ANALYZE
analysis of claims about
stakeholders, Problem scenarios current
field studies practice
DESIGN
metaphors, Activity iterative
information scenarios analysis of
technology, usability
HCI theory, claims and
guidelines Information scenarios re-design
Interaction scenarios
PROTOTYPE & EVALUATE
summative formative
evaluation Usability specifications evaluation
Norman’s Stages of Action
A different look at design
1
Stages of Action
• What makes something difficult to do?
– What are you trying to do?
– What ways can you achieve it?
– How do you execute one of those ways?
– What happened as a result?
Action
• Start with goal (goal formation)
• You have to do something (execution)
• Check to see that goal is made
(evaluation)
2
Four parts
• Goal
• What is done to world
• The world itself
• Check on the world
Not that easy…
• Real tasks are imprecisely defined
– Get to work, get some food
• Goals do not state what to do
– Intentions: lower level statements of what
is to be done
– Still not enough: too vague
3
Execution
• Three stages
– Intention
– Action sequence
– Execution
Evaluation
• Three stages
– Perceiving what happened
– Interpreting it
– Evaluating (did what happened match
what we wanted?)
4
7 Stages of Action
• Forming the goal Activity design
• Forming the intention
• Specifying an action Interaction design
• Executing the action
• Perceiving state of world
• Interpreting state of world Information design
• Evaluating the outcome
Notes
• Only approximate model
• Stages are not discrete
– Not in sequence
– Some activities satisfied by single actions
• Continual feedback
– Results of one activity feed goals of
another
5
Stages of Action in HCI
focus of
Interpretation information
Perception
design
Making GULF OF
sense EVALUATION
Last month’s
budget... ?
GULF OF
Execution focus of
System EXECUTION
goal interaction
Action plan design
What are Gulfs?
• The distance between the mental
representations of the person and the
physical components and states of the
environment
• Illustrates difficulty in deriving
relationships between mental intentions
and interpretations and the physical
actions and states
6
Example: Gulf of Execution
• Going from users’ task concept to system concept:
the cognitive distance between two models
– Mental model held by users tells them what to do
– This must make connection with designers’ model that
is conveyed and supported by the user interface
cognitive distance
• The closer the match, the easier to find and
pursue a relevant goal
Stages of Action in HCI
focus of
Interpretation information
Perception
design
Making GULF OF
sense EVALUATION
Last month’s
budget... ?
GULF OF
Execution focus of
System EXECUTION
goal interaction
Action plan design
7
Suggesting Goals to the User
• Menu titles, folder names, application names, ...
• Decreasing the distance via direct manipulation:
– UI controls appear as physical analogs of real objects;
their affordances suggest interaction goals
– Key ideas are visual representation, immediate and
continuing feedback, and simple reversibility
• Visual or auditory UI elements sometimes lead to
opportunistic selection of goals
– Interesting object or message intrudes on a task
– Or user is paused, choosing among things to do;
especially common among novice users
Gulf of Evaluation
• Reflects amount of effort that a person
exerts to interpret physical state of a
system
• Small gulf when system provides state
information in a form that is easy to
get, easy to interpret, and matches the
thinking
8
Stages of Action in HCI
focus of
Interpretation information
Perception
design
Making GULF OF
sense EVALUATION
Last month’s
budget... ?
GULF OF
Execution focus of
System EXECUTION
goal interaction
Action plan design
About Gulfs
• Present in all interfaces
• Most are unremarkable and invisible
• Users blame themselves or decide they
are incapable
– Water faucets, temperature controls, stove
tops, etc.
– Sewing machines, washing machines,
digital watches
9
Design Aids
• Each stage requires special design
strategies
• Simple questions
How easily can one:
Determine function of device?
Tell possible actions? System in
desired state?
Determine Mapping? Mapping?
Perform action? What state is
system in?
Design Advice
• Visibility: can user tell state of system and
alternatives for action?
• Good conceptual model: consistency in
presentation of operations and results
• Good mappings: relationships between
actions and results, between controls and
effects, system state and what we see are all
clear
• Feedback: full and continuous feedback on
results of actions
10
SBD: From Activity to
metaphors and
Interaction
ongoing
information analysis of
technology usage
opportunities
Activity Design
scenarios and
and claims
constraints
Information Design
Interaction Design
7 Stages and SBD
metaphors and ongoing
information analysis of
technology usage
Forming the
opportunities
Goal Activity Design
scenarios and
and claims
constraints
Perceiving world
Interpreting world Information Design
Evaluating outcome
Forming the intention
Interaction Design
Specifying an action
Executing the action
11
Coming up…
• Information design
• Interaction design
• Prototyping
• Evaluation
12
