Presence vs. Immersion in Clinical VR: Why It Matters

Why the Difference Between Immersion and Presence Is Clinically Decisive

When a clinical psychologist evaluates whether a virtual reality tool fits into their practice, the typical sales conversation revolves around technical specifications (resolution, refresh rate, field of view) and the visual appearance of the scenario. What that conversation usually leaves out is the one variable that actually matters to the psychologist: whether the patient will respond to the virtual stimulus as if it were real.

That response doesn’t depend directly on technical specifications. It depends on an intermediate construct, presence, which is subjective, measurable, and only partially predicted by hardware characteristics. The literature has distinguished presence from immersion since 1997, but the confusion persists in the market and, consequently, in some purchasing decisions with real clinical impact. blog

In this article, we cover what each construct is, what instruments measure it, what predicts clinical presence, and why there are meaningful differences between a clinical-grade headset used in practice and low-cost solutions marketed under the generic label of “therapeutic virtual reality.”

Slater and Wilbur (1997): The Foundational Conceptual Framework

Mel Slater and Sylvia Wilbur published a seminal paper in 1997 in which they defined immersion as an objective property of the system. Immersion describes how capable the technology is of delivering sensory stimuli that replace those of the real physical environment. It is a function of variables such as the extent of the field of view, color fidelity, the latency between head movement and system response, the realism of spatial audio, body-tracking capability, and the number of sensory modalities covered (sight, hearing, and eventually touch or proprioception).

Presence, on the other hand, is the user’s subjective response. Slater and Wilbur defined it as the sensation of actually being inside the virtual environment, not merely observing it from outside. Presence includes several sub-dimensions: spatial presence (feeling physically in the place), social presence (in scenarios with virtual characters), and involvement (attention devoted to the virtual environment versus the physical one).

The relationship between the two constructs is asymmetric. High technical immersion is an enabling condition but does not ensure presence. Two patients with the same headset and the same scenario can experience very different presence depending on their expectations, their capacity for focused attention, their proprioceptive sensitivity, or their degree of cognitive detachment. Conversely, high presence almost always requires a minimum level of technical quality: below a certain latency or resolution threshold, presence collapses due to sensory mismatch.

Measurement Instruments: IPQ, MEC-SPQ, and Witmer and Singer

For presence to be useful in clinical and research practice, it must be measurable. The literature has consolidated three main instruments.

The IPQ (Igroup Presence Questionnaire), developed by Tobias Schubert, Frank Friedmann, and Holger Regenbrecht, is probably the most widely used instrument in clinical research. It is brief (fourteen items), assesses three factors (spatial presence, involvement, and realism) plus one global item, and is validated in several languages. Its brevity makes it especially suitable for use after a clinical session without overburdening the patient.

The Witmer and Singer questionnaire (1998), one of the field’s pioneering instruments, has more items and delves into components such as control over the environment, naturalness of interactions, and focused attention. It is more extensive than the IPQ and provides useful detail in studies aiming to dissect the components of the experience.

The MEC-SPQ (Measurement, Effects, Conditions Spatial Presence Questionnaire) is a more extensive instrument developed by a European consortium (Vorderer, Wirth, and colleagues) that addresses spatial presence with an explicit theoretical framework for the cognitive processes involved (spatial situation model formation, acceptance hypothesis). Its clinical use is less common, but it contributes theoretical robustness.

For everyday clinical use, the IPQ probably offers the best balance of brevity, validity, and applicability. It allows clinicians to build longitudinal series per patient and detect when a session has produced sufficient presence or when the exposure workflow should be adjusted.

Why Presence Predicts Clinical Response

Diemer, Alpers, Peperkorn, Shiban, and Mühlberger (2015) systematically reviewed the relationship between presence and emotional response in VR. Their main conclusion is that presence correlates positively and significantly with affective activation (subjective fear, autonomic response). When a scenario evokes high presence, the limbic system responds as it would to the real stimulus; when presence is low, activation falls short and therapeutic potential is reduced.

This mechanism is consistent with what we know about perceptual-emotional processing. The amygdala and associated subcortical structures do not require rational validation of the stimulus: they respond to perceptual patterns that sufficiently match those that trigger the fear response in the real world. Presence is, in this framework, the indicator that this perceptual match is sufficient.

The clinical implication is direct. A VR exposure session with low presence is not a failed exposure because “VR doesn’t work”; it is an exposure that has not activated the patient’s fear network. If presence is persistently low, the answer is not to increase exposure intensity or change the hierarchy: the right question is what is preventing presence (latency, anthropometric fit, distraction, negative expectation) and to correct it. This requires the clinician to keep the construct in mind as a process variable, not as an academic subtlety.

Differences Between a Clinical-Grade Headset and a Cardboard Viewer

At the low end of the market are solutions that combine a smartphone with a cardboard or plastic viewer. At the high end, contemporary standalone headsets (with six-degrees-of-freedom tracking, latency below twenty milliseconds, spatial audio, and adjustable anthropometric fit) offer a qualitatively different experience.

The most relevant technical difference is not resolution but latency. The latency between user movement and system response, when it exceeds certain thresholds (the literature typically places these around twenty to fifty milliseconds depending on context), produces sensory mismatch. The brain detects that the virtual world is not responding as it should to physical movement, which has two consequences: a sharp drop in presence and the onset of cybersickness. Non-professional cardboard viewers with smartphones rarely achieve clinically acceptable latencies.

Other variables that matter: six-degrees-of-freedom tracking allows the patient to move through physical space and see the virtual world respond coherently, which increases spatial presence. Spatial audio (sound that changes according to head orientation and user position) reinforces the sensation of being inside the environment. Ergonomics and anthropometric fit have less influence on presence and more on tolerance for extended sessions, but they indirectly affect clinical response because a session interrupted by discomfort is a session that loses therapeutic value.

There is also a dimension that gets little discussion: scenario design. A technically excellent headset with a poorly designed scenario (flat textures, implausible character behavior, audio disconnected from the environment) produces low presence. A mid-range headset with a clinically well-designed scenario can produce high presence. Presence is the joint product of hardware and content, not an exclusive property of the device.

Implications for the Clinical Purchasing Decision

When a psychologist evaluates which VR tool to bring into their practice, the presence-immersion model suggests questions that the typical vendor conversation tends to omit. First, what effective latency the system offers under real-world conditions, not optimal ones. Second, what clinical content is available and how it was designed: with clinical input? with prior validation in real use? with the ability to modulate the stimulus during the session? Third, what presence-measurement instruments are built in or applicable after the session.

Fourth, a less technical but equally relevant question: what does the system do to sustain presence throughout the session? Presence is not a static property; it can be maintained or eroded depending on the pace of exposure, technical interruptions, and the clinical framing. A well-designed system minimizes interruptions, allows quick return if the patient momentarily steps out of the environment, and lets the clinician adjust the workflow without breaking perceptual immersion.

Finally, it is worth being skeptical of absolute claims. No system can promise high presence for every patient; what a serious system can offer is to maximize technical immersion and minimize the barriers to developing subjective presence. In the end, presence is built by the patient; the clinician and the system facilitate it.

Limitations of the Framework and Areas Under Discussion

The presence-immersion framework is not without debate. Some authors have proposed integrating presence with other constructs (sense of agency, plausibility illusion in Slater’s own later work), and the relationship between presence and clinical response, while robust at the correlational level, still has open causal questions: what presence thresholds are clinically meaningful? how do they vary across disorders? how do individual characteristics (attentional capacity, neuroticism, expectations) influence them?

There is also debate about the reliability of self-reported presence versus objective measures (galvanic skin response, heart rate, oculomotor patterns). Self-reports are more practical but can be contaminated by expectations; objective measures are more robust but require additional instrumentation. In practice, the IPQ remains a reasonable and applicable tool.

Finally, presence is a process variable, not a therapeutic outcome. One patient may have high presence and respond well clinically; another may have high presence and respond less well due to other variables (resistance to exposure, comorbidity, therapeutic alliance). Presence is necessary for exposure to work, but it is not sufficient.

Another open question is the temporal dynamics of presence. The available literature usually treats it as a single-measurement variable (one questionnaire at the end of the session), but clinical experience suggests that presence fluctuates during the session: it rises as the patient engages with the scenario and dips momentarily when attention shifts to the patient’s own body or when there is a small technical glitch. Recent work is beginning to address this dynamic with continuous measures (sampled self-reports, physiological indicators), but integration into clinical practice is still in its early stages.

Closing: Presence as a Clinical Quality Criterion

If we had to reduce this article to one operative idea for practice, it would be this: presence is the variable that matters, and it is measurable. A psychologist who incorporates VR into their practice with clinical seriousness should be able to discuss presence as naturally as they discuss therapeutic alliance or adherence. It is a process variable that informs decisions (continue, adjust, pause) and distinguishes a clinically useful session from one that is visually striking but therapeutically flat.

To dig deeper into how this logic connects with the mechanisms of the fear response, see the article on Barlow’s model applied to VRET. If you want to review the evidence compared with in-vivo exposure, the entry on efficacy and meta-analyses provides the context. To see how all of this translates into concrete scenarios, you can book a guided demo.

This article is for informational purposes for psychology professionals. It is not clinical advice for any individual case and does not replace the judgment of the licensed psychologist in charge. VRET is professional clinical-support software, not a CE-marked medical device.