Presence and Performance Within Virtual Environments Woodrow Barfield, David Zeltzer, Thomas Sheridan, and Mel Slater

1. Presence and Performance Within Virtual EnvironmentsWoodrow Barfield, David Zeltzer,Thomas Sheridan, and Mel Slater Presented by Brett Keaffaber

2. Introduction • Impressive advances in VR hardware • Lack framework to guide research • Lack a set of metrics to quantify presence • No real theory of presence, virtual presence, or telepresence

3. Introduction • How do measure presence? • How does sense of presence impact performance? • What characteristics of the medium and message produce a sense of presence?

4. Presence in the World • Sense of being present in time or space at a particular location • No need to stimulate every sensory system to create presence (movie)

5. Definitions • Presence - The extent to which human participants in a virtual environment allow themselves to be convinced while experiencing the effects of a computer-synthesized virtual environment that they are somewhere other than where they physically are. (Slater and Usoh)

6. Definitions • Telepresence - The human operator receives sufficient information about the teleoperator and the task environment, displayed in a sufficiently natural way, that the operator feels physically present at the remote site • Virtual presence, virtual environment, virtual reality, artificial reality - experienced when sensory information generated only by and within a computer compels a feeling of presence

7. Components to a VR Experience • Models proposed by: • Wells • Lavroff • Robinett • Zeltzer

8. Components to a VR Experience • Wells tried to characterize the factors associated with the VE experience • Immersive • Interactive • Intuitive • Lavroff adds • Manipulation • Navigation

9. Components to a VR Experience • Robinett attempts to characterize the variety of VE systems • Display type • Sensor type • Action measurement type • Actuator type

10. Components to a VR Experience • Zeltzer’s AIP cube • Autonomy - objects exhibit some level of autonomy • Interaction • Human/machine interface • Access to model and system parameters at run-time • Presence - Rough lumped, measure of the number and fidelity of sensory input and output channels

11. Zeltzer’s AIP Cube Autonomous agents Virtual reality Autonomy Interaction Complex Work Domains Presence Immersive Interfaces

12. Augmented Reality • Captures the richness and complexity of the real world using video • Alleviates need for high-powered graphics rendering machines in most cases

13. Techniques for measuring presence and performance • Need measures of virtual presence that are: • operational/repeatable • reliable • robust • Presence is a mental manifestation similar to workload

14. Principal Determinants of Presence • Sheridan proposed 3 determinants • Extent of sensory information • Control of relation of sensors to environment • Ability to modify the physical environment • Unclear how the function of presence is affect by the 3 determinants • Determinants are task dependent • Task difficulty • Degree of automation

15. Principal Determinants of Presence • Determination of the dependent variables • Sense of presence • Training efficiency • Task performance

16. Multidimensional Aspectsof Presence • Level of presence related to the number of variables which add to sense of presence • Field-of-view • Frame rate • Capability of system to match human senses • Resolution • Level of trade-off’s • Type of hardware

17. Techniques for measuring presence and performance • Psychophysical and subjective measures • Questionnaires • Psychophysical measures • Relate stimulus magnitude to subjective rating • Physiological measures • e.g. - pupillary responses, EEG • Performance measures • Reaction to stimulus?

18. Empirical Studies of Presence • Case controlled experimental study • 3 aspects considered • “Sense of being there” • Leading of participant to experiencing objects as real • How does the person remember it? • Subjective questionaire

19. External and Internal Factors • External Factors - Those resulting from the VE system • Hardware • Software • Internal Factors - The persons perception of the VE • Mental models • Beliefs • Personal capabilities

20. External and Internal Factors • Strong relationship found between sense of presence and internal factors • People rely differently on on visual, auditory, and kinesthetic data

21. The Virtual Body • Held and Durlach (telepresence) • Operator can view effector movements • High correlation between operator and slave movements • Identification between operator’s body and slave’s body • Similarity in operator/slave visual appearance

22. The Virtual Body • Slater and Usoh • Use of kinesthetic VB increased sense of presence • Identification is crucial • Some participants modify their motions to reflect what the VE is portraying • Association also showed to improve presence • VB representation also shown to improve presence

23. Continuity • McGreevy - “Continuity of continuous existance is the glue that binds the will, via locomotion and manipulation, to predictable translation and rotation relative to objects within a relatively predictable environment.” • Environment must be “place-like”

24. Enjoyment • Presence highly correlated with reports of enjoyment - (Barfield and Weghorst) • Can also postulate increased task performance