Some terms of interaction
domain – the area of work under studye.g. graphics design
goal – what you want to achievee.g. create a solid red triangle
task – how you go about doing it– ultimately in terms of operations or actions
e.g. … select fill tool, click over triangle
Note … traditional interaction … use of terms differs a lot especially task/goal !!!
Donald Norman’s model
Seven stages user establishes the goal formulates intention specifies actions at interface executes action perceives system state interprets system state evaluates system state with respect to goal
Norman’s model concentrates on user’s view of the interface
execution/evaluation loop
user establishes the goal formulates intention specifies actions at interface executes action perceives system state interprets system state evaluates system state with respect to goal
system
evaluationexecution
goal
execution/evaluation loop
user establishes the goal formulates intention specifies actions at interface executes action perceives system state interprets system state evaluates system state with respect to goal
system
evaluationexecution
goal
execution/evaluation loop
user establishes the goal formulates intention specifies actions at interface executes action perceives system state interprets system state evaluates system state with respect to goal
system
evaluationexecution
goal
execution/evaluation loop
user establishes the goal formulates intention specifies actions at interface executes action perceives system state interprets system state evaluates system state with respect to goal
system
evaluationexecution
goal
Using Norman’s model
Some systems are harder to use than others
Gulf of Executionuser’s formulation of actions
≠ actions allowed by the system
Gulf of Evaluationuser’s expectation of changed system state
≠ actual presentation of this state
Human error - slips and mistakes
slip understand system and goal correct formulation of action incorrect action
mistake may not even have right goal!
Fixing things?slip – better interface designmistake – better understanding of system
Common interaction styles
command line interface menus natural language question/answer and query dialogue form-fills and spreadsheets WIMP point and click three–dimensional interfaces
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/abbreviations should be
meaningful!
Typical example: the Unix system
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
Restricted form of full WIMP system
Natural language
Familiar to user speech recognition or typed natural
language Problems
vague ambiguous hard to do well!
Solutions try to understand a subset pick on key words
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 1-2-3MS 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
… or windows, icons, mice, and pull-down menus!
default style for majority of interactive computer systems, especially PCs and desktop machines
Point and click interfaces
used in .. multimedia web browsers hypertext
just click something! icons, text links or location on map
minimal typing
Three dimensional interfaces
virtual reality ‘ordinary’ window systems
highlighting visual affordance indiscriminate use
just confusing!
3D workspaces use for extra virtual space light and occlusion give depth distance effects
flat buttons …
… or sculptured
click me!
THREE LEVELS of design
Play part in shaping one’s experience
Important
Require a different approach by the designer
visceral | behavioural | reflective
QUOTE visceral design
“ Package designers and brand managers are looking beyond graphic elements or even the design as a whole to forge an emotional link between consumers and brands ”
The entire success of a product PACKAGE, not content
VISCERAL DESIGN what?
Is what nature does
Powerful emotional signals from the environment are automatically interpreted at this level
Culturally
Perception of “pretty”
Visceral design is all about emotional impact
DOMINATING FACTORS
Physical features
LOOK
FEEL
SOUND
These principles are wired in, consistent across people and cultures
VISCERAL DESIGN: how?
About initial reactions
Studied Putting people in front of a design Waiting for reactions
What is the reaction the visceral designer strives for?
I want it What does it do? How much does it cost?
BEHAVIOURAL DESIGN
“Use and performance”
Four components
1. Function
2. Understandability
3. Usability
4. Physical feel
TRICKY
Question: what does a product do, what function does it perform? Answer: it has to fulfil needs
Difficult: why ? People’s needs are not as obvious as might be
thought
Importance for designers
Designers have to watch their customers
to understand how they will use a product
PRODUCT DEVELOPMENT
Enhancement = making an existing product or service better Easiest: comes primarily by watching how people
use what exists today
Innovation = completely new way of doing something that
was not possible before Difficult to access: cannot be evaluated by asking
potential customers for their views
UNDERSTANDING
The secret
= to establish a proper conceptual model Three mental images
1. Designer’s model
2. User’s model
3. System image
= conveyed by the product and written material (advertising and manuals)
The system image of the final design conveys the proper user model
FEEDBACK
“Component of understanding”
To give continual feedback
Computer
Amazing: many products give inadequate feedback
To be effective? Enhance the conceptual model Indicating precisely
What is happening and what remains to be done?
USABILITY
Complex topic
“a product that does what is required and is understandable, may still not be usable”
E.g. guitars, violins, piano
Usage = the critical test of a product: How well does the product perform? How comfortable does it feel to use?
Challenge = UNIVERSAL DESIGN
PHYSICAL FEEL matters
Designers worry a lot about the physical feel of their products
Make huge difference in our appreciations
They are critical to our behavioural assessment of a product
Physical feel matters: why? We are biological creatures: interaction between
our sensory systems and the environment
+ BEHAVIOURAL DESIGN +
Human-centered
Understanding and satisfying the needs Observation
Visceral and behavioural reactions are subconscious Make us unaware of our true reactions and their
causes
REFLECTIVE DESIGN what?
Message, culture, meaning of a product
The image we present to others
The essence of reflective design: it’s all in the mind of the beholder
ATTRACTIVENESS <> BEAUTY
Attractiveness Visceral level
The response is entirely to the surface look of an object
Beauty Reflective level
It is influenced by knowledge, learning and culture
Advertising
can work at either the visceral or the reflective level
REFLECTIVE LEVEL product
Shows person’s overall impression
Customer relationships play a major role A good relationship reverse a negative
experience
Is about long-term customer experience Service Providing a personal touch Warm interaction
CONCLUSION
A human-centered approach works well for behavioural design, but it is not necessarily appropriate for either the
visceral or the reflective side
Conclusion If you want a successful product, test and revise If you want a product that can change the world:
let it be driven by someone with a clear vision
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