D&D 5E Perception/Investigation/Medicine?

[Morrus]

This was prompted by somebody who asked me "what's the difference between Investigation and Perception"?

That bit in Lost Mine where the PCs find the two dead horses near the beginning highlighted to me different skills that could be used to gain information, especially in a CSI type scenario.

So examining those two horses - Perception? Invetigation? Medicine?

The info to be gained is pretty much:

1) Arrows are goblin-made.
2) The horses have been dead for a day.

Additionally, there's some tracking info that could be gained through Survival.

What are your personal guidelines on the difference between a Perception and an Investigation check? What about Medicine when the target is a dead body? How have you handled it so far?

 

[Ranes]

1. This warrants an investigation check to me, if the player inspects the arrows. It's the attention to detail the player is applying to the situation that suggests investigation. I see perception being more appropriate to the wider environment. But I can see a valid interpretation of perception applying here.

2. That seems to me to be a medicine check. It's about knowing how far necrosis has set in.

Edit: To add, I get the impression that perception is more about noticing things, whether looking for them or not, whereas investigation seems to be an active pursuit of the PC in relation to looking for clues.

 

[77IM]

I'd allow any or all of these skills, as I feel it's better to keep the game moving than to dither over exactly which skill is best.

That said, I might vary the DC based on skill, with more specific or appropriate skills having a lower DC. For something like time of death, I might call this a DC 10 Investigation check, DC 15 Perception check, or automatic if you are proficient in Medicine.

 

[Quickleaf]

1) Arrows are goblin-made.

Investigation DC 10. Automatic for rangers with favored enemy (goblins), PCs who've fought a lot of goblins in their day, PCs with a goblin in the party (who they can get an honest answer out of), or a PC with artisan tool proficiency covering arrowcraft.

2) The horses have been dead for a day.

Medicine DC 10. Investigation DC 10 might provide clues based on what I know of forensics, but I would not come out and say "one day ago", rather I'd say "rigor mortis has set in, the wounds are fresh, there are flies by no larvae and no sign of animals feeding on the carcasses."

What are your personal guidelines on the difference between a Perception and an Investigation check? What about Medicine when the target is a dead body? How have you handled it so far?

Perception is about detecting the presence or source of something.

Investigation is about examining
something you're already aware of and deducing conclusions from known facts.

A good example that gets into the grey areas is eavesdropping. The rogue comes to a door and listens to it. Clearly this is Perception to detect presence of creatures. Lets say the DM reports goblin voices. The PC happens to speak goblin, and so the DM shares a few overheard words "...nasty dwarves... Thodgrim... slaves... the shaman." The rogue player wants to listen further to get a better picture if what they're talking about, asking what check they can make. Perception or Investigation?

In this case I'd be tempted to go with neither. The rogue heard all they could thru the thick wooden door. Nothing has changed in the scenario so I don't see why another check would gain anything.

However, lets say that the rogue just wants to keep listening, then no check is needed, I just keep given them broken bits of goblin dialogue. Lets say the rogue wants to pinpoint (as accurately as possible) the location of the goblins; that's Perception for sure and could either be based on the previous check or a new one, depending on the scenario. Lets say the rogue wanted to deduce what some of the missing words were to figure out the gist of what the goblins were talking about; that's Investigation for sure.

 

[Tormyr]

Perception to perceive (see/hear/sense) something: hidden characters, traps

Investigation to determine something using the information at hand: the arrows are goblin made, scratches in the floor indicate there is a trap behind the door.

Medicine to determine medical stuff: the horses have been dead for a day, the character is poisoned, the character has ingested a Kyuss slow worm.

Those are my general guidelines.

 

[DEFCON 1]

After reading "Wisdom (Perception) check" about six dozen times in both passive and active form throughout Hoard of the Dragon Queen and every other check appears like 10 times total... it reiterated a feeling of mine that Perception as a skill is just too much. Thus I've already made my own change for my own game:

Wisdom is used only for Passive spotting or noticing. Intelligence is used for Active spotting or noticing.

Perception is a "danger sense" for noticing enemies... only used against things that could make sound *and* motion that you could possibly spot or hear. Basically any living things that are hiding from you.

Investigation is for details... used to notice or find cracks, wires, covered things, and other inanimate objects that don't move. So traps and secret doors would be included in this.

Then you combine the pairs as you need. When people are hiding from you... your Passive Perception (Wisdom (Perception) + 10) is the number you always have out there to notice them. If their Dexterity (Stealth) is higher than that and thus you don't passively notice them... you can use an Action to roll Intelligence (Perception) to find them on your turn.

By the same token... your Passive Investigation is (Wisdom (Investigation) + 10). When walking through a dungeon, you will notice any secret doors or traps whose DC is less that that. If you don't.... you can use an action to roll Intelligence (Investigation) to find them.

This will make both skills used more equally and make me much happier as a DM.

 

[fba827]

General rule of thumb for me has been....

Checking something specific -- a body, a desk, a bookcase, etc. are investigation.

Checking a room or the surroundings, stuff on that scale, is perception.

Slight tangent but I really think that investigation and perception aren't both needed. You have a wisdom check, and if you're trained in perception you add your proficiency, or you have an intelligence check and if you're trained in perception you add your proficiency. That precedent is already there about using the appropriate ability score and then adding proficiency if proficient. Anyway that's just my ramble.

Oh, medicine can be used in place of investigation if it's a body that you're checking. That's how you learn any medical information ( such as maybe length of death, or cause of death though cause of death might also be found through investigation)

 

[GX.Sigma]

Perception: There is a dead horse with black arrows in it. (Automatic success, no need to roll)
Investigation (or History, I guess): The arrows are of goblin-make.
Medicine: The horse has been dead for a day.

 

[Tormyr]

Perception: There is a dead horse with black arrows in it. (Automatic success, no need to roll)
Investigation (or History, I guess): The arrows are of goblin-make.
Medicine: The horse has been dead for a day.

Followed up shortly by:
Passive perception insufficient.
Perception: "You look down and see black arrows sticking out of you." (Automatic success, no need to roll)
Investigation: They are the same as those in the horse. (Automatic success, no need to roll)
Medicince: Your blood is flowing out of the arrow holes. (Automatic success, no need to roll)

 

[dd.stevenson]

What are your personal guidelines on the difference between a Perception and an Investigation check? What about Medicine when the target is a dead body? How have you handled it so far?

In my game we do our exploration free-form, but it seems reasonably clear to me the designers intended the DM to choose the best-sounding skill based on the player's narration.

"I'm giving the scene a good once-over looking for clues." Investigation.
"Does anything pop out at me as being out of place?" Perception.
"I'm looking over the horse's body. Can I tell how it died?" Medicine.