The adorable and puissant Iris Ophelia asks: "In RL there are 5 (debatably 6) senses. How many are there in SL? Do we just lose some of them, or do we also gain some?"

Excellent question. I've posted previously about the efficacy of eating animations, which you could argue approaches the question about the experiential senses in SL. And despite this post, I think it's time to take another look at how SL approximates our senses, and if it offers any new ones.

Sight
Sight is probably the most utilized sense in SL. There's so much that competes for your attention, and not just those things that content creators want you to see. There is visual feedback for when textures haven't loaded completely, region and ban lines for certain parcels of land, and signs of improper build artifacts. We receive important information about the client's performance visually: lag, stutter, objects passing through other objects, animations looping improperly, poses not working correctly, etc.

Additionally, there's the interface itself, with its menus, windows, and the radial selections, all geared toward visual communication with your brain. Let's not forget text chat, in both common and IM forms, whether or not you use bubbles for further spatial orientation. Let's face it, you could have all sounds turned off (and I frequently do), and navigate SL just fine. Hell, you can even see when voice users are speaking without needing to hear them!

The question is, can users with sight deprivation enjoy SL? Let's find out after the jump.
Hearing
Sound in SL is still a fledgling thing, despite how much content there is out there. Streaming delivery of musical events can be spotty, depending on a number of factors. Sometimes there is sound lag, or dropped signal. The addition of voice has made good use of directional sound, which is evident with the use of a good set of headphones. There are a bunch of incidental UI sounds, along with ambient environmentals like wind and footsteps, though these are almost always turned off, in my experience. As I mentioned earlier, I usually have sound turned off; I can only hear so much goofy audio clips before it becomes wearying, and I get really tired of the music spam that invades my ears as I travel between sims.

Given all of that, is the sense of hearing underutilized in SL? Well, let's not deny the power of the human voice to make an immediate impression. Text is great for expressing ideas, but it's nothing compared to the immediacy of hearing someone speak, which conveys an almost ridiculous amount of information in a visceral way, slipping just below the transom of consciousness. You make immediate judgments about someone when hearing their voice whether you realize it or not.

And, as also previously mentioned, there is a wealth of music in SL that is simply unavailable elsewhere. Music and voice chat: the two best reasons to keep your speakers on. Are there others?

Smell
Now we begin to enter into slightly more difficult territory. Obviously, the sense of smell has no direct SL analogue, but it is possible to make associations that might induce a corresponding pseudo-smell sensation in your mind.

It's been said that scent is a gateway to memory, and you can do experiments with yourself to prove the validity of that idea. That said, is it possible to generate a reverse-directed impulse, where a set of images so closely resembles a remembered scenario that your mind activates the olfactory sense to complete the association? I once visited a site in SL that took pains to recreate a Tibetan temple, such that I could just about smell the joss sticks burning on the altar, and the sandalwood that permeated the air. As visual fidelity grows (oh please, oh please let it grow), so too will the associative power of the images, which in turn will increase the verisimilitude of SL in general.

Let's hope that no one creates a smell-o-vision component to SL; I'm quite satisfied with merely watching griefing, thank you.

Taste
There are so many restaurants, delis, eateries, nightclubs with bars, and assorted foodie-type places that it's easy to forget that, sophisticated dining animations aside, you can't taste a virtual morsel. There's not too much to say about the sense of taste as it's represented in SL. I've gone my entire span of residency without missing it even once, though perhaps that statement ought to be mitigated by considering the range of adult sexual animations where taste would surely play an important part if similar activities were experienced in RL.

There might also be something to be grateful for here. I think of all the hilarious things I've seen in SL, and many of them involve holding things in your avatar's mouth that you wouldn't hesitate in RL to shy away from. I myself am the proud possessor of an animation called 'doggie cleaning' that replicates the actions of canines when they clean themselves ... you know ... down there. Brought out at the right moment, in the right company, and it's a killer -- but I don't wanna taste it. 'Nuff said.

Touch
Despite a lack of any possible force-feedback devices (including teledildonics), there is still a great deal of tactile sensation in and around SL. Directly, we watch our avatars walk, fly, crash, dance, skid, sink, and all manner of other phenomena, and sometimes that subconsciously produces a response in ourselves, a kind of Body English, where we move in sympathy, trying to influence our avatar's movement.

There are also the constant pressures beneath your hands of the mouse and keyboard, which is no trivial sensation. You know immediately when you're typing on an unfamiliar keyboard, and movement with the directional keys makes a huge difference in your navigation of the world. There are even certain areas in SL (like an amusement park I once visited, for instance), that requires active participation from the user -- a swing that only works if you provide the motive power, or a timing game that requires the precise application of a button press to win.

Trivial though they may seem to this examination, eye strain and muscle fatigue also add to the tactile and somatic experience of SL. When you've been chatting all night long, staring at the same distance of your monitor, your body lets you know in no uncertain terms that it's time to do something different, and you ignore that warning at your peril.

There are researchers and innovators constantly playing with tactile interfaces, ways for us to squeeze every possible erg of information from our virtual experiences. Given how quickly technology changes, it's certainly possible that in 10 years' time we'll be fully interacting with SL (if it's still around) with all 5 of our common senses, in a fully-immersive environment, or with special suits. And those are the Big 5, but are there others?

Other Senses: Balance
In his amazing novel 'The Once and Future King', T.H. White talks about the senses we're born with, and senses we develop as we grow older. His 'sixth sense' is nothing to do with telepathy or ESP; he makes the case that the sixth sense is the sense of Balance.

It's certainly evident that infants and toddlers do not immediately possess this sense. They develop it over time through trial and error. Is there a correspondence in SL? Certainly. Walking takes some getting used to, and until it's mastered, avatars will walk into walls, fall off of ledges, slip into open water, and all manner of mishaps before it becomes second nature. And this doesn't even take into account flying, with its special needs. Added to this, there's camerawork. It's a tricky bit of maneuvering to find exactly what you want to focus on, and I've experienced vertigo many times trying to get it just right. And let's not even mention Mouselook *shudder*.

Knowledge of the World
T.H. White goes on to mention a seventh sense: What he called Knowledge of the World. This means, as I understand it, how, as we get older (or in the case of SL, more experienced), we begin to lose the passions of youth and start to settle into our lives having seen patterns develop around us, patterns which are repeated and explicable. We start to relax somewhat, and life becomes less troubling and worrisome. From the novel:

"Further back, there were times when we wondered with all our souls what the world was, what love was, what we were ourselves."

"All these problems and feelings fade away when we get the seventh sense. Middle-aged people can balance between believing in God and breaking all the commandments, without difficulty. The seventh sense, indeed, slowly kills all the other ones, so that at last there is no trouble about the commandments. We cannot see any more, or feel, or hear about them. The bodies which we loved, the truths which we sought, the Gods whom we questioned: we are deaf and blind to them now, safely and automatically balancing along toward the inevitable grave, under the protection of our last sense."

That last sense, the Knowledge of the World, is clearly applicable to SL. Some might call it being jaded, which isn't far from the truth, despite its negative connotations. After some time in SL, you begin to settle into things. You learn what to expect, certain phenomena are no longer strange and inexplicable, behavior becomes predictable. This makes life in general more bearable, but it's a fight sometimes to balance this sense with one final sense I'd like to mention: the sense of Wonder.

Wonder
With specific regard to SL, I consider this the most important sense to cultivate and keep active. The sense of wonder is likely the chiefest motivating factor in bringing people to SL, or at least in keeping them there. Those who are dismissive of our favorite platform simply haven't invested the time and patience in opening themselves to the wonder of it all. Think on it: in any given area, we're seeing someone's thoughts made visible. Silly, serious, frightening, epic, playful, artistic, these things all existed only in someone's head at some point. SL had given these creators the tools with which to directly communicate with us, with anyone, an invisible audience who sometimes merely stumbles across their work accidentally. Very little in SL would even exist without these dreams-made-real. Surely there is wonder in this.

Then there is the getting to know someone, represented by an avatar, existing somewhere on this planet, possibly across an unimaginable distance, sometimes right next door. Think of the relationships SL has brought to fruition, the lives it has touched, the connections it has engendered. Think of the hilarity of a dance line in the Shelter, the rapport developed between a musician and her audience, the almost casual knowledge displayed at a trivia game. As many times as I've retreated from the vicissitudes of maintaining SL friendships, and the peculiarities of writing for SLI, I've always returned when the call of all things wondrous becomes strong enough. I'll always return, I think; there's just so much to feel there.