Milton

Do’s and Don’ts of using Videoconferencing for Remote Teaching:

A Human Factors Approach

Milton Chen, PhD

Human Computer Interaction Lab

Stanford University

Presented at the 21st NORDUnet Network Conference 8/27/2003

Executive Summary

1. Don’t use video if the task doesn’t need it

2. Don’t use “non-fluent” video

3. Don’t make call setup difficult

4. Don’t use voice activated switching

5. Don’t sacrifice audio

6. Do show self view

7. Do show audience

Distance education at Stanford

6000 students, $20 M in tuition each yearCan hear but not see the remote students

a 1969 classroom

a 2003 operator console

a 2003 lecture viewer

Consequence of not seeing the students

Little interaction with remote students– Local students asked 3 questions per session– Remote students asked 1 question in 6 month

* based on classroom observation of 4 CS classes

F2F interaction is crucial for discussions

Importance of f2f interaction

0%

50%

100%

students TAs faculty

extremely

very

moderately

somewhat

not

* 120 students, 15 TAs, and 41 faculty[Report to the School of Engineering Dean’s Office ’01]

Distance learning

The consequence

student of the future teacher of the future

The visionany where, any time

The realityany where, any time except live

The Stanford Video Auditorium

desktop interface

15’ x 5’ video wall

The Stanford Video Auditorium

AccomplishmentsIntel President Paul Otellini demonstrated vsee

during his keynote at IDF

Candidate system for International Space Station• With Bob Bradford, MSFC

Featured Internet2 project to break video wall record• Attempt to see all 200 members of Internet2 simultaneously

Videoconferencing Solutions

Max video links

Max video resolution

Bandwidth at 352x288 15fps

Microsoft NetMeeting,

Yahoo Super Webcam

1 352x288 ~200 Kbps

Polycom, Tandberg, … 4 352x288 ~200 Kbps

vsee ~16 720x480* ~100 Kbps

* At 30 fps on a 3 GHz Pentium 4

Instructor’s view Student’s view

Independent Students

StanfordIceland

The great expectation

19271st demo by AT&T

1964PicturePhone

1991/92Mbone VICCUseeMe

1996NetMeeting

expe

ctat

ion

first mobile phone, 1924 first handheld phone, 1973

1st Revolution: Possible 2nd Revolution: Ubiquitous

first videophone, 1927

Tyranny of real classroomsvsee

A history of failuresHarmful effect of video

“We express ourselves into existence.” - Iris Murdoch

Harmful effect of video

Time and resource sink

Make user look bad– Gaze less potent => are you ignoring me?

– Gesture less potent => am I not interesting?

– Slow response => user is slow?

– Lack of lip sync => user is not believable?

– Lack of eye contact => user is not motivated? [Reeves and Nass ’96]

Eye contact stirs us to action

[Sharbat Gula, photographed by McCurry ‘83]

Eye contact fires up our brain

[Kampe et al. ’01 Nature]

Methodology

Observers watch videos of looker

Large display with camera at the center

Eye contact?

Sensitivity is asymmetric

* 16 observers judged recorded videos of 1 looker

An anatomical explanation

looking at you looking sideways

looking up

looking down eye closing

Illustrations from The Artist’s Guide to Facial Expression[Faigin ’90]



Eye contact findingLip sync finding

“We shape our tools, and there after our tools shape us”

- Marshal McLuhan

Why read lips

Improves comprehension – Background noise [Sumby and Pollack ’54]– Hearing loss [Binnie, Montgomery, Jackson ’86]

[Yarbus ’67]

Audio ahead of the video

Videoconferencing– 1 msec to encode 30-msec audio with TrueSpeech– Up to 250 msec to encode a 720x480 frame with

high-quality MPEG-4

Detectable skew130 msec [Dixon and Spitz ’80]

80 msec [Steinmetz ’96]

Conventional lip synchronization

encodenetworkdecode

A

a v

time

Unsynchronized

encodenetworkdecodesync

a, v

Audio delay lineA

delayskew

Attribute delay and skew to remote person

=> person is slow?

=> person is not believable?

[Reeves and Nass ’96]

encodenetworkdecode

A

a v

time

Unsynchronized


a, v

Audio delay lineA

delayskew

A new lip sync method


synchronized and low perceived latency

a v a v

encodenetworkdecode

A

a v

time

Unsynchronized


a, v

Audio delay lineA

Round trip delay

Methodology

Recorded 3 speakers– 44.1KHz x 16 bps uncompressed audio– 320x240x30fps uncompressed video– Sentences consist of easy to lipread words

Speaker 1female native

speaker

Speaker 2male native

speaker

Speaker 3male non-native

speaker

Perception of variable AV skew

* 16 subjects judged recorded videos of 1 speaker

0

25

50

75

100

200,unsync 200,slow 200, fast sync

initial skew (msec) , stretch period

lip s

ynch

roni

zatio

n (%

)



Eye contact findingLip sync findingDo’s and Don'ts

“The heart is stirred more slowly by the ear than by the eye.”

– Horace

1. Don’t use video if you don’t need it

Benefit of video medium

Facilitate communication process– Stimulate interactivity when group is medium size

– Support tasks that require complex collaboration• Negative feedback

• Negotiation

Build relationship– Establish identity

– Build trust

– Form friendship


A language fluency model for videoconferencing

Are you fluent in videoconferencing ?

Factors that make gaining fluency difficult– Disruption

• Audio quality < 8KHz x 8 bits per sample

• Video quality < 320 x 240 x 10 fps

– Loss of control• Voice-activated switching

• Room-to-room

– Expressiveness• No lip sync

• No eye contact


Videoconferencing today?

Ericsson’s mobile phone, 1901


3 sins

Activate peripheral vision

Out of sight out of mind

Artificial social hierarchy


Less tolerant of audio artifacts

Push button to talk

Half-duplex

Latency

Network loss


Mental model discrepancy

We think face-to-face

We see through a tube

7. Do show audience

Convey vs. feedback

Where do you actually look?

The typically class layout

Do’s and Don’ts

1. Don’t use video if the task doesn’t need it






7. Do show audience

A plane that does not fly is not a plane

First flight, Wrights 1903

A videophone that limits communication is not a videophone

What is a videophone

SummaryTyranny of real classrooms

– Case study: not seeing => no participation

VSee

A history of failures– Poor video can be worse than no video

• Findings on eye contact and lip sync

Do’s and Don’ts

Acknowledgement– Prof. Ebba Hvannberg

– Prof. Pat Hanrahan and Terry Winograd– Prof. Cliff Nass, Tom Moran, Anoop Gupta

I would love to hear from you!– http://vsee.stanford.edu

Collaborate on the Internet2 demo?

Economy & Finance

Milton