D&D 5E Perception vs Investigation

[Sunseeker]

Sure, investigation could be applied if you're trying to deduce something based on clues obtained during a conversation when the outcome of the deduction is uncertain. But that's just one situation where Investigation might be used to resolve uncertainty.

At first glance, perception/investigation looked like the spot/search dichotomy in 3e.

The former is alertness and awareness of what's significant among the things you happen to see, the latter is close examination and analysis. They could almost be the same proficiency with spot/listen/perception being passive & wisdom based and search/investigation being active & int-based.

I think you're on to something with the Wis/Int difference. Wisdom is your ability to recognize things quickly from experience, Intelligence is your ability to understand them. So I think it's fair to say that one might recognize a trap with Perception, but have no clue how it functions without good Investigation.

 

[SirAntoine]

It's a little clearer in the DMG, but I agree - the definitions in the PHB are really, really bad.

Perception allows you to notice something is wrong.
Investigation allows you to determine what is wrong.

In the case of traps, Perception allows you to notice that there's something wrong about the area - less travelled, strange holes, that sort of thing.
Investigation allows you to discover a pit trap or a flame jet or whatever, with a little searching.

In this case, you can only attempt a disarm check if you've succeeded at an Investigation check first.

However, that may not be what's intended.

I'm very tempted to instead of putting in an Investigation or Perception DC to instead have a "Detect DC" and let individual DMs work out what skill applies. I'd appreciate any thoughts on this!

Cheers!

I would prefer that.

 

[Psikerlord#]

Passive perception and perception and investigation are a mess.

I typically say wisdom (perception) when you are reacting to something (ambush, trap, whatever) but Int (investigation) if you tell me you're taking positive action, looking around, ie investigating!

I also often just say make a wis or int perception or investigation check ... and let players choose.

Frankly the line is so blurry I am tempted to just do away with investigation entirely, let perception do all the work, and just say the players can always use either Wis or Int, their choice. So any rules reference to investigation would mean perception (eg: if your background gets investigation, it now gets perception instead).

I'm not sure there is any great usefulness in separating the two concepts in the way it's been done.

 

[Celtavian]

I agree. They are very bad. I'm assuming Investigation is meant to be like Search and Perception is Perception. I tend to use them interchangeably myself for many situations. My only hard rule is Perception goes against Stealth, not Investigation.

 

[Fralex]

And then there's the weird thing where if you're looking for clues, but you're doing it to track someone, it's no longer Investigation, but Survival.

 

[77IM]

I often allow either skill to work. I used to be adamantly against "skill overlap" on the grounds of niche protection, but now I am in favor of overlapping skill functions. It turns out that allowing players to do stuff encourages them to do stuff and keeps the game moving, and allowing different skills to produce the same outcome lets each PC seem a little bit different.

E.g., in my current group the default "scouting party" is a very stealthy monk and very very stealthy rogue. They can both spot traps -- the monk using Wisdom (Perception), the rogue using Intelligence (Investigation). But the monk is much better at spotting a hidden ambush, and the rogue is much better at actually disarming the trap.

I have similar policies in place for Athletics vs. Acrobatics (for climbing and jumping), Nature vs. Survival (for identifying edible plants, predicting the weather, that sort of thing), Arcana vs. History vs. Religion (for different sorts of monster lore and other lore -- often these skills will generate slightly different information), and all the social skills (my players typically use a multi-pronged approach of combining threats with promises of aid and a few lies thrown in for good measure; the difference between the three skills is mostly in how NPCs react on a failure).

 

[Steven Winter]

Until there's some official measure to clear up the vague and unhelpful rules in this area, I consider it to be an official blessing to do whatever suits your taste.

Decades ago, I was a big fan of perception-type skills in RPGs. Over the years, I've come to see them as generally a bad thing -- or at best, as a good thing badly implemented. A person's ability to notice and use small clues should be dependent on his or her knowledge of the thing in question, not on some vague "sixth sense," which is how most games use Perception. Looking for tracks in the wilderness? Make a Nature check. Looking for a secret door in a dungeon? Make a Dungeoneering check. Trying to figure out how to open a secret door? Depending on the door, that could rely on Dungeoneering, Arcana, Nature, Streetwise, Thievery, raw Intelligence, or Dexterity if it depends on sensing a tiny catch with your fingertips. Including a blanket Perception skill -- or worse, two competing skills with no clear border between them -- devalues all the other skills and clashes with real-world experience.

Steve

 

[MerricB]

Thinking about it, Search, Spot and Listen were the successors to the oD&D/AD&D mechanics of Find Traps (thief), Detect Secret Doors (elf) and Hear Noise (thief). By 5E, they became Investigation and Perception. Long and slightly odd history of the mechanics - before the unified mechanics of 3E, they were handled quite differently in the rules of AD&D, and probably even more differently from table to table...

(I have a feeling that some early DMs often allowed a thief to find traps automatically, then only made the roll to remove them successfully).

Cheers!

 

[mlund]

It's just a matter of Perception vs. Cognition, and that's why they are broken apart they way they are. While the two are often used in concert, someone who is very perceptive (in the sensory sense of the word) may be very bad at actually realizing the meaning of what they are perceiving while someone who is very good at discerning clues might have poor ability to locate them by just observing their surroundings.

Animals generally have great Perception, but basically no capacity for Investigation. A bloodhound can track with its nose, but it can't figure out a fugitive's destination, take a short cut, or decide to go up and down a river until it finds a place where the fugitive likely came out and start searching there to pick up the trail again.

Likewise, Mr. Magoo could have the analytical mind of Sherlock Holmes but he's not going to be able to solve the crime unless someone with exceptional Perception meticulously describes everything he or she observes about a crime scene.

Many sorts of investigative efforts are going to combine Perception and Investigation skills. Perception shows you where to use your Investigation. They'll also be plenty of times where you only need to use one or the other because the other part is obvious. If you find the seam to a secret door and it just opens inward when you push on it hard enough that's all Perception and no Investigation check is rolled. Likewise if someone has just fled the scene of a ghastly murder without time to cover his tracks all the evidence is out in the open. Analyzing the crime scene is purely an exercise in Investigation and requires no Perception roll. Use Perception and Investigation independently if the other one's role is so simple it should require a roll.

Marty Lund

 

[jgsugden]

My simple approach: Perception is detection, other skills are understanding. You may wish to use just perception, just another skill or both depending upon the circumstance ... and make different decisions even when the fact pattern is similar.

For example, let's say that there is a trap dungeon with three rooms. In each, the PCs must find the puzzle and then solve it to move on to the next room.

Room 1: The puzzle is a set of giant buttons on the wall that must be pressed in the right order. The order is hinted at by the symbols on the buttons. In this instance, I might have the party skip a perception roll (the buttons are easy to see). I'd ask them what they want to do to interact with or view the buttons and then give them an investigation roll (perhaps with advantage or disadvantage) with the results determining how many additional hints or misleads I give them.

Room 2: This room's puzzle is that the exit is a secret door in the floor of the center of the chamber. Once you find it, all you have to do is pull it open. This would be a pure perception roll to see if they find it with no other roll involved.

Room 3: This room is filled with thousands of tea cups. Each teacup is placed carefully on a shelf. There are dozens of different style of teacups. Each teacup has a letter on the bottom. If the PCs study the teacups, they can realize that there is a pattern to the placement of the teacups. Once they figure out the pattern, they can identify which teacups to look at to get the letters ... which spell out a riddle. Then they need to determine the answer to the riddle and figure out which tea cup needs to be switched with which other tea cup to get the door to open. This would be a series of checks, some perception (do you see that the patterns in the teacups repeat?, can you find the teacups described by the riddle?) and some other (investigation to note the pattern? investigate to get clues on the riddle? arcana to determine that there is an enchantment surrounding certain of the cups?).

In the end, the answer is to let the DM determine what makes sense to the DM, to have the PCs roll the dice, and then move on without worrying if the DM's choice of skills was perfect or not. This is a subjective situation and the best thing for subjective situations in D&D is to ask the DM, get an answer and move on...