Making VR real relies heavily on psychologically moving a user into a virtual world. It can either aim to imitate reality or not; however, making users believe they are somewhere else is a key. To achieve this, VR content creators have to consider immersion, presence and reality trade-offs [Jason Jerald, The VR Book: Human-Centered Design for Virtual Reality].
Immersion is a perception of being physically present in a non-physical world. This perception is created by placing the user into the 3D environment deploying one or the combination of different senses: sight, sound, touch, smell, taste; as well the sense of balance, vibration, pain, thermoception, kinesthetic sense, and various internal stimuli like hunger and thirst, and other senses.
Immersion can be divided into 4 categories: emotional, spatial, sensory-motoric, and cognitive immersion [Staffan Björk and Jussi Holopainen, Patterns In Game Design].
- Emotional (narrative) immersion occurs when a user becomes invested in a story, and is similar to what is experienced while reading a book or watching a movie.
- Spatial immersion occurs when the simulated environment is perceptually convincing for the users. They feel like they are really there and that a simulated world feels real too.
- Sensory-motoric (tactical) immersion is closely related with the rhythm-based actions, which by nature implies repetition. This is especially the case when the actions are tied to some rhythm-based stimuli and sensory feedback such as the background music or the visual presentation of game elements.
- Cognitive (strategic) immersion is associated with mental challenge. Chess players, for example, experience cognitive immersion when choosing a correct solution among a broad array of possibilities. In the VR context, users become immersed in a goal-based scenario that’s pretty independent of reality.
When creating immersive experiences, one should also consider aspects such as extensiveness as the range of sensory modalities presented to the user (visuals, audio, and physical force), matching between sensory modalities (appropriate visual presentation corresponding to head motion and a virtual representation of one’s own body), surroundness of the panoramic cues (wide field of view, spatial audio, 360◦ tracking), vividness (resolution, lighting, frame rate, audio bitrate), and interaction as the capability for the user to make changes to the world, its response to the user’s actions, and the user’s ability to influence future events [Jason Jerald, The VR Book: Human-Centered Design for Virtual Reality].
To summarise, immersion helps users to perceive and interpret the presented stimuli. It can lead the mind but cannot fully control it. What helps the user to subjectively experience the immersion is presence.
Presence is a sense of being inside a space. It helps users interact with and feel within the mentally or technologically simulated world.
Presence is an internal psychological state of the user; but also is a function of immersion. The difference between the two lies in immersion being the VR ability to trick users into feeling they are somewhere else; while presense is how they are really engaged and how much they feel they are inside that virtual space.
In the VR context, there are a few components that promote or enhance presence and the associated behaviours [M.P. McCreery, A sense of self: The role of presence in virtual environments]:
- Being in a stable spatial environment — the most important part of presence. It occurs due to all of a user’s sensorial responses in VR matching with those in the real world. The environments also don’t necessarily have to be photorealistic, but should incorporate elements of the real world.
- Self-embodiment is the perception that the user has a body within the virtual world. We are used to perceiving our own bodies through various senses. Even VR experiences without a personal body can make feel users quite present. But when they are given a virtual body that properly matches their movements, they quickly realise that there are different levels of presence. Then if a user sees a visual object touching the skin while a physical object also touches the skin, presence is greatly strengthened and experienced even more deeply [Body transfer illusion].
- Physical interaction—looking around is not enough for people to believe that they are in an alternate world. Adding some form of feedback such as audio, visual highlighting, or a rumble of a controller can give the user a sense that they have in some way touched the world. Ideally, the user should feel a solid physical response that matches the visual representation. As soon as one reaches out to touch something and there is no response, then a break-in-presence can occur.
- Social communication / engagement— as the perception that one is really communicating (both verbally and through body language) with other characters in the same environment.
- Ecological validity — belieavability of the environment.
- Negative effects — disorientation, headache, dizziness, tiredness, that also impact the link between a virtual avatar’s personality and their behaviours.
Trade-offs of reality
Despite what one might think, presence does not require photorealism. Being in an abstract world can also feel very real. Realism in this case would rely heavily on such presence-inducing cues as responsiveness of the system, character motion, and depth cues [Jason Jerald, The VR Book: Human-Centered Design for Virtual Reality].
To design immersive realistic experiences, VR creators should consider:
- Representational fidelity in VR conveys a place that is, or could be, on Earth. It might include everything in-between photorealistic immersive film, to purely abstract, cartoon or non-objective worlds. These may have no reference to the real world, simply conveying emotions, exploring pure visual events, or presenting other non-narrative qualities.
- Interaction fidelity identifies how physical actions for a virtual task correspond to physical actions for the matching real world task. It can include interaction techniques that require no physical motion beyond a button press, or techniques where users are able to do things they are not able to do in the real world such as grabbing objects at a distance.
- Experiential fidelity identifies how the user’s personal experience matches the intended experience of the VR creator.
- Uncanny valley is a unsetting feeling people experience when humanoid objects appear almost — but not quite — like real humans. Such objects evoke uncanny, or strangely familiar, feelings of eeriness and revulsion in observers.
- Creating a fully immersive VR experience relies on making users believe they are somewhere else. To achieve this, VR content creators have to consider immersion, presence and reality trade-offs.
- Immersion is reached by deploying a combination of human senses: sight, sound, touch, smell, taste; as well the sense of balance, vibration, pain, thermoception, kinesthetic sense, and various internal stimuli like hunger and thirst, and other senses.
- To make a VR experience an immersive one, we should consider emotional, spatial, sensory-motoric, and cognitive immersion.
- To promote and enhance presence, we should consider aspects such as self-embodiment, sense of ‘being there’, physical interaction, engagement, ecological validity, as well as negative effects.
- Fidelities to consider when creating a VR experience include: interaction, experiential, and representational fidelities.