D&D 5E Perception vs Investigation

[Tormyr]

The high passive perception has been something I have been struggling with as well. Our monk has eyes of the eagle and a 22 passive perception. Our rogue/monk has passive perception of 21 and will probably end up at 27 by level 20. Figuring out the Perception DC for traps converted from 3.5 has been a challenge. I have taken to using the perception for just a description of something being out of place and working it into the description of the rest of the room. Then having an Intelligence (Investigation) check to determine if it is a trap and how to disarm it.

 

[iserith]

Wouldn't they make an Intelligence (History) check or something to see if they knew where tattoos like that came from? I've tried to get Investigation to work in a way that feels consistant, but it always just feels like "the knowledge skill for all the other stuff not covered by the rest of the knowledge skills."

I agree with Greenstone.Walker's call here. An Intelligence (History) check or other "knowledge skill" is generally for recalling lore. Perception is for noticing a thing. Investigation is for deducing something given clues in hand.

I try to get my players into the habit of saying "I try to recall if I know..." or "I try to notice..." or "I try to deduce whether..." so that we have a consistent way of signalling a particular approach. Then I can decide if the character automatically succeeds, fails, or whether a check is in order. For example, I may decide that the aarakocra pirate character Beakbeard automatically succeeds in the deduction that the tattoo indicates the NPC to be a sailor. The criminal rogue Chuck Dagger may or may not make the deduction and makes a check. The hermit monk from the inland mountains, Ivana Stavemoff, may just fail to deduce anything.

 

[Tony Vargas]

Basic Rules, page 59: "A passive check is a special kind of ability check that doesn't involve any die rolls. Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster."

So it can go either way. Reasonable enough for 5e.

So on the one hand we have ourselves a mechanic that says it's for resolving the uncertainty in the outcome of a task that's done repeatedly versus, as in aforementioned the LMoP example, DCs that are set as if the character wasn't doing anything but walking around. Then you have the mechanics for exploration, pages 64 and 65 which show that if you're doing anything other then actively looking out for threats (uncertainty of which is governed by a passive check), then your passive check doesn't get applied when determining if you notice a hidden threat. You're just surprised, or whatever.

While inconsistent on the face of it, also reasonable for 5e. A module is just some DMing work done for you - just as you can rule differently at different times, a module needn't align with mechanics or DMing advice given in the core books, the author can exercise the same DM's latitude for purposes of the adventure he's designing, and the actual DM can decide what to go with.

So DC 10 if you're actively searching, DC 15 to just notice it passively is OK.

So is DC 15 either way. So is automatic failure unless you describe looking for a specific thing at a specific spot.

This all reads to me like the designers are not on the same page with how this works. Or they designed it this way so some tables could treat it like radar and other tables could treat it like any other check. (I'm not sure I'm willing to give them the benefit of the doubt on the latter even if it happens to work with the "Do whatever" paradigm.)

That's your prerogative, of course.

 

[iserith]

So it can go either way. Reasonable enough for 5e.

While inconsistent on the face of it, also reasonable for 5e. A module is just some DMing work done for you - just as you can rule differently at different times, a module needn't align with mechanics or DMing advice given in the core books, the author can exercise the same DM's latitude for purposes of the adventure he's designing, and the actual DM can decide what to go with.

So DC 10 if you're actively searching, DC 15 to just notice it passively is OK.

So is DC 15 either way. So is automatic failure unless you describe looking for a specific thing at a specific spot.

That's your prerogative, of course.

All "okay" but for the fact that many people tend to treat official materials as how a thing works, including modules. So if they have an understanding of how a thing works by the Basic Rules and then it's not made to work that way in a published adventure, confusion and discontent ensues. I submit as evidence comments in this thread and in others I've participated in over at WotC. I think the designers could stand to be a little more consistent on this score.

 

[Tony Vargas]

Taking an example of how you might do something in one instance, as a dictate of how you must do it every time does seem like a problem. But, honestly, I think the developers of 5e have done a more than adequate job of getting out the message that 5e is rulings-not-rules, and of being fairly clear what that message means.

It's presumably easier and more practical to get that message out than to be consistent from one rulebook and published adventure to the next.

 

[Fralex]

I agree with Greenstone.Walker's call here. An Intelligence (History) check or other "knowledge skill" is generally for recalling lore. Perception is for noticing a thing. Investigation is for deducing something given clues in hand.

I try to get my players into the habit of saying "I try to recall if I know..." or "I try to notice..." or "I try to deduce whether..." so that we have a consistent way of signalling a particular approach. Then I can decide if the character automatically succeeds, fails, or whether a check is in order. For example, I may decide that the aarakocra pirate character Beakbeard automatically succeeds in the deduction that the tattoo indicates the NPC to be a sailor. The criminal rogue Chuck Dagger may or may not make the deduction and makes a check. The hermit monk from the inland mountains, Ivana Stavemoff, may just fail to deduce anything.

Heh, well now we come to the whole "how exactly should I use the knowledge skills" thing. Different tables treat them in all sorts of different ways. In my case, I don't limit them to just remembering things. Let me try to explain my point of view better.

The reason I have a problem with Investigation is that "deduction" isn't really a skill all on its own. You can't train yourself in figuring out what any given clue means. People investigate by applying relevant knowledge to the object of interest. Any time you make a deduction, you're drawing upon things you already know, and finding connections to discover new information. As others have said, Wisdom makes you aware of potential clues, and Intelligence lets you make sense of the things you notice.

So the process of investigating something would depend on 1) how sharp your mind is and 2) how much you know about that something. To me, it seems the best way to handle that in-game would be to have Investigation just be a pure Intelligence check. The proficiency bonus implies specialization. You add it to the Int check if you know a lot about a topic relevant to the investigation.

Pure deductive reasoning and the like is the raw, cognitive power behind every Intelligence check. Intelligence skills represent the things you've learned how to do using that cognitive power. It's just like how Charisma is the pure strength of your personality, and the various skills are different things you can do with it. There's no Charisma (Influence) skill because influencing others is what every Cha skill does. That's the way I see Intelligence (Investigation).

The books never describe it as anything more specific than processing information about your surroundings, but processing information is what every Int skill does. So when I try to work out what it's for my brain just... shuts down.

I liked the idea someone proposed about tying it to things you figure out about objects, and tying Perception to living creatures. That gives it direction. Ideally, I'd like to just replace it with a different skill entirely if I can't figure it out. It seems like thinking about it has only confused me more... >:

 

[iserith]

Heh, well now we come to the whole "how exactly should I use the knowledge skills" thing. Different tables treat them in all sorts of different ways. In my case, I don't limit them to just remembering things. Let me try to explain my point of view better.

The reason I have a problem with Investigation is that "deduction" isn't really a skill all on its own. You can't train yourself in figuring out what any given clue means. People investigate by applying relevant knowledge to the object of interest. Any time you make a deduction, you're drawing upon things you already know, and finding connections to discover new information. As others have said, Wisdom makes you aware of potential clues, and Intelligence lets you make sense of the things you notice.

So the process of investigating something would depend on 1) how sharp your mind is and 2) how much you know about that something. To me, it seems the best way to handle that in-game would be to have Investigation just be a pure Intelligence check. The proficiency bonus implies specialization. You add it to the Int check if you know a lot about a topic relevant to the investigation.

Pure deductive reasoning and the like is the raw, cognitive power behind every Intelligence check. Intelligence skills represent the things you've learned how to do using that cognitive power. It's just like how Charisma is the pure strength of your personality, and the various skills are different things you can do with it. There's no Charisma (Influence) skill because influencing others is what every Cha skill does. That's the way I see Intelligence (Investigation).

The books never describe it as anything more specific than processing information about your surroundings, but processing information is what every Int skill does. So when I try to work out what it's for my brain just... shuts down.

I liked the idea someone proposed about tying it to things you figure out about objects, and tying Perception to living creatures. That gives it direction. Ideally, I'd like to just replace it with a different skill entirely if I can't figure it out. It seems like thinking about it has only confused me more... >:

I think it's reasonable to assume that people have a talent for or can be trained to recall, notice, and deduce things better than other people who have not received that sort of training or who lack that natural talent.

 

[Tormyr]

Pure deductive reasoning and the like is the raw, cognitive power behind every Intelligence check. Intelligence skills represent the things you've learned how to do using that cognitive power. It's just like how Charisma is the pure strength of your personality, and the various skills are different things you can do with it. There's no Charisma (Influence) skill because influencing others is what every Cha skill does. That's the way I see Intelligence (Investigation).

Except Intelligence is more than just deductive reasoning. It includes all aspects of cognitive ability.

It seems to me that people can also get better at investigation. Police detectives receive training after all. Sounds like it works as a skill to me.

There is no Charisma (Influence) skill because it is too generic. There is Deception, Intimidation, and Persuasion for influence, but Performance is a bit different. This is quite similar to how most of the skills normally associated with Intelligence are recalling lore skills.

Going back to the general thoughts about Perception and Investigation: a Wisdom (Perception) check notices that there is a bucket on the counter in my lab. It sticks out of the rest of the stuff because it is propped up so that it is tilted. Opening the lid sees that there is sand immersed in water inside. An Intelligance (Arcana) or Intelligence (Investigation) check could both apply to figure out that the aggregate was soaking as the first stage of specific gravity testing.

 

[Fralex]

Except Intelligence is more than just deductive reasoning. It includes all aspects of cognitive ability.

It seems to me that people can also get better at investigation. Police detectives receive training after all. Sounds like it works as a skill to me.

What would they be taught to do, though? I would think getting better at investigating, say, crime scenes would depend on learning about forensics and such. I can't really picture a scenario where somone learns how to investigate things better without being taught new knowledge for a specific kind of investigation. The skill just seems weirdly generic; can't every Intelligence skill be used to figure things out based on clues? Getting better at Investigation sounds like it would be an ability score improvement to help you better use specific kinds of knowledge.

 

[Majoru Oakheart]

Then you have the mechanics for exploration, pages 64 and 65 which show that if you're doing anything other then actively looking out for threats (uncertainty of which is governed by a passive check), then your passive check doesn't get applied when determining if you notice a hidden threat. You're just surprised, or whatever.

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.