Perception checks, really basic rules question

[tchntm43]

This is probably going to get laughed at for being such a basic question, but we're still not entirely clear on perception checks when the entire party is present.

Suppose I have a situation where there is a small object in plain view, not hidden, but possible to miss. Assuming the party is not actively investigating, that calls for perception check. Suppose the DC is on the moderately difficult end, 15. There are 5 characters present. What is the correct way to determine if they find it?

If I go by passive perception, then there is no luck involved. I would know when I'm writing the adventure if they notice it or not. If I want there to be a chance, then this option is no good. Players like rolling dice.

If I have each character roll perception, then even with a DC of 15 it is extremely likely someone will notice it since there are 5 of them. Even if all 5 characters have +0 to their perception checks, they would have a 76% chance. I know that the size of the party can help with things but it shouldn't help to that extent.

Do I treat it the same way as a character making a strength check with assistance? I.e. pick the character with the best Perception bonus, have him roll, and then add +1 for each other character in the party? That seems the fairest option but I don't remember seeing that in the PHB (I don't have it with me at the moment).

[JackPhoenix]

Either option is possible, you're the GM, you decide how you want to do it. As long as you're consistent, it doesn't matter.

The important question is, does finding or not finding the object matter? Are the characters searching for the object? Is it just a scenery? Is it worth rolling at all?

[Tanarii]

Assuming the party is not actively investigating, that calls for perception check.
That is not correct. Assuming the party is actively investigating or actively looking for danger, and there isn't time to investigate fully by taking ten times as long to automatically find anything that can be found, then they get to either use passive perception (for investigating repeatedly as they go or for secret checks) or roll perception (when neither apply).

If they're doing something else instead of actively investigating or actively looking for danger, then they don't get to make a check. Examples given in the PHB are Tracking, Navigating, Foraging or Mapping. But other activities may apply. Note that also means they'll be automatically surprised if they're doing that activity ... or looking for something instead of watching for danger.

For example, my players typically divided into several groups: one for tossing a room or bodies and another watching for approaching threats. The ones tossing usually do it quickly because of wandering monsters, and get to use passive perception. Ones watching for approaching threats get to use it for threats coming from the direction(s) they're watching, so those folks won't be surprised if there is an ambush.

When moving, they usually have folks in front with decent Investigation looking for traps or tracking, Perception for enemies, and someone behind with perception looking for enemies. The guys doing the mapping, navigating and other tasks, including looking for other things (often using passive lore skills) are in the middle. Because they won't get to use passive perception if they're ambushed, and will automatically be surprised.

[kazaryu]

This is probably going to get laughed at for being such a basic question, but we're still not entirely clear on perception checks when the entire party is present.

Suppose I have a situation where there is a small object in plain view, not hidden, but possible to miss. Assuming the party is not actively investigating, that calls for perception check. Suppose the DC is on the moderately difficult end, 15. There are 5 characters present. What is the correct way to determine if they find it?

If I go by passive perception, then there is no luck involved. I would know when I'm writing the adventure if they notice it or not. If I want there to be a chance, then this option is no good. Players like rolling dice.

If I have each character roll perception, then even with a DC of 15 it is extremely likely someone will notice it since there are 5 of them. Even if all 5 characters have +0 to their perception checks, they would have a 76% chance. I know that the size of the party can help with things but it shouldn't help to that extent.

Do I treat it the same way as a character making a strength check with assistance? I.e. pick the character with the best Perception bonus, have him roll, and then add +1 for each other character in the party? That seems the fairest option but I don't remember seeing that in the PHB (I don't have it with me at the moment).
the book answer is, passive perceptions. Outside of that, you're in houserule territory. some people/groups will have a sort of average roll. where everyone gets a check, but success failure is determined by group average-ish, or by based on how many people 'passed'. others will just, explicitly only let 1 or 2 people roll in spite of realism.

[Bobthewizard]

Not to derail the thread, but I would use passive investigation here. For me, looking for danger is perception. Noticing a small item or clue is investigation. Perception is important enough that I don't want to add more to it.

I can see the argument for perception, since they aren't looking for it, but then I don't know when I'd ever use passive investigation, and we know it is a thing since the observant feat gives you +5 to it.

[Sorinth]

In most cases it would be passive perception unless a player said they were glancing about/searching in which case it would be an actual die roll.

For dealing with multiple people doing the same thing your options are everybody rolls and single success is all that's needed or a group check (Need half to succeed).

But in a lot of cases the answer is simply do you the DM think it will be more fun/interesting if they notice it or not and just go with that as the default if no one chooses to actively investigate/perceive.

[Rynjin]

Suppose I have a situation where there is a small object in plain view, not hidden, but possible to miss. Assuming the party is not actively investigating, that calls for perception check. Suppose the DC is on the moderately difficult end, 15. There are 5 characters present. What is the correct way to determine if they find it?

If I go by passive perception, then there is no luck involved. I would know when I'm writing the adventure if they notice it or not. If I want there to be a chance, then this option is no good. Players like rolling dice.

This is, quite literally, the exact scenario passive Perception was created for. The object is not hidden. It does not require searching. Perhaps it is small and easy to miss. That means it has a "you must have a Perception bonus this high to ride" sign tacked onto it.

If they decided to actively search the room later, that is when the roll happens (and I'd agree with another user that said it should be Investigation if it's a roll). The passive Perception is there to see if a cursory glance around the room spots it. The more naturally perceptive the character is (i.e. the higher their bonus), the more likely it is they will pick out things a normal person would miss at a glance.

[kingcheesepants]

This is probably going to get laughed at for being such a basic question, but we're still not entirely clear on perception checks when the entire party is present.

Suppose I have a situation where there is a small object in plain view, not hidden, but possible to miss. Assuming the party is not actively investigating, that calls for perception check. Suppose the DC is on the moderately difficult end, 15. There are 5 characters present. What is the correct way to determine if they find it?

If I go by passive perception, then there is no luck involved. I would know when I'm writing the adventure if they notice it or not. If I want there to be a chance, then this option is no good. Players like rolling dice.

If I have each character roll perception, then even with a DC of 15 it is extremely likely someone will notice it since there are 5 of them. Even if all 5 characters have +0 to their perception checks, they would have a 76% chance. I know that the size of the party can help with things but it shouldn't help to that extent.

Do I treat it the same way as a character making a strength check with assistance? I.e. pick the character with the best Perception bonus, have him roll, and then add +1 for each other character in the party? That seems the fairest option but I don't remember seeing that in the PHB (I don't have it with me at the moment).

Several things, first off don't be embarrassed for asking a basic question everyone starts somewhere and there's no shame in being a beginner. Secondly if by assisting in a strength check you mean the help action that's actually advantage not +1.

As for how to run perception checks usually, I'd say that your initial description of the room should be based on the highest passive perception. If that means they see the hard to spot thing (cause a character was built to be good at perception) than great the character is doing what the player built them for. If they want to look for things beyond what's been described then you ask for a perception check.

Remember that if they're making a check that means 10 minutes absorbed in the task and not doing other stuff, if the whole team is spending their time looking for stuff it makes sense that they'd find it. Think about if you lost the remote and you spend 10 minutes looking for it, maybe you can find it maybe you can't. Now imagine that you ask 4 friends to help you look. Do you think it would be strange if 5 people looking around a room for 10 minutes were able to find a moderately difficult to find remote? No you'd think it was strange if they couldn't find it.

Also to your example of a small object in plain sight that actually sounds like something that you'd describe in the initial description of the room and then ask for an investigation check if they want to learn more about it (like figuring out if it's s component of a trap or a secret door or something).

[tchntm43]

I always thought perception meant "finding stuff you weren't looking for" and investigation was "finding stuff you are looking for". Hm.

The issue I have with passive checks is that I'm writing the adventure for this group of players. I already know what all of their passive perceptions are. So if I set a DC for something that I know is going to have a passive check, it's functionally the same as me just deciding now that they find it or don't find it.

[Kane0]

The issue I have with passive checks is that I'm writing the adventure for this group of players. I already know what all of their passive perceptions are. So if I set a DC for something that I know is going to have a passive check, it's functionally the same as me just deciding now that they find it or don't find it.

And that's fine, the same adventure played by different characters or under different conditions might have a different result.

Also keep in mind that disadvantage to perception translates to a -5 to passive perception, which is important to remember when dealing with dim lighting, travelling at faster speeds, and so on.

[tchntm43]

Secondly if by assisting in a strength check you mean the help action that's actually advantage not +1.

Oh yeah. I misremembered that, definitely. Actually, that's probably because the group has never used the help action once. It's tough, we have so much time between sessions these days that a few of our players are practically back to 0-knowledge at the start of each session. Have to remind them how attack rolls work, spell slots, etc. I'm pretty sure none of them even know about the help action.

Anyway, the gist of what I'm getting at is that they really like rolling dice and getting rewarded by good rolls. Passive checks don't let them have any involvement in success or failure. That's not as much fun.

[Rynjin]

I always thought perception meant "finding stuff you weren't looking for" and investigation was "finding stuff you are looking for". Hm.

The issue I have with passive checks is that I'm writing the adventure for this group of players. I already know what all of their passive perceptions are. So if I set a DC for something that I know is going to have a passive check, it's functionally the same as me just deciding now that they find it or don't find it.

I think this is the wrong mindset. It is them deciding if they find it or not, by their investment in Perception. You merely have foreknowledge of it happening when it does.

Trust me, players appreciate their competency being acknowledged. "Players like to roll dice", sure. But players also like to be told "your characters are good at this thing, so you triumph". There needs to be a solid mix of challenge and triviality so the former stands out.

[kazaryu]

I think this is the wrong mindset. It is them deciding if they find it or not, by their investment in Perception. You merely have foreknowledge of it happening when it does.

Trust me, players appreciate their competency being acknowledged. "Players like to roll dice", sure. But players also like to be told "your characters are good at this thing, so you triumph". There needs to be a solid mix of challenge and triviality so the former stands out.

to add on to this, there is also situational bonus' you can add. for example, advantage increase passive checks by 5. depending on what they do, you might give them adv/disadv.

[da newt]

My recommendation for dealing with things that are not hidden is simple - if they ask what's in the room, I tell them everything that isn't hidden. If they don't RP any sort of looking around, then I only tell them the really obvious stuff.

For things that are hidden, that's when you roll.

For clues, I always tell them everything they see - all the mundane crap and the important stuff just the same so they can try to figure out what is important.

[solidork]

You could include something that is easier to spot for them to notice with their passive perception, which could prompt them to look around more closely and actually make rolls to see what they find.

[Kane0]

Anyway, the gist of what I'm getting at is that they really like rolling dice and getting rewarded by good rolls. Passive checks don't let them have any involvement in success or failure. That's not as much fun.

To cheat have them roll and if they dont beat their passive just use that from behind the screen, or have them roll and use the passive regardless

[Lunali]

I always thought perception meant "finding stuff you weren't looking for" and investigation was "finding stuff you are looking for". Hm.

The issue I have with passive checks is that I'm writing the adventure for this group of players. I already know what all of their passive perceptions are. So if I set a DC for something that I know is going to have a passive check, it's functionally the same as me just deciding now that they find it or don't find it.

I play it as finding stuff with your senses vs finding stuff based on clues, which means a lot of perception and very little investigation most of the time.

One solution for the passive check problem is to give things a +bonus to hide based on how well you think they'd be hidden and roll a d20 against passive perception ahead of time. If it's interesting for some people to notice things and others not, roll separately for each character.

[Rukelnikov]

Not to derail the thread, but I would use passive investigation here. For me, looking for danger is perception. Noticing a small item or clue is investigation. Perception is important enough that I don't want to add more to it.

I can see the argument for perception, since they aren't looking for it, but then I don't know when I'd ever use passive investigation, and we know it is a thing since the observant feat gives you +5 to it.

For me, the difference is, Perception is to be able to see/hear something, Investigation is to be able to interpret it.

For instance, there may be some runes etched into a wall, they are not hard to see, everyone sees them, but passive investigation allows you to realize, there's a pattern to some of them.

[Mastikator]

I think it depends on the object and how you want the players to interact with the room. If it's OK that they miss it and just move through the room then passive perception is good enough. If you call for a perception check from the group when they enter the room they will think there is something or someone there.

[Psyren]

If I go by passive perception, then there is no luck involved. I would know when I'm writing the adventure if they notice it or not. If I want there to be a chance, then this option is no good. Players like rolling dice.

It's not enough to say "players rolling dice is good, players not rolling dice is bad." There are a number of other questions you need to consider before calling for a roll. Can they fail the roll? If yes, what happens? Is there a meaningful consequence for that failure? Can they try again? If so, how many times? Is there a time limit? Is the object they may or may not perceive necessary to progress the plot, or is it purely a bonus?

Note that "they don't see the item" is not an inherently meaningful consequence either.


I think this is the wrong mindset. It is them deciding if they find it or not, by their investment in Perception. You merely have foreknowledge of it happening when it does.

Trust me, players appreciate their competency being acknowledged. "Players like to roll dice", sure. But players also like to be told "your characters are good at this thing, so you triumph". There needs to be a solid mix of challenge and triviality so the former stands out.

This too. Not rolling can be just as satisfying as rolling, it's all in how you describe it.

[Khrysaes]

If i want a group to use and roll perception, i treat them as a group check, much like group stealth. If at least half make the dc, then the entire group passes. If more than half fail. The entire group fails.

Again this is only if i want them to roll as a group. Not using passive perception or one specific player rolling.

[da newt]

Some times a DM's call for 'roll perception' can be a great red herring too. It can aid in building suspense or help trigger more involved play too.

An alternate method could be if the Players don't RP looking for things, the DM can make a behind the screen 'luck check' roll - pick a DC or odds vs evens and use that to determine if they see the McGuffin.

[KorvinStarmast]

Suppose I have a situation where there is a small object in plain view, not hidden, but possible to miss. Assuming the party is not actively investigating, that calls for perception check. Suppose the DC is on the moderately difficult end, 15. There are 5 characters present. What is the correct way to determine if they find it? There are a lot of ways to do this:
1. Group Perception check. (See chapter 7 for how to do a group check, and remember that it's at disadvantage in dim light or darkness). If 3 pass they see it, if 2 pass they dont).
2. Group Investigation check. (Same as above, but if they aren't actively searching for things this one might not feat right.
3. Passive investigation check. (You just narrate success of failure).
4. Passive perception check. (Same)
Here's a way to avoid your DC problem ....
5. Item rolls a stealth check. (what? hear me out).
This one is a bit odd ball, but if you want it to be hiding in plain sight, then consider that it is performing Hide action, and then roll a stealth check for the item when the party enters the room. Compare your stealth score to to the passive perception of the PCs (and the dim light disadvantage again applies; if they have a light source it does not).

I think that solution 5 probably fits what you are trying to achieve best, even though it's a bit unorthodox.

If I go by passive perception, then there is no luck involved. I would know when I'm writing the adventure if they notice it or not. If I want there to be a chance, then this option is no good. Players like rolling dice. Players roll dice when you call for a roll. You don't have to call for a roll, but if you really want there to be a roll involved, you can have them roll perception, group check, (and for that matter, for your "hiding in plain sight item", go ahead and roll the Stealth check for the item at the time) but if they fail, they know they rolled and are now wondering "what was that all about?"

Which is why I'd use suggestion number 5.

But most importantly: what is the consequence of them finding or not finding that item? How important is this item to what happens next (either sooner or later) during the adventure? That's probably the first question you have to ask yourself before you consider how you want to deal with the PCs checks.


If they're doing something else instead of actively investigating or actively looking for danger, then they don't get to make a check. Examples given in the PHB are Tracking, Navigating, Foraging or Mapping. But other activities may apply. Note that also means they'll be automatically surprised if they're doing that activity ... or looking for something instead of watching for danger.

For example, my players typically divided into several groups: one for tossing a room or bodies and another watching for approaching threats. The ones tossing usually do it quickly because of wandering monsters, and get to use passive perception. Ones watching for approaching threats get to use it for threats coming from the direction(s) they're watching, so those folks won't be surprised if there is an ambush.

When moving, they usually have folks in front with decent Investigation looking for traps or tracking, Perception for enemies, and someone behind with perception looking for enemies. The guys doing the mapping, navigating and other tasks, including looking for other things (often using passive lore skills) are in the middle. Because they won't get to use passive perception if they're ambushed, and will automatically be surprised.

For me, looking for danger is perception. Noticing a small item or clue is investigation. Perception is important enough that I don't want to add more to it. I tend to approach it this way.

That means it has a "you must have a Perception bonus this high to ride" sign tacked onto it.

If they decided to actively search the room later, that is when the roll happens (and I'd agree with another user that said it should be Investigation if it's a roll). Also a good approach.

Also keep in mind that disadvantage to perception translates to a -5 to passive perception, which is important to remember when dealing with dim lighting, travelling at faster speeds, and so on. So easy to forget; as a DM I have to keep a little sticky up to remind me.

[Bobthewizard]

I always thought perception meant "finding stuff you weren't looking for" and investigation was "finding stuff you are looking for". Hm.

Do you ever use passive investigation?


The issue I have with passive checks is that I'm writing the adventure for this group of players. I already know what all of their passive perceptions are. So if I set a DC for something that I know is going to have a passive check, it's functionally the same as me just deciding now that they find it or don't find it.

I will sometimes roll the DC for things. Announce to the party, the DC is 10+this die and roll a d10.

Edit: It looks like Korvin just posted the same thing. I agree with their #5.

[KorvinStarmast]

Edit: It looks like Korvin just posted the same thing. I agree with their #5. Glad to see that was well received by at least one person.
His/him/he for me :smallsmile:

[Psyren]

But most importantly: what is the consequence of them finding or not finding that item? How important is this item to what happens next (either sooner or later) during the adventure? That's probably the first question you have to ask yourself before you consider how you want to deal with the PCs checks.


This is indeed the big one.

[Keravath]

There are a lot of ways to do this:
1. Group Perception check. (See chapter 7 for how to do a group check, and remember that it's at disadvantage in dim light or darkness). If 3 pass they see it, if 2 pass they dont).
2. Group Investigation check. (Same as above, but if they aren't actively searching for things this one might not feat right.
3. Passive investigation check. (You just narrate success of failure).
4. Passive perception check. (Same)
Here's a way to avoid your DC problem ....
5. Item rolls a stealth check. (what? hear me out).
This one is a bit odd ball, but if you want it to be hiding in plain sight, then consider that it is performing Hide action, and then roll a stealth check for the item when the party enters the room. Compare your stealth score to to the passive perception of the PCs (and the dim light disadvantage again applies; if they have a light source it does not).

I think that solution 5 probably fits what you are trying to achieve best, even though it's a bit unorthodox.
Players roll dice when you call for a roll. You don't have to call for a roll, but if you really want there to be a roll involved, you can have them roll perception, group check, (and for that matter, for your "hiding in plain sight item", go ahead and roll the Stealth check for the item at the time) but if they fail, they know they rolled and are now wondering "what was that all about?"

Which is why I'd use suggestion number 5.

But most importantly: what is the consequence of them finding or not finding that item? How important is this item to what happens next (either sooner or later) during the adventure? That's probably the first question you have to ask yourself before you consider how you want to deal with the PCs checks.

I tend to approach it this way.
Also a good approach.
So easy to forget; as a DM I have to keep a little sticky up to remind me.

I just wanted to emphasize the point Korvin made that the important part isn't HOW they find it but the consequences to the plot of IF they find it or not.

If the item is essential to the plot moving forward then the DM wants to add some tension to the description but you do NOT want to have an important plot relevant item gated behind any sort of die roll that the party can fail.

I've seen an entire group roll less than 8 on a perception check for a DC10 observation. If that had been a plot relevant observation then having them roll was a bad idea especially if that is the only way that the DM planned to get the information to the characters. The DM then finds themselves scrambling to improvise another way to obtain the information when they fail the check the DM thought they would never fail.

If the item is not important to the plot then what are the consequences of the party missing it? Can they move forward? Do they end up taking more time? Does the entire party die (could happen if the item is a key to a trap or similar)?

Players like rolling dice - yes - but the DM doesn't want them rolling if failure means that the plot is disrupted. So the DM needs to balance the effect out - if the DM wants them to roll then they also need to provide an alternate method of finding things.

In your present case, the object is easy to notice, it isn't hidden, it is sitting in the open - it is small. Most of the characters probably saw the item in their look around the room since it is in plain sight. However, the characters don't recognize the significance of the item or whether it is worth looking closer. In my opinion, this makes it investigation rather than perception - since the issue isn't noticing the item, it is understanding or figuring out that it matters.

If you want it noticed then use passive investigation and set the DC so that someone notices it. You can narrate them finding it and make that character shine because of their investigation skill.

If you want to randomize it then Korvin's suggest of randomly setting the DC (make the item stealthy :) ) and then checking that against passive investigation also might work.

Keep in mind that if the characters aren't actively looking around the room, are aware and watching for stuff, then they don't get a passive check. Passive is referring to the PLAYER being passive and not rolling dice - the character is NOT passive - they are taking an action of some sort that would justify the check in the first place.

A character actively looking is enough to justify either passive perception or investigation depending on the nature of the problem.

If you want to leave it entirely to luck - roll a d20 for the DC to notice the item then ask for investigation checks in the room if the characters are looking around - then neither the DM or the players would have any idea whether the item will be noticed or not. However, in that case, make sure that the item itself has no real significance - it might be useful or helpful but it can't be essential.

[Psyren]

I just want to add that "make the object roll Stealth" isn't as silly as it sounds. You're not literally making the object hide from the PCs, rather the roll might represent how well-placed it was by whoever put it there.

Again though, that takes a back seat to whether the players should be rolling in the first place and how plot-critical the item is (i.e. the meaningful consequences of failure.)

[Mjolnirbear]

With respect to Investigation Vs Perception, if I am unsure which to call for I ask myself if an animal can do it.

If it can, Perception. If it can't, investigation.

This is based entirely on the relevant ability scores: animals on average have good wisdom but crap intelligence. And though I typically run skills as being useable with a variety abilities (str-indimidation as the classic example) perception uses your senses which is always wisdom.

Sure, the animal can find the tripwire. But it won't recognize it as a tripwire. It won't understand the danger it represents. Understanding the significance of something like that requires knowledge and intelligence.

And I dislike the idea of "perception then investigation": Perception to notice the scratch in the floor, investigation to realize it was made by a bookcase that swings open. If it's gonna revert to investigation anyways, I'll just call for that. So in my games, perception is still really useful for ambushes, surprise/hiding, listening at doors, and the like, but it isn't useful for traps or secret doors.

With respect to passives, I've seen it used three ways:

1: take ten. You have the time to keep trying something and there are no consequences for failure.
2: hiding secret rolls, so the players don't metagame
3: some mystical skill floor or Reliable Talent that only works for perception.

In the first case, just let them succeed. In the third, I totally reject that. I only really use it for the second option and only if secrecy is really important, and so I tell players pretend you've never heard of passives, and options or rules that refer to passives are ignored. Observant is banned.

[Kurt Kurageous]

Do you ever use passive investigation?

Yes. I consider it 'detect traps' when you are not trying to detect traps, or 'determine cause' when an effect occurs without an apparent cause.

I always make a point of honoring the choices/priorities the players made when the built their PCs. If someone (as I did once) chooses variant human (giving up about a +2 worth of ability scores) rogue with expertise in investigation, +2 modifier in INT, and dungeon delver to end up with a PI of 21, they are going to passively find every DC10, 15, and 20 trap given normal circumstances.

It doesn't matter, but this PC was Guy from the 750 word backstory thread. With the right circumstances, he might very well have become the greatest thief of the age. But we will never know. He dies in a completely predictable campaign collapse.

[Demonslayer666]

You do.

As the DM, you decide when they need to roll, or when to use a passive check. You also decide how difficult it is: automatic success or failure, or determine a DC.

You could roll randomly to see which character might notice it first, and have that character make a check. People look different places when entering a room, especially one after another. You could also have the first person entering the room roll, and continue down the line until someone notices. The problem here is that you have now let them know something is in here to notice even if they all fail. This is where passive perception is handy.

When you feel like having the entire party roll to notice something not important, I would not bother rolling for anything less than a DC 20. Just tell them they notice it. We waste so much time at the table rolling perception and then the DM just tells all of us what some of us notice anyway. It's silly. I lean towards automatic a lot.

I do not use Perception as an assisted skill, only individual.

[JackPhoenix]

Do you ever use passive investigation?

No, and I've changed Observant feat to apply to passive Insight, which gets used as a DC against Deception the same way passive Perception is used against Stealth.

[Rynjin]

With respect to Investigation Vs Perception, if I am unsure which to call for I ask myself if an animal can do it.

If it can, Perception. If it can't, investigation.

This is based entirely on the relevant ability scores: animals on average have good wisdom but crap intelligence. And though I typically run skills as being useable with a variety abilities (str-indimidation as the classic example) perception uses your senses which is always wisdom.

Sure, the animal can find the tripwire. But it won't recognize it as a tripwire. It won't understand the danger it represents. Understanding the significance of something like that requires knowledge and intelligence.



I'm gonna guess you haven't spent much time trapping or hunting?

Even a mouse understands the danger of a mousetrap. It's why you need to bait them with something sticky, like peanut butter, not something that can be swiped. Because they know what a mousetrap is, and will snatch the food from it safely. IIRC raccoons will even deliberately snap mousetraps and then take the food afterward.

You could argue that it doesn't "understand" the trap, just that it's different, unexpected, and therefore assumed dangerous, but there's very little difference in a practical sense. An animal is not just gonna see a tripwire and then ignore it. It's going to go out of its way to not touch it, because it doesn't know what will happen.

[Psyren]

No, and I've changed Observant feat to apply to passive Insight, which gets used as a DC against Deception the same way passive Perception is used against Stealth.

We did this change too and it makes Observant way better. "Passive Investigation" always felt like an oxymoron.

[KorvinStarmast]

We did this change too and it makes Observant way better. "Passive Investigation" always felt like an oxymoron. I think it was a way to get at the AD&D 1e thing with elves who could detect secret doors just by walking by them. Yeah, it was a thing.

[Tanarii]

Passive means the player doesn't roll dice. Not that the character is passive. Or if you prefer, not because the a character is not active.

It's entirely possible to have Passive Athletics, Passive Acrobatics, etc. Any skill can be a Passive check, as long as the character is doing the task repeatedly but only one instance matters (usually because it's being done as they travel or done over a larger area), or the result needs to be secret from the player.

[Mjolnirbear]

I'm gonna guess you haven't spent much time trapping or hunting?

Even a mouse understands the danger of a mousetrap. It's why you need to bait them with something sticky, like peanut butter, not something that can be swiped. Because they know what a mousetrap is, and will snatch the food from it safely. IIRC raccoons will even deliberately snap mousetraps and then take the food afterward.

You could argue that it doesn't "understand" the trap, just that it's different, unexpected, and therefore assumed dangerous, but there's very little difference in a practical sense. An animal is not just gonna see a tripwire and then ignore it. It's going to go out of its way to not touch it, because it doesn't know what will happen.

The mouse avoids everything unfamiliar. It has nothing to do with being a trap and everything to do with fear of the dangers of the unknown, especially new unknowns smelling of humans where humans rarely go.

It still doesn't recognize a tripwire or why it is dangerous. That requires intelligence. Some animals, such as crows, are easily able to associate Unknown Thing with Bad Thing, or can reason their way around Bad Thing to get Thing They Want, but most animals cannot understand it.

A mouse can go all sorts of places humans can't; like your pantry, or your delicious electrical wires hidden in the walls. That doesn't mean they can recognize a secret door as a secret door, or that these scratches were caused by a door, because this requires knowledge of a door: a barrier to entry that can selectively be opened or closed at need. Again there are exceptions such as trap-door spiders, but I'm speaking in general terms.

A human avoiding a trap needs to recognize it is a trap. That means they need to recognize the trigger, and the intent, and the reset mechanic, and you know they'll try to find the exact nature of the threat. We don't randomly associate all wires with danger, only tripwires (or electric wires, etc). Nor do we associate all holes with danger, trypophobia aside. We recognize THIS wire or pit is a danger, and why.

That ability to distinguish random wire from trap requires intelligence.

[Rynjin]

I'm kind of baffled by this opinion. Do you see random wires, ropes, vines, etc. and then if you recognize it's not "a trap" still decide to walk into and trip over them anyway?

You don't need to recognize any further danger than "this is an obstacle to be avoided".

[Mjolnirbear]

Trip over? Sometimes if I wasn't paying attention, or simply lost my balance. Have you never tripped on a wire, then?

Walk on? Sure. Those car-tracking ones are interesting and feel interesting in my arches. I wear zero-rise shoes because I like feeling the ground when I walk.

That is not the point. The point is there is a marked difference between avoiding something in your way and avoiding something because you know it's dangerous. And more importantly intelligence will help you deduce its dangerous if it's something you've never seen before, identify the source or nature of the threat, and provide options to deal with it, such as locating and disabling trap mechaniisms. Intelligence better sees through deceit and misdirection, such as laying a trip wire and digging a pit trap right where your foot would land after stepping over it.

An animal's options to danger are freeze, run, and fight, which do not solve the problem of how to get past the trap. You want to do that, right?

[sambojin]

If an animal can do it? Great. You'll have a familiar in the party if there's a Wizard/ Druid/ magic-feated PC in the party, at least a bit of the time.

Do you know what really good familiars get? Advantage on sight rolls. Or perception passives. Like owls do. So have considerably better passive perception than is in their stat-block for "seeing or hearing" stuff.

Like, 13+5(advantage) passive Perception on "seeing stuff". Yep. DC18 done...

So, I'd roll stealth for the item, as mentioned above. With +'s to the roll, considering what the party is actually doing. Starts at DC12+D10, but it gets +2-4 plusses and/or advantage if no-one is actually looking for stuff in the area. Sure, they can have their passives, they can actually roll perception (or investigation, if anyone actually has it) if they actually look for stuff, but the item is "hidden", in plain sight. It gets to roll though, not the players, unless they do.

Depending on what they are doing. It's not doing anything. It's just hidden. Pretend you're rolling for a trap or something. D10's cover that story for you :)

[Rynjin]

Trip over? Sometimes if I wasn't paying attention, or simply lost my balance. Have you never tripped on a wire, then?

You trip on it when you...don't see it. I.e. fail Perception. I guess if you're exceptionally clumsy you can trip over something you're looking at? But that ain't normal.


That is not the point. The point is there is a marked difference between avoiding something in your way and avoiding something because you know it's dangerous. And more importantly intelligence will help you deduce its dangerous if it's something you've never seen before, identify the source or nature of the threat, and provide options to deal with it, such as locating and disabling trap mechaniisms. Intelligence better sees through deceit and misdirection, such as laying a trip wire and digging a pit trap right where your foot would land after stepping over it.

An animal's options to danger are freeze, run, and fight, which do not solve the problem of how to get past the trap. You want to do that, right?

But none of this has any bearing on FINDING the trap. Knowing what to do with it is something else, and not Investigation either. In 5e it's proficiency with Thieves' Tools.

So at no point does Investigation or, by proxy, intelligence come into it. Perception is used to find traps, a tool proficiency (that uses Dex) is used to disable them.

I'm just really not sure what you're on about here. It's not true to life (where, quite literally, animal intelligence, well, ANIMALS can recognize and bypass or disable traps) and it has no bearing on the game mechanics either.

[sambojin]

The other way of doing it is just a "If the party spends some time looking around for stuff, they find it! If they don't, they'd want to have some pretty high passive perception/investigation to be given it as a freebie".

This works too.

Even on the "Hey boss, I think you missed something back there!" telepathic message from your owl familiar. So they'll go and look for it. It'll still feel pretty awesome, just as a class feature ☺️

Familiars and summons are just as good for a DM on storytelling, as they are for a PC, if used correctly. They're in your world, remember 💖

[Mjolnirbear]

You trip on it when you...don't see it. I.e. fail Perception. I guess if you're exceptionally clumsy you can trip over something you're looking at? But that ain't normal.



But none of this has any bearing on FINDING the trap. Knowing what to do with it is something else, and not Investigation either. In 5e it's proficiency with Thieves' Tools.

So at no point does Investigation or, by proxy, intelligence come into it. Perception is used to find traps, a tool proficiency (that uses Dex) is used to disable them.

Thieves tools do not require the use of Dexterity. There's no associated stat at all. It is very common that DMs do this, but it's a legacy of previous editions and of the "other uses for dexterity" in the ability scores section where the words "the DM might call" figure prominently. I use Intelligence where the player is figuring out the trap or lock, or dexterity if the figuring out part isn't necessary or relevant.


I'm just really not sure what you're on about here. It's not true to life (where, quite literally, animal intelligence, well, ANIMALS can recognize and bypass or disable traps) and it has no bearing on the game mechanics either.

If animals can recognize and bypass or disable traps, why did we bother learning to use snares and pit traps at all if they don't work? If we can't trap a measly rabbit, why bother learning trapping at all?

But we can trap them, we did learn it, and it's because of our brains we can do so. Some species are exceedingly clever or some individuals lucky, but we use traps because they work.

It has any bearing on a skill check the DM calls for, because I decide the relevant stat. That's the mechanics of calling for an ability check: deciding what ability is relevant. And when there's confusion about what stat to use, I consider whether you are engaging your brain. If you're engaging your brain, I call for an Intelligence check, whether it's searching for secret doors or disabling traps or identifying locks.

And you're missing the rest of my initial post, where I said "I dislike Perception, then Investigation". You find the wire (or the mouse does), now you have to figure out what the wire does, what danger you're in, and how to safely get past the trap. The finding part was never the issue I was describing. That post and subsequent ones in this thread all refer to getting past the trap, not finding it, because I thought you'd read my entire point.

Because "you see a wire crossing the space between you and the rest of the hall" will then be followed with by "it looks like it will trigger a trap" and then by "if you cut the wire the trap will also trigger, but if you..." I don't make my players roll a million checks to decide one minor challenge. Seeing the wire isn't the challenge, getting past the trap is. If the actions the players use in figuring our the trap and getting past the trap requires intelligence, I will condense the checks to the most relevant ability score instead of calling for seven different rolls.

I mean, unless they just choose a different path and turn around as soon as they see a wire. My players have never, ever done that, but if they did, I could see calling for only a perception check.

[Rynjin]

Thieves tools do not require the use of Dexterity. There's no associated stat at all. It is very common that DMs do this, but it's a legacy of previous editions and of the "other uses for dexterity" in the ability scores section where the words "the DM might call" figure prominently. I use Intelligence where the player is figuring out the trap or lock, or dexterity if the figuring out part isn't necessary or relevant.

The book specifically calls it out as a potential use for Dex, and pretty much every single mention of Thieves' Tools mentions a Dexterity check, and a specific DC (locks, manacles, etc. are a DC 15 Dex check). The default assumption is Dex, with a little wiggle room for rare scenarios something else might be called for. Assuming that any given check for Thieves' Tools is going to be a Dex check is entirely reasonable, the same as assuming if you're trying to tear open a chest with a crowbar it's gonna be Str in 99.99999% of circumstances.



If animals can recognize and bypass or disable traps, why did we bother learning to use snares and pit traps at all if they don't work? If we can't trap a measly rabbit, why bother learning trapping at all?

They work because you hide them. If you set a rope snare out in the middle of bum**** nowhere, with no attempt to hide it, it ain't gonna catch a rabbit. Or it will, sometimes, because animals vary in experience and intelligence the same way humans do.

But when you're setting a snare, or other trap, your primary concern is going to be taking advantage of the animal's usual instincts, habits, and so on. Put them in high traffic (for the animal in question) areas, hide them, bait them, some combination of the three.

This is not a zero sum game where traps either work on animals 100% of the time, or zero. It's going to vary depending on the skill of the trapper, and the wariness of the animal.




And you're missing the rest of my initial post, where I said "I dislike Perception, then Investigation". You find the wire (or the mouse does), now you have to figure out what the wire does, what danger you're in, and how to safely get past the trap. The finding part was never the issue I was describing. That post and subsequent ones in this thread all refer to getting past the trap, not finding it, because I thought you'd read my entire point.

Because "you see a wire crossing the space between you and the rest of the hall" will then be followed with by "it looks like it will trigger a trap" and then by "if you cut the wire the trap will also trigger, but if you..." I don't make my players roll a million checks to decide one minor challenge. Seeing the wire isn't the challenge, getting past the trap is. If the actions the players use in figuring our the trap and getting past the trap requires intelligence, I will condense the checks to the most relevant ability score instead of calling for seven different rolls.

I mean, unless they just choose a different path and turn around as soon as they see a wire. My players have never, ever done that, but if they did, I could see calling for only a perception check.

I'm still unclear where, at all, Investigation comes into it is I think my issue. Is that a common rule people roll with? Investigation to find and determine the effect of a trap? Maybe that's where the disconnect is here; I'm not sure why "Perception, then Investigation" was mentioned at all. Because by the book, and by all logic as I know it, Investigation, and the Intelligence stat, should never enter into this equation at all.

It's Perception...then Thieves Tools. Which is usually a Dex check.

[Mjolnirbear]

The book specifically calls it out as a potential use for Dex, and pretty much every single mention of Thieves' Tools mentions a Dexterity check, and a specific DC (locks, manacles, etc. are a DC 15 Dex check). The default assumption is Dex, with a little wiggle room for rare scenarios something else might be called for. Assuming that any given check for Thieves' Tools is going to be a Dex check is entirely reasonable, the same as assuming if you're trying to tear open a chest with a crowbar it's gonna be Str in 99.99999% of circumstances.

Your default assumption is dex. So is a lot of people. But there is no rule, at all, saying "thieves' tools are used with dex”. Your word exactly is "assumption".

You assume it's dex and if that works for you great. I use "DM determines relevant ability score". If they have to figure it out, then it's intelligence. If they don't, it's likely dexterity.



They work because you hide them. If you set a rope snare out in the middle of bum**** nowhere, with no attempt to hide it, it ain't gonna catch a rabbit. Or it will, sometimes, because animals vary in experience and intelligence the same way humans do.

But when you're setting a snare, or other trap, your primary concern is going to be taking advantage of the animal's usual instincts, habits, and so on. Put them in high traffic (for the animal in question) areas, hide them, bait them, some combination of the three.

This is not a zero sum game where traps either work on animals 100% of the time, or zero. It's going to vary depending on the skill of the trapper, and the wariness of the animal.

I never claimed it was. I said intelligence will help you determine what a trap does and the best way to ruin it, avoid it, or turn it to your advantage. For instance, by "taking advantage of an animals instincts and habits" to snare a rabbit despite their high perception scores.




I'm still unclear where, at all, Investigation comes into it is I think my issue. Is that a common rule people roll with? Investigation to find and determine the effect of a trap? Maybe that's where the disconnect is here; I'm not sure why "Perception, then Investigation" was mentioned at all. Because by the book, and by all logic as I know it, Investigation, and the Intelligence stat, should never enter into this equation at all.

It's Perception...then Thieves Tools. Which is usually a Dex check.

The argument comes from "use perception to notice the scratch in the floor, then investigation to figure out it's a secret door" argument. Which is a valid argument and makes sense but which I still disagree with from a practical POV.

Look. You run it however you want. I'm tired of arguing with you about how I run it in my games. You keep your perception superskill that covers all matter of figuring stuff out simply because everyone wants to dump INT.

I will continue to call for Intelligence checks when an ability check requires engaging your brain instead of your instincts, and making a useful distinction between investigation and perception that is easy to explain and makes sense to me and my table.

All I wanted was to offer an option for people they might like and might find useful. If you don't, then don't use it.

[KorvinStarmast]

I use Intelligence where the player is figuring out the trap or lock, or dexterity if the figuring out part isn't necessary or relevant. That's an interesting approach. I'll see what my players think of that.

[JLandan]

I always thought perception meant "finding stuff you weren't looking for" and investigation was "finding stuff you are looking for". Hm.

Very well put. I have to advise that I will use this, but you will get full attribution.

To the original posted question:

First; if the object is paramount to the story, just make them find it.

Second; if it is not, there's three options
A) passive perception for everyone
B) active investigation for anyone looking
C) group check (an often overlooked mechanic) investigation for everyone.

If it's important but not necessary, give them a clue. A real clue, nothing so cryptic they can't figure it out. So they'll at least look for it. And lower the DC.

If it's not really important, then it's not important. They find it or they don't. It doesn't matter.

[Psyren]

I'm with Mjolnirbear on this one.

A reminder that tool proficiency doesn't just relate to physically employing the tool or its components - it also covers "facets of the trade or profession that are not necessarily associated with using the tool" (XGtE 78). Moreover, thief tool proficiency itself specifically grants you "general knowledge of traps and locks" (XGtE 84).

In other words, Thief Tool proficiency gives you broader benefits than physically cutting a tripwire or jamming a pressure plate. It gives you insights into the general workings and commonalities of all traps and locks. Moreover, the tools themselves include components that are usable with non-Dex ability scores, like the mirror.

An Intelligence (Thief Tools) check to disrupt a magic trap is not just supported in the rules, it makes sense within the fiction.

[JLandan]

I'm with Mjolnirbear on this one.

A reminder that tool proficiency doesn't just relate to physically employing the tool or its components - it also covers "facets of the trade or profession that are not necessarily associated with using the tool" (XGtE 78). Moreover, thief tool proficiency itself specifically grants you "general knowledge of traps and locks" (XGtE 84).

In other words, Thief Tool proficiency gives you broader benefits than physically cutting a tripwire or jamming a pressure plate. It gives you insights into the general workings and commonalities of all traps and locks. Moreover, the tools themselves include components that are usable with non-Dex ability scores, like the mirror.

An Intelligence (Thief Tools) check to disrupt a magic trap is not just supported in the rules, it makes sense within the fiction.

Tool use, and the checks there of, are often subjective to differing abilities, and often require a DM call as to which ability to use. Another example:

Making a steel suit of armor using smithing tools.
Does one use Str for working metal?
Does one use Dex for fine work like joints?
Does one use Dex or Cha for filigree or embossing decoration?
Does one use Int for general design of the suit?

One common mistake, at least at my table, is using Animal Handling to operate a wagon and team. By RAW, it should be Land Vehicle tool set, with whatever ability modifier the DM deems appropriate.

[Psyren]

One common mistake, at least at my table, is using Animal Handling to operate a wagon and team. By RAW, it should be Land Vehicle tool set, with whatever ability modifier the DM deems appropriate.

I wouldn't call that a "mistake" - rather, I would allow either approach to work. The Fighter who learned to drive land vehicles as a footman and the Ranger who is adept at getting the horses/oxen pulling it to do what he wants would thus both get to apply their proficiency bonus to the check*.

*And most likely, simply driving a wagon and team wouldn't involve a check at all. A check would be more likely if they're attempting a dramatic maneuver of some kind like shaking pursuers during a chase, or stopping suddenly before they might trample a wayward NPC.