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Presence in Virtual Reality. Kyle Johnsen. Presence. The sense of “being there” “Mental Immersion” Is it possible to truly believe you are in a virtual space? Recent advancement in theoretical model (Slater 2009) Place Illusion and Plausibility Illusion. Place Illusion (PI).
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Presence in Virtual Reality Kyle Johnsen
Presence • The sense of “being there” • “Mental Immersion” • Is it possible to truly believe you are in a virtual space? • Recent advancement in theoretical model (Slater 2009) • Place Illusion and Plausibility Illusion
Place Illusion (PI) • User perceives body as located in the virtual environment • Bounded by immersion • Your actions affect what you observe as you would expect • Your ability to function naturally in the virtual world
Plausibility Illusion (PSI) • Scenario depicted is actually occurring (i.e. it is not a bunch of pixels) • Ascribing real traits to virtual things • The virtual world affects you as would be expected • Do you “accept” the programming? • The Media Equation (Media = Real) [Reeves and Nass 1996]
Therapy Pain control Rehabilitation Entertainment Training Education Where is presence (PI and PSI) important?
How to measure Presence? • Let’s first take a look at some of the cybertherapy applications of VR • http://www.vrphobia.com/ • How would they measure • How ‘successful’ their systems are? • The level of immersion • The participant sense of presence • Subjective measures • Objective measures • All measures are indirect! For now…
Subjective measures I had a sense of being “really there” inside the virtual environment? Strongly Disagree Strongly agree 1 2 3 4 5 6 7 My interaction with the virtual objects felt “real” Strongly Disagree Strongly agree 1 2 3 4 5 6 7
Common Presence Questionnaires • Largely measure Place Illusion • Witmer and Singer • 30+ questions • Steed Usoh Slater (SUS) • 7 questions Likert scaled • Neither are all that good, SUS slightly more consistent • Compare apples to apples • Example: Study comparing reality to similar virtual reality – no difference in presence
Objective measures • Physiological measures • Subconscious • Performance measures • Task completion time • Behavioral Observation • Subconscious and Conscious
Physiological measures • Humans experience changes in physiological parameters in response to novel or unusual stimuli in the “real” world • Cardiovascular, Respiratory, Nervous, Sensory • Given sufficiently realistic stimuli in a virtual environment, the human should experience similar physiological changes.
Performance measures • Task performance • Finishing a puzzle faster • Solving a math problem correctly • Suspension of belief • Instinctual responses • Ducking at boxer’s punch • Sense of vertigo • Socially conditioned reactions • VH sneezing • Anthropomorphism of VHs
Pit Experiment • Designed to test sense of presence • Staging room and pit room • Able to achieve high PI and PSI with most people • Most people walk around the edge
What increases Presence? • Rendering • Poly count • Shadows • Lighting • Low latency • Head tracking • Field of view • Multiple senses • Audio • Haptics (passive if nothing else) • Interactivity • Travel • Avatar
What decreases presence? • High latency • Poor interactivity • Disjoint Senses • what you expect • what you experience • No Avatar • Disembodied voice • Cables • Audio (people, lab, etc.) • Called ‘breaks in presence’ (BIPs)
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
Open Questions • 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? • What about MR and AR?
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. • 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) • Increase through “cued gestalt”, better tech, more realistic behavior of VEs.
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. • Not only can we cause reactions, but we can change them in the future.