Do Bystanders and Dialog Participants Differ in Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels?Preferences for Telecommunications Channels?

---- The Effects of Noise and Delay The Effects of Noise and Delay ----

Why?Nigel WardNigel Ward

Anais G. RiveraAnais G. RiveraAlejandro VegaAlejandro Vega

University of Texas at El PasoUniversity of Texas at El Paso

The MysteryThe MysteryMobile 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?Is it the Channel?

Transmission Rating Factor (ITU-T Rec G.107)R = Ro – Is –Id –Ie-eff + A

Channel properties affect user perceptions.The E-model can predict these, for infrastructure design purposes.

Ro = signal-to-noise ratioIs = simultaneous impairmentId = delay impairment factorIe-eff = equipment impairment factor (e.g. codec)A = advantage factor

But what about bystander preferences?

Potential SignificancePotential 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>70PHONES!

Perceptions of DelayPerceptions of Delay

We know that delay affects talkers’ perceptions

How Line Delay Affects How Line Delay Affects Conversation DynamicsConversation Dynamics

(Emling & Mitchell 1964)

Likely 1st Order Effects: • more awkward silences • more overlaps

Likely 2nd Order Effects: • more explicit turn-taking cues

annoyance

lack of audibleinterlocutor

feeling ofembarrassment

channelproperties

involuntarylistening

• delay• noise• echo

negative attitudes tocell phones

handsetproperties

• lack of sidetone

• low volume

negativeimpressionsof talker

• bossy• show-off• insensitive• etc.

changedspeaking style

• loud• exaggerated

prosody• etc.

differentsituationat remote end

• incongruous speaking styles

• incongruoustopic

• lack of sharedawareness

cognitiveeffects

• uncertaintyabout receipt

• frustration• cognitive load

Likely Effects on BystandersLikely Effects on Bystanders

Hypothesis 2Hypothesis 2

Hypothesis:Bystanders dislike channel delay more than do talkers

where we measure “more” relative to a standard impairment: codec quality

Experiment DesignExperiment DesignTalkers’Perception

Bystanders’Perception

High NoiseLow Delay(Cn)

goodgood

Low NoiseHigh Delay(Cd)

less goodgood

GSM-FR150 ms

G.711350 ms

T Δ = TCn - TCd B Δ = BCn - BCdHypothesis 2:

compared to talkers, bystanders dislike delay morei.e. T Δ < B Δ, i.e. T Δ - B Δ < 0

unfortunately not supported

Software/Hardware ConfigurationSoftware/Hardware Configuration

extra delay (CD) or extra noise (CN) recorder

• channels emulated on Linux machines

• talkers in different rooms

ProceduresProceduresTwo Talkers Two to Eight Bystanders1. welcome2. dialog with Cn or Cd3. questionnaire4. dialog with Cd or Cn5. questionnaire6. debrief

1. welcome2. overhear3. questionnaire4. overhear5. questionnaire6. debrief

usually with same stimuli, different judgessometimes 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)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)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

ResultsResults

TΔ = talker preference re channel quality (Cn – Cd)BΔ = bystander preference re less-annoying (Cn – Cd)

ResultsResultsOn the last experiment:

Subjects’ preferences for Cn over Cd,as talkers and as bystanders

SummarySummarySummary 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 Do Bystanders and Dialog Participants Differ in Preferences Participants Differ in Preferences

for Telecommunications Channels?for Telecommunications Channels?

---- The Effects of Noise and Delay The Effects of Noise and Delay ----

Nigel WardNigel WardAnais G. RiveraAnais G. RiveraAlejandro VegaAlejandro Vega

University of Texas at El PasoUniversity of Texas at El Paso

Do Bystanders and Dialog Participants Differ in Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels?Preferences for Telecommunications Channels?

---- The Effects of Noise and Delay The Effects of Noise and Delay ----

Why?Nigel WardNigel Ward

Anais G. RiveraAnais G. RiveraAlejandro VegaAlejandro Vega

University of Texas at El PasoUniversity of Texas at El Paso

TDialog-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.)

excellentgoodfairpoorbad

108642

0

excellentgoodfairpoorbad

108642

0

firstdialog

seconddialog

B. What differences did you notice between the two connections?

date ___________session ________subject A Brecording# 1 _________recording# 2 _________

C. What do you think affected your ratings of the two connections?

BDialog-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.)

excellentgoodfairpoorbad

108642

0

excellentgoodfairpoorbad

108642

0

firstdialog

seconddialog

B. What differences did you notice between the two samples?

date ___________session ______subject A Brecording# 1 _________recording# 2 _________

C. What do you think affected your ratings of the two samples?

RDialog-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.)

excellentgoodfairpoorbad

108642

0

excellentgoodfairpoorbad

108642

0

firstdialog

seconddialog

B. What differences did you notice between the two samples?

date ___________session ______subject A Brecording# 1 _________recording# 2 _________

C. What do you think affected your ratings of the two samples?

Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels?The MysteryIs it the Channel?Potential SignificancePerceptions of DelayHow Line Delay Affects Conversation DynamicsHypothesis 2Experiment DesignSoftware/Hardware ConfigurationProceduresExperiment Conditions (1)Experiment Conditions (2)ResultsResultsSummaryDo Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels?Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels?