This lecture discusses presence in virtual reality. It defines presence as the subjective experience of being in a virtual environment rather than the physical one. Presence is influenced by how immersive a VR system is at stimulating the senses through sights, sounds etc. to generate realistic sensations. High presence leads to greater engagement from users and more natural reactions. The lecture compares presence to immersion and outlines different dimensions and methods of measuring presence, highlighting the importance of multi-sensory stimulation for creating strong feelings of presence.

1. LECTURE 2: PRESENCE IN
VIRTUAL REALITY
COMP 4010 - Virtual Reality
Semester 5 - 2016
Mark Billinghurst, Bruce Thomas
University of South Australia
August 2nd 2016

2. Are We Living In a Simulation?
• https://www.youtube.com/watch?v=hprf4Mgi9lE

3. Are We In the Matrix?

4. • https://www.youtube.com/watch?v=aVLexf_dyCM

5. What is Reality?

6. How do We Perceive Reality?
• We understand the world through
our senses:
• Sight, Hearing, Touch, Taste, Smell
(and others..)
• Two basic processes:
• Sensation – Gathering information
• Perception – Interpreting information

7. Simple Sensing/Perception Model

8. What is Virtual Reality?
• https://www.youtube.com/watch?v=gBuW6mFEnpo

9. Goal of Virtual Reality
“.. to make it feel like you’re actually in
a place that you are not.”
Palmer Luckey
Co-founder, Oculus

10. Creating the Illusion of Reality
• Fooling human perception by using
technology to generate artificial sensations
• Computer generated sights, sounds, smell, etc

11. Reality vs. Virtual Reality
• In a VR system there are input and output devices
between human perception and action

12. Example: Virtual Cocoon
• Virtual Cocoon concept
• Univ. Warwick, Univ. York (2009)
• Multi-sensory VR display
• All 5 senses stimulated
• Visual, 3D audio, smells, etc
• Cross modal effects improve
VR experience
• E.g. taste + sound > taste alone
http://www.wired.com/2009/03/realvirtuality/
Chalmers, A., Howard, D., & Moir, C. (2009). Real virtuality: a step change from virtual reality.
In Proceedings of the 25th Spring Conference on Computer Graphics (pp. 9-16). ACM.

13. FeelReal – FeelReal.com
• https://www.youtube.com/watch?v=mIin6K_iNSA

14. Birdly - http://www.somniacs.co/
• Create illusion of flying like a bird
• Multisensory VR experience
• Visual, audio, wind, haptic

15. Birdly Demo
• https://www.youtube.com/watch?v=gHE6H62GHoM

16. ‘Virtual Reality is a synthetic sensory experience which may
one day be indistinguishable from the real physical world.”
-Roy Kalawsky (1993)
Today
Tomorrow

17. Types of Human Experience
Lee, K. M. (2004). Presence, explicated. Communication theory, 14(1), 27-50.

18. Presence Definition
“Presence is a psychological state .. in
which even though part or all of an
individual’s current experience is generated
by .. technology, part or all of the individual’s
perception fails to .. acknowledge the role of
the technology in the experience.”
International Society for Presence Research, 2016
https://ispr.info/

19. In Simple Terms, Presence is ..
“The subjective experience of being in one place or
environment even when physically situated in another”
Witmer, B. G., & Singer, M. J. (1998). Measuring presence in virtual environments: A presence
questionnaire. Presence: Teleoperators and virtual environments, 7(3), 225-240.

20. Immersion vs. Presence
• Immersion: describes the extent to which technology is
capable of delivering a vivid illusion of reality to the senses
of a human participant.
• Presence: a state of consciousness, the (psychological)
sense of being in the virtual environment.
• So Immersion, defined in technical terms, is capable of
producing a sensation of Presence
Slater, M., & Wilbur, S. (1997). A framework for immersive virtual environments (FIVE):
Speculations on the role of presence in virtual environments. Presence: Teleoperators and
virtual environments, 6(6), 603-616.

21. Three Dimensions of Presence
• Personal Presence, the extent to which the person
feels like he or she is part of the virtual environment;
• Social Presence, the extent to which other beings
(living or synthetic) also exist in the VE;
• Environmental Presence, the extent to which the
environment itself acknowledges and reacts to the
person in the VE.
Heeter, C. (1992). Being there: The subjective experience of presence.
Presence: Teleoperators & Virtual Environments, 1(2), 262-271.

22. Benefits of High Presence
• Leads to greater engagement, excitement and satisfaction
• Increased reaction to actions in VR
• People more likely to behave like in the real world
• E.g. people scared of heights in real world will be scared in VR
• More natural communication (Social Presence)
• Use same cues as face to face conversation
• Note: The relationship between Presence and Performance is
unclear – still an active area of research

23. Measuring Presence
• Presence is very subjective so there is a lot of debate
among researchers about how to measure it
• Subjective Measures
• Self report questionnaire
• University College London Questionnaire (Slater 1999)
• Witmer and Singer Presence Questionnaire (Witmer 1998)
• ITC Sense Of Presence Inventory (Lessiter 2000)
• Continuous measure
• Person moves slider bar in VE depending on Presence felt
• Objective Measures
• Behavioural
• reflex/flinch measure, startle response
• Physiological measures
• change in heart rate, skin conductance, skin temperature
Presence Slider

24. Example: Witmer and Singer (1998)
• 32 questions in 4 categories/factors
• Control (CF), Sensory (SF), Realism (RF), Distraction factors (DF)
• Answered on Likert scale from 1 to 7 ( 1 = low, 7 = high)

25. Example: UNC Pit Room
• Key Features
• Training room and pit room
• Physical walking
• Fast, accurate, room scale tracking
• Haptic feedback – feel edge of pit, walls
• Strong visual and 3D audio cues
• Task
• Carry object across pit
• Walk across or walk around
• Dropping virtual balls at targets in pit
• http://wwwx.cs.unc.edu/Research/eve/walk_exp/

26. Typical Subject Behaviour
• Note – from another pit experiment
• https://www.youtube.com/watch?v=VVAO0DkoD-8

27. Results
• Physiological measures can be used as a reliable measure
of Presence - especially change in heart rate (HR)
• Change in HR agreed with UCL subjective questionnaire
• HR increased with passive haptics, and increase in fps
Meehan, M., Insko, B., Whitton, M., & Brooks, F. P. (2001). Physiological measures of presence
in virtual environments. In Proceedings of 4th International Workshop on Presence (pp. 21-23).

28. How to Create Strong Presence?
• Use 3 Dimensions of Presence
• Create rich multi-sensory VR experiences
• Include social actors/agents that interact with user
• Have environment respond to user
• What Influences Presence
• Vividness – ability to provide rich experience (Steuer 1992)
• Using Virtual Body – user can see themselves (Slater 1993)
• Internal factors – individual user differences (Sadowski 2002)
• Interactivity – how much users can interact (Steuer 1992)
• Sensory, Realism factors (Witmer 1998)

29. Presence Guidelines (Sadowski 2002)

30. Oculus 5 Key Technical Ingredients
• Persistence
• > 90 Hz refresh, < 3 ms persistence, avoid retinal blur
• Optics
• Wide FOV > 90 degrees, comfortable eyebox, good calibration
• Tracking
• 6 DOF, 360 tracking, sub-mm accuracy, no jitter, good tracking volume
• Resolution
• Correct stereo, > 1K x 1K resolution, no visible pixels
• Latency
• < 20 ms latency, fuse optical tracking and IMU, minimize tracking loop
http://www.roadtovr.com/oculus-shares-5-key-ingredients-for-presence-in-virtual-reality/

31. Relevant Papers
• Slater, M., & Usoh, M. (1993). Representation systems, perceptual positions, and presence
in immersive virtual environments. Presence, 2:221–233.
• Slater, M. (1999). Measuring presence: A response to the Witmer and Singer Presence
Questionnaire. Presence, 8:560–565.
• Steuer, J. (1992). Defining virtual reality: Dimensions determining telepresence. Journal of
Communication, 42(4):72–93.
• Sadowski, W. J. and Stanney, K. M. (2002) Measuring and Managing Presence in Virtual
Environments. In: Handbook of Virtual Environments: Design, implementation, and
applications.http://vehand.engr.ucf.edu/handbook/
• Schuemie, M. J., Van Der Straaten, P., Krijn, M., & Van Der Mast, C. A. (2001). Research on
presence in virtual reality: A survey CyberPsychology & Behavior, 4(2), 183-201.
• Lee, K. M. (2004). Presence, explicated. Communication theory, 14(1), 27-50.
• Witmer, B. G., & Singer, M. J. (1998). Measuring presence in virtual environments: A
presence questionnaire. Presence: Teleoperators and virtual environments, 7(3), 225-240.
• Lessiter, J., Freeman, J., Keogh, E., & Davidoff, J. (2000). Development of a new cross-
media presence questionnaire: The ITC-Sense of presence. Paper at the Presence 2000
Workshop, March 27–28, Delft.

32. www.empathiccomputing.org
@marknb00
mark.billinghurst@unisa.edu.au