Models of Performance and Behavior Patty Sakunkoo CS 376 May 21, 2009

1. Models of Performance and Behavior Patty Sakunkoo CS 376 May 21, 2009 Patty Sakunkoo Stanford University

2. 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.

3. 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-Interaction Design of technologies/UI for Human-Information Interaction

4. 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

5. How much time to spend on a patch? • Analogous to food foraging • Diminishing Returns Curve • Diminishing returns curve is natural • 80% of users don’t scan past the 3rd page of search results • Charnov’s Marginal Value Theorem • R* = steepest slope from origin = tangent from origin • If tb is low, then people tend to switch more easily. (web snacking)

6. How well does this model describe your website switching behavior? Exceptions? “strong similarity” “clear connection” “accurate” • Limitation of analogy? website~patch, info~food • 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?

7. “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?

8. Claims “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) Rational Choice Assumption. Too rational? Goal-oriented? People are quite irrational and often don’t see big pictures of what they’re 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)? http://www.musicovery.com/ http://www.youtube.com/watch?v=GZUaXDm4qik

9. Increasing the rate of gain of valuable information always increases fitness (ability to predict and control the environment in order to solve the problems)? Burt’s Brokerage, Granovetter’s 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?

10. 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

11. Positives • “extremely important” “accurate” “novel” “insightful” “surprising” • Application to web designs today: • Google, Twitter, Social Foraging (Digg)

12. A Morphological Analysis of the Design Space of Input Devices Patty Sakunkoo

13. Main Points • Design for HMI: Design an artificial language to communicate between H and M • This paper H -> M • Mackinlay M -> 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.

14. Generating Design Space Primitive Movement Vocabulary <M,In,S,R,Out,W>

15. Generating Design Space Composition Operators <Merge, Layout, Connect>

16. Taxonomy

17. Testing the devices self-explained? • 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.

18. Predictions The pinch Multi-touch Fingers = high bandwidth : could beat the mouse.

19. Integration of Design Space Generating and Testing Is the relationship betweenpositions in the structured design spaceand 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?

20. Thank you. 