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 Why?

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? Transmission Rating Factor (ITU-T Rec G.107) R = Ro – Is –Id –Ie-eff + A But what about bystander preferences? Channel properties affect user perceptions. The E-model can predict these, for infrastructure design purposes. Ro = signal-to-noise ratio Is = simultaneous impairment Id = delay impairment factor Ie-eff = equipment impairment factor (e.g. codec) A = advantage factor

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: NO B>70 PHONES!

Perceptions of Delay We know that delay affects talkers’ perceptions

(Emling & Mitchell 1964) How Line Delay Affects Conversation Dynamics Likely 1 st Order Effects: more awkward silences more overlaps Likely 2 nd Order Effects: more explicit turn-taking cues

annoyance lack of audible interlocutor feeling of embarrassment channel properties involuntary listening delay noise echo negative attitudes to cell phones handset properties lack of sidetone low volume negative impressions of talker bossy show-off insensitive etc. changed speaking style loud exaggerated prosody etc. different situation at remote end incongruous speaking styles incongruous topic lack of shared awareness cognitive effects uncertainty about receipt frustration cognitive load Likely Effects on Bystanders

Hypothesis 2 Hypothesis: Bystanders dislike channel delay more than do talkers where we measure “more” relative to a standard impairment: codec quality

Experiment Design High Noise Low Delay (C n ) Bystanders’ Perception Talkers’ Perception good Low Noise High Delay (C d ) less goodgood T Δ = T Cn - T Cd B Δ = B Cn - B Cd 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 G ms GSM-FR 150 ms

Software/Hardware Configuration channels emulated on Linux machines talkers in different rooms extra delay (C D ) or extra noise (C N ) recorder

Procedures 1.welcome 2.dialog with Cn or Cd 3.questionnaire 4.dialog with Cd or Cn 5.questionnaire 6.debrief 1.welcome 2.overhear 3.questionnaire 4.overhear 5.questionnaire 6.debrief Two TalkersTwo to Eight Bystanders 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 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 The Mystery Remains

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? -- The Effects of Noise and Delay -- Nigel Ward Anais G. Rivera Alejandro Vega University of Texas at El Paso Why?

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.) excellent good fair poor bad first dialog second dialog B. What differences did you notice between the two connections? C. What do you think affected your ratings of the two connections? date ___________ session ________ subject A B recording# 1 _________ recording# 2 _________ T excellent good fair poor bad

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.) excellent good fair poor bad first dialog second dialog B. What differences did you notice between the two samples? C. What do you think affected your ratings of the two samples? date ___________ session ______ subject A B recording# 1 _________ recording# 2 _________ B excellent good fair poor bad

Dialog-Based Evaluation of Mobile Phone Infrastructure Phase 3 date ___________ session ______ subject A B recording# 1 _________ recording# 2 _________ R 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.) excellent good fair poor bad first dialog second dialog B. What differences did you notice between the two samples? C. What do you think affected your ratings of the two samples? excellent good fair poor bad