Elderly Text-Entry Performance on Touchscreens

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My presentation at ACM ASSETS 2012. …

My presentation at ACM ASSETS 2012.

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  • 1. Elderly Text-EntryPerformance onTouchscreensHugo Nicolauhman@vimmi.inesc-id.ptJoaquim Jorge
  • 2. Mobile evolution
  • 3. … led us to touchscreens
  • 4. Direct Manipulation
  • 5. Engaging
  • 6. Adaptable[Findlater et al., 2012]
  • 7. Hard to select targets[Jin et al., 2007]
  • 8. Occurs to everyone[Nicolau, 2012]
  • 9. Elderly
  • 10. Hand tremor[Strickland and Bertoni, 2004]
  • 11. Small targets [Jin et al., 2007]
  • 12. Text-Entry is a challenge
  • 13. Transversal task Communication Document Note editing takingTextInput Managing Web contacts browsing
  • 14. Re-visiting adaptability
  • 15. Provide the knowledge
  • 16. User Study
  • 17. Text-Entry Performance
  • 18. Hand tremor
  • 19. ApparatusTablet:20x10 mmMobile:10x10 mm
  • 20. Participants15 participants (4 males)67 to 89 years oldRight-handedNo severe visual impairmentsNo familiarity with touchdevices
  • 21. Two Phases1st - Familiarization2nd - Evaluation
  • 22. FamiliarizationExplanation and exemplificationCopy tasks30 minute practice session
  • 23. Physiological tremor assessmentAction tremor (task-specific)Archimedes Spiral [Bain et al., 1993]Postural tremorAccelerometer data [Selker et al., 2011]
  • 24. Copy Task1 practice sentences / condition5 test sentences / conditionPortuguese languagerepresentative corpusError correction was notavailable
  • 25. Dependent MeasuresSpeed:Words per minuteAccuracy:Minimum String Distance error rateSubstitution error rateInsertion error rateOmission error rate
  • 26. Results
  • 27. Tremor ProfileTask-specific TremorArchimedes Spiral DrawingsPostural TremorHand Oscillation[Oulasvirta et al., 2011]Peak Magnitude[Salarian et al., 2007][Elble and Koller, 1990]
  • 28. Tremor ProfileTask-specific TremorArchimedes Spiral DrawingsPostural TremorHand Oscillation[Oulasvirta et al., 2011]Peak Magnitude[Salarian et al., 2007][Elble and Koller, 1990]
  • 29. Text-Entry Performance
  • 30. Error RateMinimum String Distance (MSD) Error Rate 26% 17% Mobile Tablet
  • 31. Tablet Compensates ErrorsMinimum String Distance (MSD) Error Rate Statistically Significant [Z=-2.417, p<.05] 26% 17% Mobile Tablet
  • 32. Correlation with Hand OscillationMinimum String Distance (MSD) Error RateHand OscillationNon-dominant handY [Pearson r=.751, n=9, p<.05]Z [Pearson r=.613, n=9, p=.079] 26% 17% Mobile Tablet
  • 33. Types of ErrorsError Rate 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 34. Omissions
  • 35. Omission were the most commonError Rate 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 36. Omission were the most commonError Rate No Significant Difference [Z=-.722, p>.4] 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 37. Blank space was recurrently omittedOmission Error Rate in Mobile condition 28% 23% 16% 15% e i v x m p u zSPACE s w o r k n q y c t d f g h j a b l
  • 38. Forgetfulness and coordination arereal issues#13 Usually forgot to transcribe words atmiddle and end of sentences#8 “where was I?”
  • 39. Unintentional touches
  • 40. Insertions
  • 41. Insertion Error Rate 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 42. Few Insertions with TabletError Rate Statistically Significant [Z=-2.103, p<.05] 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 43. Bounces and Accidental TouchesError Rate 1.5% 3.3% 2.2% 1.1% Mobile Tablet Bounces Accidental
  • 44. Few Accidental Touches with TabletError Rate Statistically Significant [Z=-2.292, p<.05] 1.5% 3.3% 2.2% 1.1% Mobile Tablet Bounces Accidental
  • 45. Correlations with Hand TremorError RateDominant Hand OscillationX [Spearman rho=.596, n=14, p<.05] Non-Dominant Hand Oscillation Y [Spearman rho=.762, n=9, p<.05] 1.5% 3.3% 2.2% 1.1% Mobile Tablet Bounces Accidental
  • 46. Deal with Insertion ErrorsRequired: r e c e i t a d o (English: prescribed)Transcribed: rreceiittadoo
  • 47. Substitutions
  • 48. Substitution Error Rate 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 49. Few Substitutions with TabletError Rate Statistically Significant [Z=-2.731, p<.01] 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 50. Correlation with task-specific tremor Error Rate[Spearman rho=.624, n=15, p<.05][Spearman rho=.541, n=9, p<.05] [Spearman rho=.539, n=15, p<.05] 6% 8% 13% 4% 4% 9% Mobile Tablet Insertions Substitutions Omissions
  • 51. Substitution PatternsMobile Error Rate
  • 52. Right-Bottom Substitution PatternLift Points – Mobile condition
  • 53. Similar and Symmetrical Substitutionsp -> qi -> j , i -> lParticipant #11: m -> w , n -> uCognitive errors?
  • 54. Most Substitutions are due to Poor AimingError Rate 1.1% 6.7% 0.2% 3.5% Mobile Tablet Slip Poor Aiming
  • 55. Most Substitutions are due to Poor AimingError Rate Statistically Significant Statistically Significant [Z=-2.944, p<.01] [Z=-3.107, p<.01] 1.1% 6.7% 0.2% 3.5% Mobile Tablet Slip Poor Aiming
  • 56. Preferences andComments
  • 57. Participants Preference 2 13 Mobile Tablet
  • 58. Participants Comments“I am always hitting neighboring keys”“The hardest thing is trying not to tremblewhile typing”“The main difficulty for me is in knowingwhere the letters are. I am not used to it(the keyboard)”
  • 59. InclusiveKeyboards
  • 60. Implications
  • 61. ImplicationsShift keyboard layout
  • 62. ImplicationsShift keyboard layoutAvoid errors by understanding typingbehaviors
  • 63. ImplicationsShift keyboard layoutAvoid errors by understanding typingbehaviorsDeal with poor aiming rather than finger slips
  • 64. ImplicationsShift keyboard layoutAvoid errors by understanding typingbehaviorsDeal with poor aiming rather than finger slipsUse language-based correctors
  • 65. ImplicationsShift keyboard layoutAvoid errors by understanding typingbehaviorsDeal with poor aiming rather than finger slipsUse language-based correctorsAllow personalization
  • 66. ImplicationsShift keyboard layoutAvoid errors by understanding typingbehaviorsDeal with poor aiming rather than finger slipsUse language-based correctorsAllow personalizationCompensate hand tremor
  • 67. ConclusionElderly Text-Entry PerformanceEmpirical Body of KnowledgeError PatternsDesign Implications
  • 68. Future WorkAnalyze hand tremor dataDevelop touch modelsCompensate input errors Touch + Intended key Accelerometer data
  • 69. The End.Hugo Nicolauhman@vimmi.inesc-id.pthttp://web.ist.utl.pt/hugo.nicolau/