History Main / TheoryTunnelvision

* Warhammer40K: Part and parcel of the CrapsackWorld nature of the setting, since the Imperium runs on fundamentalism and rigid discipline. One reason ork kommandoes (seven foot tall killing machines who are stealthy and able to perform covert missions in addition to being the charge-happy dakka-shooting lunatics we know and love) are successful is that a guardsman who tried to report their existence was executed for cowardice as what he said went against Imperial doctrine.


[[AC:{{Video Games}}]]
* In ''SuperPaperMario'', upon hearing that Mushroom Castle was attacked and Princess Peach was kidnapped (AGAIN!), Luigi immediately decides that Bowser must've been behind it.

* In ''LightNovel/DenpaOnnaToSeishunOtoko'', 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.

** 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 fall 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 interpenetrates as further evidence of the Order's evil; they "tricked" her into abandoning her vows.]]

** 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 fall 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.]]

* Tsukiko in ''Webcomic/TheOrderOfTheStick'' firmly believes that HumansAreBastards, and as the opposite of the living, undead are good underneath everything, despite the total lack of evidence for this. She starts to realize she may be wrong as [[spoiler:her wights are controlled into draining her to death.]]

* In ''Literature/HarryPotter'', the eponymous character seem to be dead set to blame anything and everything that goes wrong at Hogwarts on Snape or Malfoy.

* ''{{Dexter}}'': Multiple times throughout the show, a character will suspect something is off (to the point of a CassandraTruth) and Dexter will have to invent evidence to turn them away. It often works. One extreme example when it doesn't is when Laguerta adamantly believes that Doakes is innocent and no matter what evidence Dexter plants to the contrary, she still stands by this belief.
* In ''{{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.

* Psychosis is defined as the loss of contact with reality. The surest way to diagnose it is if the patient has delusions; delusions are beliefs the patient has, not shared by his culture or those around him, that are maintained despite being contradicted by evidence or logic. Note, however, that not all people who have delusions are psychotic and, in fact, many disorders can produce them.

* In ''HarryPotter'', the eponymous character seem to be dead set to blame anything and everything that goes wrong at Hogwarts on Snape or Malfoy.
** In ''The Half Bood 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.

NoRealLifeExamples, please. [[RuleOfCautiousEditingJudgement Saying that this is Truth In Television as a general principle is plenty.]]

* In ''DenpaOnnaToSeishunOtoko'', 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.

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 TheoryTunnelvision 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 TheoryTunnelvision, and several reasons for someone suffering of it:
* Pride/stubbornness: Bob is just too proud or stubborn to say that they've been wrong, instead keeping up their own version of reality.
* Familiarity: Bob has been told every day of his life that group X is evil. As a result, nothing group X will ever do can change Bob's vision. Even if someone from group X would rescue Bob from a burning building, all he'd say is to let go of him.

* Prejudice: Bob has been betrayed so many times in his life that he simply cannot believe that someone would ever do something good. Even if Alice helps him pay his monthly bills, he sees it as a way to get him in debt with her.

* Mental disorder: Due to a handicap, Bob believes that whatever he thinks is true, is in fact true; anyone who states otherwise is deemed a liar. In these cases, Theory Tunnelvision is always justified.

Tunnelvison Theory can be both positive and negative, and the person suffering from it can be proven right in the end. The key point is that someone who suffers from it will [[SelectiveObliviousness discard any and all evidence]] that proves him or her wrong, no matter how solid it is.
If someone suffering from TheoryTunnelvision at some point ''does'' break, expect a HeroicBSOD, along with muttering about how this should be impossible. A fair warning though: Do not try to break TheoryTunnelvision on purpose, as there is a good chance that you'll lose your friendship with the sufferer... or worse.

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 TheoryTunnelvision may start out as AggressiveCategorism.

TruthInTelevision, even normal non-neurotic people will take considerable evidence to overwhelm a strongly held theory, let alone those in psychological denial who'll get angry at people pointing out reality.

NoRealLifeExamples, please.

* 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]].
* In ''DenpaOnnaToSeishunOtoko'', 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 ''{{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

* In ''TheLastBattle'', Dwarves are in paradise eating a feast but they believe they are in a hut eating slops. This does at least have a mystical explanation, as it is caused by Aslan's power, and is part of Lewis' AuthorTract on how atheists could have God and Heaven right in front of them but be unable to see it.
* Something of a recurring theme with guards in [[ForgottenRealms Ed Greenwood]]'s novels, who seem to be prone to theorizing that ''anyone at all'' they don't personally know and who wants to get past them is up to no good and therefore needs to be brushed off, arrested, or simply killed outright. A classic example in the "Shadow of the Avatar" trilogy has the protagonists come back from a patrol for the Lord of Shadowdale and be accosted by guards ''of'' the Lord of Shadowdale who casually dismiss all their claims and seem all too eager to engage in some casual bloodshed for their own amusement (to be fair, those particular guards were newly hired, but still).

* 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.)

* Tsukiko in ''Webcomic/TheOrderOfTheStick'' firmly believes that HumansAreBastards and as the opposite of the living undead are good underneath everything, despite the total lack of evidence for this. She starts to realize she may be wrong as [[spoiler:her wights are controlled into draining her to death.]]

* Psycosis is defined as the lost of contact with reality. The surest way to diagnosticate it is if the patient has delusions; delusions are beliefs the patient has, not shared by his culture or those around him, that is mantained despite being contradicted by evidence or logic. Note, however, that not all people who has delusions are psychotic and, in fact, many disorders can produce them.

* In ''HarryPotter'', the eponymous character and his friends seem to be dead set to blame anything and everything that goes wrong at Hogwarts on Snape
** Really just Harry. The others swing between finding his prejudice annoying, believing him and humouring him.

* In the ''{{Buffy the Vampire Slayer}}'' episode "I Only Have Eyes For You," Giles is convinced that a haunting is [[spoiler:Jenny]] trying to communicate, despite all evidence to the contrary.

* In ''TheLastBattle'', Dwarves are in paradise eating a feast but they believe they are in a hut eating slops.

* Tsukiko in ''OrderOfTheStick'' firmly believes that HumansAreBastards and as the opposite of the living undead are good underneath everything, despite the total lack of evidence for this. She starts to realize she may be wrong as [[spoiler: her wights are controlled into draining her to death.]]

* In ''{{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.
* ''ElGoonishShive'' got those two [[http://www.egscomics.com/?date=2010-04-16 alien]] [[http://www.egscomics.com/?date=2010-12-27 enthusiast]] [[http://www.egscomics.com/?date=2011-06-20 nerds]] annoying people. Hilariously enough, they never noticed real aliens and half-aliens in their town.

** Really just Harry. The others swing between finding his prejudice annoying and humouring him.

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 TheoryTunnelvision will stick with whatever idea he or she has for way longer than what would be normal. Even if Bob meets hundreds of {{GoodSamaritan}}s, he'll keep stating that HumansAreBastards, and Alice will never trust Chris even though he saved her life several times now.

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 TheoryTunnelVision may start out as AggressiveCategorism.

!! Examples

* In the {{Buffy the Vampire Slayer}} episode "I Only Have Eyes For You," Giles is convinced that a haunting is [[spoiler:Jenny]] trying to communicate, despite all evidence to the contrary.

* In {{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

* In HarryPotter, the titular character and his friends seem to be dead set to blame anything and everything that goes wrong at Hogwarts on Snape
* Narnia book 7, Dwarves are in paradise eating a feast, they believe they are in a hut eating slops.

* In SuperPaperMario, upon hearing that Mushroom Castle was attacked and Princess Peach was kidnapped (AGAIN!), Luigi immediately decides that Bowser must've been behind it.
* Played for laughs in the ''Hordes of the Underdark'' expansion for ''NeverwinterNights'' - if you have Deekin with you in Hell, he interprets the signs of battle between Demons and Devils as the remnants of something long and complicated involving dragons.

* In ''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 ''{{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]].

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 TheoryTunnelvision will stick with whatever idea he or she has for way longer than what would be normal. Even if Bob meets hundreds of {{GoodSamaritan}}s, he'll keep stating that HumansAreBastards, and Alice will never trust Chris even though he saved her live several times now.