->'''Jon:''' OW! ...Did you do that?!\\
'''Garfield:''' Nope.\\
'''Jon:''' You kicked me!\\
'''Garfield:''' If you didn't see it, it didn't happen.
-->-- ''ComicStrip/{{Garfield}}'', [[http://www.garfield.com/comics/vault.html?yr=2008&addr=080112 January 12, 2008]]

''If the audience can't perceive it, it doesn't exist.''

The audience of a movie will know only what they can see and hear. This means that nothing really exists in a movie unless you can see or hear it (because if it does, you're going to have to explain why it was BehindTheBlack). As a result, a kind of accepted audio-visual shorthand has been created over many years, to help the audience understand what they're looking at and what's going on.

Tropes based on this phenomenon include:

* AcousticLicense\\
If the audience can hear (or see speech bubbles for) a sound, then the characters are also aware of it, physics be damned. (It can also work the other way around.)
* AllNaturalGemPolish\\
Gems are naturally shiny and pre-cut so that the audience can recognize them.
* AgeIsRelative\\
Characters who are more competent will also look older/more mature.
* TheAirNotThere\\
You can't see air; therefore, it does not exist.
* AsYouKnow\\
The characters already know this exposition, but the viewers don't, so it has to be stated onscreen.
* AudibleGleam\\
If it just looks shiny then it could be mistaken, but if it makes the noise too then you know it's meant to be taken as shiny.
* AudibleSharpness\\
It's easy to tell when a blade is sharp because it makes a "sharp noise."
* BeepingComputers\\
Computers beep so that you can tell they're doing something.
* BehindTheBlack\\
Anything that's offscreen is invisible.
* BriffitsAndSqueans\\
Stationary images have to do ''something'' to represent motion.
* BulletSparks\\
Bullets spark when they ricochet to make it obvious where they hit.
* CartoonCheese\\
Cheese is always immediately recognizable by a distinctive shape and color.
* ChainsawGood\\
Chainsaws are flashy and make a lot of noise, so they must be really powerful.
* CharacterTics\\
You can tell he's frustrated because he's doing that thing he does when he's frustrated.
* ChristianityIsCatholic\\
Given that Catholic churches tend to be more ornate in design and features of Catholic services are more identifiable (eg. mass, confession), if you want to make it clear it's a church service then this is the easier kind to spot.
* ConcealmentEqualsCover\\
If you can't be seen, you can't be hit.
* ConvectionSchmonvection\\
Fire and lava are only dangerous if you touch them directly.
* ConvulsiveSeizures\\
If a character has a seizure, the writers will make it the most visible kind of seizure.
* CowerPower\\
You can tell a character is terrified by their exaggerated cowering.
* CultureBlind\\
The audience probably doesn't know about foreign cultural norms, so the characters will be clueless as well.
* DoNotTouchTheFunnelCloud\\
If you don't touch the ''visible'' part of a tornado, the most it can do is whip your hair around a little.
* DramaticStutter\\
A clear, auditory representation of a character's shock.
* EditorialSynaesthesia\\
Non-visual senses like smell and pain have to have some form of visual representation.
* EmotionalMaturityIsPhysicalMaturity\\
If the character looks physically young, they will be emotionally young as well, even if they're OlderThanTheyLook.
* ErmineCapeEffect\\
Fancy clothing is an easy way for us to tell which characters are royalty.
* EveryBulletIsATracer\\
Bullets leave visible trails in the air to make it easy to tell which way they went.
* ExactEavesdropping\\
The person who gets to eavesdrop will almost certainly come in when something important is being talked about.
* ExactProgressBar\\
Everything has a progress bar, even if it logically shouldn't, so the viewers know how close it is to being done.
* ExtremeGraphicalRepresentation\\
Computers use flashy, unnecessary graphics.
* FlashOfPain\\
You can tell a video game character just got damaged because they briefly flashed a different color.
* FluorescentFootprints\\
When you're tracking someone, their trail will glow brightly so the audience can see it too.
* FrickinLaserBeams\\
Lasers behave in unusual ways that make them more visible.
* {{Gonk}}\\
Particularly in animated medium, if a character is supposed to be considered ugly then the best way to do so is to lay it on thick.
* HalfIdenticalTwins\\
Fraternal twins need to be (nearly) identical too, or the audience won't recognize them as twins.
* HesDeadJim\\
There will always be an obvious cue so we know the exact moment when a character dies.
* HighlyVisibleNinja\\
Ninjas are stealthy, but they can't be so stealthy that the audience doesn't know they're there.
* HighSpeedMissileDodge\\
As long as you don't touch the rocket, you'll be okay.
* HollywoodDarkness\\
It's dark, but not so dark that we can't see what's happening.
* HologramProjectionImperfection\\
Holograms have little flickers and static effects and such so that it's obvious they're not real.
* KungFoley\\
Physical blows make loud noises so the audience knows when someone gets hit.
* LaserHallway\\
A type of security system that is conveniently easy to see.
* LaserSight\\
Snipers use laser sights so that the audience can tell where they're aiming.
* LuckilyMyPowersWillProtectMe\\
If it's not visually obvious that your superpowers are protecting you, you'd better state it explicitly in dialogue.
* MadeOfIron\\
The audience can't feel the character's pain, so the character won't be incapacitated by what should be serious injuries.
* MidairBobbing\\
When a character is bobbing up and down, you know they're floating in the air and not just misaligned with the background.
* MindControlEyes\\
If his eyes are glazed over or spiralling, it's a good indication to the viewer that he's being brainwashed.
* MorphicResonance\\
When a character shapeshifts, there are visual cues that make it easy to tell they're the same person.
* MotiveRant\\
If the writers want the audience to know the bad guy's motives, he has to actually explain them at some point.
* NarratingTheObvious\\
For the benefit of the audience, having characters narrate events that should be extremely obvious to them.
* NationalStereotypes\\
How else will you know that it's foreign?
** [[NationalStereoTypes/NorthAmerica National Stereotypes North America]]
** [[NationalStereoTypes/{{Asia}} National Stereotypes Asia]]
** [[NationalStereotypes/WesternEurope National Stereotypes Western Europe]]
** [[NationalStereotypes/EasternEurope National Stereotypes Eastern Europe]]
* NoPeripheralVision\\
The camera doesn't have peripheral vision, so neither do the characters.
* NotTheFallThatKillsYou\\
As long as you don't ''splat'' into the ground, you'll be okay.
* OneDimensionalThinking\\
Fleeing characters could avoid mishap by stepping aside rather than continue rushing forward.
* OffscreenInertia\\
As long as a character is offscreen, it's assumed that they continue doing whatever it was we last saw them doing.
* OffscreenRealityWarp\\
Implausible changes are accepted if they happen offscreen.
* OffscreenTeleportation\\
Offscreen characters are in a sort of limbo that allows them to reappear wherever they like when they come back onscreen.
* OutrunTheFireball\\
As long as you can escape the visible blast, you won't be hurt by the invisible shockwaves that would tear you to bits in real life.
* PowerEchoes\\
Super-powerful characters have a voice that echoes or reverbs dramatically.
* PowerFloats\\
Ordinary people can't float, so if a character can then he must have some sort of mystic power.
* PowerGlows\\
Power is represented with a highly-visible glowing effect.
* PsychicNosebleed\\
A strictly-mental injury is represented with the more-visible effect of a nosebleed.
* PunyParachute\\
Parachutes are small enough to fit on the screen.
* RadioVoice\\
You can tell the voice is coming from the radio because it's slightly distorted.
* RepeatingSoTheAudienceCanHear\\
We can't hear the other end of his telephone conversation, but that's okay because he'll repeat it back for us.
* SeeNoEvilHearNoEvil\\
If it isn't visible, it isn't audible either.
* SoftWater\\
Why shouldn't water be softer than dry land?
* SomeKindOfForceField\\
A visible disruption effect in the air, usually with appropriate sound effects, accompanies a force field.
* SoundingItOut\\
A character reads something out loud for the benefit of the audience, even though there's nobody else around to hear.
* SoundsOfScience\\
When scientific minds are engaged in scientific debate, they will mutter in a scientific manner so everyone can tell that's what they're doing.
* SpaceFlecks\\
If you can see the stars moving out the window, you know you're moving through space.
* SpaceIsNoisy\\
There is sound in space because the viewers want to be able to hear what's going on.
* StockCostumeTraits\\
Certain visual cues let the audience instantly identify a character's profession.
* StockVisualMetaphors\\
An index of visual shorthands that help the audience understand what's going on.
* StrayShotsStrikeNothing\\
The bullet missed the target, therefore it no longer exists.
* StreamingStars\\
If the stars seem to be stretching into lines as they go by, you're moving through space very quickly.
* TechnicolorToxin\\
Poison is brightly-colored so it's easy to tell that it's poisonous.
* TertiarySexualCharacteristics\\
For obvious reasons, you can't just display a character's genitalia, so you've got to find ''some'' way to make it clear who's a boy and who's a girl.
* TheatricsOfPain\\
Actors exaggerate pain for the benefit of the audience.
* TranslationConvention\\
The characters may be foreigners, but the audience has to understand what's going on, so they're speaking English (or whatever the audience's language is).
* TravelingPipeBulge\\
When a character is traveling through a pipe, the pipe will bulge to show their location.
* TronLines\\
Glowing blue lines over everything are a good indicator of advanced technology.
* ViewerFriendlyInterface\\
Computer interfaces are designed for the viewers watching them on TV, not the characters who are actually using them.
* VisibleInvisibility\\
The audience needs to be able to see what an invisible character is doing.
* VoiceoverLetter\\
We can't see the actual text of the letter, so instead we hear a voiceover of the person who wrote it.
* VoicesAreMental\\
If characters swap bodies, their new body will talk in their old voice so that you can tell it's the same character.
* WalkInChimeIn\\
A character just entering the set has somehow heard what the characters already there were talking about before they walked in--the audience knows, after all, so the characters should too.
* WaterIsBlue\\
In drawn media, water is always depicted as a clean blue rather than clear. This way, it's much easier for the audience to see it.
* WhenItRainsItPours\\
There's no point in having it rain so lightly that the audience can't even tell it's raining, so if it's gonna rain, it rains a ''lot''.
* WormSign\\
When something is tunneling underground, you can tell where it is because it will displace dirt or break floorboards on the surface.
* XRaySparks\\
You can tell he's being electrocuted because his skeleton is showing through his skin.

A lot of these violate RealLife physics because RealityIsUnrealistic. But TropesAreNotBad. Remember, this is in [[ViewersAreMorons consideration to the audience]], so if you're looking for realism, go check out ''[[http://en.wikipedia.org/wiki/Naturalism_%28theatre%29 naturalism]]'', aka SliceOfLife. The Rule of Perception is the whole reason Foley artists and sound mixers exist.

Related to TheCoconutEffect, in that the Rule of Perception is often what causes the initial drift away from reality.
!!Unsorted Examples:

* ''Manga/DetectiveConan'' often has people whose actions the audience is suppose to know, but whose specific appearance is unknown to the other characters, rendered as all-black silhouettes even in places where there would be no shadows (even outdoors in the middle of the day).
* ''Manga/DeathNote'': Light Yagami's eyes turn [[RedEyesTakeWarning red]] and [[GlowingEyesOfDoom glow]] during his most psychotic moments. Unlike other fictional characters with glowing red eyes, Light isn't magical (not that [[DealWithTheDevil the option wasn't offered multiple times]]) so his eyes aren't actually glowing in-universe; it's just visual shorthand to show us [[JumpingOffTheSlipperySlope how far]] [[AxCrazy he's gone]].

* In a feminine-hygiene ad, some blindfolded women try to identify the rhinoceros standing between them. Their guesses are all inanimate objects, based entirely on the shape of its body parts that are seen on screen ("It's a rope", "It's a pillar", etc). None of them notice that it smells like a big freakin' animal, that it's warm to the touch, or that ''it's moving'' slightly.
** A case of Rule of Perception meets CompletelyMissingThePoint, as in the original parable that inspired this scenario (which involves an elephant), the blind investigators ''know'' it's an elephant, and are asked what the animal is ''like'', not what it is.

* [[Comicbook/FantasticFour Sue Storm]]'s "invisible" self and force field are visible to the audience, by dotted outlines in the comics and ConspicuousCG ''Franchise/{{Predator}}''-like distortion [[Film/FantasticFour in the movies]].
** Played with in both. When they want the audience to see that Sue is doing something, such as sneaking around invisibly or deploying an invisible force-field, they will be rendered visibly. When they want Sue's reveal to be a surprise, they will leave her and her force fields totally invisible until the reveal.
** Improvement in art quality has removed the infamous dotted lines from the comics and replaced them with the same effect used for glass.
* In the Creator/DonRosa story "The Three Caballeros Ride Again," [[Disney/SaludosAmigos Jose Carioca]] hides out in DonaldDuck's trunk and asks him to help him flee from a bandit. The two exchange several lines of dialogue, but do not recognize each other until they are face to face--apparently in a comic book, neither of them can hear the other's [[GratuitousForeignLanguage distinctive]] [[SpeechImpediment speech patterns]]...
* When ComicBook/JeanGrey[=/=]Marvel Girl of the ComicBook/{{X-Men}} uses telekinesis, visible (to the reader) pink energy is often shown moving from her head to whatever she's manipulating. Other telekinetics often have similar effects (light blue for Justice/Vance Astrovik, purple for Psylocke, dotted lines or translucent white for the Invisible Woman, etc.). Rarely, if ever, is it made clear whether this energy is supposed to be visible or not. Often, onlookers will clearly be unable to tell why an object is moving seemingly under its own power, but on at least one occasion another character referred to Jean's telekinesis as "pink stuff."
** For that matter, pretty much every mental power gets a visual representation. Examples include concentric yellow circles for Aquaman's animal control powers, lightning bolts around his head for Professor X's telepathy (rarely used anymore), a wavelike effect for Magneto's magnetic powers, squiggly lines around his head (with half of his face turning into his mask if he's in his civilian ID) for Spider-Man's spider sense, etc.
*** A strange result of this was the case of Ink, a character who thought he had the mutant ability to simulate others' powers by getting an appropriate symbol tattooed on his body (it turned out he was a normal human - it was the tattoo artist who had super powers). One of his tattoo powers was telepathy, which he got from having lightning bolts tattooed on his head, just like the ones used to show Professor X using his powers in old school ComicBook/{{X-Men}} comics. The question this raises: how would someone who'd never read an X-Men comic know to associate telepathy with lightning bolts?
**** Actually Marvel comics do exist in the 616.
* Comicbook/DoctorStrange's [[AstralProjection astral self]] is represented by a 'ghosted' version of himself with various other visual effects. Whether other characters can see him is indicated by dialogue. He also has visual indications when spellcasting, usually in the form of a [[PowerGlows glow around his hands]].

* MyImmortal is blissfully unaware of the Rule of Perception, as a result of which characters often seem to materialise out of nowhere.

* ''Film/GodzillaVsMegaguirus'': We know that large insects are noisy. One would think that Megaguirus, being a monstrous dragonfly-like insect almost as big as Godzilla, would be pretty loud. But no, turns out she is as stealthy as a {{ninja}}. Godzilla and humans alike tend to fail to detect her until she is right on top of them.
* In ''Film/WillyWonkaAndTheChocolateFactory'' (1971), none of the visitors recognize that the chocolate river ''is'' chocolate until Mr. Wonka tells them. At least one asks something along the lines of, "What is in that river?" Clearly, the chocolate ''smells'' no stronger near the chocolate river than anywhere else in the confection-filled room.
** ''Film/EpicMovie'' has a characteristically boneheaded take on the same scenario: Edward drinks from the "chocolate river," and apparently likes it just fine, until someone tells him it's [[VulgarHumor actually a sewage line]].
* In ''Film/StarTrekVITheUndiscoveredCountry'', Scotty is shown sitting alone in the conference room studying some blueprints shortly before discovering a major plot point. The blueprints consist of small-scale external views of the ''Enterprise''. This is the sort of basic information we'd expect the chief engineer to have committed to memory. But it tells the viewer that Scotty is hard at work, better than a random electrical schematic might.
* In the 2010 version of ''TrueGrit'', the speed of sound issue is noticibly averted. When Rooster Cogburn fires a rifle as a signal from across a valley, we see a plume of smoke shoot silently out of the gun, followed seconds later by the distant crack.
** Rule of Perception is one of many tropes that Creator/TheCoenBrothers make a habit of averting and subverting in most of their films.
* In ''Film/{{Cloverfield}}'', the eponymous monster [[OffscreenTeleportation just shows up]] practically on top of the protagonists in central park at the very end, yet [[SeeNoEvilHearNoEvil no indication of its approach]] is shown beforehand, like the fact that the ground quakes when it walks, and it tends to clumsily destroy the surrounding environment wherever it goes. The creature just appears out of nowhere to the protagonists [[BehindTheBlack because]] it appears out of nowhere to the audience.
* In ''[[Film/{{Selfless}} Self/Less]]'', Madeline doesn't recognize [[spoiler:the body of her husband]] until he turns around, despite having a good view of him from behind and hearing him speak. Granted he's wearing different clothes and [[spoiler:was thought to be dead]], but she seems to think he's a complete stranger until he turns around and she sees his face.

* Literature/ThursdayNext retreats to a [[TrappedInTVLand fictional world]] for a while in the ''The Well of Lost Plots'', and notices several things, like wallpaper, underwear, and breakfast, are missing because they're not usually mentioned in stories. She also finds that she is one of the only people with a sense of smell.
** And a sense of hearing, at least as we understand it. Although Bookworlders aren't deaf, they can only hear what's explicitly stated in the text. For example, they can't distinguish voices unless something like "Thursday said" appears after the quote.
* In ''Literature/HushHush'', Nora finds a gun in Patch's car, which is splattered with a red substance that she assumes is blood. Patch explains that the gun is a paintball gun and that the red substance is paint from a game a few days ago. It's possible that Nora simply can't tell the difference between a paintball gun and a real one, but the smell, texture, and color of several-days-old blood is different than several-days-old paint. (For starters, dried blood gradually darkens to black.)

* In "The Pine Bluff Variant" of ''Series/TheXFiles'', Mulder and Scully's conversation is bugged with a laser beam against the window of Mulder's apartment. The laser is bright red (so we know it's there), instead of infrared, which would be a lot more discreet.
* ''Series/{{Heroes}}'':
** When Matt Parkman reads someone's mind, the audience usually hears a jumble of sounds, with an ''occasional'' clear sentence bubbling through the chaos.
** Parkman usually tilts his head when reading minds. Lampshaded in an episode where all powers were lost but Parkman wasn't immediately aware of it. He tried to read someone's mind, but the target simply said "why do you keep tilting your head?"
** Many of the other powers in ''Heroes'' take this to an almost absurd degree. Peter and Ted's hands glow when they are emitting radiation. Elle's electricity is in the form of blue sparks. Sylar's lie-detection skill is indicated with a shake of the camera (and usually his saying "You're lying!" directly aferwards).
** In the earlier seasons, Hiro's powers require ''intense concentration'', AKA screwing his face up.
* A ''LawAndOrder'' episode had the detective miss a dead body directly in their line of sight until the camera could see it.
* In a ''CSI'' arson investigation, Greg must compare a used match from the crime scene to a large pile of matchbooks taken from a suspect's home. In through-the-microscope views of him holding the torn match end to the matchbooks, the used match's cardboard shaft is dark in color, while the books' matches are light. This makes it more obvious to viewers that they aren't a [[IncrediblyLamePun match]] for one another, but begs the question of why Greg bothered comparing those samples microscopically at all, when their colors are so visibly different.
* ''Series/DoctorWho'' uses this combined with RuleOfScary in "Blink". The Weeping Angels cannot move if they are being looked at, which means ''on camera'' specifically. TheFourthWallWillNotProtectYou.
* ''Series/HowIMetYourMother'' frequently uses this and it became a hallmark for the show. They constantly play with the use of narration in how the story unfolds and how the characters perceive a situation. One notable example was "Three Days of Snow" where Ted explains "This is a three day story" and we see three different plots going on simultaneously, only for a twist in that each story takes place on a different day. Another episode "No Tomorrow" has Ted believes himself to be experimenting with an unusually lucky night he was having at the bar. But Marshall shows him an accidental audio recording of Ted's evening where Ted's dialogue is the same but changed from curious and honest to sleazy.

* In the music industry, if you're not in the public eye people assume you're not doing anything, or have "Fallen Off". Usually happens when an artist isn't properly promoted, or ignored by media outlets.
* Music/BoneThugsNHarmony hit this trope HARD in the 2000's, They would release mainstream albums and people would still say "I thought they broke up?", Or "I didn't know they had a new album out". Despite having previous albums people seem to have short attention spans thanks to the FleetingDemographicRule.
* Good luck hearing The Beatles' catalogue the same way after reading and listening to some of the examples [[http://wgo.signal11.org.uk/wgo.htm here]].

* The Eve's Garden strip club in ''VideoGame/{{Bioshock|1}}'' probably qualifies; the sign includes the anachronism "XXX", which would not come into use in RealLife until the 1970s. But players instantly recognize the shorthand.
* Any VisualNovel with multiple routes, and the challenges facing the heroine in her route are assumed to occur regardless of whether or not the [[HGamePOVCharacter main character]] is involved with her. Potential NightmareFuel [[FridgeHorror without this trope]], especially if the heroine will meet a horrible fate without the intervention of the main character. Does not apply if intervention by the main character causes her suffering circumstantially or directly.
* In the {{Super Mario Bros}} series, any pipe with a Piranha Plant will only hurt you if you can see the plant. If the Plant is currently inside the pipe, you can go inside the pipe without taking damage.
* PlayedWith in Stick It To The Man. The hand you use to interact with the world is invisible to most characters.
* This is likely the only explanation as to why everyone keeps mistaking Shadow for Sonic in ''VideoGame/SonicAdventure2'' despite several cameras getting close-ups of his very different face from Sonic's. The player has to know that the hedgehog going around wreaking havoc is different from Sonic.

* ''Webcomic/TheCartoonChroniclesOfConroyCat'' naturally toys with this one now and again. The "off panel" aspect of this trope is one that Conroy picks up on incredibly quickly during his 'toon training, to Doggy's irritation.
* In Webcomic/TheOrderOfTheStick, whenever Elan plays his [[MagicMusic bard song]], green musical notes fill the air. As part of the strip's general MediumAwareness, one (green) character notices that they are the same color as she is.

* In ''Series/{{Noob}}'', [[TheCracker Tenshirock's]] avatar seems to exist for interaction with players, [=NPCs=] and in-game objects. However, erasing it is treated as the same thing as keeping him from doing anything to the game and the effects of his hacking only seem to ever happen a short distance away from him.

* In the second season pilot of ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', Discord corrupts Twilight Sparkle's friends one by one. When the ponies turn into jerks, they also become sepia-toned and later turn gray. Spike and Pinkie Pie are the only ones to note the color change, and both characters are among the only ones to have openly broken the fourth wall before.
** More generally, the [[ColorCodedWizardry colored auras]] that show up around unicorns horns or levitated objects are purely for the benefit of the audience. Some fans forget that the characters are incapable of seeing them.
* In ''WesternAnimation/AvatarTheLastAirbender'' and ''WesternAnimation/TheLegendOfKorra'', Airbending can be seen as visible gusts. Given how people normally can't see air, this is done to give scenes a little extra flair. And to avoid having a character look like a dork throwing their arms around without some sort of visual to show that they are doing something.

* In his classic essay "[[http://en.wikisource.org/wiki/That_Which_Is_Seen,_and_That_Which_Is_Not_Seen That Which Is Seen, and That Which Is Not Seen]]", the 19th century French economist Frederic Bastiat argues that many destructive government policies arise from tendency of people to only focus on what is obviously visible.
* Inverted in quantum theory, since observing a quantum phenomenon actually changes the output of the quantum effect.