D&D 5E Perception vs Investigation

[iserith]

I got the impression from that section that it only applied when doing overland movement. That when you were travelling in "exploration turns" you had to declare what actions you were taking and making a map meant you weren't keeping an eye out for threats. Which makes sense to me.

However, I didn't think it applied the rest of the time. So if you were in a dungeon and walking down the corridor that you got your passive perception on all secret doors you passed and all monsters that tried to sneak up on you.

I can't imagine telling my players "Sorry, you were looking at the map so you didn't hear the monster sneak up behind you." Someone would say "Does reading a map suddenly mean my ears stop working?" and there would be an argument over it.

I don't get that impression. If your attention is turned to something else, then it's not on noticing hidden threats. That makes sense to me. Why should there be a difference between keeping an eye out for hidden threats while travelling and any other time? If I'm rifling through the heap of broken furniture searching for treasure, I don't get to notice the giant spider sneaking up behind me. But the PC who opted to keep watch while I did that might. There wouldn't be an argument over this at our table because the players are aware that mechanics are only brought into play when there is uncertainty and the DM determines whether or not there is uncertainty.

Edit: I will add that treating it this way creates a meaningful choice during play instead of just a matter how much a player chooses to pump Perception during character creation and advancement.

 

[Blackbrrd]

I don't get that impression. If your attention is turned to something else, then it's not on noticing hidden threats. That makes sense to me. Why should there be a difference between keeping an eye out for hidden threats while travelling and any other time? If I'm rifling through the heap of broken furniture searching for treasure, I don't get to notice the giant spider sneaking up behind me. But the PC who opted to keep watch while I did that might. There wouldn't be an argument over this at our table because the players are aware that mechanics are only brought into play when there is uncertainty and the DM determines whether or not there is uncertainty.

Edit: I will add that treating it this way creates a meaningful choice during play instead of just a matter how much a player chooses to pump Perception during character creation and advancement.

I would say that if you are occupied doing something that requires a skill check, you are at a disadvantage (or possibly, your opponents are at an advantage). Giving someone no chance to detect an incoming attack is something I would reserve for flying, invisible, silenced opponents.

The PC that stands guard would of course not be at a disadvantage, since he is actively standing guard. Except if he has been distracted, talking with another character on guard or whatever. I think this kind of differentiation makes for good RP, since you would then also reward your players for trying to distract guards, or wait for guards to be distracted.

 

[Majoru Oakheart]

I don't get that impression.

The section you quote is in the part of the book talking about exploration turns and the actions you can take during exploration. That section also says that exploration turns take hours. Notice how "search a room for treasure" and things like that aren't even on the option list. Your reading of it is slightly out of context because it essentially says "if you take an action other than watching for threats[as your exploration action] then you don't use your passive perception to detect ambushes made on the party while you are travelling."

The section even says that you shouldn't use exploration turns when doing things like exploring dungeons room by room.

Context is important when reading rules.

The section on using stealth and perception just says that any time a creature wants to sneak up on someone they need to have cover and they need to make a stealth check opposed by the passive perception of anyone who can see or hear them.

If your attention is turned to something else, then it's not on noticing hidden threats. That makes sense to me. Why should there be a difference between keeping an eye out for hidden threats while travelling and any other time? If I'm rifling through the heap of broken furniture searching for treasure, I don't get to notice the giant spider sneaking up behind me. But the PC who opted to keep watch while I did that might. There wouldn't be an argument over this at our table because the players are aware that mechanics are only brought into play when there is uncertainty and the DM determines whether or not there is uncertainty.

Except there is definitely uncertainty in that situation. You may not be paying complete attention to everything going on. That doesn't mean it's impossible for you to detect hidden threats, just harder. As I said, you don't turn your ears off simply because you are searching. If the monster isn't 100% silent then you could hear them sneaking up on you. Some people have better senses than other people and are better able to detect noises or spot movement than other. That's the point of the Perception skill. I might give them disadvantage on their check if I felt they were distracted, however.

So, in theory, one person with high Perception skill might be rifling through the heap of broken furniture only to hear faint pattering of spider footfalls behind him and will turn around before it attacks. Another person might be so distracted by what he is doing that he never hears the spider. That makes there be some uncertainty as to the outcome. It depends on how stealthy the spider is and how perceptive the person in question is.

The DM can determine whether there is uncertainty, true. But in this situation it's fairly clear that there is. Which is why if I ruled that there wasn't, my players would feel that I unfairly ruled against them in an attempt to kill them. I already ruled this way once only to get half the players at the table very angry at me. It was a slightly different situation in that I ruled that an enemy didn't need cover to sneak up on them because they were all facing a different direction paying attention to a person they were talking with. I still had the person sneaking up on them make a stealth check. But my players were annoyed that a person was able to walk across the room in plain sight without being seen.

I can only imagine how angry they'd get if I told them they had absolutely no chance to hear the person either.

Edit: I will add that treating it this way creates a meaningful choice during play instead of just a matter how much a player chooses to pump Perception during character creation and advancement.

Technically, pumping Perception IS a meaningful decision. You had to choose it over another skill. Even then, that doesn't make you great at it, just good. In order to be great, you need to spent a feat or invest something like your Expertise choice into it. Those are options you didn't spend elsewhere. You should get some benefit from making these choices.

I feel like "Sorry, you didn't say you were looking for threats, you are automatically surprised" is a meaningful choice. It feels more like a gotcha.

 

[iserith]

I would say that if you are occupied doing something that requires a skill check, you are at a disadvantage (or possibly, your opponents are at an advantage). Giving someone no chance to detect an incoming attack is something I would reserve for flying, invisible, silenced opponents.

Sure, I think it's supposed to be ruled on a case-by-base basis and will vary based on the situation and the DM.

The section you quote is in the part of the book talking about exploration turns and the actions you can take during exploration. That section also says that exploration turns take hours. Notice how "search a room for treasure" and things like that aren't even on the option list. Your reading of it is slightly out of context because it essentially says "if you take an action other than watching for threats[as your exploration action] then you don't use your passive perception to detect ambushes made on the party while you are travelling."

The section even says that you shouldn't use exploration turns when doing things like exploring dungeons room by room.

Context is important when reading rules.

Where does it say the bolded? I've just reread the section a couple of times and damn if I don't see it. Maybe I missed it?

As for "Search a room for treasure," that's covered by "However, a character not watching for danger can do one of the following activities instead, or some other activity with the DM’s permission."

This makes it a trade-off: Either you're watching out for danger and making use of that sweet, sweet passive Perception score you invested in or you're doing something else. For those concerned about passive Perception being overused and too powerful, there's the answer.

The section on using stealth and perception just says that any time a creature wants to sneak up on someone they need to have cover and they need to make a stealth check opposed by the passive perception of anyone who can see or hear them.

The section on ability checks says that an ability check is called for only when there is uncertainty as to the outcome as determined by the DM. If the DM decides you're surprised based on his or her reading of the situation, then you're surprised. So this will vary DM to DM and situation to situation under the same DM.

Except there is definitely uncertainty in that situation. You may not be paying complete attention to everything going on. That doesn't mean it's impossible for you to detect hidden threats, just harder. As I said, you don't turn your ears off simply because you are searching. If the monster isn't 100% silent then you could hear them sneaking up on you. Some people have better senses than other people and are better able to detect noises or spot movement than other. That's the point of the Perception skill. I might give them disadvantage on their check if I felt they were distracted, however.

So, in theory, one person with high Perception skill might be rifling through the heap of broken furniture only to hear faint pattering of spider footfalls behind him and will turn around before it attacks. Another person might be so distracted by what he is doing that he never hears the spider. That makes there be some uncertainty as to the outcome. It depends on how stealthy the spider is and how perceptive the person in question is.

The DM can determine whether there is uncertainty, true. But in this situation it's fairly clear that there is. Which is why if I ruled that there wasn't, my players would feel that I unfairly ruled against them in an attempt to kill them. I already ruled this way once only to get half the players at the table very angry at me. It was a slightly different situation in that I ruled that an enemy didn't need cover to sneak up on them because they were all facing a different direction paying attention to a person they were talking with. I still had the person sneaking up on them make a stealth check. But my players were annoyed that a person was able to walk across the room in plain sight without being seen.

I can only imagine how angry they'd get if I told them they had absolutely no chance to hear the person either.

That is your ruling. Other DMs may rule differently and be equally right as far as that goes. I can't speak for how your players react to things except to say mine don't act that way because we share an understanding about how Perception works and they trust my reading of the context of the situation.

Technically, pumping Perception IS a meaningful decision. You had to choose it over another skill. Even then, that doesn't make you great at it, just good. In order to be great, you need to spent a feat or invest something like your Expertise choice into it. Those are options you didn't spend elsewhere. You should get some benefit from making these choices.

The quote of mine you're replying to specifically says "meaningful decisions during play." Of course pumping Perception comes with an opportunity cost. But my position is that once in play, it's not "always on." If you do anything else other than watch for dangers, you risk not detecting them.

I feel like "Sorry, you didn't say you were looking for threats, you are automatically surprised" is a meaningful choice. It feels more like a gotcha.

It feels like a gotcha because it lacks context and because your "Sorry..." quote seems to imply that the DM assumes that the players aren't doing anything else. I assume that the characters are always on the lookout for hidden threats unless they have chosen to do something that is distracting them.