History Main / TheoryTunnelvision

* In ''Series/{{Monk}}'', there was an episode with a nudist. Adrian's theories got crazier and crazier as he tried to explain how the nudist was guilty.

Everyone has their own view of the world and what happens around them. Maybe Bob believes that HumansAreBastards. Maybe Alice thinks Chris is going to betray her. Given enough time, though, these views and opinions can change, allowing Bob to see the good in man, and Alice to start to trust Chris. This trope is when that never happens; A character suffering from Theory Tunnel Vision will stick with whatever idea he or she has for way longer than what would be normal. Even if Bob meets hundreds of {{Good Samaritan}}s, he'll keep stating that HumansAreBastards and Alice will never trust Chris even though he saved her life several times now.

* SunkCostFallacy: This may overlap with others. Bob has used up too much time/effort/etc acting on a specific belief. If he admits he was wrong, all of that would be wasted.

* In ''LightNovel/GroundControlToPsychoelectricGirl'', Erio was in a tragic accident wherein she went missing for three months and then turned up on a beach without any memory of the intervening time. Her reaction was so bad that she invented a story that she had been abducted by aliens and convinced herself that was the only explanation. After a few months, she tried to test her theory... only be injured ''again''. But again, because she was far too fragile to face reality, she only drew even further into her fantasy world, to the point of becoming a {{Hikikomori}}. Later, her cousin forcibly proves to her that she isn't an alien, but after an initial highly negative reaction, she seems oddly okay and is even willing to regain society again.

* ''Fanfic/ShadowsOverMeridian'': Caleb is so convinced that Jade/Kage is a minion of Phobos that he [[IRejectYourReality refuses to acknowledge any evidence to the contrary]], relying on [[ConspiracyTheorist increasingly convoluted theories]] to justify his viewpoint. Even the Guardians rebuking him and Elyon herself [[WhatTheHellHero chewing him out]] for clinging to his paranoid beliefs can't get him to drop them.

* Henrietta Garland from ''Fanfic/CatarinaClaesMustDie'' is the reincarnation of a bullied girl that found relief watching ''[[FictionalVideoGame Fortune Lover]]'' HateSink bully Caterina Claes die in the bad ends. So when she is reincarnated in the world of ''LightNovel/MyNextLifeAsAVillainessAllRoutesLeadToDoom'', she remains firmly convinced that Caterina is a villainess who should end in doom, despite evidence that Caterina is now a NiceGirl thanks to regaining memories of her past life. For example, when hearing how Caterina is treated like a beloved [[ClassPrincess Saint]], Henrietta is convinced that she is really a BitchInSheepsClothing that secretly bullies her adopted brother Keith and the commoner student Maria when in actually the latter two are among of Catarina's loved ones.

* In the ''WesternAnimation/GravityFalls'' episode "Little Dipper" after Mabel determines that Dipper's spontaneous growth spurt is the result of magic, she accuses him of hiding a wizard in the closet after she opens the door to find an empty closet she accuses him of hiding an ''invisible'' wizard in the closet, and even after Dipper shows her what the real cause of his growth spurt was (a flashlight fitted with a magic crystal that refracts light into growth and shrink rays) she still thinks there's an invisible wizard hiding in the closet.

Everyone has their own view on the world and what happens around them. Maybe Bob believes that HumansAreBastards. Maybe Alice thinks Chris is going to betray her. Given enough time, though, these views and opinions can change, allowing Bob to see the good in man, and Alice to start to trust Chris. This trope is when that never happens; A character suffering from Theory Tunnel Vision will stick with whatever idea he or she has for way longer than what would be normal. Even if Bob meets hundreds of {{Good Samaritan}}s, he'll keep stating that HumansAreBastards, and Alice will never trust Chris even though he saved her life several times now.

There are several kinds of Theory Tunnel Vision, and several reasons for someone suffering of it:

SelectiveObliviousness is the supertrope of this; FlatEarthAtheist and TheScully are subtropes. A staple technique of the TautologicalTemplar. TheFundamentalist is the logical extreme of this, building everything around a few notions held this way. What develops into Theory Tunnel Vision may start out as AggressiveCategorism. Also compare IRejectYourReality, PsychologicalProjection and SelfServingMemory.

* In ''Anime/KillLaKill'', Ryuko comes to believe that StudentCouncilPresident Satsuki Kiryuin was responsible for her father's death before the start of the series, since Satsuki claims to have knowledge about why it happened. She becomes so fixated on this that her flashbacks from when she barely saw the killer fleeing the scene start to shift so the figure resembles Satsuki, meaning that when [[spoiler:the ''real'' killer, Nui Harime, whose twintails make her a dead ringer for the initial silhouette, reveals herself, it comes as quite a shock to her]].

* The {{ComicBook/Daredevil}} comic "Seventh Circle" has him run into ComicBook/ThePunisher during a Russian gangster's high-profile trial that Matt Murdock is trying to move to Texas, since it'd be impossible for the gangster to get a fair trial in New York. Frank is convinced Matt is trying to get the trial held in a state where the death penalty applies and calls Matt a killer, one using a jury rather than a gun... [[DramaticIrony to Daredevil]].

** Many depictions have Jameson utterly fixated on the idea that anybody who wears a mask to hide their identity ''must'' have nefarious motives. After all, police don't wear masks but bank robbers do. He refuses acknowledge that the existence of supervillains far more dangerous than ordinary criminals means that superheroes have an actual legitimate reason to hide their civilian identities.

** This is effectively Alya's FatalFlaw: despite claiming that 'a good reporter always checks her sources', in ''practice'', she sees no need to do so once she's set her mind on something. This makes her an ideal pawn for [[ManipulativeBitch Lila]], who transforms her from [[WeUsedToBeFriends Marinette's best friend]] to [[TheHeavy her personal one-girl attack crew]].

* Henrietta Garland from ''Fanfic/CatarinaClaesMustDie'' is the reincarnation of a bullied girl that found relief watching ''[[FictionalVideoGame Fortune Lover]]'' HateSink bully Caterina Claes die in the bad ends. So when she is reincarnated in the world of ''LightNovel/MyNextLifeAsAVillainessAllRoutesLeadToDoom'', she remain firmly convinced that Caterina is a villainess who should end in doom, despite evidence that Caterina is now a NiceGirl thanks to regaining memories of her past life. For example, when hearing how Caterina is treated like a beloved [[ClassPrincess Saint]], Henrietta is convinced that she is really a BitchInSheepsClothing that secretly bullies her adopted brother Keith and the commoner student Maria, when in actually the latter two are among of Catarina's loved ones.
* In ''Fanfic/{{Daemorphing}}: The Herdmoot'', Arbron's parents assumed he died years ago when his [[WiseTree Guide Tree]] went dormant. After learning he became a Taxxon [[ShapeshifterModeLock nothlit]], they still think he died years ago and another Taxxon is pretending to be him in the present, because it's easier than accepting that Taxxons are people.
* Flat out [[LampshadeHanging lampshaded]] in ''Fanfic/GirlDays'' where [[Manga/RanmaOneHalf Kunou, Ryouga and Mousse]] are all mentioned to "take the facts and jam them into their viewpoint."

* Invoked in ''Fanfic/LostInCamelot'', when Arthur learns that Bo, Merlin and Morgana are in a triad relationship and ask how they intend to keep their relationship secret from Uther. Since Uther believes that Morgana's involvement with Bo is basically just them indulging a youthful interest, and he is also convinced that Merlin is involved with ''Arthur'', Morgana doubts that Uther will properly register anything that contradicts that perspective for a while at least.

* ''Fanfic/RainbowDoubleDashsLunaverse:'' The Element Bearers are utterly incapable of seeing Corona (also known as [[spoiler:Celestia]]) as anything but an arrogant, cruel, greedy monster who'd kill them all given half a chance. This backfires when they're [[EnemyMine forced to work together]], and the six of them think backstabbing the PhysicalGod who's agreed to work with them is a better idea than stopping the necromancer who's trying to become immortal. In fairness, though, they're part of a culture that's been fed a thousand years worth of stories about how evil she is, and when they first met, she kidnapped some of their loved ones, on account of being completely insane. But even after she's cooled down somewhat, they still refuse to think she's not pure evil.

* ''Film/SherlockHolmes2009'': Holmes and Watson discuss this trope, in regards to Lord Blackwood's apparent resurrection from his execution. Watson, having seen his fair share of weird shit during his military career, suggests that this time the case could have [[AWizardDidIt genuine supernatural elements]] to it. While Holmes is open to the possibility, he also warns Watson to wait until they have all the facts first, similar to his MO in the Literature section below. "Inevitably one begins to twist facts to suit theories, instead of theories to suit facts."

* In ''Webcomic/{{Homestuck}}'', Terezi finds the corpse of [[spoiler:Tavros]] and immediately concludes that Vriska is the most likely suspect. As she searches the crime scene for clues, Terezi admits to herself that she's only pretending to not already know who the murderer was. Then she finds the bodies of [[spoiler:Feferi and Nepeta]] and concludes that Vriska's on some kind of killing spree. She's a bit taken aback when Vriska freely admits to killing [[spoiler:Tavros]], but isn't even aware that the others died.

** Miko is unable to comprehend that anyone who is good might disagree with her methodology, therefore the Order (who defend Belkar, who is evil) are also evil. Her determination to stick to this belief in the face of all the evidence eventually leads her to full-blown paranoia [[spoiler:and falling from paladinhood when she concludes that her sworn lord, since he "conspired" with the Order, is also evil... and betrays her oath by killing him. This, of course, she interprets as further evidence of the Order's evil. They "tricked" her into abandoning her vows]].

* In ''WebVideo/ThereWillBeBrawl'', Mario immediately assumes Bowser is behind Peach's latest kidnapping, and refuses to hear any other explanation... not that you could blame him, of course. He only relents when [[spoiler:Luigi tells him of Bowser's death]].

* In ''VisualNovel/AceAttorney'', Miles Edgeworth's initial approach towards prosecuting was this. Unlike other prosecutors who merely wanted to win (such as his mentor Manfred von Karma), or those who only want to seek the truth (such as Klavier Gavin), Edgeworth worked on the premise that the defendant was ''always'' guilty of the crime they were accused of, and prepared his cases and arguments around that.[[spoiler: He thinks this way because of PsychologicalProjection; he believes that he is a KarmaHoudini for accidentally killing his father as a child and assumes that all other defendants are in the same position he was- guilty but faking innocence]]. His character arc in the original game involves getting over this view; it starts to crack in case 1-3 when Phoenix convinces him that Will Powers was innocent and [[spoiler: Dee Vasquez]] was suspicious, and Edgeworth ends up being the one to force the critical testimony that ends the case in a Not Guilty verdict, and it falls apart entirely after he becomes the defendant of 1-4[[spoiler: and Phoenix provess that not only is he innocent of the original crime, he never killed his father, and Manfred von Karma taught him to believe in his own guilt because ''Manfred'' was the true murderer.]]

* In ''Webcomic/SchlockMercenary'', during the Mahuilotu arc, the local police just cannot get over the idea that the [[EverythingsEvenWorseWithSharks killer shark]] was some kind of "murder-sub" built by John der Trihs. (They knew that their terraformed planet didn't have any sharks. Why blame John? They probably figured that he who smelt it dealt it.) The Toughs later threaten to sue the idiots for what their lawyer calls "impersonating a police force".

* In ''Anime/KillLaKill'', Ryuko comes to believe that StudentCouncilPresident Satsuki Kiryuin was responsible for her father's death before the start of the series, since Satsuki claims to have knowledge about why it happened. She becomes so fixated on this that her flashbacks from when she barely saw the killer fleeing the scene start to shift so the figure resembles Satsuki, meaning that when [[spoiler:the ''real'' killer, Nui Harime, whose MegaTwintails make her a dead ringer for the initial silhouette, reveals herself, it comes as quite a shock to her]].

* Frequently played for laughs in ''Literature/SupposeAKidFromTheLastDungeonBooniesMovedToAStarterTown'', where much of the comedy involves various characters being EntertaininglyWrong about outlandish circumstances or {{contrived coincidence}}s. For example, Selen believes that [[TheHero Lloyd's]] love for her unlocked the cursed belt that covered her face all her life. From there, she also assumes that love is the man she's destined to spend her life with and, when the belt turns out to also be a magical artifact that protects her from any harm, that it has been blessed and thus represents the strength of their destined love. Whenever evidence or a person contradicts any level of this logic, Selen will either dismiss it, [[MovingTheGoalposts add a new insane theory]], or just flat out [[{{Yandere}} murder/destroy]] whatever's causing the contradiction.

* In ''LightNovel/GroundControlToPsychoelectricGirl'', Erio was in a tragic accident wherein she went missing for three months and then turned up on a beach without any memory of the intervening time. Her reaction was so bad that she invented a story that she had been abducted by aliens and convinced herself that was the only explanation. After a few months, she tried to test her theory... only be injured ''again''. But again, because she was far too fragile to face reality, she only drew even further into her fantasy world, to the point of becoming a {{Hikikomori}}. Later, her cousin forcibly proves to her that she isn't an alien, but after an initial highly negative reaction, she seems oddly okay and is even willing to regain society again.

* In ''Anime/{{Monster}}'', detective Lunge initially believes protagonist Dr. Kenzo Tenma to be the serial killer. Over the course of the series, evidence that Johan is the real killer is practically thrown at him, from close acquaintances of Johan to criminal psychiatrists. However, Lunge continues to believe that Johan is a pseudonym for Tenma. It isn't until [[spoiler:near the very end, when Lunge sees Johan with his own two eyes, that he realizes Johan is a real person]].
* Frequently played for laughs in ''LightNovel/SupposeAKidFromTheLastDungeonBooniesMovedToAStarterTown'', where much of the comedy involves various characters being EntertaininglyWrong about outlandish circumstances or {{contrived coincidence}}s. For example, Selen believes that [[TheHero Lloyd's]] love for her unlocked the cursed belt that covered her face all her life. From there, she also assumes that love is the man she's destined to spend her life with and, when the belt turns out to also be a magical artifact that protects her from any harm, that it has been blessed and thus represents the strength of their destined love. Whenever evidence or a person contradicts any level of this logic, Selen will either dismiss it, [[MovingTheGoalposts add a new insane theory]], or just flat out [[{{Yandere}} murder/destroy]] whatever's causing the contradiction.

* Mentioned by the narration in the ''Literature/FatherBrown'' story:
-->A man warmly concerned with any large theories has always a relish for applying them to any triviality.

* ''TabletopGame/GeniusTheTransgression:'' A common form of madness for Geniuses in general, but a particular ailment of the Etherites, who are convinced their theory of everything is the correct one and will ignore, or outright eradicate all evidence to the contrary and get very violent with all that try to challenge their theory.

* Lex Luthor once discovered evidence that Clark Kent is ComicBook/{{Superman}}... and promptly dismissed it, because why would a PhysicalGod use such a humble personality? A lot of his rage can be put down to [[EvilCannotComprehendGood Superman not acting the way Luthor would act with all that power]], and it drives Luthor nuts.

* In ''Literature/HarryPotter'', the eponymous character is dead set on blaming anything and everything that goes wrong at Hogwarts on Snape or Malfoy. In ''[[Literature/HarryPotterAndTheHalfBloodPrince The Half-Blood Prince]]'', Harry is convinced that Draco has become a Death Eater and is up to some evil scheme. Even after compelling evidence is offered showing Draco wasn't even around when a certain event occurs, Harry refuses to consider the possibility that Draco wasn't involved. In a case of RightForTheWrongReasons, Draco actually ''was'' up to something, and was involved in several of the mysterious events, but Harry was drawing his conclusions from gut instinct and his personal hatred for Draco rather than any actual evidence. It's also a case of DramaticIrony, as a chapter at the start of the book proves to the readers that Voldemort has set Draco some unspecified task, but none of the good guys knew about it.

* In ''VisualNovel/AceAttorney'', Miles Edgeworth's initial approach towards prosecuting was this. Unlike other prosecutors who merely wanted to win (such as his mentor Manfred von Karma), or those who only want to seek the truth (such as Klavier Gavin), Edgeworth worked on the premise that the defendant was ''always'' guilty of the crime they were accused of, and prepared his cases and arguments around that. Part of the plot of the first ''Ace Attorney'' game is about Edgeworth realizing the error of this way. The moment the tunnel vision collapses is actually seen in-game - during 1-3, when Edgeworth realizes [[spoiler:Dee Vasquez was the real killer]], he goes through a nervous breakdown on the spot, then begins ''actively prolonging the case'' so the real killer doesn't escape.

SelectiveObliviousness is the supertrope of this; FlatEarthAtheist and TheScully are subtropes. A staple technique of the TautologicalTemplar. TheFundamentalist is the logical extreme of this, building everything around a few notions held this way. What develops into Theory Tunnel Vision may start out as AggressiveCategorism. Also compare IRejectYourReality and PsychologicalProjection.

* In ''VisualNovel/AceAttorney'', Miles Edgeworth's initial approach towards prosecuting was this. Unlike other prosecutors who merely wanted to win (such as his mentor Manfred von Karma), or those who only want to seek the truth (such as Klavier Gavin), Edgeworth worked on the premise that the defendant was ''always'' guilty of the crime they were accused of, and prepared his cases and arguments around that. Part of the plot of the first ''Ace Attorney'' game is about Edgeworth realizing the error of this way.

* In ''Fanfic/{{Daemorphing}}: The Herdmoot'', Arbron's parents assumed he died years ago when his [[WiseTree Guide Tree]] went dormant. After learning he became a Taxxon [[ShapeshifterModeLock nothlit]], they still think he died years ago another Taxxon is pretending to be him in the present, because it's easier than accepting that Taxxons are people.

* Parodied (rather [[BlackComedy darkly]]), with ''[[http://slimebeast.com/forum/stories/mario-is-a-monster/ Mario is a Monster]]'', a {{creepypasta}} story by Creator/SlimeBeast similar to his earlier ''FanFic/IHateYou''. The narrator is dead-set on making [[Franchise/SuperMarioBros Mario]] out to be [[RonTheDeathEater the true villain of his series]] by describing all his actions in his 8-bit and 16-bit games in the most heinous-sounding way possible. It gets to the point that the narrator discusses a "spooky lost game" (in typical ''Mario''-related creepypasta style) called "Mario Nights" full of terrifying and gory content like poorly-lit BlackoutBasement levels, "gibbering bogeymen", masked worm creatures that pop out of the ground only to get their pale flesh burnt by Mario's flashlight, Yoshi puking out acid, and the {{Nightmare Face}}d BigBad eating a chunk out of Princess Peach's skull if you lose. The narrator is so focused on portraying Mario himself as a bad guy that he glosses over all the frightening stuff happening ''around'' Mario in "Mario Nights" -- and is confused when no one else he talks to knows about the game.

* Parodied (rather [[BlackComedy darkly]]), with ''[[http://slimebeast.com/forum/stories/mario-is-a-monster/ Mario is a Monster]]'', a {{creepypasta}} story by Creator/SlimeBeast similar to his earlier ''FanFic/IHateYou''. The narrator is dead-set on making [[Franchise/SuperMarioBros Mario]] out to be [[RonTheDeathEater the true villain of his series]] by describing all his actions in his 8-bit and 16-bit games in the most heinous-sounding way possible. It gets to the point that the narrator discusses a "spooky lost game" (in typical ''Mario''-related creepypasta style) called "Mario Nights" full of terrifying and gory content like poorly-lit BlackoutBasement levels, "gibbering bogeymen", masked worm creatures that pop out of the ground only to get their pale flesh burnt by Mario's flashlight, Yoshi puking out acid, and the {{Nightmare Face}}d BigBad eating a chunk out of Princess Peach's skull if you lose. The narrator is so focused on portraying Mario as a bad guy that he glosses over all the frightening stuff in "Mario Nights" and is confused when no one else he talks to knows about the game.

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