Why “Embodiment” is More Important Than “Immersion” – Inside XR Design

By
Ben Lang
-
23

Our series Inside XR Design examines specific examples of great XR design. Today we’re looking at the game Synapse and exploring the concept of embodiment and what makes it important to VR games.

You can find the complete video below, or continue reading for an adapted text version.

Defining Embodiment

Welcome back to another episode of Inside XR design. Today I’m going to talk about Synapse (2023), a PSVR 2 exclusive game from developer nDreams. But specifically we’re gonna to look at the game through the lens of a concept called embodiment.

So what the hell is embodiment and why am I boring you talking about it rather than just talking about all the cool shooting, and explosions, and smart design in the game? Well, it’s going to help us understand why certain design decisions in Synapse are so effective. So stick with me here for just a minute.

Embodiment is a term I use to describe the feeling of being physically present within a VR experience. Like you’re actually standing there in the world that’s around you.

And now your reasonable response is, “but don’t we already use the word immersion for that?”

Well colloquially people certainly do, but I want to make an important distinction between ‘immersion’ and ‘embodiment’.

‘Immersion’, for the purposes of our discussion, is when something has your complete attention. We all agree that a movie can be immersive, right? When the story or action is so engrossing it’s almost like nothing outside of the theater even exists at that moment. But has even the most immersive movie you’ve ever seen made you think you were physically inside the movie? Certainly not.

And that’s where ’embodiment’ comes in. For the sake of specificity, I’m defining immersion as being about attention. On the other hand, embodiment is about your sense of physical presence and how it relates to the world around you.

So I think it’s important to recognize that all VR games get immersion for free. By literally taking over your vision and hearing, for the most part they automatically have your full attention. You are immersed the second you put on a headset.

But some VR games manage to push us one step further. They don’t just have our attention, they make us feel like our whole body has been transported into the virtual world. Like you’d actually feel things in the game if you reached out and touched them.

Ok, so immersion is attention and embodiment is the feeling of actually being there.

And to be clear, embodiment isn’t a binary thing. It’s a spectrum. Some VR games are slightly embodying, while others are very embodying. But what makes the difference?

That’s exactly what we’re going to talk about with Synapse.

Cover You Can Feel

At first glance, Synapse might look like a pretty common VR shooter, but there are several really intentional design decisions that drive a strong sense of embodiment. The first thing I want to talk about is the cover system.

Every VR shooter has cover. You can walk behind a wall and it will block shots for you. But beyond that, the wall doesn’t really physically relate to your actual body because you never actively engage with it. It’s just a stationary object.

But Synapse makes walls and other cover interactive by letting you grab it with your hand and pull your body in and out of cover. This feels really natural and works great for the gameplay.

And because you’re physically moving yourself in relation to the wall—instead of just strafing back and forth with a thumbstick—the wall starts to feel more real. Specifically, it feels more real because when you grab the wall and use it as an anchor from which to move, it’s subconsciously becoming part of your proprioceptive model.

Understanding Proprioception

Let’s take a second here to explain proprioception because it’s a term that comes up a lot when we’re talking about tricking our bodies into thinking we’re somewhere else.

The clearest example I’ve ever seen of proprioception in action is this clip. And listen, I never thought I’d be showing you a cat clip in this series, but here we are. Watch closely as the cat approaches the table… without really thinking about it, it effortlessly moves its ear out of the way just at the right time.

This is proprioception at work. It’s your body’s model of where it is in relation to the things around you. In order for the cat to know exactly when and where to move its ear to avoid the table without even looking at it, it has to have some innate sense of the space its ear occupies and how that relates to the space the table occupies.

In the case of the cover system in Synapse, you intuitively understand that ‘when I grab this wall and move my hand to the right, my body will move to the left’.

So rather than just being a ‘thing that you see’ walls become something more than that. They become relevant to you in a more meaningful way, because you can directly engage with them to influence the position of your body. In doing so, your mind starts to pay more attention to where the walls are in relation to your body. They start to feel more real. And by extension, your own body starts to feel more present in the simulation… you feel more ‘embodied’.

Mags Out

And walls in Synapse can actually be used for more than cover. You can also use them to push magazines into your weapon.

Backing away from embodiment for just a second—this is such a cool design detail. In Inside XR Design #4 I spent a long time talking about the realistic weapon model in Half-Life: Alyx (2020). But Synapse is a run-and-gun game so the developers took a totally different approach and landed on a reloading system that’s fast paced but still engaging.

Instead of making players mess with inventory and chambering, the magazines in this game just pop out and float there. To reload, just slide them back into the weapon. It might seem silly, but it works in the game’s sci-fi context and reduces reloading complexity while maintaining much of the fun and game flow that comes with it.

And now we can see how this pairs so beautifully with the cover game’s cover system.

The game’s cover system takes one of your hands to use. So how can you reload? Pushing your magazine against the wall to reload your gun is the perfect solution to allow players to use both systems at the same time.

But guess what? This isn’t just a really clever design, it’s yet another way that you can engage with the wall—as if it’s actually there in front of you. You need to know if your arm is close enough to the wall if you’re going to use it to reload. So again, your brain starts to incorporate walls and their proximity into your proprioceptive model. You start to truly sense the space between your body and the wall.

So both of these things—being able to use walls to pull yourself in and out of cover, and being able to use walls to push a magazine into your gun—make walls feel more real because you interact with them up close and in a meaningful way.

And here’s the thing. When the world around you starts to feel more real, you start to feel more convinced that you’re actually standing inside of it. That’s embodiment. And let’s remember: virtual worlds are always ‘immersive’ because they necessarily have our full attention. But embodiment goes beyond what we see—it’s about what we feel.

And when it comes to reaching out and touching the world… Synapse takes things to a whole new level with its incredible telekinesis system.

Continue on Page 2: Extend Your Reach »

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Ben Lang
Ben is the world's most senior professional analyst solely dedicated to the XR industry, having founded Road to VR in 2011—a year before the Oculus Kickstarter sparked a resurgence that led to the modern XR landscape. He has authored more than 3,000 articles chronicling the evolution of the XR industry over more than a decade. With that unique perspective, Ben has been consistently recognized as one of the most influential voices in XR, giving keynotes and joining panel and podcast discussions at key industry events. He is a self-described "journalist and analyst, not evangelist."
  • Dragon Marble

    Another great episode of the excellent XR design series. And thanks for arming us with a new word to describe VR. I had debates with some who claimed they could have equal “immersion” in flat games or movies. Now they can’t have “embodiment”. Checkmate.

  • ViRGiN

    Anton from H3VR (Hot Dogs, Horseshoes & Hand Grenades – SteamVR exclusive) – no, I’ll stick to doing the same shtick I’ve been doing since 2016 – more guns, less design

  • XRC

    Watched your video on YouTube a couple of days ago, very well put together and what a fantastic game design! Thanks for your ongoing work looking at this subject.

    One interesting thing to try re proprioception, from an article I wrote on index controller for Skarredghost back in 2019:

    Proprioception relating to body image is very interesting, here is a simple experiment:

    Try closing your eyes, move your arms above your head; now try touching the end of your nose with your right index finger – I’d be very surprised if you miss?

    Another test, place a piece of paper on a table in front of you, sit and then draw an “X” in the middle of the paper.

    Take a look at the X, close your eyes, raise your pen arm up and then bring it back down to where you think the X will be, make a mark, open your eyes, try again several times and see how your accuracy improves, this is proprioception recalibration on the fly!

    We maintain a surprisingly accurate body image based on the rich wealth of proprioception generated as we inhabit our bodies, which can be leveraged with interesting results when using immersive computing platforms like Virtual Reality.

    • kool

      I gotta an example of proprioception (love that word!). I’m an led engineer and I build huge led walls with ten of thousands of connections alot of the time in the dark. I used to use a headlamp but at some point you stop using your eyes and can do the job without even looking in the direction your working and access other problems while your hands just do the job without your input. In vr two examples of proprioception are when I’ve looked over the edge of a cliff and my ears popped and going deep into a cave and getting goose bumps!

  • I love this series of article. Thanks for the great insights!

  • NotMikeD

    You know I’ve got to hand it to you–I began reading this article with my arms firmly crossed, prepared to die on the hill that “we already have ‘immersion’ and ‘presence’, ALL VR games are commanding your full attention by being in-HMD, and we DON’T need yet another jargon word.” But one by one your article seemed to anticipate and address each of my points. You convinced me! (and “hand it to you” plays right into your argument too, supporting your concept of ’embodiment’)

    • Ben Lang

      Dang that’s a really awesome compliment. Thanks so much for reading with an open mind!

  • Octogod

    These are my favorites pieces on the site. Thank you for another thought provoking article.

  • John G

    Ah, now I understand why Synapse is so far only on the PSVR2, the eye tracking is obviously core to it’s mechanics.

    Fantastic article, thank you.

    I always felt the way Natural Locomotion uses foot tracking to help presence was also key – even though it’s not ‘walking’ because moving your foot up and down was so tightly tracked with how far you move, it really helped presence.

    == John ==

  • Ondrej

    Presence can be achieved with zero physicality of user’s existence.
    Even immersion is a much closer term to it.

    Your first definition of embodiment in the article – “physically present” – makes much more sense than conflating it with the pure sense of presence, which is a much more subjective phenomena.

    Embodiment requires complex game design with implementation of physics, like collissions.
    Presence can happen even with zero-design-camera and PlayStation 2 graphics, if very good roomscale tracking is used and the user is easily immersed.

  • Andrew Jakobs

    I’m sorry to tell you this, but the whole article depends on your different interpretation on the word immersion, most of the people talking about immersion in regard to VR are talking about what you call embodiment.
    For me there is no difference between ‘physically’ pull a lever or using the environment to reload the gun.
    It’s still a nice article but it’s just saying what we already feel what VR is about since day one, full immersion.

    • Ben Lang

      Sure, but I think we all acknowledge that some VR games are more “immersive” than others (if that’s the word we’re going to use). So what makes the difference? If the only thing that mattered was being in a headset, then all VR games would be equally immersive.

      So the point isn’t really about which word is “right,” it’s about separating the concepts so we can have a discussion about what factors drive the feeling like your whole body has been transported into the game vs. just having your vision taken over by the game.

      • Alexander Fewings

        I agree with the previous poster. I think really whats happened here is companies like Apple and others have basically reclaimed the word (Fully) ‘Immersive’ to mean, anything we shove in your face, as you’re pretty much describing here. And thus, yes XR devs are forced to fallback to some more specific term to describe what we’ve all been talking about for most of the last decade. Its sad but its surely not the last time it’ll happen :(

      • LegoKnockingShop

        Disagree – using the right words IS important, and the concepts are already separate, and these discussions already exist and have long been going on. Why try to redefine terms that have been in use for a long time?

        Embodiment already has a long-established definition in VR academia and development, which isn’t this unfortunately. So do Presence and Immersion. You even suggest at the end that the three words are kinda interchangeable, but they absolutely shouldn’t be seen that way, it helps nobody and sows confusion.

        Immersion is a spectrum – you can be immersed in a book but you don’t believe you’re in a book, in that world, living it – which is what Presence represents in the loosest terms, the full illusion that you’re there and present in that reality, not IRL. You don’t have to feel embodied to achieve presence (but it sure can help!). Immersion is a function of both software design and hardware engineering, and Presence is the generally desired experiential goal of that immersion. Embodiment is specifically the user’s acceptance that the virtual body they’re seeing is their own body. Its purely about aspects of body ownership can be a contributing factor to achieving Presence, not just an alternate name for it.

        There’s obvious benefit in adopting a unified accepted lexicon as our medium grows. If you wanted to argue that these names are traditionally mis-assigned, then go for it, it’s healthy for these established definitions and scopes to be examined periodically to make sure they’re still applicable and useful terms. Maybe that’s the aim here? But if so, I’m puzzled why you don’t reference or acknowledge the existing use of these terminologies as a starting point.

        • psuedonymous@mailinator.com

          Yep! I have a hard enough time trying to explain to people that “Presence” and “Immersion” are not the same thing, now I’m going to have to fight against the misuse of “Embodiment” too. Deliberately mixing existing defined terms is not OK!

        • Ben Lang

          As long as the participants of a given conversation know the definitions being used, the specific terms don’t really matter. That’s why I said these were the definitions I was using “for the purposes of our discussion.”

          Call my definitions of immersion ‘A’ and embodiment ‘B’ if you’d like.

          Now if we have that settled we can talk about the point of the video, which is that A and B are two different things and are driven by different aspects of the experience. Considering those difference aspects is important to the outcome of what someone is building.

  • Ben Lang

    I’m very curious to hear what you think after reading this article and then playing the game. Have fun!

  • Dan

    Hi, I rarely read reviews everywhere about video games. Anyway if you add “embodiment” to your reviews I would like to read for it when a new review comes out. Thx for your attention

    • Ben Lang

      Thanks! All of our reviews have an ‘Immersion’ score. We use the colloquial term there (because not every reader is going to want to learn these particular distinctions between ‘Immersion’ and ‘Embodiment)’, but that score mostly encompasses the feeling of embodiment as defined in this article.

  • NicoleJsd

    Finally someone else who gets it. It used to be called just presence

    Latency and FOV are crucial things to it and whole valve index was engineered around to maximise feeling of presence. (Hence the amazing speakers directional sound)

    People who only used quest have no idea what it is which is sad because it is unbelievably cool feeling. You try to explain to them but it’s like explaining colors to a blind person

    • psuedonymous

      Presence was achieved many years before development work on Index started. It was achieved with pre-DK2 tracked DK1 demos, and both CV1 and Vive could achieve it in practice as long as developers did not screw up (e.g. breaking orthostereo by messing with the horizon).

      Needless to say, Quest 1 could easily acheive presence, not to mention 2, 3, and Pro. It is not some special provision of the Index alone.

  • g-man

    Good article (again), thanks. It’s interesting you threw in the bit about presence at the end because I was thinking about it since the paragraph where you defined your terms.

    I define them slightly differently. Immersion is when the media takes over or engrosses your consciousness, which can be something like VR or even just being really engrossed in a movie on TV. Presence is the sense that you are actually in that location rather than your real world location. Embodiment is the feeling that you are the protagonist, the one doing the things you see.

    You can be immersed without feeling like you’re there, and you can have presence without embodiment, for example in third person VR adventures where you’re “there” but are more like the camera than an actual entity in the game.

    Anyway just some pedantry for you, great stuff :)

  • The game certainly makes good use of things… that have already been done in tons of VR games before them. Nothing new. Any game that lets you climb allows you to use grip cover. Telekinesis has been in shooters since “Psi-Ops: The Mindgate Conspiracy” back in 2004. Half Life 2 made it very physics based. The only innovation in Synapse was leveraging eye tracking, which only PSVR2 games really can, at this time.

    Also, what’s with renaming “VR” as “XR”? You too cool for “VR”? Too passe? Need something more pretentious?