by MotionBrothers

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:

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augmented reality (AR)

by MotionBrothers

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

by MotionBrothers

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.

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by MotionBrothers

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

by MotionBrothers

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.

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by MotionBrothers

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.

dollhouse view

by MotionBrothers

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.

embodied presence

by MotionBrothers

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.

erfahren experience

by MotionBrothers

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

by MotionBrothers

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

by MotionBrothers

(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.

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by MotionBrothers

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



by MotionBrothers

(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


by MotionBrothers

a form of non-verbal communication through the body – typically the hands or head – that, when tracked by a motion sensing camera attached to a computer, can be interpreted as movement and mirrored in virtual reality

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ghost story

by MotionBrothers

(see also: the Swayze effect)

a virtual reality (VR) experience where the user is a disembodied observer in an unfolding narrative – as if watching a movie – but incapable of making changes to the world or talking to the characters


by MotionBrothers

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.


by MotionBrothers

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.

interactive narrative

by MotionBrothers

(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.


by MotionBrothers

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.


by MotionBrothers

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

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Overview effect

by MotionBrothers

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.

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plausibility illusion (Psi)

by MotionBrothers

the acceptance that the scenario being depicted is actually occurring

Another way of thinking of this illusion is as the automatic and rapid response from the experiencer to the important question: Is this really happening? If the response is ‘no’ then the illusion is broken.

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Poison Berry theory

by MotionBrothers

the ‘Poison Berry’ theory is an evolutionary idea behind virtual reality sickness

It suggests that experiencing sensory input that is different than what is expected, combined with dizziness, are symptoms associated with being poisoned. From an evolutionary perspective people who are poisoned benefit from throwing up quickly.

positional audio

by MotionBrothers

audio that is triggered based on the position of the headset

For example, in a crowded scene the experiencer would be given the ability to choose which conversation they listen to based on where they are looking.

New Wave by Directors Samir Mallal and Aron Hjartarson demonstrates the positional audio approach.

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by MotionBrothers

(also known as: ‘telepresence’)
(see also: active presence, embodied presence, emotional presence, and social presence)

a feeling of being in and of the virtual world, and the ignoring of physical world distractions

It is the strong illusion of being in a place in spite of the sure knowledge that you are not there.1

1. Mel Slater. Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments Pg 5.

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redirected walking

by MotionBrothers

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)

by MotionBrothers

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.


by MotionBrothers

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.

sensorimotor contingencies

by MotionBrothers

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.

Swayze effect

by MotionBrothers

(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.

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virtual reality sickness

by MotionBrothers

(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.


by MotionBrothers

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

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