In some universes, ignoring the antics of the main characters goes beyond the Bystander Syndrome. It seems that with your average person, their attention span is wholly taken up with the gray mundanity of their everyday lives. They simply refuse to see anything too strange.
Sometimes invoked for seriousness, such as an explanation in which exploits go on ignored by most people... but often, this is just one part of the Rule of Funny. Magic battles, alien invasions, and all other sorts of supernatural happenings often happen right in front of people's faces... and yet they merely glance out the window, and go back to their morning coffee, sometimes either not noticing it or just saying some excuse.
If it's ignored because they're incapable of seeing it, it's Invisible to Normals. Compare Bavarian Fire Drill, which exploits similar psychological tendencies. Contrast the Fisher Kingdom, where the world itself is the censor. Frequently Pink Elephants are invoked when the only evidence of the character's having drunk anything is what he claims to have seen that is being dismissed as a hallucination.
One of many things that enables the Masquerade, especially its extra strength variant, and allows Muggle characters to act like real people despite the extraordinary things that go on in their universe every day. When it's an actual power, becomes subject to You Can See Me? And they, in fact, can be seen By the Eyes of the Blind.
This can sometimes lead to Artificial Atmospheric Actions where NPCs merely treat all sorts of odd stuff as an everyday occurrence. Can also lead to the protagonists, especially if they're a small group or completely isolated from others that can see through the effect, seriously wondering if they're the ones who are seeing things wrong, or just insane.
Also see City of Weirdos. Possibly overlaps with Supernatural Proof Father.
Compare and overlap Unusually Uninteresting Sight, where something blatantly looks out of place to the viewer, but nobody notices (or cares to notice.)
Compare Perception Filter, which causes people to overlook something regardless of whether or not it's "weird."
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Anime and Manga
Became a running joke in Transformers: Robots In Disguise, in which one woman is constantly harassed by Sideburn—who is trying to get jiggy with her car. By narrative convenience, she starts being in range of the giant robot battles nearly every episode.
In contrast, Transformers Armada has maybe five people actually see the constant robot battles. This is partially justified as apparently all but a few of the Mini-Con panels appear in unpopulated areas, but still.
Ah! My Goddess: No matter how pyrotechnic the magic, the antics of the goddesses and demons never draw the police (or possibly the Army). Not even humongous monsters like Garm. This was explained in the manga as the townspeople being desensitized to weirdness due to the neighborhood kids pulling off epic level pranks on a regular basis, or some similar Hand Wave.
They do live in the same town as a technical engineering college. If those people get bored enough, they can disassemble your car and then reassemble it. Inside your living room.
Amazingly enough, the fire brigade actually turned up in one of the latest manga chapters. They ended up thinking it was a false alarm though, as all the damage had already been fixed with supernatural means.
Bludgeoning Angel Dokuro-chanlampshades this in the first episode. She introduces herself to the class as an angel (after turning a classmate into a monkey and making another one completely vanish) despite Sakura's insistence that she keep it a secret, but they just nod and accept it fully. In fact, Sakura is the only one who seems the slightest bit weirded out by the situation. "This should really bother you! Say 'Ahh! Angels exist?!' or something!"
The citizens of the Dragon Ball Z universe seem to quickly get over the fact that several towns and cities suddenly explode when a Monster of the Week comes by. In one episode, Nappa is seen destroying a naval fleet sent out to stop him, but after that, the military is never seen retaliating against future villains other than against Perfect Cell.
Perhaps the most blatant example of this was how the entire world became convinced that Cell was just a monster and chi attacks were just special effects. This despite the fact that not two decades earlier one of those special effects blew up the moon on global television.
Not to mention King Piccolo nuking a city live on television and everyone knowing he was more than capable of destroying West City when he made his announcement. There was also his son who destroyed the island where the Martial Arts Tournament is held, canceling the event for a number of years.
The military also goes up again Majin Buu, before sending in Mr. Satan.
There is also the fact that the citizens on Earth are happy to go back to their everyday lives after only briefly wondering if they were killed by Majin Buu and their cities destroyed. Then again, since this is Dragon Ball, maybe mass revivals became so common that not even the muggles care anymore.
In Sailor Moon SuperS, a gigantic evil circus tent appears right in the middle of Tokyo, in obvious plain view. Among the other random massive evil fortresses and demonic whatnots that show up in the middle of that same city in other seasons. Part of what makes this one stand out in the show is a lack of this problem in most cases: the evil base in the first season was underground in Antarctica, the base is second season was on a distant planet in the far future, the base in the third season is a covert underground lab, and in the fifth it appears to be located in another dimension. The circus thing was actually lampshaded by the Lemures immediately after its appearance - they mocked the citizens for not noticing it.
In Ikki Tousen nobody seems to care that students attack each other's high schools and commit openly visible acts of extreme violence. You'd at least expect that the police would try to intervene - or that the army would be called in to do something about the genocide that's taking place.
In the manga a doctor commented in it being more or less a bunch of delinquents beating each-other to death. He seems to be the only one that has noticed.
In Windy Tales, almost nobody notices the huge amounts of cats that fly around on air streams, not even when they're cluttered together in a huge ball consisting of dozens of them during a typhoon.
In Princess Tutu, the typical townsperson (and the majority of the main cast in the beginning) doesn't question any of the "odder" stuff that goes on in Kinkan, including ballerina-dancing Anteaters (and other anthropomorphic animals). Even visitors to the town are affected—one women wonders if her troupe leader used to be an electric eel before arriving to the town, then quickly brushes it off. Later on in the series, it's revealed that it's because of the story magically controlling the town and the people inside of it. The only people that ever seem to realize something's off with the town are either important to the story, or actively go looking for something odd in the town.
Nobody seems to notice their friends strange behavior and obvious paranoia, or at least do anything about it, in the answer arcs of Higurashi no Naku Koro ni.
This trope is subverted in Tatarigoroshi-hen, or actually any arc where they try to save Satoko. In Tataragiroshi-hen in particular, Rena and Mion notice Keiichi's paranoia, unlike Onikakushi-hen, and try to cover his actions up.
And in Umineko no Naku Koro ni Battler uses it to deny that the Beato/Virgilia battle happened even better example in ep 5, after being defeated by Battler on the gameboard Erika suddenly stands up in her chair during the meal and starts talking in blue truth and exclaims to her master Bernkastel that she has won and has to be acknowledged. Then she suddenly sits down in her chair eating. The family collectively thinks they were hallucinating
Unusually Uninteresting Sights abound within the Academy, but no one except Chisame notices the blatantly odd things surrounding them. It was later revealed that mages keep their Masquerade protected by spells put in place to heighten people's ability to disbelieve information (they also rely on people's inherent ability to doubt). This naturally makes for interesting situations whenever the very odd is shown.
Muggle 1: I see, if it's a robot, it all makes sense. Muggle 2: A-a-ah, I see, sure. Muggle 3: Yep yep'' Chisame: Wait a second you punks! Doesn't that seem weird to you!?
In volumes 1 and 9, a spell version (like a Somebody Else's Problem Field) is mentioned to be used by mages when they do or discuss magic publicly, and don't want to be found out. In vol. 9. Asakura runs head first into it when she and Sayo try to follow Negi, and describes it as a sudden desire not to go into the area protected by it (Sayo, as a Ghost, is unaffected). Once she's noticed the effect, she can resist it, but is physically straining to do so the further in she goes.
In chapter 301, Natsumi Murakami's pactio artifact weaponizes this trope, rendering anyone holding hands with her unnoticeable. Fate Averruncus himself acknowledges it as a rare and dangerous artifact for the enemy to have.
It also seems to apply to more than just magic. For example, Negi (a mage) is completely oblivious to the extremely obviously roboticRobot Girl in his class. Chisame is the only one who seems to completely lack a weirdness censor.
In Twin Spica, nobody wonders about the weird stuff that sometimes happens involving Lion-san, for example when Asumi gets twirled around at the playground by some unseen force.
Usually this is the case, including people it's happening to, like Kasane on the merry-go-round. There is one little girl that comments on sake flying through the air, which gets her grandfather scolded for giving alcohol to the kids.
In Bleach, any fighting done in the mortal realm is invisible to most of the human population, but despite that there are a few things that still should stick out. Whenever a human who can see spirits addresses one of them it looks like they're talking to thin air to a normal bystander. When a human turns into a Shinigami their spirit leaves their body, while most Shinigami compensate and have a temporary soul inhabit their body, Ichigo tends to just leave his body lying around out in the open. Nobody at all ever seems to notice either of these events until the first movie, which is roughly 100 episodes into the continuity, and it's hardly mentioned again, if ever at all.
Somewhat explained with all the level of Brainwashing the Shinigami pull off. Also, there's another "substitute soul-reaper" there, as well as is reasonable to think the Technological Department, considering Karakura-town (or whatever) is the set of many, MANY altercations, may have devised something to make the townspeople unaware to what's going on under their noses. Even Ichigo was close to having his memories removed, Orihime had the process applied on her, Ichigo's sisters etc. At this level, It's surprising more of the characters don't die of brain cancer...
Averted when they handle Ichigo leaving his body lying around in one of the movies. Exactly as Rukia said would happen, someone found his body and some paramedics were trying to restart his heart.
Although, there are occasions where the fights actually caused damage to nearby structures, which is hardly ever mentioned. The only times it's mentioned is in the first episode, where a Hollow breaks the glass on a nearby building, (only Ichigo can see what did it). Also when Shinji fights Grimmjow, he mentions that their fight is breaking the roofs of houses and asks him to be more careful.
It's implied by Yumichika that Soul Society actually factors in this sort of damage into their missions- when the battle against Grimmjow's Fraccion seems to be getting more heated than expected, he calls up Mission Control telling them to set a 'spatial freeze' around the battling shinigami and add repairs to the mission budget.
Used maybe as irony in Code Geass: "You will disregard any strange events." The geassed people usually reply if they're asked why they're not doing anything about a crisis situation, or even reassure themselves, or warn the watcher that they are geassed with the line "I see nothing out of the ordinary."
In Uta Kata nobody wonders about the tsunami that threatens Kamakura out of the blue, or about the fact that it is deflected by a flying, screaming young girl.
In the anime version of Prétear, Shin's spell Beyondios creates a dimensional zone wherein the Leafe Knights can fight Demon Larvae without destroying nearby real estate. Obviously this is impossible to do when Shin isn't around, or when the monsters can't be placed under the shield for whatever reasons — but they still manage to stay unnoticed even by the protagonist's family, who only become aware that something is going on when the Big Bad invades their Big Fancy House. And then, it takes awhile for them to notice. At least a few episodes. In which they go on a "ghost hunt".
In Venus Versus Virus, only a few people can see a Virus. Not only that, the Virus likes to attack people who are able to see it.
Played with in Love Is In The Bag, where everyone except the London transfer students know about Kate turning into a bag.
A Certain Scientific Railgun has a girl whose special ability is Dummy Check. It makes her invisible to the naked eye but not to cameras. Apparently she can also use it as a Weirdness Censor in order to avoid drawing attention to herself (mainly due to her massive eyebrows).
Much of the humor in Buso Renkin stems from the fact that the author took all the usual components of sci-fi superhero series, reached over to switch labeled "Weirdness Censor" and flipped it to "off." All of this is completely unknown to the main cast (except Tokiko, who lampshades it occasionally) who behave as flamboyantly as possible, fully believing that the Weirdness Censor is in full effect.
This is often played for laughs in the typically bizarre world of One Piece. Particularly because the captain of the Strawhat Pirates, who is literallymade of rubber, and who has recruited a large cast of truly freaky charaters into his crew, finds extremely random things to be weird. For example, he has a talking reindeer as his ship's doctor, but is shocked and baffled to meet a talking bear on another crew.
Lampshaded in the yaoi manga Sex Pistols: any "Madararui talk" overheard by the "normal" humans is automatically and subconsciously discarded. The art plays it literal for laughs: inside the normal people thought-clouds, a paper with "Madararui talk" written on it is crushed into a ball and then thrown into a garbage bin.
In Berserk, this explains why normal people literally cannot see supernatural creatures of the less-antagonizing variety, as people only bother to remember what they can explain (or what's not trying to rape and eat them).
The title character, despite seeking anything weird or unusual in the world, manages to remain oblivious to the weird things that happen around her, aiding the other characters in keeping her Locked Out of the Loop.
Kuyou Suou / Suou Kuyou is a Humanoid Abomination who is just so...off that normal people don't even react to her presence. When some people (like Kyon) are forced to acknowledge her, they're creeped out by just how obviously yet subtly wrong everything about her is.
In Kamichu! a middle school girl becomes a goddess. It's just another after school job as far as most of the townsfolk are concerned.
In Is This a Zombie?, the heroes normally erase the memories of the normal people to keep The Masquerade. In the first episode of season 2, Ayumu is forced to fight a tentacled monster in broad daylight, yet everybody seems to only give it a passing glance and concentrate on the fact that Ayumu is in a dress. After defeating the monster, the device Ayumu uses to erase memories breaks down, leaving him a laughingstock as everyone brings up the crossdressing for a long, long time. At the very least, Taeko noticed the monster and thanked him for saving her life.
Weaponized and enforced by the villains in Kill la Kill, who by the end of the series are roaming the streets eating everyone they see - and deleting memories of anything being out of the ordinary from everyone who hasn't built up resistance to their power, ensuring that nobody but the heroes notice enough to avoid getting eaten or even panic.
The plot of the comic Black Hole centers around a sexually transmitted disease that horribly mutates high school students, yet none of their parents, teachers or, indeed, any adults in the town seem to realize or do anything about it.
In The Invisibles, it is revealed that babies are capable of seeing all kinds of strange beings and concepts but lose the ability once they learn language, which makes it impossible for them to express these concepts and thus impossible for them to register them in their heads.
Up until the "Gang War" storyline several years ago, the writers of DC retconnedBatman so that he was still an urban myth not believed in by everyone in Gotham. An air of mystery around him is believable, or even confusion over what he is, but it was often taken too far. It's hard to explain away the thousands of criminals Batman has taken down, along with the Bat Signal shining up every night, the dozens of supervillains committing crimes just to get his attention, as well as numerous public appearances with the Justice League of America. And apparently, a guy like Superman is perfectly normal, but a guy dressed as a bat is ridiculous. As Monkey Joe says, "A hero operating as an urban myth only works in his first year. Tops."
Aztek, for DC Comics, is about a technologically enhanced superhero working in the town of Vanity. Aztek's support group, believing his existence will help save the earth, employ active weirdness censors to help him out. Shouting out his secrets in the halls of his secret identity's workplace does nothing.
For a while, Professor X would use his telepathic powers to erase the memories of local citizenry. Yes, he has done this to save lives, which is fine, but he used to do this just to simply act as a Weirdness Censor and keep the X-Men secretive. Professor Xavier is a jerk.
Issue 75 of the adjectivelessX-Men series, set before the X-Men's headquarters became known to the world, has two cops talk about how the local wind produces weird audio effects occasionally. What they don't realize is the wind is actually giant robots attacking the mansion, demon attacks, the Juggernaut ploughing through half the ground floor... things of that nature. To further drive home the point, an X-Man who falsely thought he was out of his gourd is whisked away from confessing to the very same cops, causing confusion.
One appearance of The Abomination had him walking through a crowded street in the rain without being noticed. The Abomination is an eight-foot-tall musclebound reptilian monster. Everyone else was staring at their feet for fear of making eye-contact with a stranger. Even worse, there was a six-month period of time with him as a teacher of dramatic writing or something, and no one of his students or anyone else for that matter has anything to say of the 8-foot gravely voiced covered from head to feet guy except that "he looks sad" or something. Seriously, if the Hulk used a semi-decent suit he wouldn't attract any attention at all.
There was a period when the Gray Hulk worked in Vegas as an enforcer named "Mr. Fixit." People regarded him as just a huge guy. "Either he's part black and part Native American, or else he tans real weird." (It helped that everyone thought of the Hulk as green.)
The Marvel crossover storyline Inferno had Manhattan Island being overrun by demonic forces for what seems like a period of several weeks. Once things return to normal, a very weak Masquerade blaming hallucinations is accepted by the public. How hallucinations can explain the sheer amount of infrastructure damage or the many deaths during the event or the amount of time lost during those "hallucinated" days, is one question. Why a public that's already accepted the reality of superbeings, aliens and gods would have any trouble believing that New York was attacked by demons is another.
In Proposition Player, the dispossessed gods Anubis and Moloch try to track down the protagonist in Las Vegas. Moloch suggests they conceal their appearances, but the jackal-headed Anubis doesn't bother since hey, it's Las Vegas.
Fabletown in Fables has a magical protection to keep mundies from noticing their magical society in the middle of New York City. At one point they have to rely on rain to act instead, and in another point their filter (and the magic holding the buildings together) fails, forcing them to leave as New York discovers one of it's neighborhoods is now suddenly in ruins for no discernible reason.
In Doctor Strange, magic is frequently explained away by "they must be shooting a movie." People still get out of Dr Strange's way, but they don't understand why. (see Strange Tales vol. 1 #120 (May, 1964))
Amusingly, sometimes Doc and his associates have to chase down misbehaving magic, since the dragon/ogre/giant rabbit is something "even Greenwich Village would notice."
In the first arc of the Zatanna solo series, detective Dale Colton explains to Zatanna that people have a lot of trouble accepting the truth about magic, even though Zatanna herself is a world-famous Stage Magician with actual magical powers who is a member of the Justice League of America. No matter how often there is verifiable documentation of legitimate supernatural affairs people prefer to look the other way and hum really loudly, which explains why magic is still a "secret" in the DC Universe. This is particularly frustrating, even to Zatanna herself, because here there is no masquerade, the supernatural world wants to be recognized, but the people are not listening.
A running gag of the Italian Disney Comics of old was that Goofy was a massive skeptic, steadfastly refusing to believe in magic and supernatural, no matter how many times Witch Hazel tried to impress him. Of course, this didn't stop him to take part in various sci-fi and fantasy adventures by various artists.
In His Wife Is A Hen, the husband is completely unaware his wife is a hen, despite the fact that she makes no effort whatsoever to hide it.
Overlaps with Failed a Spot Check in Knight and Day. After June exits the bathroom on the plane, she fails to notice that everyone on board except for herself and Roy is dead. She continues to block it out when Roy points this out to her. It's not until Roy takes control of the aircraft and June sees the bodies fall out of their seats that she's finally convinced.
Occurs quite often in Spider-Man (film): Peter Parker jumps around, climbs up walls, shoots webs and acknowledges himself as Spider-Man when getting money off a man who runs the wrestling. He also beats the snot out of another student, and nobody makes the connection.
The only time they could clearly see Peter Parker doing any of that stuff was the fight he got into. Other than that, you had some guy jumping on roofs once that someone might have seen at a distance or not, and Spider-Man in a worse costume doing wrestling. Maybe it would have been possible to get a hint of his identity by tracking clues through the wrestling establishment, but it wasn't evident from any other character's perspective these isolated incidents were tied together.
He does get unmasked on the L train in Spiderman 2. But no one knows a name to go with the face, and they promise not to reveal his identity anyway since he saved their lives.
In The Amazing Spiderman, Peter shatters a basketball goal when dunking the ball and later throws a football so hard that it slams into and bends a goal post. Each of these events had multiple witnesses who knew Peter, but nothing seems to come of them.
Mentioned in the background material for the The Matrix films. Apparently (it's not well conveyed on-screen) as well as the The Matrix's ability to revert an area and people's memories to remove an incident from history, the leads are supposed to have a "bubble effect" which prevents passers-by (NPCs, if you will) from noticing them or interacting with them unless they do something dramatic (like stealing their phone).
The Ghostbusters films use this as an excuse to Snap Back in the sequel. In spite of a 50 ft tall marshmallow man rampaging through the city, by the sequel everyone has become convinced that it was all a hoax and the Ghostbusters are ordered to pay the damages.
In Stephen King's IT, despite the fact that Derry has had far, far more child deaths, arsons, psychotic breaks, and industrial accidents than is healthy for a small town, no one notices it's out of the ordinary because It does something to the townspeople. It gets to the point where the characters wonder if It has become part of Derry, or if Derry's just always been an extension of It. Given that, in the book at least, It's destruction is immediately followed by Derry falling apart (literally!), the latter seems more likely.
In Shaun of the Dead, Shaun goes a whole day and into the next morning without noticing the Zombie Apocalypse that has already started. This is part of his characterization that he's trudging through his life like a zombie.
In The Truman Show, this explains why Truman takes so long realizing that his world is fake. "We accept the reality of the world with which we are presented." It also explains why all the people around him studiously ignore Truman when he starts to act out.
They ignore Truman's antics because that's what they are paid to do.
Mary Poppins: Admiral Boom fires a cannon twice a day so regularly you can set your clock by it, which results in tremors akin to an earthquake for any nearby houses, including the Banks residence. However, they're so used to it at the time of the film that it barely fazes them; they just take their posts to make sure that no valuables are broken, then go back to whatever they were doing before.
A minor example with the eponymous character; Mary doesn't generally let people see her magic (with the exceptions of Jane, Michael, and those who are already aware of it like Bert and Uncle Albert), but near the start of the film, Ellen sees her and the children sliding down the banister and exiting the door to head for the park (the door opening and closing on its own). And how does she react? She simply smiles and waves, happy that she doesn't have to take on the responsibility of looking after Jane and Michael now that they have a good nanny.
In the first Blade, no one even glances at the dude driving the souped-up muscle car, with the funny hair and tats, dressed in a black leather duster with a sword handle sticking out of it. He beats up a uniformed cop on a populated street in broad daylight and no one cares.
In prose, at least early on, the police denied that The Shadow existed, claiming he just represented a contemporary rumor. In the 1994 Alec Baldwin film, a woman scoffs at the Shadow as just a rumor to get people to listen to the radio and read newspapers. (Earlier, the Shadow, while as Lamont Cranston at the Cobalt Club, used his powers of suggestion to dissuade Commissioner Wainright Barth from assigning his officers to investigate the rumors of the Shadow.)
This happens often in film adaptations, which tend to focus on either the origin or early years, instead of going for a more en media res approach. In 1996's The Phantom, someone scoffs at reports of the Phantom as "just a rumor" and in Daredevil in 2003 the police deny Daredevil as nothing more than a rumor until, in an early scene, reporter Ben Urich lights a drawing of flammable chemicals that Daredevil left behind as a Zorro mark to spell out DD.
In the first film version of the Mack Bolan imitator The Punisher, the public did not at first feel sure that the Punisher amounted to more than a rumor. In the Lundgren film, as stated in dialogue several times, Castle had apparently died in the car explosion that slew his family five years previous to the main events of the film. In the main action of the film, people still think of Castle as dead, with only his former partner thinking of him as the true identity of the Punisher. Several newspaper headlines suggest that the public did not accept that the Punisher actually operated until he started leaving knives with his skull symbol on the handle behind. (When we see the Punisher in action before the police officially identify him as the hitherto though dead Castle, though, he does not seem to have made any effort to disguise himself. Somehow, no security cameras managed to get a recording of him, it seems Before anyone says "Maybe he looked different before the explosion, maybe he had plastic surgery", sorry, when we see him in flashback, he looks the same.)
In Guyver: Dark Hero, a newspaper headline reads "Verdict Still Out on Armored Vigilante" perhaps indicating that much of the public has not accepted him more than a rumor.
In one of the Darkman sequels, a newspaper headline refers to Darkman as "an urban Bigfoot", suggesting that the public thinks of him as a rumor.
In Beetlejuice the dead are Invisible to Normals because the living ignore the "strange and unusual." However Lydia can see the Maitlands because, as she says "I myself am strange and unusual."
The X-Men movies play fast and loose with this trope. The world knows mutants exist to the point where governments are trying to pass laws against them, there are entire studies done on them, the issue is being discussed in the media, and people are actively protesting for/against them. Despite this, people are usually shocked when they see mutants displaying their powers with only a few exceptions. This even includes Wolverine who finds the concept of the X-Men bizarre despite the fact that he is a mutant himself.
Justified in that mutants are a minority who mostly try to keep their powers a secret. As such, seeing them use their powers would be unusual even if you knew they existed.
In High Anxiety fugitive Richard Thorndyke invokes this trope when he tells Brisbane that people tend to ignore strange things. In order to pass customs without incident, they behave like an outrageously obnoxious bickering old Jewish couple.
In the Indiana Jones franchise, the weirdness censor is Dr. Jones himself. This serves also as a disclaimer that the movies are not what real archaeology is about.
One of the primary responsibilities of the Men In Black (the other being handling lawful extraterrestrial alien visitor traffic) is policing illicit alien activity on Earth. Part of that duty is ensuring that the humans on Earth outside the agency are completely oblivious to the aliens among them, be they legal or otherwise.
In The Howling, there is a live werewolf transformation on the evening news. Many of the locals pass it off as special effects.
Played with in R.I.P.D.. Nick/old Chinese guy gets crushed by a car and a group of bystanders rush to help him. The Dead-o's actions do not go unnoticed by the media.
In Life, the Universe and Everything, this tendency has been harnessed and distilled into a device called the Somebody Else's Problem field. An example is given of a man who lost a bet about making a mountain disappear when people noticed a suspicious extra moon - it would have been much simpler to just paint the mountain pink and put an SEP field on it.
In Mostly Harmless, Arthur ends up on a planet that has a race of birds that ignore everything out of the ordinary that happens around them. For example, they fail to notice a giant crashing spaceship. On the flip side, everything normal comes as a huge shock to them. In the author's own words: "...and the sunrise always took them completely by surprise."
The entrance to Diagon Alley, a street filled with shops for wizards, is hidden behind a pub called The Leaky Cauldron which muggles never notice because they don't pay attention to their surroundings and don't expect it to be there. Though with memory charms, "Muggle repelling wards" and the charms that make Hogwarts look like a pile of rubble, it's not so much that Muggles willfully ignore magic as that any interaction with magic tends to involve them getting parts of their cortex melted.
Arthur Weasley also notes that Muggles who are the victims of such magical pranks as shrinking keys will always insist that they simply lost them.
Arthur: Bless them, they'll go to any lengths to ignore magic, even if it's staring them in the face...
In Order of the Phoenix the majority of wizarding Britain was putting one on themselves with the Minster's smear campaign against Harry, and willful denial of Voldemort's return.
This is a big part of H.P. Lovecraft's Cthulhu Mythos; the premise being that if the vast majority of human beings actually inquired into the weirdness and vastness around them, they'd go insane from the knowledge of "gods" and monsters. From Call of Cthulhu:
The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age.
In The Magician's Nephew, Uncle Andrew is incapable of believing animals can talk. When he encounters animals talking, the narrator takes glee in describing how Andrew's own Weirdness Censor engages at that moment, rendering him incapable of understanding them. Ironic in that Uncle Andrew spent his whole life looking for magic, and when he was finally confronted with real power, he just couldn't handle it.
The Last Battle has another instance set after Narnia's end, where the dwarves eat delicious food in a beautiful meadow but perceive it as stale bread in a muckhole due to their cynical incapability to accept the paradise.
In The Voyage of the Dawn Treader, after entering Narnia Eustace Scrubb seems completely certain he is just somewhere else on Earth and not the magical place his cousins claim he's in, despite the fact that he was pulled through a picture in the wall.
The wizards in the Young Wizards series depend on this to get away with doing some forms of magic out in the open. The bullies can't hit you because your spell is deflecting their blows? They convince themselves that they didn't want to hit you, because invisible force fields are impossible. Vanish off a subway platform via teleporting? Whoever saw you thinks you simply moved deeper into the crowd while they weren't looking.
Uses this to explain why you never hear stories about trolls, vampires and magic. Everyone just writes it off as something mundane that, at the time, they thought was impossible. If they're attacked by a troll, for example and they're asked about it in a few months or so, they'll just claim that it was a large drug addict or something (the first few months will just have them staying quiet, afraid of people thinking they're crazy or for thinking that they 'themselves' have gone off the deep end). It also helps that supernatural happenings tend to screw up any kind of recording equipment, making efforts to actually record evidence of the supernatural turn out to be grainy, filled with static, and generally seeming like badly distorted or faked content.
It helps that the people who do outright report what they have seen tend to be dismissed at best, or tossed into the loony bin, or in certain cases attacked by the very things they witnessed. A good example of this is the coroner, Butters, who reports that several bodies he examined were clearly not human, and was thus suspended for three months and put into a psych ward for observation as a result.
The author makes a point of justifying this every now and then, and gives at least one long speech about it. It actually makes sense, so you accept the blatant use of this trope.
It also helps that the various supernatural powers in play have a pretty big stake in making sure humanity does not find out about them, given that for all the contempt most of these creatures have for humans, the last thing they want to do is get humanity as a whole riled up.
Employed more subtly in the Discworld novel Interesting Times. Rincewind, on yet another foreign jaunt, figures out nobody really notices men on horseback because doing so tends to get people stabbed.
An unusual example is in Mort, where the titular character changes history by saving the life of a princess doomed to die, and everyone in the kingdom except a wizard find themselves unconsciously acting as though she had died, and feeling upset and nauseous when confronted with the fact that she still lives, then revert back to believing her dead once away from her.
Inverted in Maskerade, wherein the cast of the Opera House can't come up with the most obvious solutions because those just aren't theatrical enough.
Subverted in Wyrd Sisters: Death was visible because the audience expected he was an actor. He fit in quite well, since he forgot the lines just like the other actors.
The Weirdness Censor appears to have been (mostly) left out of The Amazing Maurice and His Educated Rodents. When said rodents decide to have a talk with the townspeople, it takes a few minutes for most of the humans to accept the existence of talking rats.
Lord Rust in Jingo confirms that it's not just the supernatural that falls subject to this trope on Discworld: his personal Weirdness Censor is so strict that it even blots out his perception of rudeness, on the grounds that a lowborn churl like Sam Vimes wouldn't possibly dare snark off to an aristocrat like him.
Moreover, it is described in both Moving Pictures and Guards! Guards!! as a kind of permanent level of intoxication generated by the brain to be able to ignore things that could drive it to madness, which can happen if one were to ever become "knurd" (a state of sobriety so stark that the Weirdness Censor is shut off). Some people are born "knurd", or it can be achieved by, say drinking extra-strong Klatchian Coffee.
There's also Thief of Time, where an actual horse (Binky) walks into a library to pick up Susan. Except that everybody knows that that doesn't happen, so it's obviously not real and therefore nothing to be concerned about.
"The historians paid him no attention. Horses did not walk into libraries."
This is one of the central themes of Pratchett's lesser known works, the Johnny Maxwell Trilogy, where the title character explicitly lacks those kind of mental filters, so he's usually the first (and sometimes only) one to notice the weird things around him. Ironically, that same lack of mental agility makes him best equipped to actually deal with said weirdness, as his friends tend to try to deal according to the way things are "supposed to" go.
In the Clan Of The Cave Bear series, the Clan are unable to see someone who has been sentenced to death. The person sentenced isn't killed; the medicine man says "you are dead" and everyone else assumes that to be true. Even if they do "see" the person they assume it's an evil spirit pretending to be that person. Ayla (the main character) even tells her BF in a later book that if she were to tell some Clan people they've just met that she had been sentenced to death they would instantly be unable to see her.
The explanation in the books regarding this is quite fuzzy. The Clan don't appear to physically lose the ability to see the person; they just believe the person is a spirit, and that if the spirit is ignored for long enough, they will disappear.
Lynn Mims uses this in a story in a Darkover anthology—Caleb Hargrave’s Weirdness Censor is so strong that it cancels out psi powers. He’s a walking telepathic damper... but it only works when he’s nearby.
In the Hitman novels of the 1970's, featuring Mike Ross, private investigator who operated in the guise of the hockey masked figure the Hitman, the Hitman stood as legendary figure only hinted at by the media. Possibly some cover occurred.
In Christopher Fowler's novel Roofworld. Why has no one noticed a shadow community living on the rooftops of London, rappelling along telegraph lines? They just don't look up much, and dismiss a glimpse of anyone they see up there if do.
The Lost Thing ends with the main character noting that he might have stopped noticing the lost things, implying that the people of the dull place he lives in are too mundane to notice something out of the ordinary like that. Earlier on, his parents don't notice that there's a giant thing in their living room until he draws their attention to it.
In Sergey Lukyanenko's Night Watch and its sequels, the Others use pretty basic spells to keep humans from noticing anything out-of-the-ordinary. This is done in order to prevent world-wide witch hunts. For example, the headquarters of the Moscow Night Watch are located on several floors of an office building, but these floors are invisible to humans (i.e. they think the building is smaller). It is common for crowds to simply pass by an Other hiding himself from humans without knowing why they are leaving a small area open. Also, no Other has to worry about burglars, as other spells make humans instinctively want to avoid certain places. This is mentioned by Anton when he has to pretend to be a human for several days and is not allowed to use any magic. He suddenly realizes his car could be stolen without any active wards.
Verge Foray's novella "Practice" has an incident of this. A school for "disturbed children" is actually for psychic children. A private institute, it's subject to surprise accreditation inspections and the children conspire in The Masquerade with the non-psychic adults. When one of the kids does make a minor slip, another kid checks the inspectors' minds and finds that one of them "saw it, but he didn't believe it, so he didn't see it."
Frank Herbert played with this more than once, e.g. in "The Featherbedders":
...he was well within the seventy-five percent accuracy limit the Slorin set for themselves. It was a universal fact that the untrained sentience saw what it thought it saw. The mind tended to supply the missing elements.
Secret City: While a general Masquerade is in effect, most humans will easily believe claims that data were forged, witnesses drunk or drugged and people claiming to use magic used clever technology or hypnotism. The eponymous Secret City dwellers also actively support skepticism in the population.
Enclaves: In an otherwise cyberpunk setting, several AncientTraditions survived and some changed, generally working by Religion is Magic. People will yet actively ignore obvious supernatural events, e.g. a person outrunning a projectile, and cite secret research or evidence failure to that end.
In Michael Kurland's The Unicorn Girl, the characters visit a Victorian-like world where most of the people literally cannot see a naked person—a fact which some thieves are very happy to take advantage of.
In the Mortal Instruments series, mundanes cannot see the Shadow World or most individuals belonging to it as they really are. The Shadowhunters, being mostly human, would normally be visible to them, but a simple bit of magic renders them unnoticeable as well. Locations, including an entire country are hidden from human perception this way.
Live Action TV
"Sunnydale Syndrome" (this trope's alternate name) is ascribed to the residents of Sunnydale, California in Buffy the Vampire Slayer, a town where people live in comical denial of the vampires, werewolves and other supernatural forces that roam its streets. This does see occasional Lampshade Hanging: people on the sly mention all the "mysterious" deaths, and musician Aimee Mann says she hates playing vampire towns. A particularly large lampshade is hung at the end of season three, where the graduating class of Sunnydale High gives Buffy an award as "Class Protector", while admitting they don't usually acknowledge there's anything to be protected from. This indicates that they probably know that something's going on with their town, and something odd as well, but they don't suspect supernatural forces to be involved. In season 6, a typical Sunnydale Times headline reads "Mayhem Caused: Monsters Certainly Not Involved, Officials Say". Then again, Snyder mentions lying about vampires attacking the high school in season 2, telling journalists it was a gang on PCP — which the chief of police says is the usual story.
Giles: People have a tendency to rationalize what they can and forget what they can't.
Early on it's strongly hinted that several things are affecting Sunnydale: the Weirdness Censor, a Mayor-led conspiracy that covers up anything overtly supernatural (that includes the police and other municipal authorities like the High School Principal) and the Hellmouth itself, which has a direct effect on anything living 'on' it. It's shown that even the dreams of a coma patient can be amplified and manifested by the Hellmouth's magical effect, and it is stated that the Hellmouth draws demons and vampires like moths to a light even if they don't realise it. Many people (usually outsiders) get the feeling that Sunnydale is a little...wrong, but have no idea what it is. By the end of Season 7 the population leave, but this seems to be the result of fear and panic rather than anything defined. This is further muddied by the fact that everyone leaves - even the normal supernatural residents, suggesting the entire population (normal or not) has been affected.
The weirdness censor is broken globally in season 8, when Harmony is photographed biting Andy Dick and vampires, demons, Slayers, and magic are brought to light.
This continues in Angel, most notably in S1's "victim of the week" stories. Unfortunately, starting from those same eps, we see half of the LA underworld, a major law firm, numerous small businesses, churches, every street gang etc all know about the supernatural; that'd be narrative convenience for you. It gets really silly when S4 sees bizarre manifestations, a rain of fire, the sun being blotted out for days, vampires swarming the city, and finally the whole city (and soon surrounding county) being brainwashed & ruled by a supernatural entity, and seemingly thousands of deaths - a number of those deaths being very public massacres. Nobody seems to remember in S5, or notice outside of LA (the government and army know about demons, where are they?)
Early Angel used the same template as Buffy, in that most of the public don't know. The exceptions were most of the people Angel Investigations interacted with, who were usually people who had seen too much to deny, people who knew the streets, corrupt lawyers or politicians and so on. That's actually a tiny minority. S4 didn't dwell on the aftermaths of the various events, but I'd bet Wolfram & Hart tapped some of their resources (probably government) in keeping the reaction down as much as they could. W&H have a vested interest in keeping the status quo until their apocalypse is due, which Angel manages to wreck in S5 - leading to the Fall and Return of LA into Hell. Even afterward, most people will probably dismiss the time in Hell - after all, they haven't been anywhere in any measurable sense, which is prime territory for 'people rationalise what they can and forget what they can't'.
In Angel: After the Fall, the masquerade gets broken for all of LA when its sent to a Hell dimension. It is put back on Earth via time reversion to the moment it was taken, undoing all deaths and damages, but everyone retains their memories. So some people want to dismiss it all as a delusion, but most know better. And one particular devil named Eddie Hope isn't letting people who committed atrocities in Hell have the luxury of engaging their inner Weirdness Censor.
By Angel and Faith, however, the weirdness censor seems to have been re-enabled, with Angel mentioning that the residents of LA no longer remember their time in Hell. This, like everything, could likely be do to the intervention of Wolfram & Hart.
Officer: [sees forcefield] What the hell is this, Sheriff? Sheriff: [sighs] Just another day in Smallville.
Taken to extremes in the surrealist BBC Three Sketch Show The Wrong Door when no-one seems to find a woman dating an Albertasaur odd at all, merely commenting on his age. Even when he eats one of their friends in front of them no one bats an eyelid.
On Doctor Who, the Weirdness Censor is used to cover the fact that the Doctor's adventures frequently take him to large, populated areas that would probably notice an alien invasion, for example. Lampshaded on a couple of occasions:
"Boom Town": The Doctor tells Mickey that people don't notice the TARDIS parked in the middle of 2006 Cardiff, despite the anachronistic look of a 1960s police box, because of this. Torchwood has the spot the TARDIS was in retain its effect permanently. "The Sound of Drums" later Ret Cons this (or adjusts the explanation) to say that the TARDIS has plot-specific Applied Phlebotinum that causes people to quite intentionally not notice, "like when you fancy someone, but they don't even know you're there."
"The Sontaran Strategem": This time, regarding a Sontaran teleporter in the office of the headmaster of a "genius school." Justified in that everyone would assume it was just another weird device invented by the genius kid. Unless, like the Doctor, they'd seen one before.
The first page quote comes from when Ace was saying that she would know if there had been an alien invasion in her recent history. The Seventh Doctor informs her that there have been several alien invasions in her recent history that she hadn't know about.
Due to more lax continuity in the 60s and 70s, there were several stories with attacks in public - The War Machines, The Invasion, Spearhead From Space, The Ambassadors of Death, Invasion of the Dinosaurs etc - in which everybody notices. The show just never mentioned it at all in later episodes or made a big deal of the Sudden Revelation (as New Who tends to do), and just carried on as if nobody had noticed without drawing attention.
Mid-90s Who book "Who Killed Kennedy" (ho ho), following a journalist during the Third Doctor days, had it that people did notice (some of) the weirdness - which was viewed as brutal terrorist attacks and disastrous failures by the government, leading to the (real life) collapse of the Harold Wilson government. This did involve casually retconning away stuff like the War Machines being a public, reported threat, but oh well...
Subverted in "Victory of the Daleks"; Amy doesn't remember a thing about the Daleks invading in "The Stolen Earth"/"Journey's End"... and the Doctor is extremely disturbed, because everyone should remember something like that, and if no one does... And later the Doctor realizes that's far from the only incident, kicking himself for not noticing that the giant Cyberman rampaging through London in "The Next Doctor" seems to have been completely forgotten. Although Doc10 did notice this at the time. When Jackson Lake said that the day would go down in history, the Doctor said something like "Yeah, funny that" with a quizical expression on his face clearly lampshading the fact that he knew no one in the early 21st Century remembered any such thing. Anyway, it turned out that these two events, at least, had been swallowed by the Cracks in Time.
In Silver Nemesis, a 7th Doctor story, an Elizabethan lady and her manservant use a magic circle to travel forward in time about 400 years. They appear, screaming, amidst green and blue flames, in the middle of the tea room that her stately home has now become. Not one of the customers even notices their arrival, let alone remarks upon it.
In the new series, there's often several large events in modern day person season that no government can, and therefore doesn't, try to cover up. It's a running joke that London evacuates at Christmas now because they're expecting trouble. And in the fourth series it was a running joke that Donna missed all these events and didn't believe they actually happened. Of course, her eyes were opened when she travelled with the Doctor... ("Except that thing about the Titanic flying over London, I mean, that had to be a hoax.")
The 11th Doctor episode "Vampires in Venice" has a very weird example of this. The titular vampires are actually piscine aliens using a perception filter to disguise themselves as humans. The vampire part is that, when the machine is working, they look like humans with fangs and no reflections. According to the Doctor, this is because the disguise doesn't change their image in a mirror, and so, when a person sees the reflection of a scary fish monster for the first time, they don't know what to make of it, so their gets rid of the image. At the same time, it claims that we can see their fangs because our survival instincts are powerful enough to override the disguise, which is actually sort of reverse weirdness censor.
In "The Runaway Bride," an entire church full of people watch as Donna vanishes from her own wedding in a flash of light, screaming piteously all the while. They conclude that it must be some sort of stage magic trick she cooked up for attention.
The amnesia pill invented by Captain Jack Harkness in Torchwood allows the titular Oddly Small Organization to erase recent memories, although it is not always permanent (certain clues can re-awaken the memories). On the other hand, they don't even bother a cover-up when lives are at stake. The people either seem to think it was all some sort of mass hypnosis or just accept it and move on, as shown by an old lady calmly pointing Torchwood towards a fish-person that was running away before muttering "bloody Torchwood."
Ianto also has mad hacking skills, allowing him to see what other people are typing on their computers and shut them down remotely. This is only done in the premiere, though, to stop Gwen from writing down all she knows before the pill takes effect.
In Teen Wolf this is pervasive. Scott and Stiles have werewolf-related conversations in school while surrounded by classmates and faculty on a regular basis. Violent incidents are routinely written off as being the result of mountain lion attacks. The police station gets shot up by werewolf hunters and it does not seem to attract attention from beyond the town. The news media, as well as any kind of state or federal law enforcement, is seemingly non-existent in the Teen Wolf universe.
No one notices Scott breaking a locker off it's hinges in the middle of the hallway.
Coach flat-out states that he does not want to know why Stiles has chains (to bind Scott during the full moon) in his locker.
Also, nobody seems to notice that Scott leaves frantically, right after the game in the second episode, both times. Right after he injures Jackson (which they also pay no mind to, except really Lydia), and right after he wins the game for them (except Stiles and Allison).
Scott bashing his head into the wall, repeatedly, during school, anyone?
New werewolf Isaac Lahey leaves visible claw marks across the locker doors without anyone commenting on it.
Inverted in Quantum Leap, in that small children, crazy people, the dying, and animals (all of whom lack a weirdness censor) can see the hologram Al, who is invisible and inaudible to everyone else but Sam. Children and crazy people can also see Sam for who he really is; Sam leaped once as the mother of a little girl, who could tell he wasn't her mother, but Sam turned the difficulty by asking her to play a "pretend game".
This was in part due to Real Life Writes the Plot since you couldn't really tell animals and small children to ignore Dean Stockwell
There was also a psychic who saw the real Sam (but not Al).
Plus the time where the "future" part of Yet Another Christmas Carol is made possible by the Scrooge stand-in having a remarkably similar brain chemisty to Sam (as the hologram was set up to be visible specifically to him).
Occurs in virtually every series of Power Rangers where no one seems quite able to make the connection between those 3 (or 5 or sometimes 6) extremely fit martial arts obsessed kids who all dress in a single colour and are always running off, and the equally mono-coloured Power Rangers who show up moments later.
Lampshaded in the Dino Thunder series when Tommy gains the Black Ranger powers, he tells his students he has to go shopping as there is a distinct lack of black in his wardrobe. True to form, he spends the rest of the season wearing lots of black. And in Jungle Fury, mentor RJ wears various clothing until he becomes the purple-colored fourth ranger, at which point all he wears besides his chef-related clothing is an outfit with a purple shirt. This happens with every Sixth Ranger arrival, and you'd think it'd get really conspicuous when a person who wore a variety of colors suddenly starts wearing one color - the same color as that new Ranger - when he begins hanging with that group of colorcoded teens.
Lightspeed Rescue also had one episode where a receptionist told a little girl "now dear, there's no such thing as monsters". In a series where Power Rangers are known public figures without secret identities. Yeeeeeahhh.
Dustin in Ninja Storm was the only Ranger of that season to believe that Rangers were more than something out of a comic book when the situation was first explained to the new team.
Humanity has gotten savvier since then - just how much they know and what team they were familiar with is usually not elaborated upon, but new teams tend to at least have some idea of what a Ranger is. When amnesiac Dillon of Power Rangers RPM asked what a Power Ranger was, his turning out to actually not know was a going-to-commercial-worthy revelation, and we came back with Ziggy asking him where he'd been. Power Rangers Mystic Force civilian Toby asked the teens to prove they were Rangers, saying "why don't you morph?" meaning that he even knows how Rangers suit up from the few-and-far-between Ranger teams that don't hide their identities. So it only took them fourteen years or so of constant monster attacks and spandex tights-wearing heroes for mankind to realize that these things happen.
This is then reversed in Power Rangers Megaforce, where the teen protagonists have never heard of Rangers before and are amazed by an alien invasion, despite two decades of both. Darn kids never pay any attention to current events.
In Young Dracula most of the breathers fail to notice the oddity that seems to surround the Dracula family.
Subverted when Vlad finally says the word "vampire" to Mr. Branaugh he realizes immediately what's been in front of his face the entire time.
Played up in The Young Ones episode "Boring" for comedic effect, and most people suffer from this most of the time.
The Father Ted episode "Speed 3": Father Dougal McGuire averts this when he moonlights as a temporary short-notice milkman. He sits in bed thinking about the day he's just had when a look of horror comes across his face. Considering his day involved his milk-float having a bomb planted on it by his predecessor, he has every right to look back with horror. However it was his weirdness censor finally failing with regard to his temporary patrons:
Fr. Dougal: THOSE WOMEN WERE IN THE NIP‼
"Kicking Bishop Brennan up the Arse": From his previous experience, Dougal gave Ted an idea on how to kick their boss up the arse and get away with it. The plan relied on the Bishop's weirdness censor kicking in: Kick him up the arse and act like nothing had happened, because such a thing couldn't possibly happen. Like Dougal, the weirdness censor failed within twenty-four hours after the event. Although Ted still managed to convince him that he'd imagined the whole thing - until he saw the 10 foot high photograph of Ted kicking him that Ted had commissioned the last night after his celebratory drinking.
The Monty Python's Flying Circus sketch "The Dull Life of a City Stockbroker" features a very boring stockbroker going about his business, not noticing things like the fact that the bus on which he is traveling is full of terrorists shooting everyone, or that the newsagent where he purchases a paper is staffed by a topless woman.
The Flash TV show had episodes where the Flash met Dr. Desmond Powell, an African-American doctor who had, in the Central City of the 1950s, operated as "the mystery man" Nightshade. More in line with the Shadow, the Nightshade, not a metahuman, ended up dismissed by most people as just a rumor, since the police hushed up his activities. (The show admitted that some of this attitude at least initially also applied to the Flash, but since the Flash had actual metahuman powers, he could not "lurk in the shadows" for very long.)
A running gag in The Flash was that police officer Bellows was constantly seeing the Flash in action but his more cynical partner Murphy always missed it, so that Murphy thought Bellows was delusional and dismissed the Flash as an urban legend.
In Twin Peaks no one seems to mind weird things such as Nadine's supernatural strength. Then again, it's arguably a case of City of Weirdos.
Bewitched: Abner is generally not in the mood to snoop on his neighbors, even if they're supposedly doing something strange.
While not magic or Sci-Fi, on Wiseguy high ranking figures in organized crime never seemed to notice that within a few months of Vinnie Terranova joining an organization, the whole operation comes crashing down.
In Lars Von Trier's Danish miniseries Riget which takes place in a haunted hospital, the head of administration Moesgaard seem completely oblivious to all the strange things that happen. For example, when one of the doctors come back from the dead (more or less), Moesgaard's first comment is an annoyed "Why am I always misinformed?". Then he just reintroduces the resurrected doctor to the staff as if nothing out of the ordinary has happened, and quickly changes the subject. In another scene, he walks in on Rigmor who is holding a gun, and she accidentally points it at him three times without him noticing it.
An episode of Lie to Me has the Lightman Group discredit a witness by revealing (to her as well) that she has the Real Life condition called change blindness, meaning she ignores anything that has changed around her while she wasn't looking. They do this by having her watch a short video and focus on certain aspects of it. They then quietly substitute the people questioning her. When the witness turns back, she just treats them as if they were sitting there the whole time.
Used liberally in the 80's War of the Worlds television series. The population at large believe that the 1953 radio broadcast (and the events of the original film) were a hoax, and (as main character Harrison Blackwood says) have suffered a form of mass amnesia about the event. This continues on into the second season, albeit differently: several characters (including a military general and a main character) are killed off, and the army refuses to assist the surviving main characters in any way, even though said deceased characters had ties to a secret government project concerning extraterrestrial invaders.
The same technique was used by Anthony Bourdain on the Washington, D.C. esisode of No Reservations, when a spy guest demonstrated how spies in the Cold War hid things in drop-off points. In one particular instance, Bourdain feigned public urination to keep eyes off of him as he hid a "tip" in a discreet spot.
In one episode of the U.S. version of The Office, the opening scene features the rest of the crew trying to figure out exactly where Stanley's Weirdness Censor ends, trying such things as bringing a pony into the office, impersonating each other, reporting sales statistics from the company's Jupiter branch, and covering his computer monitor with a box.
The doctors and police officers of the various small towns in Supernatural that Sam and Dean travel to seem remarkably good at explaining away the strange and oftentimes gory deaths that take place in their towns. For example, how can any sane person possibly explain a man's heart literally bursting out of his chest like those of cartoon characters, or people dying randomly in various fairy-tale inspired accidents, or people simply bursting for no apparent reason whatsoever?
Lampshaded by the main characters in the Season 9 premiere when the world explains every angel being banished from heaven and falling to earth as an enormous, world-wide meteor shower.
The people of Camelot in Merlin never seem to realize that the king's manservant, the title character, has eyes that glow gold and that he mumbles nonsense to himself. What's strange about this? Camelot is an Anti-Magical Faction that prides itself on its ability to catch and execute magic-users. Merlin enjoys lampshading this to their faces without them having any idea what's going on.
Arthur: [during a dice game, after he throws a bad roll] You just coughed. You're putting me off. Merlin: There is just no fooling you, is there? [proceeds to use magic to weigh the dice and win]
Star Trek has an actual Weirdness Censor built into their holodecks so that the holographic people ignore any discussions or unusual sights that don't fit within the context of whatever is being simulated. In the Star Trek: Voyager episode "Spirit Folk" the Voyager crew leave the Fair Haven simulation running too long and the townsfolk start to become aware of the weirdness of their new visitors from the crew.
One of the things Glee fans most frequently complain about when it comes to Mr. Schue is that he seems to be actively making an effort not to notice his students being bullied, so that he won't have to deal with it. He clearly knows that they are being bullied, because he mentions it sometimes, but whenever he's actually present while it's happening he never seems to notice.
One Episode of CSI: Crime Scene Investigation referenced "The Invisible Gorilla", one of the most well-known experiments in the history of modern psychology, as an explanation for why a group of bystanders just stood there and ignored a horrible crime happening in their presence: they are concentrating so hard on one thing that they miss everything else around them. The experiment happens thusly: a test group watches a video that featured six people, three in white shirts, three in black shirts, passing a basketball back and forth. The test group was instructed to carefully count the number of passes made from one person to another. Afterward, the test group was asked, "Did you notice the gorilla?" Turns out that at one point in the video, a man in a gorilla costume walks into the middle of the basketball players, thumps its chest a few times, then walks off-stage. In total, the gorilla is onscreen for nearly nine seconds, and no one ever spots (even those people who go into the experiment knowing there is going to be a gorilla tend to not spot it at all).
In The Sarah Connor Chronicles, Cameron, John, and Sarah time travel and arrive naked in the middle of the highway. The drivers either gawk or yell, "Hey streakers, get off the road!" They don't seem to notice that the trio appeared out of thin air and destroyed part of the road. Later, the incident goes on the news, and all they mention is, "Three streakers disrupted traffic today."
Played with in a few of Bob & Ray's Wally Ballou skits, wherein the newsman, searching eagerly for a story, ends up interviewing the most boring man alive (in the most memorable version, a cranberry grower) while resolutely ignoring the obvious disaster — gunshots, sirens, screams, crackling flames etc — happening all around them.
An amusing variation in Warhammer, with the level of it Depending on the Writer. The Empire refuse to believe in the existence of the Skaven (a race of technologically advanced rat-people, living just under the surface), despite the fact that half-human Beastmen, Elves, Dwarves (who exist in a constant state of war with the Skaven), magic and freaking Dragons are just a fact of life in the Empire . This has been explained back and forth by either the Empire keeping it quiet to keep everyone from panicking, the Skaven keeping it quiet in their own best interest, people just assuming they're a Beastmen variant or some innate magic of the Skaven making everyone forget.
One of the character classes of the Palladium RPG Beyond the Supernatural is the "Nega-Psychic": a person whose disbelief in the supernatural is so strong that it provides him with enhanced saving rolls versus supernatural phenomena and allows cancellation of supernatural effects. (This means that the nega-psychic character spends the entire game loudly wondering why everyone else in the party is getting so excited by "swamp gas," something which appeals to certain types of role-players, but drives others up the wall.)
The Third Edition of GURPS included an advantageous character trait called "Mundane", which at its most expensive and intense level would actively turn anything odd and unusual into the normal and boring while the character was around it.
In Werewolf: The Apocalypse, werewolves (and other shapeshifters, except werefoxes), have the Delirium. This means that (most) mortals, upon seeing a werewolf in true form, freak out hysterically, and forget about what happened later. However, relying on this to maintain the Masquerade is pointedly a stupid idea and usually outlawed in shapeshifter societies, as the various enemies who know about them can simply follow incidences of such hysteria to track down the protagonists.
In Changeling The Dreaming, changelings are prone to Banality (the death of imagination), which not only shuts down their magic, but is potentially lethal to them, and if they manage to use their magic in front of mortals, the Mists will erase the knowledge of it.
In Mage: The Ascension, humanity has been so convinced to accept a paradigm of what is and what isn't possible that anything too blatantly "magical" usually results in reality itself backlashing against mages in the form of "Paradox." The presence of normal humans actively disrupts magic. The mere act of observing a mage's supernatural abilities can cause their spells to decay into nothingness.
Mage: The Awakening keeps Paradox, but in this case, it's coded into the very laws of the universe. Human observation will cause magic to decay (due to the Lie), but the very act of performing something explicitly magical runs the risk of the universe (or... something worse) pantsing you.
Werewolf: The Forsaken has Lunacy, which is equivalent to Delirium. Instead of being the ancestral memories of werewolves culling humans, however, it's a gift by their patron goddess Luna that keeps humanity from easily finding the beasts in their midsts.
A similar effect occurs in the Second Sight splatbook, where almost all humans are latent psychics, but since they don't believe in psychics, end up using their abilities to suppress the unbelievable psychic acts of others. Conversely, it's possible for characters to gain an advantage in the form of a believing hanger-on who actually makes their psychic abilities perform better.
In Changeling: The Lost, all changeling magic (as well as the changeling's inhuman appearance) is covered by "the Mask". Demons are simply unable to use their powers when seen by (too many) unbelievers.
The Swedish horror game Kult makes this the central premise of the world's mythology: Humanity has been imprisoned in an illusory world by the Demiurge and blinded to the real world around them. When supernatural events transpire around them, the illusion-spell in people's minds makes them rationalize it away as normal accidents.
In two of the four main variants of the Tabletop Gamesd20 Modern, monsters roam the modern world. However, most humans can't believe that they exist, so they just see humans where player characters see monsters. (These settings are called Urban Arcana and Shadow Chasers, if you're wondering.) The average joe walks around in a state of autopilot, it's explained, so while they do see monsters as monsters while they're around, their mind subconciously edits it out later, remembering a troll as a massive brute of a man, the dragon's fireball as a gas leak, the gnoll in the corner a shady guy wearing a trenchcoat. They also don't notice things that the more alert player characters and "aware" NPCs do, such as aforementioned shady man having slightly protruding ears...
The Dungeons & Dragons core rule books advise the DM and the players to avoid this; if you're playing in a setting where you can buy and sell magic items fairly easily, it kind of behooves the NPCs to notice magic, and not knock it as "superstition."
Except in Ravenloft, where noticing what's spooky and magical can get you killed. Natives of domains such as Richemulot or Zherisia, where the populace is infiltrated by monsters, find it a lot safer not to admit they've seen anything suspicious, even to themselves.
There are also the ancient demon lordsPale Night and Dagon. When a mortal being encounters them, the Weirdness Censor is the only thing that keep your head from exploding.
In The Dark Eye German Pen&Paper, its fairly normal for elves and dwarfs roam the cities. The bigger cities have their mage academies. Goblins and orcs are fairly well known in the wilderness. Yet muggles are particularity shocked whenever something magical happens around them, and are fast to shrug it off as something mundane instead of magic. This is played Up to Eleven with the kobolds, which in this setting are supernatural beings of near infinite power... and only use it for mischief or if enlisted by an deity for a particular job to guard an area. Like in Real Life if some mishap is going on, they are going to handwave it towards the kobolds as fairy tale, but maybe more true as they want it to be.
Nobilis averts this. Muggles may go mad from encountering what they could not possibly understand and Nobles must take pains to ensure that this will not happen. However, their bosses, the Imperators, are powerful enough that reality itself will censor their actions. If an Imperator blots out the sun, not only will everyone believe it's a solar eclipse, but scientists will have retroactively predicted it several weeks ago.
Third edition tones this down a bit, with most miracles having a degree of muggle-safety, but pulling off stuff that's too blatant will still cause dementia animus.
Rogue Trader mentions this as a Required Secondary Power for Navigators- their Warp eye allows them to gaze into the Warp, but also edits the input into an appropriate metaphor- the examples in the book are finding a path through a storm-racked wood or navigating a roiling sea. It's actually a good thing, as Going Mad From The Revelation can be harmful to your health.
In addition, the Unremarkable trait from Dark Heresy can work like this. The Moritat assassin who is anti-social and obsessed with murder? All I see is a businessman with a bit of red on him...
In Call of Cthulhu, one possible form of insanity is Panzaism, the pathological inability to perceive extraordinary things as such. A Deep One, for example, will be seen as a normal man, or perhaps a man in a wetsuit, or at the very most, man wearing a deeply unconvincing monster suit.
"A man breaking his journey between one place and another at a third place of no name, character, population or significance, sees a unicorn cross his path and disappear. That in itself is startling, but there are precedents for mystical encounters of various kinds, or to be less extreme, a choice of persuasions to put it down to fancy; until—"My God," says a second man, "I must be dreaming, I thought I saw a unicorn." At which point, a dimension is added that makes the experience as alarming as it will ever be. A third witness, you understand, adds no further dimension but only spreads it thinner, and a fourth thinner still, and the more witnesses there are the thinner it gets and the more reasonable it becomes until it is as thin as reality, the name we give to the common experience... "Look, look!" recites the crowd. "A horse with an arrow in its forehead! It must have been mistaken for a deer."
Averted in the Assassin's Creed games, when bystanders will basically go "WTF?!" when they see Altiar, Ezio and so on climbing up a wall, and so on.
In Diablo III, pre-release information says that the majority of the world has shrugged off the events that happened 20 years ago, and are unaware that demons were responsible for the havoc caused. This is rather odd, because in the second game, the minions of the Prime Evils seemed to rampage across most of the known world, and most of the NPCs you talk to seemed aware of the cause of the problem.
Even in one of the novels, a necromancer comments that their seers suspect that Baal is responsible for the destruction of Mount Arreat in the Lord of Destruction expansion pack. Not only do the necromancers usually seem more aware of what's going on than the rest of the world, but Baal was anything but subtle during his assault. Baal wasn't exactly skipping merrily to the summit, though. He killed cities and possibly kingdoms that were in his way. Who's left to say what really went on besides some reclusive, not terribly credible barbarians?
In the absence of forensics science, evidence of the Prime Evils rests entirely on eye witnesses. The demons weren't exactly leaving a lot of those... and most of them would likely be thought insane by anyone who hadn't been involved in the previous conflicts. Marius is a clear example of this, narating his misadventures with the wanderer from inside an asylum cell.
In The Legend of Zelda: Twilight Princess, the Hyrule Castle Townsfolk do not notice, or at least have nothing to say about, their castle being taken over by an evil warlord and his moblin army, which is then encased in a crystalline force field, and especially not right after said force field is broken by a giant glowing spider demon. They do however react when the player's wolf form runs around town. The ignoring (or being completely blind to) the barrier is lampshaded by one character.
The Legend of Zelda: Majora's Mask is an aversion: though the townspeople at first ignore the moon, by the third night most of the townspeople have fled, and those who stay have resigned themselves to the probability that the world (or a large portion of it) will be destroyed.
Hilariously done in Fate/stay night, when Rin gets so angry at the protagonist that she breaks her (entirely fake) "perfect student/school idol" image in front of their classmates to shout at him. The entire area goes quiet... everybody stops and stares... and suddenly go back to what they were doing, oblivious of what happened, having subconsciously repressed those memories to maintain their "perfect" image of her. This happens on two separate occasions.
At the end of Metal Gear Solid 2, a gigantic superweapon crashes into New York City. From the wreckage emerge a white haired pretty boy wielding a sword and the former president wielding two swords and wearing a suit of tentacled power armor. They proceed to fight a battle on the roof of Federal Hall, culminating in the villain being stabbed and falling from the roof. You'd think the cops or someone would take interest, but it just shows everyone going about their daily business because it's New York and they're used to that.
Only partly averted in Prototype. Pedestrians will freak out and the military will open fire if the PC Alex Mercer reveals some of his Lovecraftian Superpowers, but running along a wall upwards, leaping across a street or gliding? Nah, that's fine. There's a small chance that a pedestrian or marine will look at you, look away, and say "fucking New York." Apparently, that sort of thing happens all the time here.
For some reason in Kingdom Hearts 358 Over 2 Days, nobody seems to notice how many monsters are in Twilight Town. For that matter; it almost seems to be a ghost town whenever you have to be in there. Bonus points go to when you consider that Xion's final form is floating in the air in front of the train station. And she's practically an Attack of the 50-Foot Whatever. How on earth did people not notice that or even come to investigate?!
In Golden Sun and both sequels, Psynergy itself is Invisible to Normals... but people still should be able to see the objects that move without being touched, fires starting and stopping, sprouts growing into giant vines in a matter of seconds, puddles freezing into giant ice pillars, and that group of Anime Haired teenagers that always seems to be around when strange things happen. The number of situations where anybody notices Psynergy in use or the effects thereof, in all three games, can be counted on one hand.
Subverted in Dark Dawn when Briggs recognizes Matthew & Co. when he spots them handwaving crates around on the other side of the dock... but it's implied that he knew what to look for since he's dealt with Adepts before (and lives with a few), making him more of an exception that proves the rule.
The iOS game Plague Inc. (similar in many respects to Pandemic) has several types of plagues that can be unleashed. The "parasite" type has additional abilities that can be evolved that hide it from notice by people. In game terms, this decreases the "severity" stat to below zero. What this means is that the symptoms can include nausea, coughing + vomiting (which enables projectile vomiting) and still not think anything is wrong. You can have the entire world have these symptoms with no one the wiser. It's not until you "evolve" deadly symptoms and people start dying by the millions that anybody starts to consider that something strange is going on. The same can be done with the special Neurax Worm plague type, but that is implied to be a semi-sentient Puppeteer Parasite.
The Mat Dickie game The You Testament has this with its citizens. It's not uncommon to watch citizens greet others, turn around and attack them, steal items, run around with missing limbs, hug a person, then turn around and attack them... you try to do any of this stuff, you're gonna get caught.
Discussed in Katawa Shoujo. After a couple of weeks of studying at a school for the physically disabled, the main character notices that he's been developing a Weirdness Censor of sorts for his classmates' various disabilities.
Psychonauts plays this quite literally. Every mind has actual censors whose job is to roam around and stamp out anything that doesn't belong. (Such as visiting Psychonauts...)
Most of the stages in Jojos Bizarre Adventure All Star Battle have onlookers, most of whom watch the fight, with some commenting on hazards. However, the background characters for the Cairo stage simply do not care about the insanity occurring right next to them. Granted, Stands are Invisible to Normals, but they should still see such things as a man teleporting around and dropping steamrollers, a woman unraveling herself into string, a man's bullets being redirected in a zig-zag pattern, or a long-dead president of the United States (though to be fair, not one from this present timeline) disappearing into an American Flag, or any one of the crazy things from the first two parts, but no one bats an eye. They don't even react when a car speeds right past their table.
In Octodad, the great majority of people don't seem to think strange a "man" walks in bizarre patterns, talks in blurbs, has tentacles instead of arms and legs or causes great amounts of property damage doing even the most mundane of tasks. The only person who knows his secret is a psychotic chef and his daughter, who assumed that everyone already knew.
In El Goonish Shive, the aliens, when walking among humans, use a system of disguise that involves wearing shirts bearing the label 'human'. Despite their natural forms looking like Little Green Men, this method somehow successfully convinces anyone who has not been explicitly informed of their existence.
The trope actually ends up being subtly deconstructed as The Unmasqued World really isn't any different from before. People still go about their lives as usual, the Men In Black still do their job as before, and most denizens of the magical world still stay out of sight. Even while The Masquerade was in place a lot of people knew about magic. It seems like people just don't let all the weirdness going on around them get in the way of living their lives, yet aren't in the least bit of denial about how strange things are. They just treat the fantastic the same way as they treat the mundane.
Narbonic partially subverts this by showing that, while Dave Davenport's brother Bill is unable to see such things as talking gerbils or dancing androids, Dave proves equally blind to Bill's flaws as compared to himself, determined to see Bill as having a better life than he does. Also, when the clone-Dave is under the effect of the Mad Science cure, he too is affected by the Weirdness Censor, even while in the midst of a running battle.
Elaborated on in the sequel, Skin Horse. Although censors don't appear to be universal even among the regular population, those who have one make for good employees or middle-men in secret projects: one is guaranteed not to spill the beans when one is not aware there are any beans to be spilled.
Nobody even seems to notice when someone or something starts breaking stuff in Tokyo, no matter if it's Ping the overpowered Robot Girl, a giant drunken turtle, or a Rent-a-Zilla. This is justified to some degree, because not only does Tokyo get destroyed so often that nobody really cares, but also because the destruction rampages are scheduled and supervised by the Tokyo Police Cataclysm Division. There is also some suggestion that many of the more outrageous aspects of Tokyo life are in fact literally Invisible to Normals, but the actual extent of this effect remains unclear. Also, the people don't look up particular iteration is alluded to in MegaTokyo as well, where Tohya tells Yuki that the civilians are "just as afraid to look up as you are to look down". In the fifth collection of Megatokyo, Gallagher FINALLY detailed his explanation for this phenomenon: "...the main theme of Megatokyo is how everyone has different perceptions of the world around them..." Everyone sees the world slightly differently. Piro and Largo are on the extreme ends of the scale—Piro only sees "mundane" things (and dismisses the fantastic things as mundane things) and Largo only sees "fantastic" things, and comes up with fantastic explanations for the mundane things he sees. Everyone else is somewhere else on this scale, nearly always between those two extremes.
It seems as though Miho has the power to turn off other people's Weirdness Censors. In this comic, she tells Kimiko to open her eyes, which leads her to notice that the restaurant is under attack by killer robots.
Most of the populace of Generictown in The Inexplicable Adventures of Bob! appears to have this trait to one degree or another (especially Mr. Bystander). Even Bob himself often refuses to acknowledge just how bizarre the situations are that he finds himself in. The only castmember completely free of this trope is Jean, leading her to exclaim at one point, "Ye gods! I'm the only sane person in town!"
In Slightly Damned, for most mortals the sight of a Demon and an Angel walking around together instead of fighting each other is so unthinkable everyone assumes that's just some people in costumes.
Played with in Shortpacked!. For some reason, everybody who works at the titular store (or, at least, the ones who weren't involved in SEMME-related adventures), don't remember any alien-related stuff that happened over the past few years. Everybody else, on the other hand, usually does.
It seems more like they just really don't care. For instance, at one point Amber goes to New York, and mentions "huh, you would never be able to tell this place was destroyed a few years ago."
Present in Thunderstruck, where supernatural entities of all descriptions operate right under the nose of the general populace — partly through passive Weirdness Censoring among the general populace, and partly through active Masquerading. Children lack Weirdness Censors, though — in fact, they're actually drawn to the supernatural.
In the Shadowgirls universe; enough templars in an area disbelieving hard enough can shut down magic users entirely. Which leads to Starkweather circumventing said limitation by somehow tapping into an older magic.
In Emergency Exit it is revealed that the Apartment has one of these only after it temporarily takes it down, allowing police attention to come to the large hole in the wall, because "It thinks it's funny" to do so.
In Zebra Girl, the lagomorphic Sam explains that he can stroll into any bar to have a drink without worrying about his appearance because most people will actively dismiss him out of hand even if he's sitting right there.
This is how people miss magical events in Errant Story. When they see something impossible (like the talking cat with wings) they think that there's no way they just saw that and then promptly forget it even existed.
This is the explanation for how the angels and demons of Elijah And Azuu are able to integrate into society... humans still physically see their horns and haloes, but simply don't process them. Though if someone is too weird looking they're simply Invisible to Normals.
In Heavenly Nostrils, the class doesn't react much when Phoebe shows a real live unicorn during show and tell. As the unicorn tells Phoebe, this is because of the "Shield of Boringness," a bit of magic that lets unicorns live undisturbed.
The Protectors of the Plot Continuum use actual SEP fields taken from The Hitchhiker's Guide to the Galaxy continuum to protect themselves from being seen by the characters in the fanfics they're sporking. Unfortunately, Mary Sue characters can see them, so they have to actively hide from the targets of their wrath. It's also possible for them to break the SEP field by attracting too much attention to themselves.
New York Magician: Lampshaded repeatedly; most New Yorkers people won't notice unless something really incredible is happening. In fact, Michel muses that it's easier for him to get away with using magic in public than it is to get away with waving a gun around; people rationalize magic, but they call the cops for guns.
In the Paradise setting, humans are randomly, permanently transformed into Funny Animals (and occasionally gender-changed) by causes unknown. A powerful "Reality Distortion Field", otherwise known as "the Veil", renders these changes Invisible to Normals, who will continue to see the Changed as their original human selves (and genders). It is only able to cover their bodies, however; they will still leave animal footprints, and any fur, horns, claw trimmings, etc. they shed will be visible to others. It begins breaking down as the series goes on and finally starts failing completely in 2009, leading to The Unmasqued World as the Changed finally make themselves fully known.
The Simpsons. The entire theme of Homer's Enemy was to plop a regular person (in the form of Frank Grimes) into the Springfield universe and have them react to just how bizarre that world really was. Frank was thunderstruck how a moron like Homer could have two cars, win a Grammy, tour with rock stars, be friends with Gerald Ford and been to space on the space shuttle.
Frank Grimes: I'm saying you're what's wrong with America, Simpson. You coast through life, you do as little as possible, and you leech off of decent, hardworking people like me. Heh, if you lived in any other country in the world, you'd have starved to death long ago.
In Danny Phantom, Danny feels perfectly secure transforming into a ghost if he ducks inside a locker or even stands behind another person to do so. Apparently nobody makes the connection that a kid moving to a just-concealed area, disappearing, and being replaced by a ghost might mean something. Also, people can be attacked by giant ghost wasps and such like at school and will run screaming as expected... but the next day, everyone's fine; law enforcement is never called and nobody seems to remember being terrorized by supernatural entities.
Also possibly subverted, in that Danny's sister witnesses him transform and fly off into the sky early in the series, and asks his two friends (who are in on the secret) "Did you see that?"... and then manages to convince them, very easily, that she is affected by the weirdness censor and thinks she was imagining it. In fact, she quickly accepts Danny's secret and later helps and supports him without his knowledge.
Paulina lampshades the first part in one episode, where she invites Fenton to her birthday party because he always seems be there whenever his alter ego shows up to save the day, meaning Phantom would come if Fenton did. She never puts two and two together, though.
Justified since none of the people inculding the ghost hunting scientists think there can be a human ghost hybrid.
The staff (with the possible exception of the janitor) of Flying Rhino Junior High, especially Mrs. Snodgrass and Principal Mulligan.
in a way, the rest of the cast to the fact that there principal is an anthropomorphic Rhinoceros and there janitor is an anthropomorphic pig
The janitor even fooled the intro, which points out that the Principle is a Rhino, but notes that the Janitor's a spy.
Lilo & Stitch: The Series has all types of aliens running around and yet hardly anyone ever give it any mind. When Lilo give a few aliens away to help with a specific job, the owners are more then happy to take them in.
Invader Zim uses this trope; though it is completely obvious that Zim is an alien (he has green skin and no ears or nose), Dib is the only one who ever notices (aside from his sister Gaz, who simply doesn't care). Likewise any time something bizarre happens most people either ignore it, or notice it but never question how or why it happened in the first place. (Or if they do, Dib usually somehow gets unfairly blamed).
Also, in the episode where they get a poltergeist, Lois pushes in some chairs around the dinner table and then turns around. When she turns back, they're all stacked in a pyramid on the table, and she says "Oh, I must have just stacked them wrong and not realized it. Yeah, that's it...."
Peter's fights with the giant chicken are treated this way. In one extreme example, Peter and Lois were interrupted mid-conversation by the chicken attacking Peter. The fight sequence (with a break for a fancy dinner) doesn't finish until hours have passed. When Peter finally returns home, battered and bleeding, Lois is still sitting there waiting for him, and they finish the conversation as if nothing happened.
Officer Barbrady does this a lot in the early episodes of South Park, whether it's political corruption or alien plots.
Played straight and subverted in the Cat Came Back cartoon when the old man takes the cat for a ride into the mountains on a train trolley. Along the way, he runs over or passes several women tied to the train tracks, unfazed. But when he spots a cow tied to the tracks...
Citizens in Phineas and Ferb who notice the larger stuff the boys do never seem to find it worthy enough for the newspaper. Candace was pretty unlucky no one ever wanted to talk to her parents about what the boys had done, especially in The Movie, where the entire town witnesses a robot invasion and never discusses it again.
There is a deleted scene where a TV news reporter states that all the robots were actually "A weather balloon"
And it's not just in the boys' hometown. In one episode, giant robots of a dragon and Queen Elizabeth I were duking it out in downtown London. While this does make it to the news, the only thing that caught people's attention was the second story of a new version of Jane Eyre being made.
In the Codename: Kids Next Door episode "Operation T.U.R.N.I.P.", the farmer is completely oblivious to the fact that his giant turnip is sending smaller ones through its roots all over the place and attacking the Sector V kids. The only thing that causes him to freak out is when it falls over and rolls into the sea.
Anyone who's not Stanley or part of his circle of frinds and such on Stanley seems to use this when confronted by things such as talking/singing pets, or wild animals popping up in places they shouldn't be, such as the roof of Stanley's house.
At the end of the second season of W.I.T.C.H. the five girls have ascended to their zenith forms (pure whatever element they are—air, earth, fire, water and quintessence) and are fighting a giant snake monster who at Phobos and gained his power. No one in the city notices this fight because the regent for the heart of Earth makes it look like it was a cartoon on a big billboard downtown.
Also, during the first season no one seems to notice or question the frequent appearance of portals or girls with wings and magical powers closing those portals.
In one early (possibly the earliest) incarnation, a few episodes after the Decepticons became active on Earth it seems the entire planet is put on a war footing, factories pumping out weapons intended to be used in the war against them, complete with old-fashioned propaganda posters.
The original cartoon had a sort of masquerade for the first few episodes, but after a bit the Transformers didn't bother with hiding from humans as a whole (though many people still seemed unaware of their existence, considering all the episodes where a human mistakes a Transformer for a normal vehicle and react with shock/fear/awe when the Transformer reveals himself). By the movie and season three, there was no masquerade anymore.
In Transformers Super God Masterforce, This was a ridiculous case when the humans completely forgotten about what Autobots AND Decepticons are despite the series (in Japan) had already established the existence of both, not in the Idiot Ball level, mind you, but it's as if they forgotten. The early episodes clearly shown that there is a few people who know about it. Maybe it's due to the fact that the Transformers had been off the Earth a long time, no one would remember them by then.
The military in Sheep in the Big City try to enforce this, not even bothering to hide their giant top secret military bases and helicopters, but instead just putting up signs telling people to ignore them.
The Galactic Grand Inquisitor from The Venture Bros. also tries to enforce this, following the characters around everywhere and yelling "IGNORE ME!!" whenever anyone looks at him.
One classic demonstration of a real-life version of this trope, which psychologists refer to as the "Selective Attention" phenomenon can be seen here. When your attention is even mildly focused on something else, you simply don't notice bizarre things happening.
Another related form of weirdness censor is called change blindness. This video demonstrates how far the brain will go to avoid acknowledging even a blatant Mind Screw.
A third type is known as a "memory bias"; a tendency to rationalize, dismiss, or otherwise distort memories that are unpleasant, unusual, or inconvenient enough. Your brain, in effect, decides that an unsettling event was just a dream or that something that has changed was always that way, and you simply never noticed. This is the reason why people idealize the The Good Old Days, for instance. They literally only recall the good parts.
When there's any kind of convention or gathering (such as cosplay) that involves people in costumes wandering around, non-participants generally fall into one of three categories — the people who are accustomed to it; the people who openly gawk at the weirdos in costumes; and the people who determinedly ignore the whole thing.
In University towns and cities, on any given night, you can determine who's a local, who's a student, and who's not from the area by their reaction to a group of students in fancy dress. The locals have Seen It All, the students wonder what the occasion is, and the out-of-towners openly gawk.
Similarly, it's said you can tell who's a foreigner and who's not at Christmas parades in the Netherlands that feature performers disguised as Zwarte Piet ("Black Pete"). That is, mischievous clown figures in Blackface, imitating the folk character who (to the Dutch, at least), is Santa Claus's black servant. Since the Netherlands has always had a very small black population, and since Europeans don't tend to associate characters like Zwarte Piet with racial inferiority, nobody complained that the parades were offensive until quite recently, and even then there was massive backlash when the Piets were made up in all different colors to avoid being offensive.) Among the crowds lining the streets for these parades, the Dutch are the ones smiling, laughing, or just passively taking in the spectacle. The foreigners - especially the Americans - are the ones with their jaws on the ground.
The game of Geocaching relies pretty heavily on this. Geocache containers can be hidden in highly unusual places, quite often by virtue of small size, camouflage coloring, or by being disguised as something so commonplace it is easily dismissed and overlooked. Searching for geocaches often calls for stealth ( http://en.wikipedia.org/wiki/Geocaching#Controversy_and_issues ); some cachers have reported that the easiest way to conceal their search is by acting mildly nuts or wandering at complete random, and thus they can find their objective without anyone taking much notice.
Invoked by various conspiracy theories, New Age mythology and fringe cults- that the human race is instinctively in denial of the true nature of reality.