Presence and Immersion

Presence and immersion are the two central psychological concepts in XR research, often conflated but carefully distinguished in the literature. Immersion describes the objective technical capability of a system — how fully it supplants the user's real-world sensory input with synthetic input. Presence describes the subjective psychological response — the degree to which the user feels they are "really there," in the virtual environment, rather than observing it from outside. The distinction matters because high immersion does not guarantee presence, and presence can sometimes arise in low-immersion systems.

The Slater–Wilbur Framework

The canonical formulation was established by Mel Slater and Sylvia Wilbur in their 1997 paper A Framework for Immersive Virtual Environments (FIVE).¹ They defined the terms as follows:

Immersion is an objective property of a technology. It describes the extent to which a VR system delivers a vivid, all-inclusive, surrounding, and vivid sensory experience. Immersion increases with wider field of view, higher resolution, lower latency, spatial audio, haptic feedback, and greater degrees of freedom in tracking. It is measurable in physical and engineering terms without reference to the user's subjective state.¹

Presence is a subjective psychological state — the sense of being inside the virtual environment rather than being in the physical world looking at a screen. It is sometimes described as the "illusion of non-mediation": the user responds to the virtual environment as if it were real, even while knowing intellectually that it is not. Presence is not a binary; it varies between individuals, across time within a session, and in response to events in the environment.¹

The relationship is one of enablement rather than equivalence: high immersion creates the conditions in which presence is more likely to occur, but does not guarantee it. A person with high simulator sickness in a high-immersion system may have low presence. A person deeply engaged with a text-based interactive narrative may report meaningful presence despite zero immersion.

Witmer and Singer's Presence Questionnaire

In 1998, Bob Witmer and Michael Singer published a standardised measurement instrument — the Presence Questionnaire (PQ) — to allow researchers to quantify and compare presence across studies.² The PQ assessed four factors: involvement (engagement and selective attention), sensory fidelity (quality of sensory information), adaptation/immersion (the system's ability to sustain presence over time), and interface quality (usability of the interaction mechanics).²

The PQ became a standard research tool, though subsequent work identified its limitations — particularly its conflation of immersion and presence within the same instrument, which made it difficult to isolate the causal direction of the relationship.

Place Illusion and Plausibility Illusion

Mel Slater's 2009 paper in Philosophical Transactions of the Royal Society B refined the framework significantly, replacing the single concept of presence with two distinct illusions:³

Place Illusion (PI) is the illusion of being in a place — the sense that the virtual space is the actual space the user occupies. It is related to what earlier literature called "presence" in its spatial sense. Place illusion is primarily driven by immersion: wider field of view, head tracking, and body representation all increase it.

Plausibility Illusion (Psi) is the illusion that what is happening is really happening — that the events in the virtual environment are real events the user is genuinely experiencing, not a simulation. Plausibility is driven less by display quality and more by coherent, reactive behaviour: if a virtual character responds naturally to the user's actions, if dropping a virtual object causes it to fall credibly, if social scenarios unfold with realistic contingency, then plausibility is high. Plausibility Illusion can be high even when immersion is modest.³

Slater's framework predicts that both illusions are required to generate realistic behavioural responses in VR — if users behave in a virtual environment similarly to how they would behave in the real world, both PI and Psi are operating. This has practical design implications: a system that maximises display fidelity but simulates non-responsive or implausible events will achieve Place Illusion without Plausibility Illusion, and behaviour will not transfer.³

Embodiment

A distinct but related concept is embodiment: the sense that a virtual body is one's own. The rubber hand illusion, demonstrated by Botvinick and Cohen in 1998, showed that a person watching a rubber hand being stroked — synchronously with stroking of their unseen real hand — would begin to perceive the rubber hand as their own, and would flinch if the rubber hand was threatened.⁵ The illusion demonstrated that body ownership is contingent and can be transferred to artificial limbs under the right sensorimotor conditions.

In XR, embodiment is induced by providing the user with a virtual body (an avatar) and ensuring that its movements match the user's real movements in real time. When synchrony between real and virtual movement is high, users report ownership of the avatar, react defensively when it is threatened, and can experience the avatar's perspective as their own. Mel Slater's lab demonstrated that white participants given dark-skinned avatars showed measurable reductions in implicit racial bias — evidence that embodiment in VR can alter attitudes anchored in body self-perception.

Jeremy Bailenson's Experience on Demand (2018) synthesised a decade of Stanford VR lab research on presence, embodiment, and the psychological effects of XR — covering empathy induction, behaviour change, phobia treatment, and pain management — and remains the most accessible summary of what is known about presence effects at consumer scale.⁶

Presence in Mixed Reality

The presence framework was developed primarily for fully immersive VR, but its concepts extend meaningfully to mixed reality. In MR systems using video passthrough, Place Illusion and Plausibility Illusion apply to virtual content within a real context: does the virtual object feel spatially present in the room, and does it behave as a real object in that room would? The challenges in MR presence are distinct from VR — users are comparing virtual content against a real-world reference they can see simultaneously, so inconsistencies in occlusion, lighting, shadow, and scale are immediately apparent and break Plausibility Illusion in ways that a fully synthetic environment does not face.