Revisiting Milgram and Kishino's Reality-Virtuality Continuum

Mary C. Whitton,Richard Skarbez,Missie Smith

doi:10.3389/frvir.2021.647997

Abstract

Since its introduction in 1994, Milgram and Kishino's reality-virtuality (RV) continuum has been used to frame virtual and augmented reality research and development. While originally, the RV continuum and the three dimensions of the supporting taxonomy (extent of world knowledge, reproduction fidelity, and extent of presence metaphor) were intended to characterize the capabilities of visual display technology, researchers have embraced the RV continuum while largely ignoring the taxonomy. Considering the leaps in technology made over the last 25 years, revisiting the RV continuum and taxonomy is timely. In reexamining Milgram and Kishino's ideas, we realized, first, that the RV continuum is actually discontinuous; perfect virtual reality cannot be reached. Secondly, mixed reality is broader than previously believed, and, in fact, encompasses conventional virtual reality experiences. Finally, our revised taxonomy adds coherence, accounting for the role of users, which is critical to assessing modern mixed reality experiences. The 3D space created by our taxonomy incorporates familiar constructs such as presence and immersion, and also proposes new constructs that may be important as mixed reality technology matures.

Highlights

In 1994, Paul Milgram and Fumio Kishino published “A Taxonomy of Mixed Reality Visual Displays,” simultaneously introducing to the literature the notion of the reality-virtuality (RV) continuum and the term “mixed reality” (MR) (Milgram and Kishino, 1994)
The first limitation is fairly straightforward, and was commented upon by Milgram and Kishino in their original paper: “It is important to point out that, we focus in this paper exclusively on mixed reality visual displays, many of the concepts proposed here pertain as well to analogous issues associated with other display modalities” (Milgram and Kishino, 1994)
We argue that this is the only type of virtual environment that could exist outside of the mixed reality spectrum

Summary

INTRODUCTION

In 1994, Paul Milgram and Fumio Kishino published “A Taxonomy of Mixed Reality Visual Displays,” simultaneously introducing to the literature the notion of the reality-virtuality (RV) continuum and the term “mixed reality” (MR) (Milgram and Kishino, 1994). Millions of consumers have access to AR experiences on their mobile phones (e.g., Pokémon GO), or VR experiences on the Facebook Oculus or HTC Vive head-mounted displays (e.g., Beat Saber) In light of this rapid technological evolution, we believe it is worth revisiting core concepts such as the reality-virtuality continuum. Hall, and Nebeling investigated the definition of mixed reality through a literature review and a series of interviews with domain experts They proposed a conceptual framework for MR (Speicher et al, 2019). Of note is that while these papers enrich the discussion regarding mixed reality, none challenges the central notion of the RV continuum, nor do they generally propose alternative definitions of mixed reality

REVISITING THE REALITY-VIRTUALITY CONTINUUM

Milgram and Kishino’s Original Taxonomy of MR Systems

Our Proposed Taxonomy for MR Experiences

Implications of Our Revised Taxonomy

CONCLUSION

DATA AVAILABILITY STATEMENT