Perception vs Investigation

Hi there!

So I do struggle to understand when I should ask my players a Percepcion or an Investigation check. In certain cases it is pretty clear, but most of the time I don't really see any difference.

I'm gonna give you several situations and I'd like you to tell me which ability check is better for that situation:

- Looking for traps or secret doors (I always ask a Perception check on these).

- Trying to see if a chest has any traps (I tend to ask for an Investigation check).

- Looking for something relevant on a table, a book, a bookshelve... (I normally ask for an Investigation check).

Thanks in advance.

The actual descriptions for the skills in the rules are:

Perception: Using a combination of senses, notice something that's easy to miss.

Investigation: Find obscure information in books, or deduce how something works.

Given that, Perception is the skill that's intended to be used for all the situations you're describing. However, in practice a lot of people use Investigation for any kind of "active" searching for something.

Quote from wagnarokkr >>

The actual descriptions for the skills in the rules are:

Perception: Using a combination of senses, notice something that's easy to miss.

Investigation: Find obscure information in books, or deduce how something works.

Given that, Perception is the skill that's intended to be used for all the situations you're describing. However, in practice a lot of people use Investigation for any kind of "active" searching for something.

So the problem would be when to use Investigation, wouldn't it? When do you usually use Investigation?

Quote from JaimeVonCarstein >>

Quote from wagnarokkr >>

The actual descriptions for the skills in the rules are:

Perception: Using a combination of senses, notice something that's easy to miss.

Investigation: Find obscure information in books, or deduce how something works.

Given that, Perception is the skill that's intended to be used for all the situations you're describing. However, in practice a lot of people use Investigation for any kind of "active" searching for something.

 

So the problem would be when to use Investigation, wouldn't it? When do you usually use Investigation?

 I would say Perception is finding the secret door. Investigation is trying to determine how to open/activate the secret door.

I do think in your examples the "Looking for something relevant on a table, a book, a bookshelf..." would be Investigation. The character isn't trying to notice something that might be easily missed, they are trying to use context clues to determine what is important to them or the situation. But I don't think Perception in that case would be wrong either.

In practice if not strictly by the current descriptions, there tends to be overlap between some skills. Like, they classified getting knowledge on Celestials, Fiends, and Undead is a Religion roll, but in a lot of D&D stories you’ll find wizards and such getting involved with fiends on a purely transactional basis or creating undead purely as a mechanical exercise of magic, so it’s rather plausible that Arcana should cover a lot of the same information.

Quote from MaximusArael020 >>

Quote from JaimeVonCarstein >>

Quote from wagnarokkr >>

The actual descriptions for the skills in the rules are:

Perception: Using a combination of senses, notice something that's easy to miss.

Investigation: Find obscure information in books, or deduce how something works.

Given that, Perception is the skill that's intended to be used for all the situations you're describing. However, in practice a lot of people use Investigation for any kind of "active" searching for something.

 

So the problem would be when to use Investigation, wouldn't it? When do you usually use Investigation?

 I would say Perception is finding the secret door. Investigation is trying to determine how to open/activate the secret door.

I do think in your examples the "Looking for something relevant on a table, a book, a bookshelf..." would be Investigation. The character isn't trying to notice something that might be easily missed, they are trying to use context clues to determine what is important to them or the situation. But I don't think Perception in that case would be wrong either.

Pretty good example. I'm gonna do it in my parties! (asking for an Investigation roll in order to find the way to open the secret door; I usually just describe how the player figures out how to open that secret door he or she has found).

Quote from JaimeVonCarstein >>

Quote from wagnarokkr >>

The actual descriptions for the skills in the rules are:

Perception: Using a combination of senses, notice something that's easy to miss.

Investigation: Find obscure information in books, or deduce how something works.

Given that, Perception is the skill that's intended to be used for all the situations you're describing. However, in practice a lot of people use Investigation for any kind of "active" searching for something.

 

So the problem would be when to use Investigation, wouldn't it? When do you usually use Investigation?

The first couple things that come to mind are researching something in a library, or examining something to figure out how it works.

Many spells (and other spell-like things) that create magical illusions also specify that succeeding on an Investigation check reveals the illusion as being illusory.

Quote from wagnarokkr >>

Quote from JaimeVonCarstein >>

Quote from wagnarokkr >>

The actual descriptions for the skills in the rules are:

Perception: Using a combination of senses, notice something that's easy to miss.

Investigation: Find obscure information in books, or deduce how something works.

Given that, Perception is the skill that's intended to be used for all the situations you're describing. However, in practice a lot of people use Investigation for any kind of "active" searching for something.

 

So the problem would be when to use Investigation, wouldn't it? When do you usually use Investigation?

The first couple things that come to mind are researching something in a library, or examining something to figure out how it works.

Many spells (and other spell-like things) that create magical illusions also specify that succeeding on an Investigation check reveals the illusion as being illusory.

Oh, yeah! That's true. Trying to figure out how something works is also an Investigation check.

Oh, yeah! That's true. Trying to figure out how something works is also an Investigation check.

But somethings (how it works)  can be determined by perception as well.   The DM just needs to determine which is a better skill to roll.

Here is how I distinguish them via examples:

Example 1: Searching an Office

Looking around an office to spot possible hiding sites or hidden safes - Perception.
Looking for pressure plates / traps - Perception.
Looking for the switch that opens a secret door - Investigation
Looking through the draws of the desk in the office to find incriminating papers - Investigation.

Example 2: Searching a Crashed Carriage

Looking for survivors/bodies - Perception
Looking for a missing wheel or lost trunk / chest - Perception
Looking for bumps or debris in the road or skid marks - Perception
Looking for evidence of sabotage of the carriage/road - Investigation
Trying to determine what kind of weapon killed the carriage driver or where the driver was attacked from - Investigation
Determining which body is likely the driver vs a passenger vs an attacker - Investigation
Looking for tracks for where the horses ran off to - Survival
Looking for good perches / hiding locations from which to ambush a cart on the road - Survival

Example 3: Searching a dungeon room

Looking for possible traps - Perception
Looking for hidden monsters - Perception
Determining how a puzzle or trap mechanism works (includes identifying levers / buttons that control it) - Investigation
Deciphering history/lore shown in pictographs, paintings or sculptures - Investigation
Recalling what is known about the history / lore of the dungeons - History

Example 4: Searching a haunted house

Looking for corpses, ghosts - Perception
Listening for footsteps, or spooky voices - Perception
Looking for secret passages, hidden doors, or creaky boards - Perception
Identifying the source of a ghostly voice - Investigation
Determining where a beam of light or reflection originates from - Investigation
Searching for a mechanism that could remotely knock books off a shelf - Investigation
Determining what triggers a trap, or what stepping on a pressure plate would do - Investigation

Quote from Agilemind >>

Here is how I distinguish them via examples:

Example 1: Searching an Office

Looking around an office to spot possible hiding sites or hidden safes - Perception.
Looking for pressure plates / traps - Perception.
Looking for the switch that opens a secret door - Investigation
Looking through the draws of the desk in the office to find incriminating papers - Investigation.

Example 2: Searching a Crashed Carriage

Looking for survivors/bodies - Perception
Looking for a missing wheel or lost trunk / chest - Perception
Looking for evidence of sabotage of the carriage/road - Investigation
Trying to determine what kind of weapon killed the carriage driver - Investigation
Looking for tracks for where the horses ran off to - Survival

Example 3: Searching a dungeon room

Looking for possible traps - Perception
Looking for hidden monsters - Perception
Determining how a puzzle or trap mechanism works (includes identifying levers / buttons that control it) - Investigation
Deciphering history/lore shown in pictographs, paintings or sculptures - Investigation
Recalling what is known about the history / lore of the dungeons - History

Example 4: Searching a haunted house

Looking for corpses, ghosts - Perception
Listening for footsteps, or spooky voices - Perception
Looking for secret passages, hidden doors, or creaky boards - Perception
Identifying the source of a ghostly voice - Investigation
Determining where a beam of light or reflection originates from - Investigation
Searching for a mechanism that could remotely knock books off a shelf - Investigation
Determining what triggers a trap, or what stepping on a pressure plate would do - Investigation

Wow! Stunning list of examples! It's a little bit more clear now. Thank you very much for your answer. 😊

If it helps, remember that the Perception is generally used with a Wisdom check and Investigation is generally used with an Intelligence check.  In 5.5e, this is further clarified by noting that an active Perception check is generally associated with taking the Search action and an Investigation check is generally associated with taking the Study action.

Search action:  " . . . you make a Wisdom check to discern something that isn’t obvious . . . " Use the Perception skill when trying to detect a "Concealed creature or object".

Study action:  " . . .  you make an Intelligence check to study your memory, a book, a clue, or another source of knowledge and call to mind an important piece of information about it . . ." Use the Investigation skill when the area of knowledge being studied involves "Traps, ciphers, riddles, and gadgetry".

Based on the description of the Investigation skill itself, the activity of figuring something out would also seem to fall under the purview of the Study action.  So, it comes down to noticing something vs remembering something and/or comprehending something and/or figuring something out.

@JaimeVonCarstein The next piece of advice from the DMG was posted in a different thread (Investigation or Perception), but it's also related to your question:

Quote from Tarod_ >>

Quote from The_Ace_of_Rogues >>

The current DMG offers advice on when to use which here.

 I like that advice. It's also the way I've been doing it in our games. Let me put the part I found interesting here:

Using the Investigation Skill. The Investigation skill applies to situations where a character is using reason and deduction to arrive at a conclusion about something under examination. Investigation applies when characters are trying to figure out how a thing works—how to open a trick door, how to get into a secret compartment, and so on.

Don’t use the Investigation skill to determine if a character notices something—that’s the purview of Perception. For example, a successful Wisdom (Perception) check allows a character to find a secret door or something that betrays its presence, such as thin seams marking the edges of the door. If the secret door is locked, a successful Intelligence (Investigation) check would allow a character to figure out the trick to opening it—by turning a nearby statue so it faces the door, for example.

Also, for the OP, here are some threads I find interesting about this topic:

• Your opinion on this specific example of the Perception vs Investigation? 
• Finding Hidden Objects -- Investigation vs Perception 

Quote from Tarod_ >>

@JaimeVonCarstein The next piece of advice from the DMG was posted in a different thread (Investigation or Perception), but it's also related to your question:

Quote from Tarod_ >>

Quote from The_Ace_of_Rogues >>

The current DMG offers advice on when to use which here.

 I like that advice. It's also the way I've been doing it in our games. Let me put the part I found interesting here:

Using the Investigation Skill. The Investigation skill applies to situations where a character is using reason and deduction to arrive at a conclusion about something under examination. Investigation applies when characters are trying to figure out how a thing works—how to open a trick door, how to get into a secret compartment, and so on.

Don’t use the Investigation skill to determine if a character notices something—that’s the purview of Perception. For example, a successful Wisdom (Perception) check allows a character to find a secret door or something that betrays its presence, such as thin seams marking the edges of the door. If the secret door is locked, a successful Intelligence (Investigation) check would allow a character to figure out the trick to opening it—by turning a nearby statue so it faces the door, for example.

Also, for the OP, here are some threads I find interesting about this topic:

• Your opinion on this specific example of the Perception vs Investigation? 
• Finding Hidden Objects -- Investigation vs Perception 

 Thank you very much. You shared very useful stuff. ❤️

My quick and dirty rule of thumb is Perception  is used with out hands.  Stand in center of the room and try to spot something it is Perception.  If you are feeling around something or moving things it is Investigation.  It does not work all the time but most time it works.  IE finding a trap with your eyes (Perception) vs poking everything with a 10 foot pole (Investigation ). 

Quote from Deathmvp >>

My quick and dirty rule of thumb is Perception  is used with out hands.  Stand in center of the room and try to spot something it is Perception.  If you are feeling around something or moving things it is Investigation.  It does not work all the time but most time it works.  IE finding a trap with your eyes (Perception) vs poking everything with a 10 foot pole (Investigation ). 

 

I loved that rule! Thank you very much. ❤️