[Basic] Advantage of the Week (#4): Acute Senses
 

Last Week: Absolute Timing; Chronolocation
Next Week: Affliction

This week we'll be covering Acute Senses (Basic p. 35), though there will be heavy referencing of the Discriminatory Senses (Basic p.48) and Sensitive Touch (Basic p.83) Advantages; I vacillated between whether to cover them all at once or restrain myself and wait until later. In particular, there was some specific rules text that influenced me:

Combined with the way the Advantages work suggests to me that ultimately Acute Senses and Discriminatory Senses may best be thought of as some multifaceted, multi-tiered "thing": the former provides simple bonuses while the latter also provides bonuses because it takes the underlying sense to its next logical level.

Acute Senses represents superior senses compared to the norm, so each level grants +1 for all Sense rolls you make that pertain to that Sense. Skills that rely heavily on a specific sense will also gain a similar bonus. In most ways an Acute Sense functions as an extremely limited, improved Perception score for that specific sense. Back in 3e, Acute Senses were capped at 5 levels: I was unable to find such a rule for 4e but have a vague memory that could be based on 3e or could simply mean I embarrassingly and repeatedly kept overlooking it in my searching. You can buy an Acute Sense for any of the major human senses, and if a character possesses a non-standard sense (like Vibration Sense), with GM permission one can purchase the Advantage for that sense as well.

All Acute Senses have the same 2 points/level cost structure, and unless it involves an already Exotic or Supernatural Advantage, is Mundane. The four generic Acute Senses are:

• Acute Hearing
• Acute Taste and Smell
• Acute Touch
• Acute Vision

Of note, there is no distinction between primary, secondary or tertiary senses. Impairment of any of these senses is a Disadvantage, but the values are diverse: total Blindness (Basic p.124) is a -50 point Disadvantage while complete Deafness (Basic p.129) is valued at -20, No Sense of Smell (Basic p.146) is only worth -5 and Numb (also Basic p.146) is worth -20.

Similarly, the value of Discriminatory Senses (of which I would include Sensitive Touch as it provides similar bonuses for the sense of Touch as the others do for their respective senses) also vary, though significantly less. Discriminatory Hearing costs 15 points. Taste and smell are bundled together for Acute Senses but separate in this more advanced state: Discriminatory Smell is also worth 15 points while Discriminatory Taste is only worth 10 points. Taste and smell being combined into one Acute Sense both reflects their overlap in much of biology and perhaps suggests that separated out the two wouldn't be as valuable. In some creatures there are similar overlaps between other senses: apparently "smound" is a thing for at least rodents, where sound and smell are blended together in perception.

Sensitive Touch, as stated above, aligns with the Discriminatory "Sense" model. There is no equivalent for Vision. Powers p.47 suggests Hyperspectral Vision, but that seems more in line with hearing being augmented by Subsonic Hearing and Ultrahearing. A major point is that much of what a Discriminatory Sense adds is already part of standard vision.

So let us discuss the Acute Senses. Please share experience and thoughts over them. If someone has a list of Skills enhanced by Acute Senses handy, please share them! I won't bother with excuses or explanations; I don't have such a list handy and it would be most conducive to this discussion. I am particularly interested in knowing if the experience (or analysis) of other players indicates that the Acute Senses are indeed evenly matched or if some are simply better than others despite being priced the same. How well they have performed in general is also quite pertinent; are all are some bargains or are they a waste and you should just invest in a better Perception or Skill level?

Re: [Basic] Advantage of the Week: Acute Senses
 

I don't think I've ever had a character with any Acute Senses.

I've seen another player with one, a Felicia-2 catgirl in THS, who had three different sense rolls for vision, hearing and smell, which actually slowed play owing to the potential for confusion.

Tactical Shooting made Acute Vision far more useful in several ways, and made me sorry that it can't be bought on existing characters, without special excuses. Still, there's always next time.

Re: [Basic] Advantage of the Week: Acute Senses
 

Maximum levels of Acute Senses achievable without being a freak of nature or a parahuman can be found in Bio-Tech: up to 3 levels.
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Acute Vision is a good deal. There's a PC in my campaign with several levels, and it's good. He's not trying to munchkinise it, though. I'm betting that a fully visually-oriented character can get an even better deal out of it. Of note, the following skills take vision modifiers: Body Language, Lip Reading, Search (when visually searching for something), Tracking, probably others whenever visually trying to find something important.
And Quick Contests against several skills benefit from it: Camouflage, Filch, Holdout, Invisibility Art, Shadowing, Slight of Hand, Stealth (if in FoV), Traps (if in FoV).
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One thing that often gets lost or forgotten:
That should probably help against some forms of Obscure.
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Given the fuzziness of how exactly Parabolic Hearing works, it's commonly a better deal to take Acute Hearing instead.

Re: [Basic] Advantage of the Week: Acute Senses
 

For comparison, the estimated best human visual acuity is a bit better than 20/10 (or 6/3 in metric scales). A 20/10 level lets you ignore a -2 range modifier, which I'd call Acute Vision +2; so I might go for Acute Vision +3 tops. Eagles apparently run around 20/4, which is five times range, which I'd call Acute Vision +4—not as a rare exception but as the species norm.

On the other hand, a cat's visual resolution is around a tenth as good as human, or 20/200—worse than my uncorrected right eye but better than my uncorrected left. That's probably a -6 modifier to vision. The best compound eyes around, those of dragonflies, are down around 1/40 of human acuity, which would be -9 or -10; probably the simplest way to describe that would be to say that insects don't get the +10 "plain sight" modifier for the Mark I Eyeball.

Bill Stoddard

Re: [Basic] Advantage of the Week: Acute Senses
 

That all makes sense.
There should be a limitation for spotting movement only, especially for Compound Eyes.

Re: [Basic] Advantage of the Week: Acute Senses
 

I like acute senses, but I often find myself picking and choosing which are available. Like, I don't much like acute smell/taste, as I'd rather have discriminatory smell/taste (unless we're all playing critters with that as a racial trait). Similarly, more than one and I think it's easier to simply raise perception.

So, my experience: EITHER Acute Sight OR Acute Hearing OR Perception, and never Acute Taste/Smell, only Discriminatory Smell. I also rarely bother with things like Telescopic vision or Parabolic hearing unless I'm doing something really specific.

Re: [Basic] Advantage of the Week: Acute Senses
 

You could call it Targeting Vision Only, maybe.

Expanded Arc, 360°, is +125%, and 240° is +75%; the comparable visual advantages are 25 points and 15 points. Targeting Only is -40%, which suggests that Targeting Vision Only might be -8 points.

Bill Stoddard

Re: [Basic] Advantage of the Week: Acute Senses
 

Limiting realistic levels to a specific value of Acute Sense as opposed to a specific value of sense roll always bothered me. Why is IQ 12, Acute Vision +2 realistic, where IQ 10, Acute Vision +4 not?

Re: [Basic] Advantage of the Week: Acute Senses
 

I have used Acute Smell for tracker types but yeah, most of the time I will go for Alertness/Perception unless its just bumping up 1 sense for concept.
Racial templates are where I see these used the most.
I disagree with you on Telescopic though, its great for snipers, spies, etc. Especially in a low tech game where you may not have gear to do it.

Re: [Basic] Advantage of the Week: Acute Senses
 

Sensing vs. Perceiving. Different processes.

Re: [Basic] Advantage of the Week: Acute Senses
 

Thank you.

Re: [Basic] Advantage of the Week: Acute Senses
 

I'm not saying that they're not great. They all have their uses. But I don't want to juggle Acute Vision +2, Telescopic Vision 1, Parabolic hearing 2, Acute Hearing +3, and so on. So I tend to pick and choose and stick with them. Except on racial templates, where I agree with you (there it's okay to start to introduce weird concepts, because a racial template is the perfect place for something like that).

Part of the problem is that there really aren't many counter-parts to these. Things like Bad Sight are really big and chunky, as opposed to Acute Vision's fine gradations. The result isn't you can't really fine tune a specific set of senses. Thus, I see people muck about with Perception more than anything else.

Re: [Basic] Advantage of the Week: Acute Senses
 

Because the IQ 10 doesn't really see less than the IQ 12 other things being equal. It's just not as good at figuring out what it is that it is seeing

Re: [Basic] Advantage of the Week: Acute Senses
 

Really, part of this is a convention of heroic fiction. GURPS says that a spider has IQ 1, a lizard has IQ 2, a dog has IQ 4, a baboon has IQ 5, and a chimpanzee has IQ 6—and a man can have IQ from 6 up to 20. Why the huge variation? Because people don't want to play characters who all have species-normal IQ, or even characters limited to ±1.

In the same way, we have body weight varying as the cube of ST for animals—so an ST 5 cat weights 16 pounds, and an ST 22 horse weights 1330 pounds—but an ST 20 man doesn't weigh half a ton!

GURPS allows human traits to vary widely, but maps animal traits onto the same scale, with human beings falling onto it around a score of 10. But the numbers aren't really measuring the same things.

Bill Stoddard

Re: [Basic] Advantage of the Week: Acute Senses
 

It ought to be IQ that scales broadly. 10 average men can drag a weight or dig a hole as well as the strongest man, but a million ordinary persons working day and night couldn't solve, for example, the Poincare Conjecture.

Re: [Basic] Advantage of the Week: Acute Senses
 

Could you explain the difference? It seems to me that the human eye can either see something or it can't.

Re: [Basic] Advantage of the Week: Acute Senses
 

You have sensory organs which register triggers (e.g. photons falling onto the retina) and send impulses to the brain; you sense brightness, or a sound, or a warm touch. You perceive as the brain interprets the signals into something meaningful - you perceive the sun, a melody, a hug.

Re: [Basic] Advantage of the Week: Acute Senses
 

Or more to the point, two people can look at the same clump of bushes, but only one of them see the machine gun position hidden in it.

Re: [Basic] Advantage of the Week: Acute Senses
 

But the human eye's resolution is limited. The way GURPS represents that is with your Vision sense--whatever that number is. I haven't done the math on it, so I don't know what the limit is, but I don't see how it makes sense to say that a person can "perceive" things at resolutions no human eye can detect. Perceptive ability of the brain isn't what's in question here. If you have two men stand next to each other, and move back away from them, eventually you (and anyone else with a human eye) will no longer be able to discern how many men are there, and that's because of how the eye works, rather than your brain's perceptive ability.

Re: [Basic] Advantage of the Week: Acute Senses
 

People tend to fail to perceive something way earlier than they stop sensing it.

Re: [Basic] Advantage of the Week: Acute Senses
 

Just because seeing the last few posts reminded me: Basic p.258 explains comprehension rolls, which are against IQ and not Perception and rolled to check against the significance of something you've noticed; you see the rabbit running from the bushes you're investigating, but you need the Comprehension Roll to realize that even though its summer said rabbit has a white winter coat, suggesting it isn't just a wild one.

Perception for a human can be bought up to 20 or lowered down to 4 according to Basic p.16. The bonus from Acute Vision I take it is just representing better-than-normal eyes... but what about people that are just good at Perception with a specific sense? It might be excessive detail, but what about levels of Perception with a "One Sense Only" Limitation (-60%). Yes, priced that way so that its 2 points per level like an Acute Sense; the difference is that it just makes a decent stepping stone for buying up Perception. Probably not needed, but does that look like it would cause problems somehow?

Re: [Basic] Advantage of the Week: Acute Senses
 

So how do you represent the difference, and how do you make sure people can't sense things outside what is physically possible? How do we mechanically represent the resolution limits of human sight, hearing, smell, proprioception, etc.? Can someone with Perception 15 and Acute Vision 2 see things the human eye can't physically see? What's going on there?

Re: [Basic] Advantage of the Week: Acute Senses
 

I look at it a bit differently. To me it seems that Acute Vision is Perception (One Sense Only, Vision, -60%) and is, in effect, a general enhancement of (visual) perception overall.

You really can't do much to boost visual acuity overall past human limits; the human fovea has single neurons as close together as is physically workable for light of visible wavelengths—reduce the diameter and the efficiency falls off catastrophically. Birds of prey do some tricks with ocular geometry, but a lot of what they have is just several levels of Telescopic Vision, which is a change in the physical optics of the lens. Similarly, Night Vision is going to represent changes in the efficiency with which the eye gathers photons, whether because of bigger eyes, wider aperture, or enhanced pooling of retinal responses (or reflective back layers like those in a cat's eyes). Or you could add pigments for UV or near IR or the ability to discriminate which way light is polarized.

This shows up better for the other senses, where for example having more densely innervated tactile receptors is Sensitive Touch, but keener tactile perception is Acute Touch.

Bill Stoddard

Re: [Basic] Advantage of the Week: Acute Senses
 

GURPS says that when you are looking for something in plain sight, you get +10 to Perception. But if you look at an eye test, the definition of 20/20 vision works out to 1 minute of arc resolution, which is 0.2 inches at 20 yards or 0.07 inches at 20 feet; that's about -3 for range and -18 for size, for a net -21! Of course you aren't trying to find the eye chart; you already know where it is, and you're trying to see the letters clearly. If you double the bonus for zooming in, to +20, on the model of Telescopic Vision, that gives you a net -1; if you say that Per 11 equals 20/20 vision you're going to have a 50% chance of reading the chart.

Bill Stoddard

Re: [Basic] Advantage of the Week: Acute Senses
 

Your vision score reflects your ability to get visual data into your head in such a way that you consciously notice the interesting things, not just the quality of your optics. Someone who notices Sir_Pudding's machinegunner in a bush may have more physically perfect eyes, but more likely he's just more observant: the data analysis software in his head works better.

(Aside: he may also have noticed the machinegunner because he knew to look for it... which could be represented by successful complementary rolls against Tactics or Soldier adding bonuses to vision... which would give players damn good incentive to make sure their characters have those skills! But I leave this, and its variants and implications, as an exercise for the reader.)

Why can you have a guy with IQ 12 and Acute Vision 2, but not a guy with IQ 10 and Acute Vision 4? IMO, you probably could; I would totally buy a fictional character who's not particularly bright but has (metaphorical) eyes like a hawk and spots things that others might not. The limit is more (IMO) to give GMs a guideline as to what's "realistic" for humans so that they're not going "hmm, how much acute vision should my upgraded human template have? 2? 5? I have no idea!" (That it's in Biotech especially makes me think this.) That, and when the guy whose PC already has IQ 15 wants to buy Acute Vision 8, the GM won't feel so arbitrary saying no.

Re: [Basic] Advantage of the Week: Acute Senses
 

Glad someone posted the Bio-Tech rule; as I've mentioned I am not actually able to play right now (very slowly getting ready to run a beginner adventure where I am the GM; pity those players) but since I have to do it online and other stuff keeps coming up... like I said, very slowly. So when I've been practicing and building guys, at least for PCs I am used to my old S.O.P. procedure from 3e: unless you absolutely need to squeeze out the points for something else, you just take Acute [Sense]+5 for 10 points for whatever compliments the character most.

So now I'll dial it back, but I still am wondering what Acute Vision is supposed to represent. I assumed it was mostly physiological, hence being required at Character Creation; this is the trait that represents superior eyesight (literally "superior sense" in RAW). Having the cognition/training/etc. to notice things better is Perception, which can be bought after character creation. Oh well, most of my characters seem to favor high PER scores anyway, so I can probably just put the points towards that.

Re: [Basic] Advantage of the Week: Acute Senses
 

An example of that is Robert Evans an amateur astronomer who found something like 50 supernovae. I can't quiet remember the quote from his mention in Bill Bryson's "a short history of nearly everything" but it was along the lines of "scatter salt over 100 tables, now add one grain and Mr Evans could spot it"

Re: [Basic] Advantage of the Week: Acute Senses
 

The US Armed Forces did a lot of research into this in order to improve their reconnaissance. One result of their research was discovering how much resolution is necessary to do more than just spot something. For example, to be able to spot something, a soldier would need it to span at least three "TV lines", which are equivalent to the resolution; at an acuity of 1.0 (20/20), this is 3 arcminutes. At an acuity of 2.0 (20/10), this is 1.5 arcminutes.

To tell which direction something is pointing in, you need 1.4 times the resolution. To tell what something is in general terms ("that's a person","that's a truck", "that's a tank", etc.), you need 4 times the resolution. To identify it fully ("that's a soldier holding a machine gun", "that's an Ural-4320", "that's a T-72", etc.) you need 6.4 times the resolution.

Using the Speed/Range table, determining orientation is -0, recognizing what kind of thing it is is -2, and identifying it is -3.

Re: [Basic] Advantage of the Week: Acute Senses
 

There is a skill to perceiving with limited sensory information.
As my visual acuity gets worse, I have adapted to maintain my official corrected vision test results. General poor vision, not just near sightedness.

Re: [Basic] Advantage of the Week: Acute Senses
 

Yes, that's what makes Sherlock Holme stand out. His ears aren't orders of magnitude keener than the ears of the average person. Nor his eyes, or his nose. But he is almost always aware of everything his senses attempt to convey to his brain, whereas you, and I, and most other people, filter most of that away.

Re: [Basic] Advantage of the Week: Acute Senses
 

I don't know that it's possible to simulate such distinctions in GURPS. You cannot have the situation where a cinematically perceptive Sherlock Holmes is unable (zero chance) to perceive, because it is absolutely below his threshold of sensory perception, but which a very keen-nosed blood hound can perceive (and may in fact have a very high probability of perceiving).

That's due to having everything on the same linear scale, the roll and the sensory acuity. Most RPG systems do it that way, if they even allow for differentiated senses (some just have a single Perception attribute of skill, and allow for no embellishments).

Re: [Basic] Advantage of the Week: Acute Senses
 

BTW, anyone paid any attention to / had experience with the option of buying Acute Sense for more inhuman senses: Scanning Sense, Vibration Sense, Detect?

Re: [Basic] Advantage of the Week: Acute Senses
 

It seems an obvious thing to me to do. Anything that's sense-like ought to be able to be made more Acute. I'd immediately fire a GM who said "no" to such a suggestion. No mercy, no second chances, fired!

The only argument against it is that in some cases 2 CP/lvl might be too expensive, e.g. for a 10 CP Detect. In some cases it might be better to use an Enhancement. But that's not the same as saying "no".

Re: [Basic] Advantage of the Week: Acute Senses
 

I once zapped past a TV docu which seemed to feature an astronomer with unusually good eyesight. I even vaguely seem to recall that he may have had an unusual eye anatomy, with some blood vessels being placed behind his retina instead of in front of it as with normal people. Although that does sound rather extreme. And it was shown on the Discovery Channel, which isn't always as editorially selective as, e.g., DR K or DR2.

Re: [Basic] Advantage of the Week: Acute Senses
 

The thing to use for that is the Reliable enhancement, which gives +1 to the roll for +5% cost (Power-Ups 4). I think this is what you use for anything where you're buying a complete ability, rather than improving a sense that you have by default.

Re: [Basic] Advantage of the Week: Acute Senses
 

Well, yes, that's what I'd assume too, but I don't see anything particularly wrong with the GM instead insisting on 2 CP/lvl for Acute Danger Sense or the like, functioning as a sub-attribute of PR, similar to Acute Vision.

On something like Detect (Gold) from DF3, which IIRC is base cost 10 CP, paying 20% extra per +1 to effective PR is rather expensive, but it's only objectively wrong if the GM says "no" and completely refuse the player to make the better.

Re: [Basic] Advantage of the Week: Acute Senses
 

I don't think that Reliable quite fits in this case. It would kind of work for a system that performs one invariant function, like a burglar alarm, where the issue is "do you or don't you notice the little man behind the curtain." And that would suit, for example, Detect Gold or Detect Poison or Detect Intruders. But full-on Detect can give you not just presence, but intensity/amount, direction, possibly distance, and kind and composition. Calling all that "reliable" strikes me as a bit much.

And for Scanning Sense, of course, there's also the ability to measure speed and direction of motion.

What I'd do is have Acute Detection, Acute Scanning, and Acute Vibration Sense, I think, at 2/level. Maybe Scanning could be split up into Radar, Ladar, Sonar, Para-Radar, and so on.

Bill Stoddard

Re: [Basic] Advantage of the Week: Acute Senses
 

By and large, we don't don't care about the range in variation between my exceptionally smart cat and my cat that kept forgetting how to stay out of traffic so that my exceptionally smart cat had to go out and keep rescuing him. It's not that the variation isn't there.

Re: [Basic] Advantage of the Week: Acute Senses
 

If people were going to play cats more often we'd want rules for that sort of thing. Or bunnies. . . .

Bill Stoddard

Re: [Basic] Advantage of the Week: Acute Senses
 

In particular, if people were going to play cats or bunnies of realistic intelligence rather than boosting them to human range.