The terms immersion and presence have several definitions within the research community. In this chapter, I will describe the most common definitions for both of these and how they were defined in the scope of this dissertation.
Presence
The term presence was introduced in a work by Akin et al. (1983), who defined it as an experience that happens when:
“at the worksite, the manipulators have the dexterity to allow the operator to perform normal human functions. At the control station, the operator receives sufficient quantity and quality of sensory feedback to provide a feeling of actual presence at the worksite.”
Presence as a phenomenon has many definitions, depending on the field and the context of research, but it is most commonly referred to as the feeling of “being there.” Witmer and Singer (1998) described presence as
“the subjective experience of being in one place or environment, even when one is physically situated in another.” Skarbez, Brooks, and Whitton (2017) stated, “presence has the advantage of being a metric that is applicable to
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any VE,” meaning that, for example, presence-related questionnaires between two completely opposite applications can be compared. They continue by defining presence as a quale (plural qualia), “a subjective and internal feeling of elicited by sense perceptions.” By their definition, this internal and subjective experience is extremely difficult to measure.
Immersion
The term immersion is still a subject of some debate, and there are discrepancies between research fields on the meaning of this term. Slater (1999) defined it as an objective characteristic of a VE application. Witmer and Singer (1998) considered it to be a “psychological state characterized by perceiving oneself to be enveloped by, included in, and interacting with an environment that provides a continuous stream of stimuli and experiences.”
Lombard et al. (2000) defined these two conceptions respectively as perceptual immersion and psychological immersion. Basically, Slater’s immersion is required to experience Witmer and Singer’s immersion, but the use of these terms interchangeably has caused some discrepancy in the terminology. Immersion has also been used synonymously with presence (for example, publications III, IV, VI, and VII; Psotka, Davison and Lewis, 1993;
Wikipedia, 2017). Slater (2009) has also stated, “Immersion provides the boundaries within which [presence] can occur.” The problem with this statement is that immersion in VE applications has other utilities in addition to enabling presence (Bowman and McMahan, 2007).
Social Presence and Copresence
One limitation of the term presence is that there are no aspects of social interaction involved. Current interpretations of this term include only single user applications and their interaction with the VE (Skarbez, Brooks and Whitton, 2017). For VEs that involve other characters or avatars, which can be controlled by either humans or computers, the definitions copresence and social presence have been developed. Copresence was first introduced by Goffman (1963), who described it as “exist[ing] when people sensed that they were able to perceive others and that others were able to actively perceive them...render[ing] persons uniquely accessible, available, and subject to one another.” Another definition by Zhao (2003) is as follows: “a condition in which instant two-way human interactions can take place,”
and even more briefly, as “being there together” (Schroeder, 2002).
Seemingly similar and clearly related, these definitions have important differences: Goffman’s and Zhao’s definitions “refer to properties of a communication medium,” thus being “objective, immersive characteristics of a system,” whereas Schroeder’s definition refers to the feeling of being together in a place (Skarbez, Brooks and Whitton, 2017). The first definition for social presence comes from Short et al. (1976), who defined as “the degree of salience of the other person in the interaction and the consequent salience of the interpersonal relationships.” Bull (1983) defined social presence as
“when one person feels another person is ‘there.’” All the definitions
mentioned overlap and share similar characteristics. This has also caused them to be used interchangeably (e.g., Blascovich, 2002). Skarbez, Brooks, and Whitton (2017) defined copresence as “the sense of being together with another or others.” For social presence, they used a description as follows:
“the moment-by-moment awareness of the copresence of another sentient being accompanied by a sense of engagement with them.” These two definitions differ to “the extent to which one’s experience depends on the other or others.” Thus, copresence is already present when another being exists in the same space and the observer is aware of this. For social presence, some kind of interaction between the users should be present, and this interaction should affect the other user’s behavior and/or vice versa. To prevent the definitions from being confusing and contradictory, instead of social presence, Skarbez, Brooks, and Whitton (2017) coined a new term, social presence illusion, referring to the “illusory feeling of being together with and engaging with a real, sentient being.” With the same terms, they suggested the term copresence illusion be used instead of copresence to refer to the
“feeling of ‘being together’ in a virtual space.”
Other Concepts Related to Presence and Immersion
Another issue regarding presence being used as a general measure is that it does not consider the level of realism that the VE provides. This aspect can be very important when VEs are being used for practicing real-life scenarios, such as training in military settings. For measuring VEs’ realism, Alexander et al. (2005) defined the term fidelity, which refers to “the extent to which the virtual environment emulates the real world.” Again, there is an overlap with the terms fidelity and immersion, but it is feasible, for example, to build a high level of immersion in an environment with low fidelity, and vice versa.
To avoid confusion concerning the presence construct, Slater (2009) divided it into two categories: place illusion (PI) and plausibility illusion (Psi). They defined place illusion as “the...illusion of being in a place in spite of the sure knowledge that you are not there,” and plausibility illusion as “the illusion that what is apparently happening is really happening (even though you know for sure that it is not).” With these definitions, PI replaces presence as the traditional definition as the feeling of “being there,” and Psi refers more to the experience of believing what you are seeing, albeit knowing that said experience is illusionary. This theoretical framework reduces the overlap and interchangeable use of the terms regarding presence.
Coherence, a definition coined by Skarbez (2016), is “the set of reasonable circumstances that can be demonstrated by the scenario without introducing unreasonable circumstances.” For instance, if the user has been led to believe he or she will be part of a VE with fantastic elements, then the presence of fantastic creatures or people performing superhuman acts would be coherent activities. However, if users are told they will participate
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in a realistic training simulation scenario, such exotic events would be incoherent, thus decreasing their feeling of presence/PI.
Another term that is commonly used within the context of VEs is embodiment. It generally refers to a representation, commonly known as an avatar, of the user in a VE. Gabbard (1997) commented, “Representing the user within a VE is known as user embodiment,” whereas Benford et al. (1995) remarked, “User embodiment concerns the provision of users with appropriate body images to represent them to others (and to themselves) in collaborative situations.” Ownership is “the sense that a body (or body part) is one’s own” (Skarbez, Brooks and Whitton, 2017). Embodiment is a prerequisite for ownership, but they are not the same phenomena. The feeling of embodiment can be achieved with technology and/or the help of tools, but does not automatically result in the user’s feeling of ownership.
The illusion of body ownership with virtual bodies has been studied by Slater et al. (2010). Another definition that is related to both the feeling of embodiment and ownership is self-presence. Biocca (1997) defined this as
“the users’ mental model of themselves inside the virtual world.” It refers to “the effect of embodiment in [a] virtual environment on mental models of the self.”
Involvement and engagement are often used interchangeably in VE literature.
Witmer and Singer (1998) have described involvement as a state of focus and/or interest. Involvement and engagement are included as subscales in the Witmer-Singer Presence Questionnaire (Witmer and Singer, 1998), the ITC Sense of Presence Inventory (ITC-SOPI) (Lessiter et al., 2001), and the Igroup Presence Questionnaire (IPQ) (Schubert, Friedmann and Regenbrecht, 2001). Skarbez, Brooks, and Whitton (2017) have argued that because presence is logically orthogonal to involvement/engagement, it should not be included in presence questionnaires.
Flow is a concept that has been studied in many contexts and commonly refers to “an optimal state of focus and concentration” or a “state in which individuals are so involved in an activity that nothing else seems to matter”
(Csikszentmihalyi, 1990). Takatalo (2002) found that more presence may provide more of a feeling of flow. Absorption is a term coined by Baños et al.
(1999), who defined it as “the ability to get lost in the task at hand whether it is watching a movie, reading a book, or experiencing VR.” Brockmyer et al. (2009) suggested this was a stronger state of engagement than flow.
Transportation is more commonly used in narrative worlds and is related to the feeling of presence in VEs (Gerrig, 1993). When in a state of transportation, the individual “loses access to some real-world facts in favor of accepting the narrative world that the author has created” (Green and Brock, 2000). Transportability is a term that refers to an individual’s “ability to be transported by a narrative” (Skarbez, Brooks and Whitton, 2017).
As this summary of presence-related terms shows, there are several factors that may affect the user’s experience in VEs. In addition, there may be VEs that are not a specific representation of a space and thus would not benefit from the feeling of “being there,” but may benefit from other features of the application, for example, immersion and fidelity. In those VEs that attempt to represent the real world as realistically as possible, a high level of fidelity and immersion are more important (Skarbez, Brooks and Whitton, 2017). In VEs where the user is performing real work, the level of involvement and flow may increase effectiveness and/or productivity. When the VE is used for training for real-world events with a sufficient level of knowledge transfer, an appropriate amount of immersion and fidelity should be provided.