Is a Perception Check against an Invisible Target made with Disadvantage?

Question

Here's the scenario:

• Creature A is invisible, in an empty room, in an arbitrary location in the room
• The room is adequately lit (call it Bright Light, for the sake of argument)
• Creature A is trying to hide (they make a Stealth Check).
• Creature B enters the room.
• Creature B is not actively searching for Creature A, so their Passive Perception is compared against Creature A's stealth check.

Does Creature B's Perception check have Disadvantage?

Answers should not make assumptions about what the rules should do or what they were intended to do. Nor should they make assumptions about how rules interact with each other. Please stick strictly to the rules as written only.

Answer 1

There need not be any rule that specifically says you have disadvantage.

By RAW, circumstances can impose disadvantage on any check.

You usually gain advantage or disadvantage through the use of special abilities, actions, or spells. Inspiration can also give a character advantage. The DM can also decide that circumstances influence a roll in one direction or the other and grant advantage or impose disadvantage as a result.

I mention this because I'm going to argue that the rules justify applying disadvantage here, even if they don't overtly require it.

Heavy obscurement is strictly more obscuring than light obscurement.

This is the part you're not going to like, so let's get to it.

Both kinds of obscurement are defined largely by example, and the sets of examples are parallel: Dim light, patchy fog, and moderate foliage are lightly obscuring; darkness, opaque fog, and dense foliage are heavily obscuring. The examples clearly show that heavy obscurement is like light obscurement, only more so.

Therefore there should be no case where anything is more visible under heavy obscurement than it would be under light obscurement. Anything that you can't see in dim light, you also can't see in total darkness.

The Hiding rules say that being heavily obscured has an effect.

One of the main factors in determining whether you can find a hidden creature or object is how well you can see in an area, which might be lightly or heavily obscured, as explained in chapter 8.

Finding a hidden creature involves a Perception check, so there must be some impact on the Perception check (or the Stealth check, but note this also applies to a hidden object, which likely wouldn't get a Stealth check).

The check doesn't automatically fail.

This point was made in Xirema's answer, but to restate it: detecting a creature's presence doesn't require sight and therefore doesn't always fail under blindness or heavy obscurement.

(Except when it does. A creature like a dormant gargoyle might give no signs of its presence except that you can see it, and if heavily obscured, would be truly undetectable.)

Light obscurement imposes disadvantage on detecting a creature's presence.

Perception checks that "rely on sight" have disadvantage in a lightly obscured area. (Note that the rule isn't "require sight".) Most of us could locate another person in a dark room by sound, but as a practical matter we rely on sight to do this.

Conclusion: the Perception check to locate a heavily obscured creature must be at least as hard as rolling with disadvantage, but there's no rule that it's any more difficult than that. The game mechanic that best fits in that space is to roll with disadvantage.

Finally, I think this needs to be said:

The text is not written to be used this way.

You say that you aren't interested in what the rules are intended to do, but that's essential context for reading them at all. The Player's Handbook is a handbook. It explains how to do a thing, namely, how to play the game. It is not a legal code or a set of tournament rules.

None of the rules mentioned here rigorously define their terms. In particular, the obscurement categories are specified mostly by a handful of examples. We had another question going recently about whether partial fog and dim light combined count as heavy obscurement, and the rules give us no way to answer that.

Similarly, if you're blind, you automatically fail "any ability check that requires sight", but ability checks don't say when they require sight. You have to figure that out case by case.

There are also some consequences of this situation that are far more obvious than "disadvantage on Perception checks" but aren't spelled out in the rules. For example, the Blinded condition says you can't see. This causes you to automatically fail at checks that require sight, but what about, say, reading a newspaper? There isn't a check for you to automatically fail, but still, you can't see. To grasp the implications of the rule, you have to apply logic and experience.

Answer 2

The check would be made normally

I've assumed for a long time that these kinds of perception checks would be made with Disadvantage because of the inability to see the invisible creature, but upon further investigation of the rules, I cannot find evidence that this is the case, and I've had difficulty finding questions on this stack that clearly deal with this case. A lot of answers presuppose that the check is made with disadvantage without actually proving it or questioning whether that's the case.

^{Not casting aspersions on that answer, FYI, since that's not what that answer is about.}

Here is why I believe the check is not made with Disadvantage.

The Invisible condition does not expressly say it confers Disadvantage on Perception Checks

• An invisible creature is impossible to see without the aid of magic or a special sense. For the purpose of hiding, the creature is heavily obscured. The creature's location can be detected by any noise it makes or any tracks it leaves.
• Attack rolls against the creature have disadvantage, and the creature's attack rolls have advantage.

—Invisible, PHB, pg. 291

You might be wondering, dear reader, whether the bolded part (emphasis mine) about the invisible creature counting as "Heavily Obscured", ought to prove that this check should definitely be made with Disadvantage. After all, Heavy Obscurement says that creatures have disadvantage on Perception Checks, right?

The rules for Heavy Obscurement do not say they confer Disadvantage on Perception Checks

In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) checks that rely on sight.

A heavily obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature in a heavily obscured area effectively suffers from the blinded condition (see the appendix). A heavily obscured area doesn't blind you, but you are effectively blinded when you try to see something obscured by it.

—Light and Vision, PHB, pg. 183

Oh.

A Blinded creature is described as automatically failing any check that requires vision; but it makes no mention about Disadvantage on Ability checks which merely make use of vision (Search using hearing, smell, etc. in addition to vision):

• A blinded creature can't see and automatically fails any ability check that requires sight.
• Attack rolls against the creature have advantage, and the creature's attack rolls have disadvantage.

—Blinded, PHB, pg. 290

And just to make sure no stone is left unturned, the Perception skill doesn't expressly call out Disadvantage on checks which require multiple senses, but for which only one sense is functional:

Your Wisdom (Perception) check lets you spot, hear, or otherwise detect the presence of something. It measures your general awareness of your surroundings and the keenness of your senses.

—Wisdom Checks, PHB, pg. 178

The rules for Perceiving Hidden Creatures mention vision impairment like Dim Light or Fog, but not Invisibility

What Can you See?. One of the main factors in determining whether you can find a hidden creature or object is how well you can see in an area, which might be lightly or heavily obscured, as explained in chapter 8.

—Hiding, PHB, pg. 177

I want to comment on this especially because detecting an Invisible creature isn't necessarily just about seeing it: it's also about detecting evidence of it. Things like footprints or disturbed dust on the ground. Things that would be necessarily harder to detect in a dimly lit room or darkness than they would be in bright light. And of course, there's also the issue of attempting to hear or smell an Invisible + Hidden creature, neither of which are impaired by vision.

The rules for Hiding call out Invisibility as a way to guarantee the option of hiding, but do not call out any benefits to the check

You can't hide from a creature that can see you clearly, and if you make noise (such as shouting a warning or knocking over a vase), you give away your position. An invisible creature can't be seen, so it can always try to hide. Signs of its passage might still be noticed, however, and it still has to stay quiet.

—Hiding, PHB, pg. 177

Conclusion: This can't possibly be right, can it?

I mean, that's really weird, right, if an invisible creature is not actually conferring disadvantage on attempts to detect it? If the spectrum of these perception checks is really just the binary of

• Make the check without Disadvantage, or
• Auto-fail the check, because of effects like Pass without Trace and/or Silence, suppressing both hearing and other tertiary effects which might leave evidence, leaving only the [in-]ability to actually see the Invisible target

But if there's evidence that definitely disproves this reading, I haven't found it.

Addendum: the creature is still "Unseen", and still confers Disadvantage/Advantage to Attack rolls

Just so it doesn't go unstated: none of this permits a creature to "see" an invisible creature. As far as I can tell, that has not been violated by my understanding of the rules. The only thing that has happened is that the invisible creature's location has been detected (or not detected) based on the results of the Perception Check.

Answer 3

No. The check would be normal to hear, but it automatically fails to see.

I apologize for the magnitude of this post, but we need to understand a few things about...

Hiding in D&D

Hiding in English is to conceal from sight but hiding in D&D is both remaining unseen and unheard. Unseen Attackers and Targets

If you are hidden--both unseen and unheard--[...]

Bright light, no invisibility

If creature A was in bright light, and not invisible, creature A could not hide, since in Stealth,

You can't hide from a creature that can see you clearly[...]

Bright light, invisibility, not hiding

You generally know the location of an invisible creature that is not hiding since, Invisible condition

The creature's location can be detected by any noise it makes or any tracks it leaves.

But otherwise the creature is heavily obscured. Meaning, they aren't in heavy obscurity, they are heavily obscured.

An invisible creature is impossible to see without the aid of magic or a special sense. For the purpose of hiding, the creature is heavily obscured.

This means, without a spell, item or feature that allows you to see invisible creatures, you would be affected by the second bullet

Attack rolls against the creature have disadvantage, and the creature's attack rolls have advantage.

But you could otherwise "see" everything in their square, just not the creature as it is heavily obscured.

Bright light, invisibility, hiding

Everything applies as above, only, your passive Wisdom (Perception) or an active check must beat* the opponent's Dexterity (Stealth) check to hear the hidden opponent.

*: Tie in Contests

If the contest results in a tie, the situation remains the same as it was before the contest.

This is normally to the hider's advantage before combat, and to the seeker's advantage during combat, but not always.

It's important to note, there can be three or more types of Perception, the most common being seeing and hearing, but also common is smell.

Thus, on any given Perception check, you could succeed a Perception check and avoid Surprise, meaning, you

notice[.] a threat

Even if you could not see the creature, your successful check means you noticed it - and therefore know it's location.

What does it mean if I can hear (or smell) a creature but I can't see it?

It means they are not hidden and you know their location and if this was the start of combat you would not be surprised. However, it does not change the invisible condition and its traits, meaning the hider would still benefit from being an unseen attacker and target.

Why doesn't heavy obscurity have a penalty to Perception?

Light obscurity has a penalty, from Vision and Light

In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) checks that rely on sight.

Note - the disadvantage is for checks that rely on sight. You have a chance to see, but not as good as if you were in bright light. This would not affect a Perception check to hear (or smell).

This also means the situation where you notice a creature, but cannot see them doesn't just apply to invisibility. For example, if a creature is hiding in light obscurity (say with Mask of the Wild), your Perception check to see them is at disadvantage, but not your chance to hear them.

But why doesn't heavy obscurity have a similar clause?

Because Perception checks that rely on sight in heavy obscurity automatically fail. This is far worse than disadvantage. You have no chance to see an invisible opponent without additional spells, abilities or features.

From Vision and Light

A creature effectively suffers from the blinded condition when trying to see something in that [heavily obscured] area.

And from Blinded

A blinded creature can't see and automatically fails any ability check that requires sight.

Effectively, the Wisdom (Perception) check (active or passive) against a creature in heavy obscurity is a Perception check to hear, only, and success would only mean you know their location. They are no longer hidden, but would still benefit from being an unseen attacker or target. Or hearing or smelling, in the case of something like a wolf.

Keen Hearing and Smell. The wolf has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Shadows

Without invisibility, you normally can't hide in bright light (see above) and in heavy obscurity, you have no chance to see, so most of the time, checks that rely on sight are made in the shadows (or other light obscurity), and at disadvantage.

Conditions to hide

Don't exist. They were in the playtest, but were left out of the official rules. I suspect this is because 5e makes no distinction between cover for an object or creature, so this would have made the lightfoot halfing's ability Naturally Stealthy worse than the conditions in the playtest. In the playtest, you could hide behind one-half cover, which is also any creature that blocks one half of your body. Naturally Stealthy allows a lightfoot halfing to hide behind a creature one size larger.

However, most have gleaned the conditions from the rules, but check with your DM as interpretations may vary.

Since

You can't hide from a creature that can see you clearly[...] and if you come out of hiding and approach a creature, it usually sees you

It is generally understood that you cannot hide in light obscurity or bright light and generally not when already noticed, without a special ability like Mask of the Wild (in some light obscurity) or Naturally Stealthy (behind a medium or larger creature) or the Skulker feat (in light obscurity). But this is essentially reverse engineering a condition to hide that otherwise doesn't exist in the rules

You can't hide while being observed.

Or, more accurately

Hiding requires total cover or heavy obscurity

At my table

You need total cover or heavy obscurity to hide, unless you have a trait or feature that allows you to otherwise, but only light obscurity to remain hidden. This is also how hiding works at Keith Amman's table, demonstrated in his examples in his excellent book, Live to Tell the Tale.

Also, after reading Live to Tell the Tale, I now have the players roll a Stealth check each time an enemy has a chance to see them. They know this, so it obviates the need for hidden rolls to avoid meta-gaming on the hider's part.

Other senses that mimic sight (or hearing? or smell?)

Blindsight, Darkvision, Tremorsense and Truesight all impact darkness and all but Darkvision impact invisibility, however, it is not always spelled out how a particular sense works, so how a special sense that isn't described is affected by a Silence spell or a deafened creature is generally up to the DM.

Eldritch Invocation Devil's Sight donut hole

It's also important to note, darkness is dim light and dim light is bright light for creatures with darkvision, with the sole exception of a warlock without darkvision that takes the Devil’s Sight invocation. They see normally in bright light and darkness, but dim light is still light obscurity for them. Devil's (and warlocks with darkvision) don't have this limitation as they already have darkvision.

Answer 4

This answer uses the DMG.

Invisibilty (pg 291 phb): An Invisible creature is impossible to see without the aid of magic or a special sense. For the purpose of hiding, the creature is heavily obscured. The creatures location can be detected by any noise it makes or any tracks it leaves.

Heavily Obscured (pg 183): A creature suffers from the blinded condition when trying to see into the area.

Blinded (pg 290 phb): A blinded creature can't see and automatically fails any ability that requires sight. (Humans are creatures that heavily rely upon sight as a primary sense.)

Hiding (pg 177 PHB): the DM compares your Dexterity(Stealth) check with that creatures passive Wisdom (perception) score, which equals 10+ the creatures wisdom modifier as well as any other bonuses or penalties (aka, DM adhoc) If the Creature has advantage, add 5. For disadvantage subtract 5.

Perception (pg 178): Your Wisdom (Perception) check lets you spot, hear, or otherwise detect the presence of something. It measures your general awareness of your surroundings and the keenness of your sense.

Investigation (pg 178): When you look around for clues and make deductions based on those clues... You might deduce the location of a hidden object...

Ability Checks (pg 174): For every ability check, the DM decides which abilities is relevant to the task and the difficulty of the task, represented by a Difficulty Class... As with other d20 rolls, apply bonuses and penalties.

DM (pg 5): The game's lead storyteller and referee... Then the DM determines the results of the adventurer's actions and narrates what they experience.

Noticing Threats (PHB 182): When traveling at a fast pace, characters take a -5 penalty to their passive wisdom (Perception) scores to notice hidden threats.

Using Ability Scores (DMG 237): Is a task so inappropriate or impossible-such as hitting the moon with an arrow-that it can't work?

Advantage/Disadvantage (DMG 239): ...They reflect temporary circumstances that might affect the chances of a character succeeding or failing at a task. Advantage is also a great way to reward a player who shows exceptional creativity in play. Characters often gain advantage or disadvantage through the use of special abilities, actions, spells... ...Consider granting advantage when: Circumstances not related to a creatures inherent capabilities provide it with an edge. ...Consider granting disadvantage when Circumstances hinder success in some way.

RAW

1. Based upon the OP's question, we will presume a stealth check is needed, because the invisibility condition says vision based things automatically fail, and Humans are primary sight based creatures unless they are blind, in which case, their secondary sense is hearing. Not all creatures rely upon sight, for many it is a secondary sense, so we are making a presumption. By attempting to make an ability check to hide, has Creature A prompted a Contested roll when there was no contested roll before? I mean, what was the DC to detect an invisible creature by walking in a room that wasn't attempting to hide? If it is now attempting to hide, has the task become a no-roll situation as detailed in the DMG?
2. We will presume that passive perception applies and say the DM ruled creature B has passive perception based upon the question, rather than forcing an investigation or active Perception check. Passive Perception is not explicitly stated as a detection method in the spell and/or invisibility condition, it is merely implied by the statement regarding what Perception is. "can be used" are the words in the PHB.
3. Continuing down this path, there is no explicitly stated advantage/disadvantage or other modifier in the spell or condition, but based upon the rules written in the DMG, stealth has advantage and passive perception has disadvantage. Creature A has an edge, Creature B is hindered. --Answer 1
4. RAW, The DM has the right to set the DC at 30 and simply not use a contested Roll, also imposing disadvantage on perception per the DMG rules above and using the typical Difficulty Classes table from page 174 of the PHB. The DM may also reward a failure with a progress/setback. Because the invisibility spell says "Impossible to see", and the Blinded condition says "automatically fails any ability that requires sight", the only way the creature B would be granted a perception check of any kind would be if creature A were making noise and the noise made was close enough to Character B, but those conditions were not made in the OP's question. --Answer 2
5. RAW, the exact same advantage/disadvantage to stealth and perception could be applied to a moving Creature A in a lightly obscured area with a Silence Spell with Creature B actively attempting to locate Creature A. Creature B would be "deaf" and Creature A would magically make no noise. Therefore, RAW the words 'impossible' and 'automatically fails' must be given weight. I bring this evidence up to demonstrate that simple advantage and disadvantage are not necessarily enough in a hiding with invisibility situation, and that "impossible" may be ruled as no check as detailed above from the DMG. --Answer 3

Scene: A human knight enters a Wizard's front door and a magical alarm goes off in the wizard's head. The wizard stands up from his plush chair sets his book aside and tweaks a ring of invisibility. He moves to the side of a book case and faces the door, barely breathing. The human knight pounds down the hallways in platemail briefly glancing into each room... does the human knight get a normal every day perception check to see a non-moving halfling wizard who got a 2 on his stealth check after moving to the bookcase because the dm deemed a stealth check was necessary to get up and move across a stone floor while a knight is bounding away downstairs? I say no, the check was a bad DM call, the invisibility spell and description of the character's actions and scene were enough to decide the DC of the passive perception was impossible or nearly impossible DC 30, the check doesn't matter. The arguments above result in: the Knight, by some mystical means that doesn't make sense to any story notices the halfling because the DM forced a roll when by the rules in the PHB, sometimes rolls aren't necessary and DnD 5th does not always require a roll to tell a story. The DM could use the answers above as options... or could rule that the 2 resulted in a book dropping to the floor from the bookcase for fun, but it is just as good of a DM call to say: look, the stealth check was unnecessary, these are simple normal things that are done, standing up and moving in your bathrobe doesn't make a ton of noise. That is why we have a DM.