[Basic] Advantage of the Week (#40): Discriminatory Senses, Sensitive Touch

[whswhs]

Originally Posted by Icelander

How do you pick pockets or locks, massage people or carve scrimshaw without a sense of touch?

If Telekinesis can perform all the same tasks as a pair of hands, it needs some equivalent sense to the sense of touch to do it.

Well, I have to grant that that argument carries a good bit of weight, at least for what TK is stated to be capable of in the Basic Set. Let's look at the details, though.

* There are forms of TK where this may well not apply. Attraction/Repulsion, for example, is effectively the tractor/pressor beams of space opera. Magnetism may also not register as "tactile"; there are Detect Magnetism and Detect Magnetic Materials, after all.

* Not all aspects of "touch" are included in TK, I think. Can you tell, using your telekinetic hands, whether something you're picking up with them is hot or cold? Can you hold them up to a fire and feel the warmth? Can they be injured and cause you to feel pain? If you telekinetically grab someone, and they have an attack with Contact Agent and Aura, does it apply to you, or to your invisible "hands"?

* Even restricting to the purely sensory and mechanical dimensions of "touch," TK might not need all of them. You have to be able to tell when your "hands" have encountered a surface, rather than have them sink into it; so they have to be able to tell that a solid (or liquid) surface is there. You probably have to be able to tell how much resistance is being given to the force you're applying. But you may not need to be able to judge textures by sliding your "fingertip" along a surface, or read Braille telekinetically (though now I think of it, that's kind of a neat image). Imagine a robot with "fingers" whose interiors contain very sensitive strain gauges, so it can apply very precisely measured force—pick up an egg without breaking it, for example—but it has no cutaneous receptors that can feel the smoothness of eggshell.

* Can you reach inside a solid object and manipulate its interior? The idea that TK miraculously aids lockpicking seems to suggest this. If you just had four hands instead of two, it wouldn't be such a big deal.

* What about this? TK does give you tactile feedback. But normal use of it is visually guided, just as normal use of hands is visually guided. To use it nonvisually, you need to buy "Work by Touch" as a technique, and it's a different technique for TK than for your hands.

[Not another shrubbery]

This old post of Kromm's is relevant to the question of TK and tactile feedback. I don't know of anything that has happened since then to justify changing that ruling.

[Icelander]

Originally Posted by whswhs

Well, I have to grant that that argument carries a good bit of weight, at least for what TK is stated to be capable of in the Basic Set. Let's look at the details, though.

* There are forms of TK where this may well not apply. Attraction/Repulsion, for example, is effectively the tractor/pressor beams of space opera. Magnetism may also not register as "tactile"; there are Detect Magnetism and Detect Magnetic Materials, after all.

* Not all aspects of "touch" are included in TK, I think. Can you tell, using your telekinetic hands, whether something you're picking up with them is hot or cold? Can you hold them up to a fire and feel the warmth? Can they be injured and cause you to feel pain? If you telekinetically grab someone, and they have an attack with Contact Agent and Aura, does it apply to you, or to your invisible "hands"?

* Even restricting to the purely sensory and mechanical dimensions of "touch," TK might not need all of them. You have to be able to tell when your "hands" have encountered a surface, rather than have them sink into it; so they have to be able to tell that a solid (or liquid) surface is there. You probably have to be able to tell how much resistance is being given to the force you're applying. But you may not need to be able to judge textures by sliding your "fingertip" along a surface, or read Braille telekinetically (though now I think of it, that's kind of a neat image). Imagine a robot with "fingers" whose interiors contain very sensitive strain gauges, so it can apply very precisely measured force—pick up an egg without breaking it, for example—but it has no cutaneous receptors that can feel the smoothness of eggshell.

* Can you reach inside a solid object and manipulate its interior? The idea that TK miraculously aids lockpicking seems to suggest this. If you just had four hands instead of two, it wouldn't be such a big deal.

* What about this? TK does give you tactile feedback. But normal use of it is visually guided, just as normal use of hands is visually guided. To use it nonvisually, you need to buy "Work by Touch" as a technique, and it's a different technique for TK than for your hands.

This is indeed what I've always assumed, yes.

It occured to me, however, that instead of buying Work By Touch for multiple skills, at some point, Sensitive Touch that worked with Telekinesis would be simpler and cheaper.

[whswhs]

Originally Posted by Icelander

It occured to me, however, that instead of buying Work By Touch for multiple skills, at some point, Sensitive Touch that worked with Telekinesis would be simpler and cheaper.

In fact, it becomes cheaper at two skills, if you assume the standard cost, or three skills, if you charge extra for being usable at range.

I would say, though, that you could plausibly have Sensitive Touch for TK without having the extra nerve endings to give it to you for your body (perhaps by mentally shrinking your TK "hands"; and you might be able to have it in your body without having it in your TK "hands." These are two different sets of manipulators, after all. I'd call +50% for the Telekinetic modifier on Sensitive Touch, which would make it work for TK hands instead of physical hands. At that point you avoid Work by Touch penalties for a potentially unlimited range of skills.

Another option, though, is to buy Talent for TK. Surely that ought to compensate for working by touch! And if you take the maximum 20 points, you have only a -1 penalty for working blind, and you get a lot of other benefits.

[johndallman]

I mistakenly wrote up Sensitive Touch myself for Advantage of the Week. I might as well post it here:

Sensitive Touch [10] is an exotic physical advantage. Your fingertips, or whatever you use for your sense of touch, are extremely sensitive, allowing you to sense things that are impossible for ordinary people. This advantage first appeared in GURPS Aliens for 3e.

This advantage gives you +4 to any task that uses the sense of touch, in addition to any bonuses for Acute Touch, and if you’re buying this, Acute Touch is only 2/level. This might, for example, let you feel the texture of leather precisely enough to tell if two pieces are from the same kind of animal (Forensics, without using a microscope), or detect small seeds hiden in the lining of clothes during while patting someone down with Search. It also lets you perceive things that normal people can’t, such as warmth in a chair after it’s cooled to room temperature as far as normal touch can tell, or vibrations in the floor from someone approaching, before any normal person can sense them by touch or sound.

There are real creatures that have this advantage, such as star-nosed moles, who are obviously a creation of Lovecraft’s Elder Things. It’s recommended for burrowing creatures that live entirely underground, who tend to have limited or no vision. Bio-Tech offers engineered Sensitive Touch at TL10, while DF3 The Next Level offers it as an option for Thieves, although DF Denizens: Thieves withdraws the offer for many of its variant thief templates. Powers adds a couple of enhancements: Stethoscopic (+50%) lets you hear sounds by touch and Ultra-Fine (+30%) lets you read print or computer screens by touch. Enhanced Senses classifies Sensitive Touch as a discriminatory imaging sense, lets it eliminate skill penalties for working by touch, and offers an enhancement for sensing microscopic objects. The Weird uses it in manipulation abilities that are quite strange, and Social Engineering gives a bonus to Body Language, if you’re in direct contact.

I’ve never seen this advantage in play, although I’m interested now that I’ve reviewed it. My sight is poor enough that I seem to use hearing and touch a little more than most people: I think I could play this.

[Pursuivant]

Sensitive Touch is a fun "primary sense" advantage if you want to play a very different sort of alien. Add Acute Touch and Vibration Sense for the full Tactile Sensorium.

I believe that a limited form of Sensitive Touch is used to model vibrissae. It's definitely handy if you're a blind or dark-adapted creature.

[whswhs]

Originally Posted by Pursuivant

Sensitive Touch is a fun "primary sense" advantage if you want to play a very different sort of alien. Add Acute Touch and Vibration Sense for the full Tactile Sensorium.

I believe that a limited form of Sensitive Touch is used to model vibrissae. It's definitely handy if you're a blind or dark-adapted creature.

I think of vibrissae more as a limited version of Vibration Sense.

[Otaku]

Originally Posted by johndallman

I mistakenly wrote up Sensitive Touch myself for Advantage of the Week. I might as well post it here...

Your writeup is nice and concise; I was going to edit it in front of my own in the first post... but doing so caused the opening post to exceed the character limit. By almost exactly what I was adding, so apparently I took it to the limit when I made my own. XP

[Varyon]

Sensitive Touch is also one of the notable features of the Fobott'r species in Schlock Mercenary. They even have a language, called Gripspeak, that lets them communicate entirely by touch, which makes it functionally impossible to intercept (I suspect an advanced AI watching from multiple viewpoints in multiple spectra could figure out what they were "saying").