Intelligence Engineering Lab. Institute of Software, CAS H. Wang 1 Dr. Hui Wang [email protected] Dec.26, 2004 Designing Affordances in UbiComp

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Invisible Computing
You don’t know you are using computers when you use them. Unconscious Interactions based on Unconscious Cognition.
Intelligence Engineering Lab. Institute of Software, CAS
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1. Establishing the goal to be achieved
2. Forming the intention for the action that will achieve the goal
3. Specifying the action sequence corresponding to the action
4. Executing the action
5. Perceiving the system state
6. Interpreting the system state
7. Evaluating the system state with respect to the goal and intentions.
(Norman, D: The Design/The Psychology of Everyday Things, 1988)
Norman’s simple theory of action
if we understand how people do things we can design better systems
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Gulfs of execution and evaluation
: distance between user’s goals and the means of achieving them through the system
:the amount of effort required to determine the system state; did it do what the user wanted in the way they expected?
These two gulfs are the potential for separation between the design model and the user model.
The wider the gulfs, the wider the distance between the designer and user and the greater the difficulty of using the system or product.
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Affordances
Automatic
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First coined by J.J Gibson in 1979:
"The affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill. The verb to afford is found in the dictionary, but the noun affordance is not. I have made it up. I mean by it something that refers to both the environment and the animal in a way that no existing term does. It implies the complementarity of the animal and the environment...
Term was first used by James J. Gibson in “The Ecological Approach to Visual Perception.” 1979. Quote from pg. 127, source from http://www.alamut.com/notebooks/a/affordances.html
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Visual perception Theories
Constructive theorists: the process of seeing is active; view of the world constructed from info in environment and previously stored knowledge
Ecological theorists: perception involves the process of picking up info from the environment; doesn’t require construction or elaboration ()
Ecological Psychology -- JJ Gibson
People developed in the real world
Human perceptual ability shaped strongly by features of the natural world
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Natural selection gave us abilities to recognize and manipulate tools
Information-Foraging Theory
Information scent
The economics of attention and cost structure of information. Natural and artificial information systems evolve toward states that maximize the delivery of more valuable information per unit cost
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Gibson’s Affordances
An affordance exists relative to the action capabilities of a particular actor.
The existence of an affordance is independent of the actor’s ability to perceive it.
An affordance does not change as the needs and goals of the actor change.
Affordances are provided by the environment, and hence are physical.
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Affordance as perceived, cultural (Norman)
“Affordance refers to the perceived and actual properties of the thing…..” Donald Normana, Psyhcology of Everyday Things
Logical constraints and cultural convention also influence what an object “affords”
Donald Norman”Psychology of Everyday Things” says afffordance can be perceived, not real.
Eg: Tom Hanks, Castaway, ice skates affords opening coconut., however ice skates do NOT afford opening a coconut for a crab.
Touch screens on pokies can offer real or perceived affordance. If buttons are there will one touch the screen or not?
Logical constraints use conceptual modelling to determine alternatives. (Castaway vs the coca cola bottle in “The Gods must be Crazy”
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Affordances and HCI
Affordances in HCI: “An aspect of an object which makes it obvious how it should be used.”
Perceived affordance in HCI can be more significant than real affordance
Keep the perceptions of the user in mind. “Just the right things have to be visible: to indicate what parts operate and how, to indicate how the user is to interact with the device. Visibility indicates the mapping between intended actions and actual operations." ( D. A. Norman, The Psychology of Everyday Things (New York: Basic Books, 1988)
Key word is obvious.
Affordance doesn’t have to be visual, sound can offer affordance as well.
Try to make things obvious as possible. Use of convention ok, but avoid too much logical constraints. ( Not everyone can figure out opening coconuts with ice skates).
Windows affords editing the registry but its probably a good thing that most users don’t perceive this.
See rest of slide show for examples.
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it is required that every individual visible feature provides recognisable affordance.
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Affordance Discussion continued
User's knowledge of affordances of real world objects used to create visually significant & perceptive environments using metaphors & analogies.
User’s ability of direct manipulation of objects presented on the GUI gives feeling of security and control
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How do we Zoom in ?
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Bad Affordance … Why?
Neither the “Site Map” or “Help” Buttons have an indication of there affordance.
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Distributed Cognition 1
Extends what is a “cognitive system” beyond the individual and includes
Resources and materials of the environment
Three principles
1) Unit of analysis extends beyond the individual to bring subsystems into coordination to accomplish a goal: functional relationship of all participants
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Distributed Cognition 2
Second principle: range of participants is large – no longer simply “symbol manipulation within single actors” but extends to animate and inanimate actors and materials
E.g external memory aids
Cog processes: distributed across a social group; internal and external coordination; or organized over time.
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Cognition is embodied:
We are not passive information transformers
Coordination among time scales and processes to stabilize the world and assign meaning to it.
JJ Gibson defined affordances as the meaningful interactions among organisms and the world: how are we able to recognize complex shapes and forms while moving through the world?
Artifacts are often melded into the way we see the world – blind mans cane
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Perceptive Affordance () Perception involves the process of picking up info from the environment; doesn’t require construction or elaboration
Action Affordance ()(Embodied Interaction)AffordancePaul Dourish ,Where The Action Is: The Foundations Of Embodied Interaction. Mit Press, 2001
Figure from Joanna McGrenere , Affordances: Clarifying and Evolving a Concept. GI 2000
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Examples
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Activity-centered Affordance
A new Information Processing Model which could take into account of Affordances.
Attention Management study
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Scandinavian’s Activity Theory 1
The role of the artifact as it stands between the user and her materials, object, and outcome was ill understood.
The idealized models created through task analysis failed to capture the complexity and contingency of real-life action.
From automation. Craftsman surrounded by his tools and material.
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Scandinavian’s Activity Theory 2
Analysis and design for a particular work practice with concern for qualifications, work environment, division of work.
Analysis and design with focus on actual use and the complexity of multiuser activity. The Notion of the artifact as mediator of human activity is essential
Active user participation in design, and focus on use as part of design.
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Future Study
Activity-centered Affordance
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Signage
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HCI Study
Context-awareness computing
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Thank You!
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To be the First
"I once asked Ivan, 'How is it possible for you to have invented computer graphics, done the first object oriented software system and the first real time constraint solver all by yourself in one year?" And he said "I didn't know it was hard."
-- Alan Kay on Ivan Sutherland.
The best way to predict the future is to invent it (...uttered by Kay in 1971 at a Xerox planning meeting.)
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From Computing Machinery to Interaction Design
Terry Winograd
Stanford University
Published online by permission from Peter Denning and Robert Metcalfe (eds.), Beyond Calculation: The Next Fifty Years of Computing, Springer-Verlag, 1997, 149-162.
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Documents

Intelligence Engineering Lab. Institute of Software, CAS H. Wang 1 Dr. Hui Wang [email protected] Dec.26, 2004 Designing Affordances in UbiComp