[HCI] 4. Interaction

What is interaction?

• communication
  • user <-> system
  • 이를 어떻게 모델링 할 수 있는지?
• interaction models
  • translations between user and system
• ergonomics (인간 공학)
  • physical characteristics of interaction
• interaction styles
  • the nature of user/system dialog
• context
  • social, organizational, motivational

1. Models of interaction: Some terms of interaction

• domain – the area of work under study
  • e.g. graphic design
• goal – what you want to achieve; or final result to be achieved
  • e.g. create a solid red triangle
• task– how you go about doing it; structured set of related activities undertaken in a sequence – ultimately in terms of operations or actions
  • e.g. … select fill tool, click over triangle
• goal과 task가 사용될 때는 마구 섞여서 사용된다.(context를 파악해야 함)
• note …
  • use of terms differs a lot especially task/goal !!!
  • system’s language vs. user’s language

Donald Norman’s model

• Seven stages

  1. user establishes the goal

  2. formulates intention
  3. specifies actions at interface
  4. executes action
  5. perceives system state
  6. interprets system state
  7. evaluates system state with respect to goal

• Norman’s model concentrates on user’s view of the interface

Execution/evaluation loop

Using Norman’s model

• Some systems are harder to use than others
• Gulf of Execution
  • Gap btw: user’s formulation of actions ≠ actions allowed by the system
• Gulf of Evaluation
  • Gap btw: user’s expectation of changed system state ≠ actual presentation of this state
  • 실제와 유저가 생각했던 것과 다를 때
• Gulf of Execution Example: VCR problem

Abowd and Beale framework

• extension of Norman…
• their interaction framework has 4 parts
  • user
  • input
  • system
  • output
• each has its own unique language interaction => translation between languages
• problems in interaction = problems in translation

Using Abowd & Beale’s model

• user intentions

  -> translated into actions at the interface

  ​ ->translated into alterations of system state

  ​ -> reflected in the output display

  ​ -> interpreted by the user

• general framework for understanding interaction

  • not restricted to electronic computer systems
  • identifies all major components involved in interaction
  • allows comparative assessment of systems
    • 시스템을 비교 평가 할 수 있다.
  • an abstraction

Ergonomics (Physical aspects of Interfaces)

• Study of the physical characteristics of interaction
• Also known as human factors – but this can also be used to mean much of HCI!
• Ergonomics is good at defining standards and guidelines for constraining the way we design certain aspects of systems

Ergonomics - examples

• arrangement of controls and displays
  • e.g. controls grouped according to function or frequency of use, or sequentially
• surrounding environment
  • e.g. seating arrangements adaptable to cope with all sizes of user
    • 모든 규모의 사용자를 수용할 수 있는 좌석 배치
• health issues
  • e.g. physical position, environmental conditions (temperature, humidity), lighting, noise,
• use of colour
  • e.g. use of red for warning, green for okay, awareness of colour-blindness etc.

Ergonomics (Industrial interfaces)

• Office interface vs. industrial interface?
• Context matters!

	office	industrial
type of data	textual	numeric
rate of change	slow	fast
environment	clean	dirty

• … the oil-soaked mouse vs. the touchpad

Indirect manipulation

• office – direct manipulation
  • user interacts with artificial world

• industrial – indirect manipulation
  • user interacts with real world through interface
• issues ..
  • feedback
  • delays

2. Common interaction styles: Command line interface

• Way of expressing instructions to the computer directly
  • function keys, single characters, short abbreviations, whole words, or a combination
• suitable for repetitive tasks
• better for expert users than novices
• offers direct access to system functionality
• command names/abbr. should be meaningful!
• Typical example: the Unix system

Query interfaces

• Question/answer interfaces
  • user led through interaction via series of questions
  • suitable for novice users but restricted functionality
  • often used in information systems

• Query languages (e.g. SQL)
  • used to retrieve information from database
  • requires understanding of database structure and language syntax, hence requires some expertise

Form-fills

• Primarily for data entry or data retrieval
• Screen like paper form.
• Data put in relevant place
• Requires
  • good design
  • obvious correction facilities

Spreadsheets

• first spreadsheet VisiCalc, followed by Lotus 1-2-3, MS Excel most common today
• sophisticated variation of form-filling.
  • grid of cells contain a value or a formula
  • formula can involve values of other cells
    • e.g. sum of all cells in this column
  • user can enter and alter data spreadsheet maintains consistency

WIMP Interface

• Windows, Icons, Menus, Pointers
  • default style for majority of interactive computer systems, especially PCs and desktop machines

• Before WIMP: Command Line Interface (CLI)
  • Needed to know each command’s keyword
  • Needed to know the syntax for each comman
  • Eg. Copy source_file destination_file

Problems With CLI

• People found it hard to use
  • Forgot command names
  • Would transpose command parameters (옵션이 많음)
  • Novices would be overwhelmed (‘blank screen’)
• Cognitive analysis
  • Many of the problems can be traced to recall vs. recognition memory
    • recall보다 recognition이 많아지도록 구성
  • Commands and syntax had to be recalled (quite hard)
  • Almost no recall cues are provided
  • Can expect even experts to make mistakes

Solution: WIMP

• Xerox invented the Windows Icons Mouse and Pointer (WIMP) interface

• Very few commands (mouse buttons), bring up options

  • Visual metaphor
  • Contextually appropriate commands are brought up
  • Drag & Drop ‘removes’ parameters

Why WIMP works

• Uses recognition rather than recall (기억보다 인지에 의존)
  • Icons show available commands
  • Menus give complete list of available commands
• Visual metaphor removes abstract syntax
  • No longer remember order of commands or positions in path trees
  • Can ‘see’ where things are, move them from place to place
• Reduced likelyhood of making syntax errors

Windows, Icons, Pointers

• Windows: Areas of the screen that behave as if they were independent
  • can contain text or graphics
  • can be moved or resized or overlapped
• Icons: Small picture or image to represent some object in the interface
  • can be many, various, highly stylized, and realistic representations.
• Pointers: WIMP style relies on pointing and selecting things
  • minimal typing
  • wide variety of graphical images

and Menus

• Set of options displayed on the screen
• Options visible
  • less recall - easier to use
  • rely on recognition so names should be meaningful
• Selection by:
  • numbers, letters, arrow keys, mouse
  • combination (e.g. mouse plus accelerators)
• Often options hierarchically grouped
  • sensible grouping is needed
• problem – take a lot of screen space solution
  • pop-up: menu appears when needed

Kinds of Menus

• Menu bar at top of screen, menu drags down
  • pull-down menu - mouse hold and drag down menu, and remains available as long as the user holds it open
  • drop-down menu - mouse click reveals menu
  • fall-down menus - mouse just moves over bar!
• Contextual menu appears where you are
  • pop-up menus - actions for selected object
    • 우클릭
  • pie menus - arranged in a circle
    • easier to select item (larger target area)
    • Quicker (same distance to any option) … but not widely used!

Menus extras

• Cascading menus
  • hierarchical menu structure
  • menu selection opens new menu
  • and so in ad infinitum
• Keyboard accelerators (단축키)
  • key combinations - same effect as menu item
  • two kinds
    • active when menu open – usually first letter
    • active when menu closed – usually Ctrl + letter
  • usually different with different applications!!!

3. Menus design issues: Buttons & Dialogue boxes

• individual and isolated regions within a display that can be selected to invoke an action
• Special kinds
• radio buttons
  • set of mutually exclusive choices
• check boxes
  • set of non-exclusive choices
• Dialogue boxes (그림 4)
  • information windows that pop up to inform of an important event or request information.
  • e.g: when saving a file, a dialogue box is displayed to get the filename and location. Once the file is saved, the box disappears.

Toolbars

• long lines of icons … … but what do they do?
  • fast access to common actions
  • often customizable:
    • choose which toolbars to see
    • choose what options are on it
• Palettes and tear-off menus
• Problem: menu not there when you want it
• Solution:
  • palettes – little windows of actions, shown/hidden via menu option. e.g. available shapes in drawing package tear-off and pin-up menus – menu ‘tears off’ to become palette

Look and … feel

• WIMP systems have the same elements:
  • windows, icons., menus, pointers, buttons, etc.
• but different window systems … behave differently
  • e.g. MacOS vs Windows menus
• appearance + behaviour = look and feel
  • easy to focus on look
  • what about feel?

4. Consideration in Interaction Error and repair

• can’t always avoid errors … … but we can put them right
• Human errors: Slip & Mistake
  • incorrect action vs misunderstanding!
• make it easy to detect errors … then the user can repair them

Initiative

• who has the initiative?
  • old question–answer – computer
  • WIMP interface – user
• WIMP exceptions …
  • pre-emptive parts of the interface
• modal dialog boxes
  • come and won’t go away!
    • 튀어나와서 안 없어지는
  • good for errors, essential steps
  • but use with care

Context & Experience

• Interaction affected by social and organizational context
  • By other people: desire to impress, competition, fear of failure
  • By motivation: fear, allegiance, ambition, self-satisfaction
  • Inadequate systems cause frustration and lack of motivation
• Experience, engagement and fun
  • Virtues of WINP design
    • designing experience
    • physical engagement
    • managing value

Experience?

• home, entertainment, shopping
  • not enough that people can use a system
  • they must want to use it!
  • 사용할 수 있는 것이 목적이 아니라 유저가 사용하고 싶어해야 한다.
• psychology of experience
  • Flow: The Psychology of Optimal Experience (Prof. Csikszentimihalyi)
    • 완전한 몰입
  • A state in which people are so involved in an activity that nothing else seems to matter
  • balance between anxiety and boredom: optimal challenge, sense of control
• education
  • zone of proximal(근위) development
  • things you can just do with help
• wider …
  • literary analysis, film studies, drama

Physical Design Constraints

• constraints are often contradictory(모순) … need trade-offs
• CONSTRAINTS:
  • ergonomic – minimum button size
  • physical – high-voltage switches are big
  • legal and safety – high cooker controls
  • context and environment – easy to clean
  • aesthetic – must look good
  • economic – … and not cost too much!
• within categories:
  • e.g. safety – cooker controls
  • front panel – safer for adult
  • rear panel – safer for child
• between categories
  • e.g. ergonomics vs. physical – earphone remote
    • ergonomics – controls need to be bigger
    • physical – no room!
    • solution – multifunction controls & reduced functionality

Fluidity(유동성)

• do external physical aspects reflect logical effect?
• related to affordance (행동유도성)
• logical state revealed in physical state?
  • e.g. on/off buttons
• inverse actions inverse effects?
  • e.g. arrow buttons, twist controls

Managing value

people use something

ONLY IF

​ it has perceived value

AND

​ value exceeds cost

BUT NOTE

• exceptions (e.g. habit)

• value NOT necessarily personal gain or money

Weighing up value

• value
  • helps me get my work done
  • fun
  • good for others
• cost
  • download time
  • money £, $, €
  • learning effort

Discounted future

• in economics Net Present Value:
  • discount by (1+rate)^{years to wait}
• in life people heavily discount
  • future value and future cost
  • hence resistance to learning
  • need low barriers and high perceived present value

Value and organisational design(조직적인 디자인)

• coercion (강제)
  • tell people what to do!
  • value = keep your job
• enculturation (문화화)
  • explain corporate values
  • establish support (e.g share options)
• emergence
  • design process so that individuals value -> organisational value

General lesson …

if you want someone to do something …

• make it easy for them!

• understand their values