1. Presence: The debate between constructive cognition and ecological perception. Nunez, D. & Blake, E. (2003) Conceptual Priming as a Determinant of Presence in Virtual Environments, ACM Database. Vicki Peace, Sian Pegler, Helen Poyer and Laura Ringham

2. Overview What is presence? How is presence explained? –Ecological v Constructive Cognition Case Study Issues of measurement Conclusions and Questions

3. What is presence? “Presence is the idea of ‘being there’ “the degree to which the virtual environment dominates over the real environment as the basis for thought” (Nunez and Blake, 2003)

4. Where is the controversy? In general, presence is a controversial area. Many debates –What actually is presence? –How can presence be measured/evaluated? –Does presence have an influence on tasks? SELECTED DEBATE: What is the basis of presence? »Ecological v Constructive Cognition

5. Basis of Presence? Constructive v Ecological CONSTRUCTIVE COGNITION Eysenk & Keane (1995) Higher level processing Top-Down Mental processing MOST important Perception and schemata Presence obtained as a process of mental processes interacting with sensory information ECOLOGICAL PERCEPTION Gibson (1979) Direct Perception Bottom-Up Sensory info MOST important Affordances Presence due to individuals perception of sensory information and action within their environment.

6. The Case Study 1 Conceptual Priming as a Determinant of Presence in Virtual Environment. Nunez and Blake (2003) Aim to determine if presence is actually constructed by the user or if it simply arises from sensory stimulation only. The study tested two hypotheses: 1. If a user has active schemata which are related to the VE which the user is experiencing, then the user will experience more presence 2. If the VE is rendered on a higher fidelity display system, the user will experience more presence

7. The Case Study 2 The experiment had a 2x2 factorial ANOVA design: –Stimulus quality of VE display system –Conceptual priming Two levels were used for each variable The dependant variable was presence 55 undergraduate participants Each participant took part in two experiment sessions, exploring two different VE and filling in two sets of presence questionnaires.

8. Monastery VE

9. Hospital VE Figure 4: Hospital VE – ward room in low stimulus quality

10. The Case Study 3 Hardware: –Non-immersive, desktop-based systems Software: –VE exploration tool DAVE VE’s: –Training environment –Medieval European Monastery –Hospital Priming: –Printed booklets either related to or not related to the theme of the VE

11. The Case Study 4 Measures: –Presence Questionnaire of Witmer & Singer –Presence Scale of Slater, Usoh & Steed Procedure: –Instruction and training stage –Priming stage –Exploration stage –Questionnaire stage –Second iteration

12. Results Relevant Prime – Hospital or Monastery –High presence in high quality environment –Lower presence in low quality environment. Irrelevant Prime – Steam Trains –Presence similar between quality Interaction of Priming and Stimulus Quality: –Priming mediated experience of presence In high quality context – prime enhanced presence. In low quality context – prime reduced presence.

13. Conclusions Mental state of user influences their experience of presence. –But only in certain instances therefore… Presence is not a scaled sum of sensory components. Presence is constructed through both sensory inputs and users mental context. Explained in terms of schemata activation: –Priming pre-allocates processing resources to related perceptions. In Irrelevant Condition: processing of unrelated perceptions is difficult – schemata deactivation In High Quality Condition: enhanced processing smooths over inconsistencies In Low Quality Condition: fit isn’t good enough for enhanced processing OR bad enough for schemata deactivation – poor processing

14. What does this add to the debate? Support for more recent constructive concepts of perception (Eysenk & Keane) over ecological perception (Gibson) –Higher processes have a mediating role in the experience of presence –However……both views have explanatory power.

15. Critique Criticisms of study –No measurement of stimulus quality or intensity of priming provided –Measurement of presence based on pen and paper questionnaires –Lack of an effective measure of presence

16. Measurement of Presence : Other methods Objective Measures - Measurement of physiological and behavioural responses Qualitative or Ethnographic Approaches - In depth studies A Stochastic Model of Presence - Participants required to report whenever a break in presence occurs while they are present in the VE

17. References Eysenk, M.W. & Keane, M.T. (1995) Cognitive Psychology: A Students Handbook. Hove: Psychology Press Gibson, J.J. (1979) The Ecological Approach to Perception, Houghton-Mifflin. Boston. Nunez, D. & Blake, E. (2001) Cognitive Presence as a unified concept of virtual reality effectiveness. Proceedings AFRIGRAPH 2001, p. 115-8 Nunez, D. & Blake, E. (2003) Conceptual Priming as a Determinant of Presence in Virtual Environments, ACM Database Witmer, B.G and Singer, M.J. (1998) Measuring Presence in Virtual Environments: A Presence Questionnaire, Presence: Teleoperators and Virtual Environments, 7(3), 225-240. Slater, M., Usoh, M., Steed, A. (1994) Depth of Presence in Immersive Virtual Environments, Presence: Teleoperators and Virtual Environments, MIT Press 3(2), 130-144.