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

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

• Presented by
• Brett Keaffaber

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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

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Introduction

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

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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)

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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)

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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

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Components to a VR Experience

• Models proposed by
• Wells
• Lavroff
• Robinett
• Zeltzer

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Components to a VR Experience

• Wells tried to characterize the factors
  associated with the VE experience
• Immersive
• Interactive
• Intuitive
• Lavroff adds
• Manipulation
• Navigation

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Components to a VR Experience

• Robinett attempts to characterize the variety of
  VE systems
• Display type
• Sensor type
• Action measurement type
• Actuator type

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Components to a VR Experience

• Zeltzers 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

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Zeltzers AIP Cube
Autonomous agents
Virtual reality
Autonomy
Interaction
Complex Work Domains
Presence
Immersive Interfaces
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Augmented Reality

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

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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

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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

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Principal Determinants of Presence

• Determination of the dependent variables
• Sense of presence
• Training efficiency
• Task performance

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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-offs
• Type of hardware

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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?

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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

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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

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External and Internal Factors

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

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The Virtual Body

• Held and Durlach (telepresence)
• Operator can view effector movements
• High correlation between operator and slave
  movements
• Identification between operators body and
  slaves body
• Similarity in operator/slave visual appearance

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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

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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

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Enjoyment

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