Using goals to guide perception vs investigation ability checks

[robus]

I was just listening to the adventure zone when the DM gave a quick definition of Perception vs Investigation that I found illuminating (and probably obvious to most, but for those that are still struggling with the difference hopefully this will help...)

After thinking about it for a bit it became clear that the stated goal of the player informs which ability check should be used.

So if the player is trying to notice something then perception is the appropriate check. For example, while wandering around a dungeon a PC might be trying to notice signs of traps and so passive perception would be appropriate. Entering a study a PC might want to see if anything seems out of place. A regular perception check works here.

When a player is trying to find something then investigation comes into play. When a PC is spending time trying to find some information in a library then passive investigation works. When a PC is trying to find a secret drawer in desk it would be a regular investigation check.

Anyway, to summarize: trying to notice things: perception, trying to find things: investigation

Now that I've finished that it all seems bleeding obvious but I still like the simple clarity of asking the player what are they trying to accomplish and picking the appropriate check.

 

[aco175]

I mostly go with Perception being anything you see while just looking around in general, and Investigation being once you need to touch something. I do use Investigation if the PC is trying to study something like a puzzle or something they think is trapped like a hallway, even while just looking at it intently.

There seems to be a lot of interpretation and leeway. Example: you walk into a room and Perception a candlestick upon the desk that looks like it has been slid back and forth a lot making grooves along the wood. The player thinks it unlocks a secret latch or something. Do I also let a PC roll an Investigation check if they are "Checking out the desk". I would think they would see this as well. The Investigation check lets them figure out that a compartment opens under the desk if the candlestick is moved. They can also see that it is trapped.

Slightly different in application, but lets information get out by using both means. Telling the Perception check person that you notice spiderwebs moving slightly in the wind coming from a crack in the brick wall basically means you notice a secret door. You now need an Investigation to find a way to open it. So now do you need to be trained in both to be useful or just have the cleric walk in front to notice things and the thief around to figure out how they work.

 

[iserith]

I prefer Perception as notice/find and Investigation as deduce.

It's Perception to find the trap; Investigation to deduce its workings before you can disable it. Perception to find the secret door; Investigation to deduce how to open it. Perception to find the hidden object; Investigation to deduce its purpose. And so on. (Standard rules apply: Check only comes up if the result of the player's stated approach to the goal has an uncertain outcome. Players don't get to ask for checks or make them unprompted.)

 

[robus]

I prefer Perception as notice/find and Investigation as deduce.

It's Perception to find the trap; Investigation to deduce its workings before you can disable it. Perception to find the secret door; Investigation to deduce how to open it. Perception to find the hidden object; Investigation to deduce its purpose. And so on. (Standard rules apply: Check only comes up if the result of the player's stated approach to the goal has an uncertain outcome. Players don't get to ask for checks or make them unprompted.)

I like that too, but perhaps deduction is more a Wis + investigation combination?

 

[ccs]

So now do you need to be trained in both to be useful or just have the cleric walk in front to notice things and the thief around to figure out how they work.

No, this is 5e. You just need to roll higher on your non-proficient skills.

 

[iserith]

I like that too, but perhaps deduction is more a Wis + investigation combination?

Intelligence (Investigation) is looking around for clues and making deductions based on those clues.

 

[Tony Vargas]

Anyway, to summarize: trying to notice things: perception, trying to find things: investigation

Just like Spot & Search in 3e, really.

 

[robus]

Just like Spot & Search in 3e, really.

Ah, not familiar with 3e but good to know.

 

[iserith]

Ah, not familiar with 3e but good to know.

Per the rules, I don't think it's really the same as 3e's Search check (though people can play it how they want). Investigation doesn't imply that clues are hidden, just that you're relying on clues in the area to make a deduction to arrive at some truth. That might include deducing the location of a hidden object. If the clues are hidden, however, then that would be a Perception check if finding them is uncertain. So my interpretation of the rules is find/notice or deduce as above.

 

[DEFCON 1]

For me, Perception is to find things that are trying to avoid your sight. Investigation is to find things that are just difficult to see.

In other words... Perception is to find living creatures that are trying to hide from you, Investigation is to find inanimate objects (like traps, secret doors) that are potentially hard to see but are just there and can't do anything to avoid you noticing it.