Head-Mounted Displays: Transporter or Tether?

In 2020, Facebook released the Oculus Quest 2. Weighing in at 503 grams, with a refresh rate of 90Hz, the Quest 2 boasted its sleek appearance, cinematic 3D sound, and lack of wires. For many, Facebook's Oculus Quest 2 was an incredible achievement in HMD Development.

A brief study of the philosophy of VR and immersion may tell a different story, however. While the achievements of the Oculus Quest 2 are no joke, there are a lot more advancements ahead of us. Modern-day HMDs are still clunky and bulky, placing a large physical load on the user. If immersion is the goal for HMD developers, we must strive for wearable, comfortable tech, even if it means pausing the advancements of graphics and realism (for now).

Beat Sabre is just one example of the hundreds of successful VR games on the market. From musical futuristic landscapes, to medieval sword fighting, head-mounted displays make experiences that we’d never think possible to be achievable things; all from the comfort of one’s living room.

Immersion

Immersion is an incredibly popular buzzword in the gaming and entertainment industries, and has become increasingly important with the development of VR technologies. Gamers and movie watchers alike often talk about the “immersion” they feel when consuming some form of media. Game developers often say that certain sound and graphical effects within their game help the users to feel more “immersed”. Additionally, when someone mentions a flaw or brings up something that doesn’t have anything to do with a game, one can frequently be caught saying something like “you’re ruining my immersion!”.

If we want to discuss the goal of immersion as it relates to VR development, we must give a foundational definition for immersion. Some thinkers in the philosophy of VR have written about immersion as it relates to realism, while others have said that it is more related to the idea of presence in a virtual environment. These two uses for the term “immersion” often get conflated together.

Immersion is the degree to which a VR user believes, or is convinced, that they are in a virtual environment, resulting in the user forgetting about their presence in the real world. Immersion has nothing to do with the level of reality that is felt of a virtual space; an individual can be equally immersed in an imaginative wonderland of simple geometric shapes as they can be in a hyper-realistic simulation. •What’s important in the discussion of immersion is simply how much a user feels as if they are spatially and temporally “here”.

Research Findings

In 2016 researchers Takanori Chihara and Akihiko Seo conducted a study in which they measured how the physical load of an HMD affects the neck and lower back torque of the user. Participants in the study viewed objects in VR in four positions: neutral, looking up, looking to the side, and looking down.

At the end of the study, researchers found that heavier HMDs had a significant effect on the neck and back-torque of the user. In other words, the heavier the VR headset, the more likely it was for the user to experience uncomfortable angles in their neck and back. Even more, the center of mass (COM) of the headset also had an effect on the user's comfort. More "inappropriate" HMDs had centers of balance at the front or back of the headset. Ideal HMDs had a center of mass in the center.

So, heavier headsets are uncomfortable. They make the HMD-wearer move in ways that they wouldn't usually move in, most notably at the neck and lower back. While this may not seem like the biggest of deals, it actually has a serious impact on the immersion that the user can feel. After all, how are you supposed to forget you have a headset on when your beck and back are moving at odd angles?

What HMD Developers Should Do Next

As discussed above, the weight, center of mass, and general physical load of an HMD can have a serious effect on the neck and lower back torque of the user. With this comes the inability to forget about one's physical presence, which is essential for immersion. How is one supposed to forget about their physical body and be transported to another virtual dimension when one is experiencing uncomfortable and unnatural bodily sensations? In order for a user to really feel spatially and temporally "here", they must be moving their head, neck, and the rest of their body in a way that is comfortable and closely resembles their real physical movement.

So, in turn, a new responsibility gets loaded onto the plate of HMD inventors. In order for HMDs to be a fully immersive experience, HMD developers must create headsets that are ergonomic. They must have an appropriate mass, ideally something along the lines of a pair of eyeglasses. Additionally, they must have an appropriate center of mass, so that the front of a user's head doesn't feel any heavier than the rest.

Crucially, this switching of emphasis may mean pausing efforts to develop graphically and computationally impressive technology. VR developers don't have to ditch the progress that they've made, of course; but rather, they should focus on taking the great tech that they already have and making it more compact and ergonomic. When the height of ergonomics and comfortability is achieved, there's nothing wrong with developers getting back on the "hyper-realism" train and trying to make their wearable tech even more visually impressive.

To illustrate this point further, let's imagine two scenarios. In the first, you're exploring a simple, geometric landscape. Nothing is all that graphically impressive in this space, but your virtual body feels exactly like your physical one. You are moving in all the ways that you normally would, exploring this virtual space. In the second example, you are exploring the streets of New York City in VR. The simulation is incredibly detailed; you can see each individual hair on a passerby's head and each pore in the concrete below you. However, you constantly feel the weight of an HMD on your face. You can't rid yourself of the feeling of its weight, no matter how hard you try. After a few hours of play, your head and neck get tired, forcing you to take off the headset.

Which experience is more immersive? Surely, it doesn't take must to illustrate that the first simulation, without the constant feeling of an HMD, is infintely more enjoyable and immersive.

The Future of HMDs

As I've discussed, the development of HMDs has a long way to go before it can reach the potential of full, uninterrupted immersion. The first necessary step is getting VR and HMD developers interested in creating wearable, comfortable tech, even if it may require them to ditch their efforts in expanding hyperrealistic technology for the time being.

On the bright side, it seems as though comfortable XR (extended reality) tech is being developed by some corporations. Some might remember Google Glass from a few years back, which attempted to bring AR into the lives of everyday users in order for them to "focus on what's important". Though Glass didn't blow up as some expected, Google's interest in the tech may lead way to advancements in the future. Apple has also taken a liking to wearable XR, with recent leaks hinting at the possibility for a tech star to break into the worlds of AR and VR. As these efforts progress, we may see a real upturn in companies interested in sleek and comfortable HMDs.