Challenging Information Foraging Theory: Screen Reader Users are not Always Driven by Information Scent

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Little is known about the navigation tactics employed by screen reader users when they face problematic situations on the Web. Understanding how these tactics are operationalised and knowing the …

Little is known about the navigation tactics employed by screen reader users when they face problematic situations on the Web. Understanding how these tactics are operationalised and knowing the situations that bring about such tactics paves the way towards modeling navigation behaviour. Modeling the navigation of users is of utmost importance as it allows not only to predict interactive behaviour, but also to assess the appropriateness of the content in a link, the information architecture of a site and the design of a web page. Current navigation models do not consider the extreme adaptations, namely coping tactics, that screen reader users undergo on the Web. Consequently, their prediction power is lessened and coping tactics are mistakenly considered outlying behaviours. We draw from existing navigation models for sighted users to suggest the incorporation of emerging behaviours in navigation models for screen reader users. To do so, we identify the navigation coping tactics screen reader users exhibit on the Web, including deliberately clicking on low scented links, escaping from useless or inaccessible content and backtracking to a shelter. Our findings suggest that, especially in problematic situations, navigation is not driven by information scent or utility, but by the need of increasing autonomy and the need of escaping from the current web patch.

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  • 1. Challenging Information ForagingTheory: Screen Reader Users are notAlways Driven by Information Scent24th ACM Conference on Hypertext and Social MediaHypertext 2013Markel Vigo1 & Simon Harper2 University of Manchester (UK)1: @markelvigo2: @sharpicmarkel.vigo@manchester.ac.uksimon.harper@manchester.ac.ukhttp://dx.doi.org/10.6084/m9.figshare.695073
  • 2. Problem• We do not know all the navigationtactics employed by screen readerusers• Key to build navigation models• Lack of navigation models for screenreader usersACM Hypertext 20132 May 2013 2
  • 3. Goal• Bridge the gap on the lack ofknowledge on navigation tactics• Survey existing navigation models (forsighted user)• Inform navigation models to makerobust models• Consider coping strategiesACM Hypertext 20132 May 2013 3
  • 4. Navigation models• High certainty about a constraineduniverse• Predict user behaviour• Interaction models: GOMS, KLM• Evaluation of interfaces• Often used in research settingsACM Hypertext 20132 May 2013 4
  • 5. Navigation models• Built on Information Foraging Theory (IFT)– Web page ≈ information patch– User ≈ consumer• Link selection=• Information scent (IS) measures therelevance of proximal cues that leadtowards distal goalsACM Hypertext 20132 May 2013MaxE(Info_Value)E(Cost)éëêùûú5
  • 6. Navigation models• Models for sighted user differ on– The conceptualisation of information scent– On the strategy for page reading• Few empirical studies are based on linkselection or navigation strategies• Low predictive powerACM Hypertext 20132 May 2013 6
  • 7. Who are screen readerusers• Blind users• Low vision users• Potentially generalisable to users ofauditory interfaces:– Applications on the move: car, walking, cycling– Situationally disabled usersACM Hypertext 20132 May 2013 7
  • 8. How do screen readersnavigate• What do we know so far?• Behaviours occurring on ideal situations• How is the navigation whenencountering:– Accessibility barriers– Design issues– Usability problemsACM Hypertext 20132 May 2013 8
  • 9. Stereotypical behavioursACM Hypertext 20132 May 20131. Miscellaneous top links2. Mast header4. Main content5. Banner3. Primarynavigationlinks6. 2ndarynavigationlinks7. Footer8. Miscellaneous bottom links1. Miscellaneous top links2. Mast header3. Primary navigation links4. Main content1. Miscellaneous top links2. Mast header3. Primary navigation links4. Main content(a) Listening to content (b) Exhaustive scanning9
  • 10. Stereotypical behavioursACM Hypertext 20132 May 20131. Miscellaneous top links2. Mast header4. Main content5. Banner3. Primarynavigationlinks6. 2ndarynavigationlinks7. Footer8. Miscellaneous bottom linksH1. Miscellaneous top links2. Mast header3. Primary navigation links4. Main content(d) Information scent driven gamblingscanning: headings navigationHHHHH1. Miscellaneous top links2. Mast header3. Primary navigation links4. Main content(c) Gambling scanning: skipline navigationskip 6 linesskip 5 linesskip 5 linesskip 5 lines10
  • 11. Analysis of coping tactics• Secondary analysis of 2 user studies– Ethnographic longitudinal– User test• 17 users• Isolated 9 coping tactics grouped by– Link selection tactics– Exploration tactics– Navigation tacticsACM Hypertext 20132 May 2013 11
  • 12. Link selection tacticsT1: Deliberately clicking on lowscented links• Accessibility problems:– “Im just going to click on one of thesethings, I don’t know what it is for ”• Information overload:– “when I was listening I heard the targetlink... you can have 30 or 230 links thatyou have to sit and listen to! ”ACM Hypertext 20132 May 2013 12
  • 13. Link selection tacticsT2: Clicking on any link• When coming across unexpectedfunctionalities or content– On a linked keyword search where searchbox expected: “does not tell me where todo this ”– On a SERP that did not contain expectedresults: “found a few links, none directlywhat I want ”ACM Hypertext 20132 May 2013 13
  • 14. Intra-page explorationtacticsT3: Escaping from useless orinaccessible content by tabbing downT4: Fast tab/arrow down the pagewithout completely listening to content– By default– On familiar pages– On content arranged according to somecriterionACM Hypertext 20132 May 2013 14
  • 15. Intra-page explorationtacticsT5: Gaining orientation• By going to the top of the page– “not sure where I am...if in doubt go backto the beginning ”• Users pay more attention in the secondreadingACM Hypertext 20132 May 2013 15
  • 16. Inter-page navigationtacticsT6: Backtracking to a shelter• When user mobility is reduced– Getting stuck: “I seem to have come to adead end here”– Looping behaviours: “I’ve got back toshorts again...shorts again!”ACM Hypertext 20132 May 2013 16
  • 17. Inter-page navigationtacticsT7: Re-checking• Fast revisitations as reassurancemechanismsT8: Retracing• Users retrace their steps from a shelterACM Hypertext 20132 May 2013 17
  • 18. WithdrawalT9: Giving up• Provoked by sequence of failures andunsuccessful interactions.• Observed on users who navigate withtrouble and encounter an obstacledifferent to ones experienced.• E.g.: encountering accessibility barriersafter escaping from a loop of pagesACM Hypertext 20132 May 2013 18
  • 19. ImplicationsInforming navigation models• Navigation models for sighted usersmimic screen reader user behaviour inordinary circumstances• To cover extraordinary circumstancesminor modifications are needed:– Gaining orientation (T5)– Re-tracing (T8)ACM Hypertext 20132 May 2013 19
  • 20. ImplicationsChallenging established conceptions• In ordinary circumstances IS is a reliableindicator• In extraordinary circumstances users arenot driven by IS but escape from problems– Click on low scented (t1) or any link (t2)– Fast tabbing down (t3, t4)– Backtracking to a shelter (t6)ACM Hypertext 20132 May 2013 20
  • 21. ImplicationsChallenging established conceptions• IFT: a hyperlink will be selected when the tradeoffbetween information gaining and cost of accessingis low• SR users: cost of accessing is minimised at theexpenses of gaining low quality information• Alternatively, SR users have low satisficing levels:any web patch is good enoughACM Hypertext 20132 May 2013 21MaxE(Info_Value)E(Cost)éëêùûú
  • 22. ImplicationsChallenging established conceptions• This behaviour reminds of that of animalsmaking risk-sensitive foraging decisions– Risk prone individuals: those undergoingextreme situations take the risk of selecting lowscented link (t1,t2)– Risk averse individuals: less severe problemstake a more conservative strategy by moving toanother web patch (t3, t4, t6)ACM Hypertext 20132 May 2013 22
  • 23. ImplicationsChallenging established conceptions• IFT: users leave a website when the scent of thecurrent page is below the average of the pagesvisited• SR users give up after overcoming a number ofproblematic interactions• We have 2 thresholds: information scent andfrustration thresholdACM Hypertext 20132 May 2013 23
  • 24. Follow up2 May 2013 24Contact@markelvigo | markel.vigo@manchester.ac.ukPresentation DOIhttp://dx.doi.org/10.6084/m9.figshare.695073Datasetshttp://wel-data.cs.manchester.ac.uk/investigations/224th ACM Conference on Hypertext and Social MediaHypertext 2013