So I'm a bit confused about just how perception works to find traps.

Here's a few examples to illustrate my confusion;

  1. The PCs enter a room and all roll perception checks just to search the room. Maybe they find some coins, etc. Assuming they get a high enough roll, would they find a trap with this kind of check, or would they have to do a separate Perception check to "find traps?" My confusion with this point comes from skills like survival which actually have a different use and you have to specify what use you are going to roll. Does perception just notice anything at all that is within the roll or are there also different uses?

    The same for secret doors, do they pop all out of the same perception check?

  2. Do they have to be within a certain proximity? Does the trap have to be within a certain range for them to find it?


Actively looking for a trap or secret door is a separate actively requested move action and not part of the general reactive Perception check you get for just looking around.

Please note as proof the Trap Spotter rogue talent, which specifically allows you to notice traps using Perception without actively looking. Without the talent, that doesn't happen. Note also that the section on secret doors says you have to be examining to find them. The Perception skill makes a somewhat-hazy distinction between just looking around and specifically examining - "Most Perception checks are reactive, made in response to observable stimulus. Intentionally searching for stimulus is a move action." Some of the understanding of this is from 3e, which had Spot and Search as separate skills, and it was Search that found secret doors and traps. They combined them in Pathfinder for simplicity but with the expectation that "passive perception" and "actively looking" were two different things.

It doesn't specify "how close to the trap" you have to be to find and/or disable it, but the general understanding is "not so close you're setting it off, but adjacent to that."


All traps should have their own DC of being perceived. After that, the DC increases by 1 for every 10 feat. Please note that mXyzplk slightly misrepresented the trap spotter rogue talent. Anyone can (and should sometimes) notice traps when not looking. Rogues specifically get to roll (via the DM doing it without the party's knowledge) when they reach within 10' of the trap--the optimal distance for perceiving it without distance increasing the DC.

"Most perception checks are reactive, made in response to observable stimulus." Unless your characters are literally walking around with their eyes closed, then they are always being visually stimulated and can be assumed to always be taking 10 on their perception checks. The difference here is that rogues (with the rogue talent) get the additional benefit of having the GM make another check automatically when within 10' of the trap.

You can argue with this with something along the lines of "well that means that I could actually roll lower than 10 and not perceive a trap I would have otherwise found if I'd just taken 10" -- yes, that is always a risk of taking 10 and is easily described away. For example, you were focusing on something that seemed dubious but was actually benign and missed the almost obvious pressure plate nearby.

  • \$\begingroup\$ Gotta love being downvoted without reason. \$\endgroup\$ Dec 30 '14 at 18:01

Scenario 1: Rogues automatically get a 1/2 x level bonus to their perception check to discover traps when rolling a check to search for something. Assuming that everyone in the party rolled to search a room, Perception is a skill that indicates how perceptive the PCs are to potential threats. A high perception roll effectively means that a Player character saw something out of the ordinary and went to investigate, such as a small hole in a wall or a tripwire.

Scenario 2: This is something that you have to judge as the Dungeon master. Questions such as "Which section of the room are you searching?" in the case of large rooms or "What exactly are you looking for?" will narrow down the effective results and allow you to circumvent the PCs perception checks to not notice traps. Don't let them know they're there, foreshadowing traps only leads to suspicious PCs.

  • 1
    \$\begingroup\$ Do you mean the +1/2 * level trapfinding bonus? That's not quite the same. \$\endgroup\$
    – mxyzplk
    Jul 19 '14 at 3:41

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