
* PRECISION

DIMENSIONS OF INTERFACE DESIGN

* PSYCHOLOGICAL & SOCIOLOGICAL I

* ETHICAL / HONESTY
* AESTHETIC / PLEASING / ARTFUL
* INTERESTING / CHALLENGING / FUN
* SELF IMAGE ENHANCEMENT
* EXPECTATIONS / MOTIVATION
* PEER RELATIONS / STATUS
* SENSE OF COMMUNITY
* HUMANIZATION / POLITE

DIMENSIONS OF INTERFACE DESIGN

* PSYCHOLOGICAL & SOCIOLOGICAL II

* SATISFACTION

* SYSTEM
* GROUP
* TASK

* MOTIVATION
* EXPECTATIONS
* PERCEIVED UTILITY
* FEELING OF PARTICIPATION

DIMENSIONS OF INTERFACE DESIGN

* ADMINISTRATIVE

* TRAINING / DOCUMENTATION
* MAINTENANCE
* JOB ENHANCEMENT
* HUMAN HELP
* ORGANIZATION RELATIONSHIPS
* SYSTEM EVOLUTION / MODIFIABILITY
* EVALUATION / FEEDBACK
* CHARGING POLICIES
* CONFIDENCE

DIMENSIONS OF INTERFACE DESIGN

* 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

GO TO START


EVALUATION OF INTERFACES

* (c) copyright 1991 Murray Turoff

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

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

GO TO START

DESIGN INTRODUCTION

* (c) copyright 1991 Murray Turoff

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

GO TO START


FOLKLORE OF INTERACTIVE SYSTEMS

* (c) copyright 1991 Murray Turoff

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

* (c) copyright 1991 Murray Turoff

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

GO TO START


GUIDELINES

* (c) copyright 1991 Murray Turoff

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

GO TO START


INDEXING

* (c) copyright 1991 Murray Turoff

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

GO TO START


USER & TASK PROPERTIES

* (c) copyright 1991 Murray Turoff

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

GO TO START


USER MENTAL MODELS

* (c) copyright 1991 Murray Turoff

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

GO TO START


COGNITIVE PROPERTIES

* (c) copyright 1991 Murray Turoff

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