Discover Virtual Reality

Terminology and Definitions

Discover Virtual Reality - Terminology and Definitions

Search our growing glossary for virtual reality (VR) and augmented reality (AR) terminology.

  • active presence

    (also known as ‘hand presence’)

    an immersive state that is reached as a consequence of using a handheld tool/device (peripheral) within a VR experience

  • agency

    (see also: ‘local agency‘ and ‘global agency‘)

    the capacity of an entity (a person or other entity) to act in, and influence, an artificial environment

  • analytics

    the information resulting from the systematic analysis of both events occurring within the artificial reality and of the device being used to create the artificial reality.

    Virtual reality analytic metrics are therefore often divided into two groups:


  • augmented reality (AR)

    in augmented reality (AR) the visible natural world is overlaid with a layer of digital content

    The differences between VR, AR, and MR are best summed up by quote attributed to Clay Bavor:

    VR is the power to take you anywhere, MR and AR is the power to bring anything to you

    The Reality Scale

    The Reality Scale

  • authorial intent

    the extent to which the human author pre-ordains the possible narrative or instills the system with the ability to creatively adapt to the experiencer

    On the one hand, strong authorial intent means the quality of experience can be ensured, according to the vision of the human author. On the other hand, greater creative freedom on behalf of the interactive narrative system can yield greater user agency at the risk of straying from the human author’s vision.1

    1. Riedl, M and Bulitko, V. Interactive Narrative: An Intelligent Systems Approach. AI Magazine Pg 6.


  • avatar

    a virtual representation of the experiencer within the virtual world

    They are the audiovisual bodies that people use to communicate with each other in the Metaverse.1

    1. Stephenson, N. (2011) Snow Crash. Penguin. Pg 33.

  • butterfly effect system

    the butterfly effect system is a storytelling mechanism for managing complex narrative structures where actions from the experiencer can have a direct influence on how the narrative plays out

    The phrase ‘butterfly effect’ derives from chaos theory where American mathematician Edward Norton Lorenz used it as a metaphor to describe the phenomenon whereby a minor change in circumstances can cause a large change in outcome.


  • CAVE

    a CAVE (cave automatic virtual environment) is a virtual reality environment made up of between three and six walls that form a room-sized cube

    Projectors display a virtual world onto the interior walls of the CAVE and are then controlled by the movement of an experiencer from within the CAVE.

  • cockpit

    a virtual anchor that is fixed to the experiencer’s view and helps to ground them in the virtual world e.g. a fighter jet cockpit

    Research has shown that grounding the experiencer’s with virtual anchors can help curb symptoms of virtual reality sickness.

  • collision detection

    detection that virtual objects have intersected, sometimes triggering haptic or visual feedback for the experiencer

  • data glove

    an interactive device – often resembling a glove worn on the hand – which connects to a computer system and facilitates fine-motion control within virtual reality

  • dollhouse view

    a top-down, external view of the entire artificial space allowing the designer to make global decisions about its composition and to enable swift prototyping

    The dollhouse view can also be combined with a first-person POV, to allow the experiencer to occupy the space they are actively manipulating, avoiding the need to switch between modes and perspectives when designing the space.

  • Duck test

    a colloquial name for a method of testing if an experiencer has reached a state of presence by monitoring their behaviour when threatened by a virtual object


  • embodied cognition

    the idea that cognition is not just limited to the brain, but distributed across the entire body

  • embodied presence

    acknowledging the existence of your body within a virtual reality VR experience

    In physical reality and first order virtual reality there is something very simple that you can do to physically establish your presence. Look down, and you will see your body, or see parts of it continuously in peripheral vision.1

    1. Slater, M. “Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments”Philos Trans R Soc Lond B Biol Sci. 2009 Dec 12; 364(1535): 3549–3557 Pg 10.

  • emergent narrative

    when non-player characters (NPCs) have complete autonomy in an interactive narrative e.g. The Sims

  • emotional presence

    a state that evokes an emotional response from the experiencer e.g. empathy, joy, or fun, within a virtual reality (VR) experience

  • erfahren experience

    an external, objective event, which the experiencer learns from

    An erfahren experience typically means that the experiencer gains something from it, usually knowledge. It is therefore directly linked to a specific moment in time, and is an experience that can be recalled in order for future decisions to be made. E.g. If I were to observe someone becoming ill from eating a certain type of berry, then I would learn not to eat that type of berry in future.

    ‘Erfaren’ is one of two German verbs that are used to define experience. The other is ‘erleben‘.

  • erleben experience

    an intense, personal experience that deeply effects the experiencer’s inner life

    An erleben experience typically describes a singular, exciting, and profound event, however these can be both positive or negative. It often involves the experiencer embodying the experience on some level.

    ‘Erleben’ is one of two German verbs that are used to define experience. The other is ‘erfahren‘.

  • Experience Manager

    (also known as a ‘story generator’)

    a generalisation of the ‘drama manager’ concept put forward by Joe Bates in Virtual reality, art, and entertainment. Originally published in Presence: The Journal of Tele-operators and Virtual Environments, Pg. 133–138, 1992.

    an intelligent, omniscient, and disembodied agent that monitors the virtual world and intervenes to drive the narrative forward according to some model of quality of experience. Often used as a surrogate for the human author.1

    1. Mark O. Riedl and Vadim Bulitko. Interactive Narrative: An Intelligent Systems Approach. AI Magazine Pg 3.


  • experiencer

    experiencer is another word for ‘user’ or ‘player’

    It originates from a quote by Donald Hoffman, Professor of Cognitive Science at the University of California, who said:

    “One aspect of conscious experience is that it seems you can’t have an experience without an experiencer.”

    And was offered up as a more appropriate alternative to ‘user’ in Steve McCarthy’s article: Has ‘User’ Become An Outdated Term


  • eye tracking

    the ability for a head mounted display (HMD) to read the position of the experiencer’s eyes versus their head

    Eye tracking is particularly useful for informing VR analytics, where the developer wants to better understand what content the experiencer is focused on in a specific scene or view.

  • field of view (FOV)

    is the view that is visible to the experiencer while rotating their head from a fixed body position

    The average human field of view is approximately 200 degrees.

  • flow

    (also known as: being in the ‘zone’)

    the mental state whereby an experiencer is so involved in the process of an activity that nothing else seems to matter

  • haptics

    haptic technology simulates the sense of touch through the sensation of pressure (usually on the hands via a glove)

    This helps to support agency by enabling the experiencer to control virtual objects or sense physical forces within the virtual environment. Haptics are a significant component in peripherals.

  • head mounted display (HMD)

    a set of goggles or a helmet with tiny monitors in front of each eye to generate images seen by the wearer as three-dimensional

  • head tracking

    the ability for an head mounted display (HMD) to monitor the position and orientation of the experiencer’s head through tracking

  • heatmap

    a graphical representation of data relating to the experiencer’s gaze during a virtual reality (VR) experience

    Gaze heatmaps are one type of analytics. They utilise a hot (red) to cold (blue/green) system of colour-coding to represent areas of interest within the experience.

  • hotspot

    an interactive spot within the artificial experience that reveal more content or options

    Hotspots can be animated and are often shown as a glowing orb.

  • immersion

    a psychological sense of being in a virtual environment

    Immersion provides the boundaries within which place illusion (PI) can occur.1

    1. Slater, M. “Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments”. Philos Trans R Soc Lond B Biol Sci. 2009 Dec 12; 364(1535): 3549–3557 Pg 6.


  • interactive narrative

    (also known as: ‘responsove narrative’)

    a form of digital interactive experience in which experiencers create or influence a dramatic storyline through their actions

    When the balance between an ordained narrative and freewill interaction is tweaked just right, it creates the perception of great “game play” – a sweet feeling of being part of something large that is moving forward (the game’s narrative) while you still get to steer (the game’s play).1

    1. Kelly, K. (2016) The Inevitable Penguin. Pg 229.

  • latency

    the time delay or lag between activating a process (change in input from the experiencer) and its accomplishment (the visual effect)

    High-latency can lead to a detached experience and can also contribute to motion sickness / dizziness.

  • local agency

    (see also: ‘agency‘)

    interactivity that flavours the experience, but is unlikely to send it down a different narrative path

  • locomotion

    refers to the process of moving from one place to another

    This is most commonly used to refer to movement within the virtual environment e.g. how an avatar navigates the virtual world, but can also refer to movement outside of the virtual environment e.g. how the experiencer navigates the real-world while in a virtual experience.

    Locomotion mechanics in virtual reality can be broken down into three primary categories:
    1. Perambulation
    2. Teleportation
    3. Transportation


  • mixed reality (MR)

    mixed reality (MR) is similar to augmented reality (AR) except virtual objects are integrated into the natural world

    For example, a virtual ball beneath your desk would be blocked from view unless you bent down to look at it.


  • occlusion

    the obscuring or hiding an object from view by the positioning of other objects in the experiencer’s line of sight

  • Overview effect

    a cognitive shift in awareness and new sense of perspective triggered after viewing the Earth from orbit

    The experience is said to evoke a sense of appreciation within the experiencer for the fragility of the Earth.


  • redirected walking

    is the name given to a technique used to extend the possible size of a virtual reality environment by imperceptibly rotating the virtual scene without the experiencer being aware

    Redirected Walking causes people to change their real walking direction without noticing it, allows for larger VEs [virtual environments], and does not induce appreciable simulator sickness.1

    1. Sharif Razzaque, Zachariah Kohn, Mary C. Whitton Redirected Walking. The Eurographics Association 2001. Pg 1.

    The technique is notably utilised in experiences created by The Void.

  • response-as-if-real (RAIR)

    a state that describes when an experiencer responds to a virtual reality as if it were real

    If you are there (PI) and what appears to be happening is really happening (Psi) then this is happening to you! Hence you are likely to respond as if it were real. We call this ‘response-as-if-real’ RAIR.1

    1. Slater, M. “Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments”Philos Trans R Soc Lond B Biol Sci. 2009 Dec 12; 364(1535): 3549–3557 Pg 11.

  • responsive narrative

    (also known as: ‘living stories’ or an ‘interactive narrative‘)

    virtual reality narratives that adapt based on interaction from the experiencer, often driven by some form of AI

  • reticle

    the reticle is a visual aid for the experiencer to target objects within a virtual reality environment with their gaze


  • room-scale

    a design paradigm that allows users to move freely within a room-sized environment while partaking in a virtual reality (VR) experience

    Through the use of kinetic locomotion mechanics (in the Perambulation category), the experiencer’s physical movements are mirrored within the virtual world and helps to contribute to a greater sense of immersion, with the body being directly engaged – a key contributor to creating a state of embodied presence.

    The term room-scale is often used to differentiate between other types of virtual reality experiences e.g. a self-contained environment of a VR room or seated or standing VR, in which the user remains stationary.

  • self-regulating behaviour

    actively making decisions in a scene and by doing so also taking account of time, which in turn makes the passing of time feel longer

  • sensorimotor contingencies

    sensorimotor contingencies (SCs) refer to the actions that we know to carry out in order to perceive

    …for example, moving your head and eyes to change gaze direction, or bending down and shifting head and gaze direction in order to see underneath something1

    1. Slater, M. “Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments”Philos Trans R Soc Lond B Biol Sci. 2009 Dec 12; 364(1535): 3549–3557 Pg 3.

  • signposts (signposting)

    environment cues with the added purpose of helping the user to interpret the virtual environment

  • social presence

    choosing to actively engage with others within a VR experience


  • Swayze effect

    (see also: ghost story)

    the sensation of having no tangible relationship with your surroundings despite feeling embodied in the virtual world

    The phrase was coined by Story Studio and the name is a reference to actor Patrick Swayze who played the protagonist in the 1990’s film Ghost. In the film, Swayze’s character dies and returns as a ghost to help his wife solve the mystery of his death. The effect observed by Story Studio, looks to describe the struggle of affecting a virtual environment and the people who occupy it when no observable feedback from the world is being received.


  • valid actions

    the actions that an experiencer can take that can result in changes in perception, or changes to the environment

  • virtual reality (VR)

    virtual reality (VR) places the experiencer in another location entirely. Whether that location has been generated by a computer or captured by video, it entirely occludes the experiencer’s natural surroundings.


  • virtual reality sickness

    (also known as: ‘motion sickness’ or ‘simulation sickness’)

    is the feeling of general discomfort caused by experiencing virtual reality

    Symptoms can include: headache, nausea, vomiting, drowsiness, and disorientation. Research suggests that discomfort – of which virtual reality sickness is a contributing factor – is a major barrier for initiating engagement with virtual reality. Therefore, significant development time has been spent trying to reduce and eradicate virtual reality sickness through innovation in technology.

    The ‘Poison Berry’ theory is one evolutionary idea behind virtual reality sickness.

  • yaw

    rotation around the vertical (y) axis

  • zeitgeber

    any external or environmental cue that entrains or synchronizes an organism’s biological rhythms to the Earth’s 24-hour light/dark cycle and 12 month cycle