I was recently reading through a bunch of forum posts here on Enworld in which people were ranking the 5th edition skill list by which skills them felt were the better skills, usually basing their answers off the usefulness of the skill, which is itself most strongly correlated with the frequency of its use and the impact of its use. At least, that is how most people on the forum chose to rank them.
I’m not about to rank skills, as I feel their usefulness varies widely based on both the DM and the players, but one thing that caught my eye was that Perception made the top of just about every list, and Investigation was found near the bottom of most lists, given that it “overlapped with Perception, which was better”. I am not in agreement with that statement but it seemed to be a fairly large consensus among most people. There were very few exceptions. The end result was that nearly all agreed Perception was a must have for every PC in a party, for it always comes up and it stops you from being surprised.
I didn’t find it all that surprising that Perception was one of the top-rated skills. What I found surprising was how little people seemed to value Investigation. After reading, I believe it to be tied to the other comment that kept bouncing around, and to which I alluded earlier.
People feel it is just a weaker Perception.
But it really isn’t. And I think that’s why a lot of people feel Perception is totally necessary for every PC to have and also why they find Investigation underwhelming.
Perception is a Wisdom skill. Wisdom is all about intuition, awareness, and being in touch with that around you. Investigation is an Intelligence skill. Intelligence is about reasoning, logic, memory, and methodical thinking.
Perception a general awareness of the ones surroundings, and the effectiveness of one’s senses. Keeping this definition in mind, the rules surrounding it in the game make a lot of sense, and help explain some of the ambiguities. It also helps when it comes to adjudicating uses of Perception vs. Investigation on the fly.
First, the stealth rules. Perception is the skill that counters stealth, one of the reasons it was rated so high by the Enworlders, but what exactly does this mean? Does your character spot the ambush in advance, seeing the goblins hiding in the bushes and thus being able to avoid being surprised? If so, can they yell to their teammates to be alert and thus prevent everyone from being surprised? After all, if I saw the goblins in the bushes I wouldn’t even walk close enough for them to hit me until everyone was aware.
I would say you do not spot the goblins hiding in the bush. And therefore can’t yell to your teammates, and therefore cannot prevent everyone from being surprised. And here’s why:
The use of Perception to counter Stealth is almost always Passive. The Passive perception of those being ambushed or sneaked upon acts as a DC for the Stealth roll (or rolls, if its a group check). As I stated previously, Perception is about general awareness and senses.
So if some goblins are hiding in bushes along the path and a group of PC’s blunders into them, the goblins roll Wisdom(Stealth), and the check is compared to the Passive Perception of the group. Anyone who’s Passive Perception exceeds the roll of the goblins is aware when the goblins enter the fray. This simply means that as the goblins come charging out of the bushes they immediately notice what’s happening and are prepared. They are not surprised, and join combat immediately. Those who fail don’t immediately catch on, and are slow to ready themselves for the incoming battle. Mechanically, this means they are surprised, and don’t come into the initiative order until the second round of combat.
Notice that regardless of the Passive Perception’s in the group, the goblins are still able to pull off their ambush. The PC’s don’t get to all ready themselves ahead of time. Even if they shout warnings the second the goblins burst forth, combat has already begun. The goblins still get the first round. Why? Because those with low Passive Perception simply aren’t as aware of their surroundings. No one saw the goblins hiding. Some people just weren’t caught flat footed (not the 3.5 mechanical meaning, the vernacular meaning), while others were.
This is important because its the sole mechanical benefit a high Passive Perception provides. And I do not feel it outweighs that of other skills. Chances are not every fight is going to be an ambush, so sometimes having a high Passive Perception carries no benefit.
Its also important to note that this makes sense in a real way, not just a mechanical one. There are some people who are way more aware of what is going on around them then others. It’s not hard to imagine the wizard who is studying a new scroll he’s obtained, or reading up on his Elvish history as the party makes their way through the forest, looking up at the shouting just in time to see a goblin swinging an long dagger at him. Its also very clear he’s in no position to counterattack, as he is probably still trying to figure out what’s going on.
Active Perception might allow you to spot those goblins. On top of general awareness, Perception is about the strength of your senses. This is the active component of the skill. And if I described to my players how the road wound its way into a forest with a dense underbrush and one of them told me they were keeping an eye on the brush, looking for hidden foes I would allow them a roll to see hints of the goblins ahead of time, and thus warn the party. But while they are doing this, they can’t be using (or making) a map of the area. They can’t be tracking using Survival. And of course, they also may just fail.
Investigation is all about reasoning, logic, memory and methodical thinking. And its this last piece that can be the key to finding things. Searching an area should be done with Investigation. Its about looking at everything, determining whether it is important or not, then moving on. This requires methodical thinking (looking at everything), and reasoning (whether it is important or not).
If someone has as much time as they need Passive Investigation should apply. This is one of the two uses of Passive checks. They will either find it or they won’t. There is no reason you couldn’t ask for an active check here, of course, but a Passive check would be appropriate.
Active Investigation should be used if there is a time constraint. The suspect comes home in twenty minutes, can you find what you are looking for before then? The searcher doesn’t have a lot of time to look, only a limited window.
As an example, lets imagine a room with three hidden objects. The first is a trap designed to go off when a trip wire is broken or pulled. The second is a secret passage behind a bookshelf. The third is a key hidden in a secret compartment in a desk drawer.
When the characters enter the room a perception check might be called, and someone with a good enough roll and perception might notice the trip wire. Or their Passive Perception might tell them if the GM decides not to call for the check. If someone notices and the trap’s mechanism is not obvious, a GM might call for an Investigation check to figure out how it works. One book is out of order in an otherwise perfectly ordered room, which an Medium DC Investigation check of the room reveals, or an Easy check if the searcher specifies the bookshelf. One may be tempted to allow a Perception check to see the out-of place book, but this shouldn’t be allowed. It’s a book. There’s nothing odd about the book itself. Only through reasoning and logic could one make the conclusion that it is out of place.
Finally, the key hidden in the drawer could only be found with Investigation. There is nothing to perceive unless you are looking methodically and then it involves realizing that the drawer has less space inside than it should.