Thinking about 'presence' when developing a game

[baroquedub]

"I feel like I'm in this place, not just looking at this place"

 Not sure how many of you watched the recent Lex Fridman interview with Mark Zuckerberg, showcasing the Meta CODEC avatars?  https://www.youtube.com/watch?v=MVYrJJNdrEg

It got me thinking about the sense of presence in VR. It's a topic I posted about on a private discord server recently and thought it might be worth sharing here too.

I work in a psychology VR lab where we use the fact that immersion triggers real physiological responses to help patients with mental health problems. When you get it right, you really can trigger involuntary fight or flight responses in a participant, or something like a palpable sense of vertigo (think Richie's Plank Experience). All the while, part of your conscious brain knows that you're still in a simulation and that duality - feeling true to life emotions in a safe virtual environment - can be used to help people try things they might not be able to do in real life. It's a form of exposure therapy that can be incredibly powerful. Giving your players that same sense of immersion is also incredibly powerful and is, for me, what differentiates VR from any other medium.

Here's that post about presence:

Someone asked me recently what qualities I thought a VR application should have. As a developer, my mind initially went to technical requirements like keeping a solid framerate, but I also think it's important to think about designing with the medium in mind. In other words, to think at a higher level about how best to trully immerse your players in your VR experience.

Something well worth thinking about is the sense of presence (immersion in the virtual world). There's a lot of research into this, with one of the most established being by a research scientist called Mel Slater. He talks about immersion (the sense of being there) as being like a house of cards that's built on two principles: the Place Illusion and the Plausibility Illusion. 

In simple terms, Place is whether things look right (it's about the visual representation, the graphical fidelity, which also encompasses things like keeping a solid frame rate). 

Plausibility is whether things act as they should (based on the world I see, does it react and behave in the way I expect it to behave). That's not to say it has to be realistic. It's more about following its own internal logic. If the VR experience depicts a fantastical world then it can behave in non-realistic ways. It also needs to be consistent. If you've allowed your player to pick-up one object and intereact with it, then they will expect to be able to pick up any and all objects that they come into contact with. Being able to pick up one object but not another will immediately break the plausibility illusion. The house of cards will collapse and your players will lose that sense of presence, of 'being there'. 

Mel Slater suggests that the Place illusion is actually quite resilient (you can get away with low poly, environments/art styles) and when broken it rebuilds itself relatively quickly. The Plausibility Illusion, by comparison, is much more fragile and perhaps more important to immersion. For example, a low poly/cartoony game with lots of physics interactions (think Job Simulator) provides a very strong sense of presence. Whereas it's much harder for a photorealistic VR simulation to hold that in place because given the hyper-realistic visual representation, players expect equally realistic interactions with that world (this includes not just hand interactions but also interactions with NPCs, movements in the space, etc.). Any jankiness will quickly break the illusion. 

Thinking about that balance between the two is particularly important for game design, UX and art direction. 

Slater's also done a lot of research into locomotion and embodiment (that sense of inhabiting someone else's body). This raises questions about whether you need a full body avatar, or just arms, or just hands. This is the body illusion. If you have feet and they don't move the way you expect them to move or the way you know they are moving in the real world (because of proprioception we're still aware of our real body while in VR) again, the house of cards comes tumbling down. It's the reason so many games have avatars that stop at the waist. But then again... Slater found that we have a surprisingly fluid sense of body ownership. Our brain very quickly accepts an alien body (tentacles for hands) or fatter/thinner or a different gender than our own. 

This really is just a brief oversimplification of Mel Slater's work. For those interested, I'd highly recommend searching out some of his research papers, and at the very least start thinking about these issues as part of your game and app development.