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Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels?. Why?. -- The Effects of Noise and Delay --. Nigel Ward Anais G. Rivera Alejandro Vega University of Texas at El Paso. The Mystery. Mobile telephone conversations are often banned
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Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels? Why? -- The Effects of Noise and Delay -- Nigel Ward Anais G. Rivera Alejandro Vega University of Texas at El Paso
The Mystery Mobile telephone conversations are often banned because they can be annoying to bystanders. But why are they more annoying than face-to-face conversations? • Is it the volume? Perhaps in part, but cell phone conversations are more annoying even when no louder than face-to-face conversations (Monk et al. 2004a) • Is it the lack of an audible interlocutor, inducing a psychological “need to listen”? Perhaps in part, but this doesn’t explain the annoyance (Monk et al. 2004b)
Is it the Channel? Channel properties affect user perceptions. The E-model can predict these, for infrastructure design purposes. Transmission Rating Factor (ITU-T Rec G.107) R = Ro – Is –Id –Ie-eff + A • Ro = signal-to-noise ratio • Is = simultaneous impairment • Id = delay impairment factor • Ie-eff = equipment impairment factor (e.g. codec) • A = advantage factor But what about bystander preferences?
NO B>70 PHONES! Potential Significance Hypothesis 1: For telecommunication channels, bystanders preferences differ from users preferences If true, there may be a technological fix to the problem Today: In a Possible Future:
Perceptions of Delay We know that delay affects talkers’ perceptions
How Line Delay Affects Conversation Dynamics (Emling & Mitchell 1964) • Likely 1st Order Effects: • more awkward silences • more overlaps • Likely 2nd Order Effects: • more explicit • turn-taking cues
Likely Effects on Bystanders channel properties handset properties different situation at remote end lack of audible interlocutor • delay • noise • echo • lack of • sidetone • low volume • incongruous • speaking styles • incongruous • topic • lack of shared • awareness cognitive effects changed speaking style • uncertainty • about receipt • frustration • cognitive load • loud • exaggerated • prosody • etc. negative impressions of talker involuntary listening • bossy • show-off • insensitive • etc. negative attitudes to cell phones feeling of embarrassment annoyance
Hypothesis 2 Hypothesis: Bystanders dislike channel delay more than do talkers where we measure “more” relative to a standard impairment: codec quality
Experiment Design Talkers’ Perception Bystanders’ Perception High Noise Low Delay (Cn) GSM-FR 150 ms good good Low Noise High Delay (Cd) G.711 350 ms good less good T Δ = TCn - TCd B Δ = BCn - BCd Hypothesis 2: compared to talkers, bystanders dislike delay more i.e. T Δ < B Δ, i.e. T Δ - B Δ < 0 unfortunately not supported by Wilcoxon sign test, chi-square, or matched-pairs t-test
extra delay (CD) or extra noise (CN) Software/Hardware Configuration • channels emulated on Linux machines • talkers in different rooms recorder
Procedures Two Talkers Two to Eight Bystanders • welcome • dialog with Cn or Cd • questionnaire • dialog with Cd or Cn • questionnaire • debrief • welcome • overhear • questionnaire • overhear • questionnaire • debrief usually with same stimuli, different judges sometimes with same judges, different stimuli (when talkers were later used as bystanders) sometimes with same judges, same stimuli (when talkers later listened to recordings of themselves)
Experiment Conditions (1) Distance from Talker to Bystanders • > 4 meters • ~ 2 meters • ~ 0.5 meters Distractors • pizza and friends • magazines • none (paying attention) Dialog Content Cn Cd • multi-digit number exchange • free dialog • single-digit number exchange
Experiment Conditions (2) Presentation • live • recorded, played over speakers • matched-content extracts, headphones Subjects • naive students • experts Survey Format • forced choice • 4 choices • 11 point scales
Results TΔ = talker preference re channel quality (Cn – Cd) BΔ = bystander preference re less-annoying (Cn – Cd)
Results On the last experiment: Subjects’ preferences for Cn over Cd, as talkers and as bystanders
Summary The Mystery Remains Summary results for Hypothesis 2: • Across 59 dialog stimulus-pairs, in various conditions - bystanders seemed to dislike Cn more than did talkers, contrary to hypothesis 2 - however the difference was small and not consistent (averaging 1.42 vs 1.47 on a scale from 0 to 3) • Even under unrealistically exaggerated conditions, line delay does not consistently impact bystanders Summary Results for Hypothesis 1: • No evidence that bystanders and dialog participants differ in preferences
Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels? -- The Effects of Noise and Delay -- Nigel Ward Anais G. Rivera Alejandro Vega University of Texas at El Paso
Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels? Why? -- The Effects of Noise and Delay -- Nigel Ward Anais G. Rivera Alejandro Vega University of Texas at El Paso
T 10 10 excellent excellent 8 8 good good 6 6 fair fair 4 4 poor poor 2 2 bad bad 0 0 Dialog-Based Evaluation of Mobile Phone Infrastructure Phase 1 A. Your opinion of the connection you have just been using. (Please place a line crossing the axis at the appropriate point.) first dialog second dialog B. What differences did you notice between the two connections? date ___________ session ________ subject A B recording# 1 _________ recording# 2 _________ C. What do you think affected your ratings of the two connections?
B 10 10 excellent excellent 8 8 good good 6 6 fair fair 4 4 poor poor 2 2 bad bad 0 0 Dialog-Based Evaluation of Mobile Phone Infrastructure Phase 2 A. Sometimes conversations can be annoying to bystanders, independent of the content, due to the way the the speaker was talking. Considering the potential for annoyance due to the speaking style, please give your opinion of the sample. (Please place a line crossing the axis at the appropriate point.) first dialog second dialog B. What differences did you notice between the two samples? date ___________ session ______ subject A B recording# 1 _________ recording# 2 _________ C. What do you think affected your ratings of the two samples?
R 10 10 excellent excellent 8 8 good good 6 6 fair fair 4 4 poor poor 2 2 bad bad 0 0 Dialog-Based Evaluation of Mobile Phone Infrastructure Phase 3 A. Sometimes conversations can be annoying to bystanders, independent of the content, due to the way the the speaker was talking. Considering the potential for annoyance due to the speaking style, please give your opinion of the sample. (Please place a line crossing the axis at the appropriate point.) first dialog second dialog B. What differences did you notice between the two samples? date ___________ session ______ subject A B recording# 1 _________ recording# 2 _________ C. What do you think affected your ratings of the two samples?