Perception

Description

Ability Score Used:	Wisdom
Usable Untrained?	Yes
Armor Check Penalty Applies?	No

Your senses allow you to notice fine details and alert you to danger. Perception is the skill of using those senses to their maximum effect, keenly finding the minute details that others miss. Perception covers all five senses, including sight, hearing, touch, taste, and smell.

Passive Perception

All creatures have a passive perception, which is equal to their perception skill's total bonus plus 10. Passive perception is always on (unless you are unconscious or your senses are somehow impaired), and is a free action to use. This is the equivalent of taking 10, except that it can be used at any time, even during combat. Passive perception has a number of drawbacks, due to the fact that you're not really looking around terribly hard, or truly prepared for surprises or danger. For example, invisible creatures, generic disguises, and traps cannot be detected with passive perception checks at all. Passive perception is subject to the same modifiers as a spot action (below), due to distance, poor lighting, etc.
Action Required:	Free action
DC of Check:	There are too many different uses for passive perception to list every possible DC here. Instead, the following list provides example DC's for various checks, ranging from very easy to very difficult. Very Obvious: To notice very obvious things, like the sound of battle, or the stench of rotting garbage, the DC is -10 Obvious: To detect fairly obvious things, like the smell of smoke, or a visible creature, the DC is 0 Noticeable: To observe the noticable, such as whether food is spoiled, the DC is 5 Subtle: To notice subtle things, such as hearing the sound of a creature walking, the DC is 10 Difficult: To notice more difficult things, such as hearing the details of a whispered conversation, the DC is 15 Very Faint: To notice very faint things, such as the sound of a key being turned in a lock, the DC is 20 Very Difficult: To notice very difficult things, such as hearing a bow being drawn, or sensing a burrowing creature underneath you, the DC is 25 What's Notable? To attempt to spot points of interest in an area, the DC is usually an Average DC for area's CR Noticing a Pickpocket: To notice a pickpocket, the DC is target's Sleight of Hand result Notice a Disguise: To passively notice a generic disguise is not possible, you must make a Spot check and expend an action. To passively notice a specifically disguised creature, the DC is target's Disguise result Notice Stealthed Creature: To passively notice a creature using stealth is not possible, you must make a Spot check and expend an action. Notice Non-Stealthed, Invisible Creature: To passively notice a non-stealthed, invisible creature is not possible, you must make a Spot check and expend an action. Notice Trap: To passively find a hidden trap is not possible, you must make a Spot check and expend an action.
Modifiers to Check	Distance to target: distance between you and the thing you are attempting to perceive increases the DC by +1 per 10 feet. Through a door: if the thing you are attempting to perceive is behind a closed door, the DC is increased by +5. Through a wall: if the thing you are attempting to perceive is through a wall, the DC is increased by +10 per foot of thickness. Favorable conditions: If the surrounding environment is particularly conducive to the sense you are using, such as bright light when using sight, or listening to sounds underwater, etc., the DC is decreased by -2. Unfavorable conditions: If the surrounding environment is not very conducive to the sense you are using, such as dim light when using (normal) sight, light misty rain falling, background noise while trying to listen to something, etc., the DC is increased by +2. Terrible conditions: If the surrounding environment is extremely bad for the sense you are using, such as being amidst overpowering stench while trying to smell something specific, or trying to eavesdrop on a whispered conversation while a bard plays a trumpet next to your table, etc., the DC is increased by +5. Distracted: If you are doing something else, such as reading or holding a deep conversation, the DC is increased by +5. Asleep: If you are asleep, the DC is increased by +10.
Take 10? / Take 20?	No (you are effectively already taking 10)
Allows Assists?	No. Allies can never assist someone who is taking 10.
Results of Success	You become aware of the stimulus which triggered the passive perception check.
Consequences of Failure	You fail to notice anything out of the ordinary.
Retry Allowed?	No, though you can attempt a spot check by using an action
Provokes AOO?	No

Spot

Perception can also be used actively, representing your character taking a moment to really look around, search for particular things, or generally be hyper-aware of their surroundings. A very common use of the spot action is to oppose an opponent's Stealth. If you are successful, you notice the opponent and can react accordingly. If you fail, your opponent can take a variety of actions, including sneaking past you or making an attack against your flat-footed AC. You can also use a spot action to quickly look around you for interesting or noteworthy details in your surroundings. This is not sufficient to actually locate the mechanism to open a secret door, but it is enough to let you know that there is something funny about the way that wall looks, and you might want to go look at it more closely. Finally, you can use a spot action to try to notice a trap before you set it off. Finding a trap requires you to be adjacent to the square you are checking for traps (unless there are feats, abilities, magic items, etc which modify that task). The difference between a spot action and a search action is that spot actions are intended to be quick, focused looks around, while a search is a more careful, methodical examination of an area or object. Spot actions are generally done in combat, and search actions are generally done out of combat, though there is no rule preventing either from being used at any time. In general, a spot action is used when you want to become alerted to a particular stimulus or circumstance, while a search action is used to carefully review and learn the details of something.
Action Required:	Move action
DC of Check:	There are too many different uses for a spot action to list every possible DC here. Instead, the following list provides example DC's for various spot checks, ranging from very easy to very difficult. Very Obvious: To notice very obvious things, like the sound of battle, or the stench of rotting garbage, the DC is -10 Obvious: To detect fairly obvious things, like the smell of smoke, or a visible creature, the DC is 0 Noticeable: To observe the noticable, such as whether food is spoiled, the DC is 5 Subtle: To notice subtle things, such as hearing the sound of a creature walking, the DC is 10 Difficult: To notice more difficult things, such as hearing the details of a whispered conversation, the DC is 15 Very Faint: To notice very faint things, such as the sound of a key being turned in a lock, the DC is 20 Very Difficult: To notice very difficult things, such as hearing a bow being drawn, or sensing a burrowing creature underneath you, the DC is 25 What's Notable? To attempt to spot points of interest in an area, the DC is usually an Average DC for area's CR Noticing a Pickpocket: To notice a pickpocket, the DC is target's Sleight of Hand result Notice a Disguise: To notice a disguised creature, the DC is target's Disguise result Notice Stealthed Creature: To notice a creature using stealth, the DC is target's Stealth result Notice Non-Stealthed, Invisible Creature: To notice a non-stealthed, invisible creature, the DC is an Average DC for the target's CR Notice Trap: To find a hidden trap, the DC varies by trap, but usually a Challenging DC for campaign level
Modifiers to Check	Distance to target: distance between you and the thing you are attempting to perceive increases the DC by +1 per 10 feet. Through a door: if the thing you are attempting to perceive is behind a closed door, the DC is increased by +5. Through a wall: if the thing you are attempting to perceive is through a wall, the DC is increased by +10 per foot of thickness. Favorable conditions: If the surrounding environment is particularly conducive to the sense you are using, such as bright light when using sight, or listening to sounds underwater, etc., the DC is decreased by -2. Unfavorable conditions: If the surrounding environment is not very conducive to the sense you are using, such as dim light when using (normal) sight, light misty rain falling, background noise while trying to listen to something, etc., the DC is increased by +2. Terrible conditions: If the surrounding environment is extremely bad for the sense you are using, such as being amidst overpowering stench while trying to smell something specific, or trying to eavesdrop on a whispered conversation while a bard plays a trumpet next to your table, etc., the DC is increased by +5. Distracted: If you are doing something else, such as reading or engaged in a deep conversation, you normally cannot make a spot check. You must instead rely on your passive perception to notice things going on nearby. Asleep: If you are asleep, you cannot make a spot check. You must instead rely on your passive perception to notice things going on nearby. (Epic Only) Sense Magic: If you have at least 21 ranks in perception, you can attempt to notice the presence of an active magical effect in your area by adding +50 to the DC. This does not allow you to know which square the effect is in, merely its presence in the room.
Take 10? / Take 20?	You can take 10 as long as you are not in combat. You can take 20 as long as the stimulus is present for at least the next 20 rounds.
Allows Assists?	No. Having friends nearby does not help, although if they notice something with a separate roll, they may certainly point it out to you.
Results of Success	You notice the stimulus in question and may take actions based upon it.
Consequences of Failure	You do not notice the stimulus in question and may not take actions based upon it.
Retry Allowed?	Special. If the stimulus is fleeting, then if you miss it, it is gone. If the stimulus is ongoing (a faint humming in the air, for example) you may retry up to once per round you are exposed to the stimulus.
Provokes AOO?	No.

Search

Perception can be used to more thoroughly scour an area for details or information. Most commonly, characters will search an area to find treasure, hidden doors or compartments, or find some specific thing within the midst of a mess of other things (the classic needle in a haystack). Search checks take considerably longer than spot checks, but they can still be performed during combat, if you feel a need to do so. You must be adjacent to the square (or squares) you are searching, even if this means you have to move around to complete your search.
Action Required:	Standard action per 5 foot square searched.
DC of Check:	Simple Concealed Door: To recognize the presence of, and identify the mechanism for opening, a simple concealed door, the DC is an Easy DC for the CR of the area. Average Concealed Door: To recognize the presence of, and identify the mechanism for opening, a average concealed door, the DC is an Average DC for the CR of the area. Good Concealed Door: To recognize the presence of, and identify the mechanism for opening, a good concealed door, the DC is an Challenging DC for the CR of the area. Superior Concealed Door: To recognize the presence of, and identify the mechanism for opening, a superior concealed door, the DC is an Hard DC for the CR of the area. Peerless Concealed Door: To recognize the presence of, and identify the mechanism for opening, a peerless concealed door, the DC is an Impossible DC for the CR of the area. Identify Potion: To identify the powers of a potion through taste, the DC is 10 + 2 x the potion's caster level Listen Carefully: To hear the details of a conversation, the DC is 0 Food Tester: To notice the taste or smell of poison in food or drink, the DC is 35 (Epic only) Notice magically concealed object: If you have at least 21 ranks in perception, you can attempt to notice the presence of an inanimate, unmoving, invisible object, by adding +40 to the DC. This does not allow you to know which square the effect is in, merely its presence in the room. (Epic Only) Pinpoint magically concealed object: If you have at least 21 ranks in perception, you can attempt to pinpoint the exact square of an inanimate, unmoving, invisible object, by adding +50 to the DC. Miss chance still applies.
Modifiers to Check	Bigger Than You: For each size category larger than you the object you are trying to locate is, the DC is decreased by -2 (cumulatively). Smaller Than You: For each category smaller than you the object you are trying to locate is, the DC is increased by +2 (cumulatively). Low Contrast: If the object you are searching for is mixed in with very similar objects (e.g. trying to find a particular statue among hundreds of other statues), the DC is increased by +5. High Contrast: If the object you are searching for is very different from the other objects around it (e.g. finding a dagger in the midst of a barrel of salt), the DC is reduced by -5.
Take 10? / Take 20?	Yes
Allows Assists?	Yes (up to 5 allies).
Results of Success	You locate the object(s) you are searching for.
Consequences of Failure	You fail to find the object(s) you are searching for.
Retry Allowed?	Yes
Provokes AOO?	Yes