Design Processes and Tools

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Models of Performance and Behavior Patty
Sakunkoo CS 376 May 21, 2009
Patty Sakunkoo Stanford University
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• Information Foraging Theory Framework and
  Method Peter Pirolli, in Information Foraging
  Theory Adaptive Interaction with Information,
  Oxford University Press, 2007, pp. 3-29.
• A Morphological Analysis of the Design Space of
  Input Devices Stuart K. Card, Jock D. Mackinlay,
  and George G. Robertson, ACM Transactions on
  Information Systems, Volume 9, Issue 2, 1992, pp.
  99-122.

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Conventional HCI Tasks (e.g. programming, math
computation)
Information-Intensive Tasks
Uncertain, Probabilistic
Well-defined possible goals, potential actions
Information Foraging Theory (optimization-based
approach including environment)
Conventional Cognitive Models
Design of technologies/UI for Human-Computer-Inter
action
Design of technologies/UI for Human-Information
Interaction
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• Information Foraging Theory
• Information Overload, Scanty Attention
• To maximize the rate of information gain.
• Patches of Information (e.g. websites)
• Basic Problem Should I continue in the current
  patch or look for another patch?
• Whether what is expected to be gained from
  continued foraging in the current patch will be
  worth the time
• How long to continue searching for information in
  that patch

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• How much time to spend on a patch?
• Analogous to food foraging
• Diminishing Returns Curve
• Diminishing returns curve is natural
• 80 of users dont scan past the 3rd page of
  search results
• Charnovs Marginal Value Theorem
• R steepest slope from origin tangent from
  origin
• If tb is low, then people tend to switch more
  easily. (web snacking)

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• How well does this model describe your website
  switching behavior? Exceptions? strong
  similarity clear connection accurate
• Limitation of analogy? websitepatch, infofood
• Different kinds of information? Article search,
  gadget purchase, health
• What does the theory imply about where users
  switch to in reality? Highly different, highly
  similar patches, or randomly?

Food - Depletable resource. Depletion in one patch does not affect other patches. - Animals are almost always likely to make decisions based on information scent, humans might not. (Juho) - Prey in wildlife try to avoid foragers.
Information - Non-exhaustible resource, but redundancy and diminishing returns affect across patches, especially given that many info patches have high overlap (e.g.Travelocity, Expedia, Orbitz) - Information needs a strategy to draw attention and attract foragers.
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Mankind hungers for information in order to
gather it as a means for adapting to the
world. Does there really need to be a
functionalist reason for why we are curious about
states of the world? A hint of
functionalist/teleological explanation?
(information hunger exists for its beneficial
adaptive consequence) Can it really be claimed
that we collect information for purposes of
survival? I think that humans in the present day
have an almost innate desire for information.
Filip Unfortunately, I have not seen this trend
apply to information foraging. - Henry Do
systems tend to evolve in ways that deliver more
expected value of information for the cost of
interaction? Any concrete examples of web site
design that conforms to this prediction? Any
Exceptions?
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Claims

• Rational Choice Assumption. Too rational?
  Goal-oriented?
• People are quite irrational and often dont see
  big pictures of what theyre doing (e.g.
  diminishing returns), sometimes not even
  boundedly rational addiction, etc. (BDT in
  Psychology).
• Any other incentives/ behavioral rules?
• Instrumental vs. Non-instrumental Info
• Random behaviors/Crossovers.
• Aesthetics? Sloppy organizer (e.g. our desktop)?
  Exploratory tasks? Emotion and hedonic
  experience? Social aspects?
• Could we consume information for pleasure? For
  self assurance? To learn more about our goals
  (hence adaptive goals like searching for where to
  vacation)?

• People tend to arrange their environments to
  optimize their rate of gain. People prefer and
  select technology design that improve returns on
  information foraging.
• it is assumed that users are optimizing their
  performance in achieving their goals. (p.18)

http//www.musicovery.com/ http//www.youtube.com/
watch?vGZUaXDm4qik
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• Increasing the rate of gain of valuable
  information always increases fitness (ability to
  predict and control the environment in order to
  solve the problems)?
• Burts Brokerage, Granovetters weak ties
  information advantage
• However, social distance (outcast), identity,
  habituation could be a concern. For example,
  users also seek social belongingness.
• We expect to see a shift in studies from HCI to
  HII (Pirolli 2007)
• Is HII broader or narrower than (or a subset of)
  HCI?

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Formal Models of Behaviors

• Formal Models vs. Empirical Methods such as
  ethnography, multivariable models
• I find the paper robust in that . and it is
  supported by mathematical foundations. Juho Kim
  
• I'm not that excited about "models" of how people
  behave. It just seems that so much more is to be
  gained by looking at the differences in
  individuals along with the trends among
  populations, rather than just describing people's
  actions as minimizing energy while maximizing
  benefit. - Jesse Cirimele
• this paper was enough to get you interested, but
  lost me in the abstraction without ever really
  reaching the pragmatic. - Eyal
• Pirolli states that frameworks "are typically not
  testable in and of themselves." I disagree with
  Pirolli that frameworks are untestable. Stephen
  Hess
• If the forager cannot estimate these values (tb)
  before undertaking a task, the model can only
  describe search efficiency after-the-fact, rather
  than prescribe how best to perform it
  beforehand. - David

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Positives

• extremely important accurate novel
  insightful surprising
• Application to web designs today
• Google, Twitter, Social Foraging (Digg)

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A Morphological Analysis of the Design Space of
Input Devices

• Patty Sakunkoo

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Main Points

• Design for HMI Design an artificial language to
  communicate between H and M
• This paper H -gt M
• Mackinlay M -gt H
• Morphological design space analysis.
• Generating the design space
• Comprehend different input device designs as
  points in a parametrically described design space
• Testing the designs.

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Generating Design Space

• Primitive Movement Vocabulary ltM,In,S,R,Out,Wgt

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Generating Design Space

• Composition Operators ltMerge, Layout, Connectgt

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Taxonomy
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Testing the devices

• Expressiveness
• conveys exactly and only the intended meaning
• Effectiveness how well this can be done
• Footprint the amount of area consumed
• Bandwidth speed of use is a joint product of
  the human, the application, and the device.

self-explained?
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Predictions

• Fingers high bandwidth could beat the mouse.

The pinch
Multi-touch
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Integration of Design Space Generating and Testing

• Is the relationship between positions in the
  structured design space and their consequences
  (e.g. footprint, bandwidth, etc.) clear?
• Perhaps, test metrics should have more
  integration with the design space. Like a 3-D
  space, the 3rd D being a performance metric.
• User-based design space?

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• Thank you. ?