[Basic] Advantage of the Week: Acute Senses

[corwyn]

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?

[vicky_molokh]

Originally Posted by corwyn

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?

Sensing vs. Perceiving. Different processes.

[ErhnamDJ]

Originally Posted by vicky_molokh

Sensing vs. Perceiving. Different processes.

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

[vicky_molokh]

Originally Posted by ErhnamDJ

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

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.

[sir_pudding]

Originally Posted by vicky_molokh

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.

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.

[ErhnamDJ]

Originally Posted by sir_pudding

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.

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.

[vicky_molokh]

Originally Posted by ErhnamDJ

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.

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

[whswhs]

Originally Posted by ErhnamDJ

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.

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

[Otaku]

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?

[whswhs]

Originally Posted by Otaku

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?

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