D&D 5E Perception vs. Investigation in UA Traps Revisited - A problem again?!

[lkwpeter]

Hey all,

there were times, where a lot of players had problems to differ between Perception and Investigation (maybe some people still do). But after some time it was quite clear:

• Perception means noticing things (through senses like spotting, hearing, tasting, etc.)
• while Investigation means deduction based on evidence.

So much so far.


A couple of weeks ago, WotC released Unearthed Arcana Traps Revisited that includes playtest rules for traps. Reading it, I realized that they call for either a Perception check or an Investigation check to avoid the trap. The rules state:

A Wisdom (Perception) check that reveals a tripwiredoesn’t tell the players what happens if they break the tripwire. They spot it before blundering into it, but must still decide what to do next. The nature of the item is not in question, but you might not spot it. A successful check reveals it.

An Intelligence (Investigation) check reveals that the scuff marks and wear pattern show that a doorknob can turn both ways, but is most often turned clockwise. The players must still decide how to open the door. The item is obvious, but its true nature is obscured. A successful check reveals the clues that point to the item’s purpose.

For the moment, this sounds plausible, but wouldn't an Investigation check require noticing those hints at first? What if a character doesn't see the evidence? Then it wouldn't be able to make deductions from it. And "scuff marks on a doorknob" are not so obvious that they doesn't require a Perception check, because they are an "auto success", are they?

It's even getting more confusing by the following example, given on page 2 (and there are more example like this within the rules):

Fiery Blast
Simple trap (level 5–10, dangerous threat)

Trigger. Anyone stepping on the mosaic causes fire to erupt from it. Those openly wearing holy symbols of Pyremius don’t trigger this trap.

Countermeasures. A DC 15 Intelligence (Investigation) check reveals ash and faint burn marks in the shape of the fiery cone created by this trap. A DC 15 Intelligence (Religion) check allows a creature to destroy the trap by defacing a key rune in the mosaic; failing this check causes the trap to activate. A successful dispel magic (DC 15) cast on the runes destroys the trap.

The descriptions speaks of "faint burn marks". So why is there no Perception check required to notice them? Usually "faint" indicates that something is "hard to see", isn't it? Contrary to this, "a DC 15 Intelligence (Investigation) check reveals ash and faint burn marks", although revealing requires Perception, not deduction (Investigation)!

So, it seems like WotC somehow handles those checks as if there would only be either one of them valid. But wouldn't it be much more plausible to require both checks for

1. noticing a trap (by senses) and
2. make deductions from those clues (if they are not obvious).

In my view, deduction can only be made, if the evidence has already been noticed/spotted!


I like the new rules about traps, but I think WotC should overthink this point. It seems like their intention of keeping the game simple is actually making it confusing (again).

Why not setting two DCs for each trap - one for perception and one for investigation. If things are really obvious (e.g. a pit trap with spears inside it), the DC for Investigation/Perception is low. But at least, that would be consistent.

Would be interested in your opinions.

Regards
Peter

 

[MarkB]

I've always understood that Perception is pretty much an instant-use snapshot of what you perceive, whilst Investigation is about a more thorough, detailed examination, often involving some physical interaction. They're both about presenting the facts to the player, not about performing deductions on the player's behalf.

 

[lkwpeter]

I've always understood that Perception is pretty much an instant-use snapshot of what you perceive, whilst Investigation is about a more thorough, detailed examination, often involving some physical interaction. They're both about presenting the facts to the player, not about performing deductions on the player's behalf.

No, this is wrong. This is how it worked in 3E. In 5E Perception/Investigation works as described. There are several statements of the game designers. Furthermore, the rules I stated in "Unearthed Arcana Traps Revisited" make it quite clear as well.

The problem is not the definition. The problem is the usage of these skills.

 

[iserith]

I haven't read the UA article, but skimming your snippets, it makes sense in the way I present traps, that is, via telegraphing them in Step 1 of the basic conversation of the game. Telegraphing is providing a clue when describing the environment. In the case of the fiery blast trap, the clue would be ash and burn marks. The subsequent Investigation check would then reveal its shape from which the PCs can deduce the AOE of the trap. There is nothing in the text you quoted that indicates the burn marks are hidden and thus require a Perception check to find.

I'll add that none of this requires a check either. That's up to the DM based on the player's stated goal and approach compared to the fictional situation at play.

 

[Quickleaf]

[MENTION=6804713]lkwpeter[/MENTION] There's inconsistencies in the UA article, but where I *think* they intended to go with their design was toward... or at least, this is how I tend to run traps...

In most cases, minor details (which may be interpreted as a indicating a potential trap by players, or they may be interpreted as something else, or overlooked entirely) are automatically communicated by the DM.

In most cases, Perception (whether passive or a check) doesn't reveal a trap. Instead, it reveals details about the environment which a savvy player may then interpolate as indicating a potential trap. Getting this narration right as a DM can be tricky, and I'd advocate for better examples in the UA article or whatever it becomes.

NOTE: Tripwires are a trap trigger that's an exception to the above rule, as finding a thin wire stretched across a passage pretty much screams "TRAP!"

Investigation involves some degree of interaction – it's a step beyond just observation. Brushing your thumb over a doorknob to feel the scuffing and wear patterns. Kneeling down to closely examine a dark patch on the floor, sifting through some of the material and sniffing it to determine that it is ash, and deducing from the cone-like shape its origin point.

 

[Caliban]

Perception is what you are aware of. Investigation is drawing conclusions from what you are aware of.

Perception finds things, Investigation tells you what they mean.

 

[jaelis]

My interpretation would be that it assumes if you look closely, you will see the scuff and burn marks, no check required. If you were trying to do it quickly or under adverse conditions, I would feel fine in requiring a perception check too.

 

[DEFCON 1]

This is another example for why I make things really easy on myself.

Perception is for finding hidden people, creatures and other living things that can move around and leave tracks/sounds and stuff.

Investigation is for finding hidden objects, traps, doors and other immobile things that someone has had to do work to try and hide and make them less noticeable.

Way easier to adjudicate and it keeps Perception from being the uber-skill.

 

[doctorbadwolf]

I've always understood that Perception is pretty much an instant-use snapshot of what you perceive, whilst Investigation is about a more thorough, detailed examination, often involving some physical interaction. They're both about presenting the facts to the player, not about performing deductions on the player's behalf.

Right, similar to spot and search.

 

[Caliban]

Right, similar to spot and search.

Except that investigation really isn't equivalent to search. At least not the way it's presented in the PHB. It's drawing conclusions about things you already know, not finding new things. (Although the skill description does allow for reading tomes or scrolls to find things to be done with an investigate check - an inconsistency on their part. I'd probably allow a perception (int) check instead if a player requested it).