Disclaimer: Presence research is not my area of expertise. I’m basically speaking as an interested layperson, and just writing down some vaguely related observations that have re-occurred to me recently.
So, presence. What is presence, and why should we care? Libraries full of papers have been written about it, and there’s even a long-running journal of that title. I guess one could say that presence is the sensation of bodily being in a place or environment where one knows one is not. And why is it important in the discussion of virtual reality? Because it is often trotted out as the distinguishing feature between the medium of VR (yes, VR is the medium, not the content) and other media, such as film or interactive 3D graphics; in other words, it is often a feature that’s used to sell the idea of VR (not that there’s anything wrong with that).
But how does one actually measure presence, and know that one has achieved it? Some researchers do it by putting users into fMRI machines, but that’s not really something you can do at home. So here are a few things I’ve observed over sixteen years of working in VR, and showing 3D display environments and 3D software to probably more than 1,000 people, both experts and members of the general public:
- If you stand at the edge of a virtual abyss, and your feet tingle and your hands start sweating, that’s presence.
- If you jump down a ledge, and your stomach rises on the way down, and when landing you bend your knees without wanting to, and you feel the impact on the floor, that’s presence.
- If you play with the Nanotech Construction Kit (see this video), and you feel the virtual atoms pushing back when you push them around, that’s presence.
- If you stick your head into a hollow virtual globe floating in front of you, and it feels warmer in there, that’s presence.
- If you are in a space with virtual avatars, or better, 3D video of actual people, and an avatar or a virtual person takes a step towards you, and you take a step back without wanting to, that’s presence.
- In the same context, if you don’t stare at the virtual people even though you want to, that’s presence.
- If you move through a virtual world, and you get motion sick, that’s not presence — that’s just bad VR.
- When the moon hits your eye like a big pizza pie, that’s not presence, that’s amore.
I think the common theme here, joking aside, is that when there is presence, your brain fills in those things that are missing from the virtual world, but would be present in the real world. By the way, motion sickness happens when your brain precisely does not fill in things that are missing from the virtual world, specifically vestibular cues, so you could say that motion sickness is the antithesis of presence.
Update: I just found this video (“Reality Check: What Does the Oculus Rift Do To Your Brain?” 6:08 minutes), which is a well-researched discussion of presence in the latter 2/3rds, and worth watching all the way through.
Disclaimer 2: If you don’t want to hear me griping, stop reading right now.
That’s all great, so why do I have some issues with the concept of “presence?” Primarily because, for a lot of VR research and VR researchers, it’s the end-all be-all of VR, the Holy Grail so to speak. Don’t ever do anything that could impact presence! But what if presence gets in the way of getting stuff done? What if you don’t necessarily care about creating the Matrix, but want to use the highly effective 3D display and user interaction methods that are the backbone of VR to do actual work?
If you want to interactively, and rapidly, change the display scale of the virtual world, because that’s the fastest way to travel from point A to point B (step 1: zoom out around current position until destination position is within reach; step 2: grab destination position and zoom back in), then who cares if that might negatively affect presence? If you want some kind of heads-up display, because you are doing virtual field work in some (scanned) real landscape, and need to know precisely in what direction you’re looking, then why not have a HUD? Would creating a 3D virtual replica of a real compass that you can hold in your hand and look at be anywhere near as practical? If you could do so in the real world, wouldn’t you rather have a HUD than a compass, and be able to travel long distances by warping space instead of taking a plane?
Did VR maybe fail to gain traction so far because almost everybody has been focusing on presence so much that they forgot making VR useful?