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

1
Do Bystanders and Dialog Participants Differ in
Preferences for Telecommunications Channels?

• -- The Effects of Noise and Delay --

Why?
Nigel Ward Anais G. Rivera Alejandro
Vega University of Texas at El Paso
2
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 doesnt
explain the annoyance (Monk et al. 2004b)
3
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?
4
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

5
Perceptions of Delay

• We know that delay affects talkers perceptions

6
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

7
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
8
Hypothesis 2

• Hypothesis
• Bystanders dislike channel delay more than do
  talkers
• where we measure more relative to a
  standard impairment codec quality

9
Experiment Design
Bystanders Perception
Talkers Perception
High Noise Low Delay (Cn)
GSM-FR 150 ms
good
good
Low Noise High Delay (Cd)
G.711 350 ms
less good
good
T ? TCn - TCd
B ? BCn - BCd
Hypothesis 2 compared to talkers,
bystanders dislike delay more i.e. T ? lt B ?,
i.e. T ? - B ? lt 0 unfortunately not
supported by Wilcoxon sign test, chi-square, or
matched-pairs t-test
10
Software/Hardware Configuration
recorder

• channels emulated on Linux machines
• talkers in different rooms

11
Procedures
Two Talkers
Two to Eight Bystanders

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

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)
12
Experiment Conditions (1)

• Distance from Talker to Bystanders
• gt 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

13
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

14
Results
T? talker preference re channel quality (Cn
Cd) B? bystander preference re less-annoying
(Cn Cd)
15
Results

• On the last experiment
• Subjects preferences for Cn over Cd,
• as talkers and as bystanders

16
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
17
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
18
Do Bystanders and Dialog Participants Differ in
Preferences for Telecommunications Channels?

• -- The Effects of Noise and Delay --

Why?
Nigel Ward Anais G. Rivera Alejandro
Vega University of Texas at El Paso
19
(No Transcript)
20
T
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?
21
B
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?
22
R
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?
23
(No Transcript)