D&D 5E Perception vs Investigation

[Fralex]

Intelligence (Investigation): "Chuck Dagger tries to figure out how this trap on the door works."

And every example above assumes that the action Chuck is taking has an uncertain outcome or else no check, passive or otherwise, would be necessary.

See, this is the sort of thing where I feel Investigation would be better-replaced by an Architecture and Engineering check. Your knowledge of how mechanical things work would determine whether you notice and figure out the hidden mechanism, 'cause you know what to look for.

 

[Jester David]

So you treat Perception as more of a saving throw than a skill? Something you only do in response to something else?

I don't think I summarized my very abstract thoughts well in that post. I'm happier with later posts in the subject.

 

[Quickleaf]

I tend to view active Perception is any time the character is stretching their senses: trying to see in the distance, trying to track down an odd smell, feeling for a trickle of air denoting a secret passage, trying to hear through a door, etc. Any time the limits of the sense comes into play, where the average person might not be able to automatically detect something. Times, when as a DM, I'd use the term "keen senses".

So when do you use passive Perception (if at all)? Only in a 3e 'take 10' sense? Or do you ever use it for noticing pits and such?

Investigation tends to be less about what can or cannot be easily seen, and more noticing what is already visible. The subtle clues. The worn patch of the floor denoting sliding stonework, the absence of a wedding band on a finger, etc. Piecing together the evidence of your senses and making connections and inferences. If a player asks the right questions, I'd generally give them the answers to a successful Investigation check. "Are any patches of the wall unusually smooth?" "Are any of the flagstones loose?" Investigation is just your character doing what the player might not be aware of. But in Perception, the character either sees it or doesn't and no asking questions will reveal the answer.

I totally agree with your assessment. Absolutely spot on.

I tend to think of rounds versus minutes. If what you're doing takes longer than an action or two, it shifts from Perception to Investigation. You can glance at a hallway or wall and, if your eyes spot something odd you succeed. But if you stop to actually make a decent check, then it becomes Investigation.

A rogue finding traps, to me, seems very much like an Investigation check. You're looking for clues and signs of the trap. It's a slow, methodical process.

Thats interesting. So, you see searching for traps as piecing together evidence about what is readily observable and making deductions about how that indicates a trap?

I guess that makes sense. Perception might notice the poison needle in the skeleton or the lack of foot traffic on the rug.

 

[Nebulous]

At the end of the day though? It probably doesn't amount to much to get this "wrong." It comes down to how you're describing your scenes and whether or not the actions described by the players have an uncertain outcome. Consider describing the environment in an interesting way that invites the players to engage with the exploration pillar by telegraphing threats and clues. In the doing, you will encourage players to make deductions about their environment and take actions accordingly. They can therefore sometimes rob randomness of its power and solve for X without ever needing to roll a die.

My players rely on their 18 and 19 Passive perceptions to detect tricks and traps before they come across them. I personally don't feel like we're doing this right. It irks me.

 

[Jester David]

So when do you use passive Perception (if at all)? Only in a 3e 'take 10' sense? Or do you ever use it for noticing pits and such?

I tend to forget and/or subconsciously ignore passive Perception.
It's handy for when monsters try and sneak up on the party and determining encounter distance and surprise, but I tend to handwave it the rest of the time. When I write adventures I tend to be aware of their Perception numbers, so PP becomes me asking "do I want them to know this automatically or require a roll?" If I'm okay with the former, I'm generally fine with it regardless of what the PP actually is. If it's the latter I either have to make the DC high enough to require a roll of 11 of better from the person with the highest Perception. Or ignore passive and just ask for a roll.

Thats interesting. So, you see searching for traps as piecing together evidence about what is readily observable and making deductions about how that indicates a trap?

I guess that makes sense. Perception might notice the poison needle in the skeleton or the lack of foot traffic on the rug.

I go back and forth depending on the traps. For example, Indiana Jones goes through a trapped temple using his brains in Raiders and Last Crusade. But you can make a case for noticing the subtle clues and signs of a trap.

Really, Perception spots traps and is handy for finding well hidden traps. Investigation is good for searching for suspected traps or figuring out how they might work.

 

[iserith]

My players rely on their 18 and 19 Passive perceptions to detect tricks and traps before they come across them. I personally don't feel like we're doing this right. It irks me.

What is it that irks you, specifically? That they're noticing hidden threats more often than not or that there is nothing interesting arising from their detection? Maybe there's a lack of player skill involved outside of how well they can construct a character? Or a lack of roleplaying because the checks matter more than the decisions and characterizations of the players?

A few things to keep in mind with regard to this:

1. If the (non-ranger) characters are doing almost anything other than constantly keeping an eye out for hidden threats, they don't get a check, passive or otherwise.

2. To get a chance at noticing something, the player has to put his character in a position to do so by being reasonably specific about what he or she is doing.

3. There's never a check - passive or otherwise - when the outcome is certain. If they've taken an action that definitely causes them to fail to notice a hidden threat, then they don't notice it, no roll. (On the flip side, if they've taken an action that definitely causes them to notice a hidden threat, then they notice it, no roll.)

 

[Ristamar]

2. To get a chance at noticing something, the player has to put his character in a position to do so by being reasonably specific about what he or she is doing.

This is also an area where the established marching order can be crucial. If the PC with a big perception bonus isn't up front, his allies are more likely to fall victim to traps before the respective passive score comes into play.

 

[Greenstone.Walker]

There is a short story where Sherlock Holmes and another character, his brother I think, are looking out the window and making some amazing deductions about people.

Things like "You must have been the captain of a sailing vessel" because a person has a small tattoo on their arm, coloured in a way only done in China, but they are wearing well-to-do clothes so probably weren't a common seaman.

In terms of D&D, Perception notices the small tattoo on the arm and Investigation deduces the person must be a sailor.

If a character has high Perception but low Investigation then they will notice the tattoo but not make any connection. If they have low Perception and high Investigation then they would miss the tattoo, but if it were pointed out to them then they would make the deduction the man was a sailor.

 

[Fralex]

There is a short story where Sherlock Holmes and another character, his brother I think, are looking out the window and making some amazing deductions about people.

Things like "You must have been the captain of a sailing vessel" because a person has a small tattoo on their arm, coloured in a way only done in China, but they are wearing well-to-do clothes so probably weren't a common seaman.

In terms of D&D, Perception notices the small tattoo on the arm and Investigation deduces the person must be a sailor.

If a character has high Perception but low Investigation then they will notice the tattoo but not make any connection. If they have low Perception and high Investigation then they would miss the tattoo, but if it were pointed out to them then they would make the deduction the man was a sailor.

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."

 

[Nebulous]

What is it that irks you, specifically? That they're noticing hidden threats more often than not or that there is nothing interesting arising from their detection? Maybe there's a lack of player skill involved outside of how well they can construct a character? Or a lack of roleplaying because the checks matter more than the decisions and characterizations of the players?

A few things to keep in mind with regard to this:

1. If the (non-ranger) characters are doing almost anything other than constantly keeping an eye out for hidden threats, they don't get a check, passive or otherwise.

2. To get a chance at noticing something, the player has to put his character in a position to do so by being reasonably specific about what he or she is doing.

3. There's never a check - passive or otherwise - when the outcome is certain. If they've taken an action that definitely causes them to fail to notice a hidden threat, then they don't notice it, no roll. (On the flip side, if they've taken an action that definitely causes them to notice a hidden threat, then they notice it, no roll.)

yeah, that it's dull, that's what bothers me. And I think there's the constant expectation of "I can't be surprised." The high perception DC becomes a zone/aura of protection around them at all times.