[NineDaysDead]

Originally Posted by whswhs

Since Perception can be bought up and down, it makes sense to say that Acute Hearing is Perception (Hearing only, -60%); and then Less Acute Hearing would be figured the same way.

From the thread "Opposite of Acute Senses"

Originally Posted by Kromm

GURPS doesn't do two things:

1. Flip signs to turn advantages into disadvantages. Something costing N points for +1 doesn't always imply that -1 is worth -N points as a disad. If that something is of near-global importance, like DX, it works that way. However, if it's a rather narrower consideration that you could build your entire character never to need, the disad is diluted or even forbidden. The reason for this decision was mainly to make life hard for "degenerate" characters, like some cold killer who gets oodles of points for gross social incompetence and not getting along with animals, which he then plows into combat skills that the player fully intends to use to kill people and animals rather than interact with them peacefully. In other words, we acknowledge that players tend to stack the deck to get lots out of their PCs' positive traits while doing their worst to avoid ever actually suffering from their negative ones.

2. Say that +1 or -1 to N things is worth N times more than +1 or -1 to just one of those N things. Look at DX vs. all DX-based skills, or just at how Detect casts its net wider and wider. There are no "package discounts" for templates, but many advantages and disadvantages can't be decomposed into parts whose values add up to the master trait's overall value; Detect (one of Ghosts, Liches, Vampires, Zombies, etc.) is 5 points, while Detect (Undead) is 10 points, not 20+ points. The reason for this decision was to group like with like at a decent price so that sharply defined characters were easier to create than generalists with a gift for "all the cool stuff I want, minus the stuff I think is lame and don't want, even though that would logically come along for the ride."

Both are, in essence, design-level attempts to thwart dodgy character design.

Fromm a different thread

Originally Posted by Kromm

Someone with low Per isn't identical to someone whose Sense rolls are equally low due to specific sensory disadvantages. All people who lack Blindness, Bad Sight, or Acute Vision see equally well in GURPS, regardless of Per. All people without Deafness, Hard of Hearing, or Acute Hearing hear equally well in GURPS, regardless of Per. And so on. Per isn't a bulk-rate way to buy these specialized traits. There's a quantitative similarity in the area of Sense rolls, but not everything hinges on a Sense roll. There's a massive and very important qualitative difference; for instance, Bad Sight gives direct combat penalties while low Per does not.

What Per does is determine how likely your innate curiosity and pattern-recognition abilities are to cue on something of importance. It's a specialized mental capacity, which is why it's derived from IQ. Low Per doesn't prevent you from seeing or hearing combat threats that are right in your face. A guy with Per 6 has better active defense rolls against such dangers than one with Per 16 and Bad Sight. Where a threat is immediate and a split-second reaction is required, the signal bypasses this processing step (i.e., the Per roll) and reflexes kick in. All that matters is whether the signal went out, and that's limited purely by your eyesight, hearing, etc., as implemented through the special penalties for disadvantages like Bad Sight.

Where low Per does matter is when the reaction isn't split-second but considered. You want to look carefully at the enemy's sword to see poison? That's Per at work. You want to notice some sneaky guy circling the fight? That's his Stealth vs. Per at work. Your Bad Sight or Acute Vision will play a role here, too, of course.

But the real limit of low Per is all of the out-of-combat rolls it hurts. Just about all adventures involve espionage, investigation, loot-finding, scouting, survival, and the like. With low Per, many important skills needed for that – Detect Lies, Lip Reading, Observation, Scrounging, Search, Survival, Tracking, etc. – are crippled. The Per-based use of vital threat-finding skills like Explosives, Poisons, and Traps is also affected. For all intents and purposes, a low-Per character won't be finding camouflaged traps, concealed snipers, hidden loot, secret doors, etc. He'll be stepping on land mines and eating poisonous berries all the time. And he'll be worthless for standing a watch, taking point, or guarding the rear.

Remember that combat always occurs in a context. It isn't just "all these threats appear at arm's reach and you start fighting." Every enemy who beats your Per with Camouflage or Stealth gets at least one free shot at you from a doorway or up a tree. If the fight is on prepared ground, you'll end up stepping on a lot of punji stakes . . . indeed, you might trip mines in some settings, which won't help your friends any. And it can be important to spot the concealed pistol before you decide to punch some guy – or to notice who has the poisoned knife once the violence starts.