1. 1 Presence in Virtual Reality Kyle Johnsen

2. 2 Presence The sense of “being there” The sense of “being there” “Mental Immersion” “Mental Immersion” Is it possible to truly believe you are in a virtual space? Is it possible to truly believe you are in a virtual space? Recent advancement in theoretical model (Slater 2009) Recent advancement in theoretical model (Slater 2009) –Place Illusion and Plausibility Illusion

3. Place Illusion (PI) User perceives body as located in the virtual environment User perceives body as located in the virtual environment Bounded by immersion Bounded by immersion Your actions affect what you observe as you would expect Your actions affect what you observe as you would expect Your ability to function naturally in the virtual world Your ability to function naturally in the virtual world 3

4. Plausibility Illusion (PSI) Scenario depicted is actually occurring (i.e. it is not a bunch of pixels) Scenario depicted is actually occurring (i.e. it is not a bunch of pixels) Ascribing real traits to virtual things Ascribing real traits to virtual things The virtual world affects you as would be expected The virtual world affects you as would be expected Do you “accept” the programming? Do you “accept” the programming? The Media Equation (Media = Real) [Reeves and Nass 1996] The Media Equation (Media = Real) [Reeves and Nass 1996] 4

5. 5 Where is presence (PI and PSI) important? Therapy Therapy Pain control Pain control Rehabilitation Rehabilitation Entertainment Entertainment Training Training Education Education

6. 6 How to measure Presence? Let’s first take a look at some of the cybertherapy applications of VR Let’s first take a look at some of the cybertherapy applications of VR –http://www.vrphobia.com/ http://www.vrphobia.com/ –How would they measure  How ‘successful’ their systems are?  The level of immersion  The participant sense of presence Subjective measures Subjective measures Objective measures Objective measures All measures are indirect! For now… All measures are indirect! For now…

7. 7 Subjective measures I had a sense of being “really there” inside the virtual environment? Strongly Disagree Strongly agree 1234567 My interaction with the virtual objects felt “real” Strongly Disagree Strongly agree 1234567

8. 8 Common Presence Questionnaires Largely measure Place Illusion Largely measure Place Illusion Witmer and Singer Witmer and Singer –30+ questions Steed Usoh Slater (SUS) Steed Usoh Slater (SUS) –7 questions Likert scaled Neither are all that good, SUS slightly more consistent Neither are all that good, SUS slightly more consistent Compare apples to apples Compare apples to apples –Example: Study comparing reality to similar virtual reality – no difference in presence

9. 9 Objective measures Physiological measures Physiological measures –Subconscious Performance measures Performance measures –Task completion time –Behavioral Observation  Subconscious and Conscious

10. Physiological measures Humans experience changes in physiological parameters in response to novel or unusual stimuli in the “real” world Humans experience changes in physiological parameters in response to novel or unusual stimuli in the “real” world Cardiovascular, Respiratory, Nervous, Sensory Cardiovascular, Respiratory, Nervous, Sensory Given sufficiently realistic stimuli in a virtual environment, the human should experience similar physiological changes. Given sufficiently realistic stimuli in a virtual environment, the human should experience similar physiological changes. 10

11. 11 Performance measures Task performance Task performance –Finishing a puzzle faster –Solving a math problem correctly Suspension of belief Suspension of belief –Instinctual responses  Ducking at boxer’s punch  Sense of vertigo –Socially conditioned reactions  VH sneezing  Anthropomorphism of VHs

12. 12 Pit Experiment Designed to test sense of presence Designed to test sense of presence Staging room and pit room Staging room and pit room Able to achieve high PI and PSI with most people Able to achieve high PI and PSI with most people Most people walk around the edge Most people walk around the edge

13. 13 What increases Presence? Rendering Rendering –Poly count –Shadows –Lighting Low latency Low latency Head tracking Head tracking Field of view Field of view Multiple senses Multiple senses –Audio –Haptics (passive if nothing else) Interactivity Interactivity –Travel Avatar Avatar

14. 14 What decreases presence? High latency High latency Poor interactivity Poor interactivity Disjoint Senses Disjoint Senses –what you expect –what you experience No Avatar No Avatar Disembodied voice Disembodied voice Cables Cables Audio (people, lab, etc.) Audio (people, lab, etc.) Called ‘breaks in presence’ (BIPs) Called ‘breaks in presence’ (BIPs)

15. 15 Cued Gestalt We enter the virtual environment carrying the baggage of our beliefs, experiences, fears and expectations. What we bring to the VE is as important as what we find there. UVA (Pausch) Star Wars example Poor VR, no back story Poor VR, w/ back story much better

16. 16 Open Questions Are there applications for which a sense of presence actually improves operator performance? Are there applications for which a sense of presence actually improves operator performance? –Yes, social facilitation [Ulinsky 2010] Can you have presence in Desktop VR? Can you have presence in Desktop VR? What about MR and AR? What about MR and AR?

17. 17 What seems to be true? A person's experience of a situation in a virtual environment may evoke the same reactions and emotions as the experience of a similar real-world situation. A person's experience of a situation in a virtual environment may evoke the same reactions and emotions as the experience of a similar real-world situation. Despite Despite –Virtual reality is consequence-poor relative to reality –virtual environment does not accurately or completely represent the real-world situation This is a reflection of high (PSI + PI) This is a reflection of high (PSI + PI) Increase through “cued gestalt”, better tech, more realistic behavior of VEs. Increase through “cued gestalt”, better tech, more realistic behavior of VEs.

18. What seems to be true? (cont.) A person's perceptions of real-world situations and behavior in the real-world may be modified based on his experiences within a virtual world. A person's perceptions of real-world situations and behavior in the real-world may be modified based on his experiences within a virtual world. Not only can we cause reactions, but we can change them in the future. Not only can we cause reactions, but we can change them in the future. 18