Confirmation Bias is the [[LogicalFallacies fallacy]] of lending extra weight to information and arguments that confirm your own beliefs while disregarding or downplaying evidence that disputes them.

This comes in several forms:
# Seeking evidence for a belief one already holds, or eagerly accepting it, while disregarding or downplaying contradictory evidence. Often known by the ironic name "Proof by Selected Instances".
# Interpreting ambiguous information with a focus on how it favors one's own beliefs.
# Rationalizing contradictory evidence [[IRejectYourReality in a way that still affirms one's own beliefs]].

In fandom, the first of these three types of Confirmation Bias is the most common. Essentially, if a book or any other media product follows a distinct philosophical, political, or religious slant, then people who agree with that slant will often like it despite any flaws it has. Conversely, people who ''disagree'' with its message will often reject it out of hand, regardless of how well written it is.

On the other hand, having this type of Confirmation Bias ''doesn't'' mean that the audience is unreasonable, despite the fact that they may not be receptive to your particular work. If a work, despite how well-written, advocates or is founded on principles that the audience finds contradictory to their sense of morality or ethical responsibility, they may find themselves unable to respond favorably (e.g. a book which advocates the genocide of a certain ethnic group won't find many supporters among that group...or the majority of people who value human life). The viewpoint of the work may be so detestable to a specific audience that the message may be ''more important'' to that audience than the beauty of the cinematography or brilliance of the acting. The reverse may be true as well. If a work displays a message that is very important to the audience, they may forgive its flaws in favor of the ideals (e.g. a film about the importance of peace and love will be better received by people who believe in pacifism and universal compassion), although [[DontShootTheMessage people are usually more critical - as in objective critique - of the style of a work they agree with]], than the style of a work whose message they despise (where the style may be ''completely'' over-shadowed by the ideology).

Keep in mind, however, that many people neither agree or disagree with a message before being presented with an argument that they find convincing. The purpose of many of the examples of this trope can legitimately be said in at least a small part to convince the undecided, rather than change someone's mind. Even so, the Confirmation Bias effect is noticeable.

It is worth noting that even if a work may be not be aimed at converting ideological outsiders, [[WeAREStrugglingTogether that doesn't necessarily mean it's not designed to convert people]].

Also note that confirmation bias does not have to favor ''positive'' beliefs. Atheists, for instance, can be just as prone to considering only arguments opposing, not supporting, the existence of God.

Also, this does not mean that everyone with a given viewpoint will like a work just because it follows that same view. Some may criticize it for not doing a good enough job persuading those who are undecided or who have the opposite view. Contrast DontShootTheMessage, which is about disliking a work because of its style even if one may agree with its message.
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!!Examples:

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[[folder:Advertising]]

* Any pro-choice/pro-life commercial assumes the message it's giving. IE, an unborn baby is a person and thus abortion is murder = Pro-Life; or they're not a person, and part of the woman thus her decision = Pro-Choice. It's doubtful anyone is ever converted by these, as both very rarely attempt to convince the viewer of the (non)person-hood of the unborn baby.
* Those Mac vs. PC ads that depend entirely on AdHominem and misconceptions to sell their points to the audience, which in most cases either already agrees, disagrees and is already aware of what is untrue about the ads, [[UsefulNotes/{{UNIX}} Took A Third Option]], or is very easily DistractedByTheShiny, which admittedly usually tends to work in Apple's favor.
** The older ads weren't quite as preachy. The newer ones, though...well, they really rely on ViewersAreMorons and what people already hate about Windows (one commercial featured all the PC's walking away and just Justin Long staying after a potential user asked for a computer [[BlatantLies that didn't have any error messages or other problems]]).
** These actually managed to make ''Microsoft Windows'' look like a put-upon underdog. As has been pointed out many times, which of these two men would you hire if they were competing for a job?
*** Notably, the above two elements in particular have combined to make these commercials frequent SnarkBait.
** The T-Mobile parody commercials weren't much better... though T-Mobile was lampooning Apple [=iPhone=], which was at the time an AT&T exclusive.
** The UK versions of the ads are even worse. The Mac and PC are played by Robert Webb and Creator/DavidMitchell, respectively. They play basically the same characters as they do in ''PeepShow'', where Webb's character is stupid, lazy, and unreliable, and Mitchell is hard-working and [[TheComicallySerious serious-to-a-fault]]. Which qualities would you rather have in your computer?
** Samsung has launched a similar ad campaign for their Android mobile devices, portraying Apple users as morons. And they actually ''directly'' attack the same exact potential customers they'd do well to convert. [[SarcasmMode Because we all know how well the Mac vs. PC ads worked.]] Yup, they're even copying Apple's failures. At this rate, soon they'll be rolling out their own maps app that tells you to drive over a lake, through your local library, and onto an airport runway.
** Microsoft's smartphone ads made it seem like phones that relied on apps were invariably hard to use, meaning you spent most of your time looking down at your phone and less time interacting with people. The Microsoft phone, however, had everything you needed on the main screen, meaning you [[BlatantLies spent less time looking down at it]]. You actually had to spend more time with it because you kept having to scroll, as opposed to just tapping an app.
* There are several [[PublicServiceAnnouncement PSAs]] that often don't bother persuading those outside of a particular group. It's almost as if the producers are told to produce [=PSAs=] like this.
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[[folder:Fan Fic]]
* One of the more prevalent biases that narrator is guilty of in the fanfic, [[FanFic/EquestriaAHistoryRevealed Equestria: A History Revealed]].
** She directly goes out of her way to ignore information that contradicts her claims, and even directly states a few times, that the rest of the "idiot historians" can be right occasionally, given that they match her beliefs. Her terrible reasoning skills in her essay, however, are thankfully [[PlayedForLaughs played for laughs]] in-universe.
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[[folder:Film]]

* The documentary ''Gasland'' about the supposed harm caused by hydraulic fracturing ('Fracking') of rock to mine natural gas. As the ''Podcast/{{Skeptoid}}'' [[http://skeptoid.com/episodes/4275 podcast points out]], it is hard to know what to make of the movie since it's devoted to proving that fracking is dangerous and generally assumes all of the ill effects to local people (such as tap water that is ''flammable'') are caused by fracking and aren't simply natural phenomena specific to the area. Yet, conversely, most of the high profile criticism of the movie has come from the natural gas industry, so it is very difficult to find an un-biased opinion on the subject.
** There's also the fact that towards the end of the movie's production, the critics it was based on who had supposedly proved many of the dangers of fracking were discovered to have been frauds. When asked how the movie was going to address it, it was suggested that in the movie, the fraudulent critics would be portrayed as secretly being in the employ of the companies that would profit from fracking and that they ''allowed'' themselves to be revealed as frauds to discredit fracking critics.
* Morgan Spurlock's ''Film/SuperSizeMe'' famously followed the filmmaker as he lived on nothing but [=McDonald's=] for thirty days, eating everything on the menu at least once and super-sizing every time it is offered. He suffered significant health and weight issues as a result. This appears to have been greatly aided by Spurlock suddenly changing to a sedentary lifestyle, eating far more than he needed to and sleeping a lot, as no one has been able to reproduce his results. Spurlock did all he could to reach the conclusion he wanted to reach, while many other studies have shown that combining [=McDonald's=] food with an active lifestyle and not overeating does not lead to health or weight issues.
* ''Film/TheUsualSuspects'': This trope is {{discussed}} by Verbal Kint, who is interrogated by Inspector Kujan at a police investigation. Later, the audience will discover that Verbal not only discussed it, [[spoiler: but exploited it]].
--> '''Verbal:''' ''To a cop the explanation is never that complicated. It's always simple. There's no mystery to the street, no [[DiabolicalMastermind arch criminal]] behind it all. If you got a dead body and you think his brother did it, you're gonna find out you're right.''

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[[folder:Literature]]

* ''Any'' book that attempts to prove or disprove a certain philosophical, religious, or political viewpoint. Reviews on amazon.com for these books tend to be either one star or five stars, due to the reviewers' opinion of the book being so heavily influenced by whether it clashes or not with their personal thoughts. ''The God Delusion'' by RichardDawkins (whose thesis is [[ExactlyWhatItSaysOnTheTin exactly what it sounds like]]) is a notable example. Naturally, when Alister [=McGrath=] wrote ''The Dawkins Delusion'' (a book that argues against Dawkins' book), almost anyone who agreed with Dawkins' book automatically disliked [=McGrath=]'s book, whereas those who disagreed with Dawkins' book were almost always immediate fans of [=McGrath=]'s book.
** As with many of these examples, [[PraisingShowsYouDontWatch very few actually]] [[MainstreamObscurity read them both]], as noted in the reviews themselves.
** The fact they appealed to people who differed not only in opinion but in the basic ways they see the world and make judgments probably has something to do with it as well.
* Creator/CSLewis' ''Literature/TheChroniclesOfNarnia'' series and Creator/PhilipPullman's ''Literature/HisDarkMaterials'' series are {{author tract}}s for Christianity and atheism, respectively. Lewis didn't originally ''intend'' his work to turn into one, while Pullman ''very much'' intentionally wrote his series with promoting atheism in mind (as well as making an anti-religious rebuttal to Lewis); as a result, ''His Dark Materials'' is a ''lot'' more frank and up-front about its message. {{Justified}} in the case of ''Narnia'' as it was never intended as a tool for conversion, but for an already-Christian readership to explore their own beliefs in a fantastic setting.
* ''LeftBehind'' is largely only liked by people who already believe in the Rapture. However, the author's beliefs regarding the rapture, the afterlife, and who is "worthy" is very old testament and controversially exclusive (the "only protestant Christians" and "you only get one chance if you've never heard of the bible until then" rules being the most obvious) make a lot of mainstream Christians uncomfortable because it reeks of DisproportionateRetribution.
* Speaking of ''LeftBehind,'' Michael D. O'Brien's ''Literature/ChildrenOfTheLastDays'' series has a similar effect, being essentially a Catholic version of the former (without a Rapture, which is not Catholic dogma). Regardless of the writing, it comes strongest to those who tend to share the author's "traditional Christian" views.
* Much of the writing of libertarian anarchist ScienceFiction author L. Neil Smith falls under this. In fact, he has explicitly stated that he writes mainly to entertain those already having an anti-state worldview.
* {{Invoked}} specifically by [[Literature/TheNumberOfTheBeast Zeb]] in his backstory. Specifically, he carefully structured his [=PhD=] thesis to "show" that biases held by all the members of his doctoral committee were widely held to be correct (crossed with AppealToObscurity, as he pulled a lot of selective quotations out of materials that hadn't been translated into English as part of his "research").
* In ''A Scandal In Bohemia'', SherlockHolmes warns us of the dangers of this fallacy in regards to investigation:
-->'''Holmes''': It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.

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[[folder: Live Action Television ]]

* The word "clapter" was coined to describe the latter effect in TV - when an audience applauds a joke more than actually laughing at it. It's an accusation often leveled at the more political years of ''Series/TheDailyShow'' after Jon Stewart took the helm. (Its synonym "clappy humor" has an entry in the [[http://www.urbandictionary.com Urban Dictionary]].)
** There are great honking buttloads of "comedians" who feed on clapter. Not surprisingly, they tend to disappear whenever the political winds shift in their favor.
** One unused stand-up bit from ''{{Seinfeld}}'' is about this. "To comedians, the truth is just bad material. The last thing you want is for people to just be thinking, "Hey, he's...right. He's a really, really ''accurate'' guy."
* ''Series/{{MASH}}'' started with a noticeable anti-war stance, but was still entertaining enough to be enjoyed by someone who disagreed with the show's views. As the series went on it seemed to become, at least within the show, increasingly required that viewers agree with every line of the Alan Alda Book Of Morality.
* This is undoubtedly one of [[AuthorTract two reasons]] that TheOReillyFactor and CountdownWithKeithOlbermann exist. By extension, any show (or book, or radio program, or ''whatever'') with a severe political slant is going to fall into this at some point as the [[PanderingToTheBase Invisible Hand]] pulls them in that direction. There's almost no pundit who doesn't.
* Panel shows try to avert this by having a variety of guests of different viewpoints (mainly because it would be boring to see a bunch of people sitting around agreeing on everything). Of course, there are plenty of ways to make a biased panel show (i.e. get a FoxNewsLiberal, stack the deck by putting [[ChewbaccaDefense aggressive "strong" debaters]] against lesser experienced ones, unevenly stack the panel on one side so [[QualityByPopularVote everyone can gang up on the minority opinion]], etc.)
* On ''Series/SaturdayNightLive'' in 2012, SethMeyers recommended that both presidential candidates stop "telling us stories about people you met at your rally who ''happen'' to agree with your positions. That's like Bret Michaels saying, 'At my last concert, someone yelled '{{Music/Poison}} rules!'"
* Totally Biased With W. Kamau Campbell: Most, if not all, of the political jokes are funny if you agree with the guy. This tropes applies even more so for almost all of the guests, the exception being Creator/ChrisRock.
* Television news stations. You can pretty accurately determine the political leanings of a person by what network they watch. Obviously, the pundits that are saying what you believe are the ones that "really get it" and "tell it like it is without all the crap."
* Creator/JoeDante has a bad tendency to do this in his TV work. This lead to the latter half of ''Series/EerieIndiana'' being unwatchable by anyone who wasn't a capital-L liberal.
* The audience of RealTimeWithBillMaher have been accused of this as they heckle guests who fall on the opposite side from the host.
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[[folder:Music]]

* [[DeadHorseGenre Certain genres of music]] may fall into this trope, particularly those that began as underground movements and became mainstream later on; artists and songs would be judged primarily on their subject matter, perceived attitude, or whether or not a message is present, rather than being enjoyed/loathed for the music itself. Hip hop music, due to its lyric-heavy, melody-sparse nature, might be the most prominent example. Particularly the artists of the PoliticalRap sub genre. The main polarizers being PublicEnemy, TheCoup, and the extremely controversial rappers Paris, and Immortal Technique. And to a lesser extent, Music/IceCube, Music/IceT, and Music/TupacShakur.
** Also affected are genres which rely on a particular philosophy: Things like [[ThreeChordsAndTheTruth Punk]] and BlackMetal come to mind.
* The actual music of Neo-Nazi and white-power punk bands like Skrewdriver is almost never discussed (it's fairly typical punk rock for the most part). Instead, most of the world slams them while their generally racist fanbases listen to little else, all because of their lyrics.
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[[folder: Newspaper Comics ]]
* Politically themed comic strips, from ''{{Doonesbury}}'' to ''MallardFillmore'' to ''PricklyCity'' to ''TheBoondocks'': if you agree with them, they're hilarious-if you don't, they're poison to the mind. If you have no bias one way or another, then you're probably just skipping over them all to see what ''ComicStrip/{{Frazz}}'' is up to today.
** Ditto for ''The Brilliant Mind of Edison Lee''. It's questionable if even the people it's allegedly preaching to find it funny. Comments on the comics SnarkBait blog [[http://www.joshreads.com The Comics Curmudgeon]] seem to indicate not...
** And ''I Drew This'', by the ''Webcomic/OzyAndMillie'' lady.
** ''The Bad Reporter'' wasn't originally this - a cartoon from the early 2000s mocked the "comic-book-ization" of the media and argued that both sides of the political aisle were engaging in {{demonization}}, without particularly insulting the followers of either side so much as their leaders. A cartoon a few years later parodied ''IAmSam'' with undecided voters in place of the mentally retarded. Not trying to win any converts now, are we, Mr. Asmussen?
** Same goes for "alt-comic" strips like ThisModernWorld, which are placed on weekly/monthly free newspapers for certain cities which have a significant liberal population.
* ''MinimumSecurity'' was mostly only published in alternative newspapers where extreme views are more common. As such, it is no surprise to see a comic strip where everyone ranging from religious people, scientists, businessmen, and people who simply eat meat are depicted as evil and stupid. The main character doesn't eat meat and advocates the destruction of society, thus, she is smarter.
* Dog-themed comics like ''Fred the Basset'' and ''Marmaduke'' tend to be praised by dog lovers and disliked by all others. ''Pluggers'' is loved by self-identified Pluggers (many of the comic ideas are sent in by readers) while people outside the demographic find the jokes incomprehensible. A similar trend follows for any other heavily themed comic.

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[[folder:Print Media]]
* The Evening Standard for 2014-08-18 published [[http://www.standard.co.uk/news/londoners-diary/naked-truth-when-reading-the-script-9676283.html a short piece about Daniel Radcliffe]] whose author took the opportunity to have a dig at ''Literature/TheCasualVacancy'', quoting from a scene and then saying that it is "not erotic". [[CowboyBebopAtHisComputer As anyone knows who has actually read the novel]], the scene takes place in primary school, and the participants are all five years old, so ''of course'' it isn't erotic -- it isn't meant to be. (And the fact that the author of the piece considered even for a moment that the scene ''might'' be erotic is deeply suspect.)
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[[folder:Radio]]

* Most political radio shows tend to be this by default. NealBoortz does his best to encourage dissenting opinions, for certain values of "encourage" and "dissenting" and "his best", because (as he said in his book ''Somebody's Gotta Say It'') shows where everybody agrees with the host tend to be extremely boring and sycophantic.
* ''TheNowShow'' can veer into this territory, although it's usually more about cynicism of ''any'' politician or celebrity than about conservatives and liberals.
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[[folder: Stand Up Comedy ]]

* JeffDunham's schtick with "Walter", a puppet who often voices Midwestern conservative views, is partly made up of "clappy humor," though mostly done to appeal to audience members who "know someone like this".
** Though Walter seems to be set up so that those who agree with him can laugh with him, and those who disagree with him can laugh ''at'' him; he's not exactly portrayed as a happy, admirable, or attractive individual after all. Obviously those who tend towards an extreme of either won't laugh at all.
* Creator/GeorgeCarlin was a master of clappy humor too. His act came to focus more and more on his general misanthropy and criticism of optimistic people regardless of political affiliation. His last tour especially played up the "grumpy old man" angle.
* Much of LewisBlack's material pre-2009 was essentially a liberal critique of the Bush administration, individuals within it, and cultural conservatives paired with over the top facial expressions and screaming in reaction to those things. Hilarious if you're a culturally liberal person but mostly just plain insulting if you aren't.
* BillMaher falls under this, hard. His highly political material, paired with his tendency to try to be edgy make him a very divisive comic prone to clapter/criticism depending on who's watching.
* Creator/RichardPryor spots 'Clapter' and calls it out in ''Live On the Sunset Strip'' when his mention of Arizona State Penitentiary gets applause. "What? You're applauding that? Arizona State Penitentiary real popular?!"
* Creator/BillyConnolly also gets exasperated on his "Live in New York" DVD by this. He begins his set by saying wearily "I'm supposed to talk about Scotland all the time," and is driven to distraction by the American crowd constantly clapping ''any'' mention of Scottish towns and cities.
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[[folder:Other]]
* The ''ComicBook/ChickTracts'', although even most people of the same view think he's insane.
* Tony Kushner not only admitted to, but ''defended'' this in [[http://www.jstor.org/stable/4337551?seq=10 a 1997 essay]]:
-->-- ''The converted need preaching to as much as the unconverted, and will usually prove far more responsive and interested in change . . . Those who are involved in the struggle to change the world need art that assists in examining the issues at hand, which are usually incredibly complex.''
** [[StrawmanHasAPoint There is some truth to that]].
* Some critics have argued that the internet would result in "echo chambers" where everyone would just view news sites, blogs, and forums that didn't challenge their views. However, according to one [[http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1588920 study]], the "echo chamber" isn't any worse than any other media (since radio, TV and print media that pander to either side do exist and always have).
** Google and other web search engines will give personalized search results, changing the order of search results based on one's web activity. The potential problems are self-evident: sites you agree with are more visited and come up higher in search results, while sites you disagree with may end up buried in the search results, even if they bring up a worthwhile point regarding a particular search. Google now has a setting to quickly switch personalized results on and off from the results page.
* The Republican National Committee, in the wake of the 2012 presidential election, admitted this as one of their problems.
* {{Played with}} in regards to Website/YouTube videos about conspiracy theories. There will be a few instances where the title points in one direction, but the content points another direction, and sometimes there will be an admission that this is done to draw in the opposing crowd.
** Conspiracy theorists tend to cite each other rather than any reputable outlet. The anti-vaccine blogosphere (''Age of Autism'', ''Natural News'') and quack "boomed" practitioners (Andrew Wakefield) they defend are a good example of this.
* This trope is simply an ubiquitous feature of the human cognitive landscape. Rigorous logic and academic thinking helps to mitigate this very human flaw most of the time.
* This trope is way more common in academia and directed research than anyone is comfortable with admitting, let alone tackling.
* A major contributor to the continued appeal of psychics and mediums. As Michael Shermer has noted, they don't tend to give out negative readings or tell people things they ''don't'' want to hear:
--> There was redemption for all - our loved ones forgive us for any wrongdoing; they still love us; they suffer no more; they want us to be happy. What else would he say? "Your father wants you to know that he will never forgive you for wrecking his car"? (On James Van Pragh)
* Critics argue that this is how horoscopes and, to a lesser extent, personality tests such as MyersBriggs work. If you don't know your star sign, try looking at all twelve of them. How many fit you, and how distinctly? Now, which one is yours?
** It's been shown in tests that a sufficiently vague astrological reading will be identified by nearly ''everyone'' as describing them, regardless of what their actual star sign is.
* For a long time it was believed that the circle was the most "perfect" and aesthetically pleasing shape and, therefore, planetary orbits would naturally tend to be circular. Measurements that didn't support this were dismissed as inaccurate until too much contrary evidence was piled up to ignore, and then ever-more-complex models involving small circular micro-orbits ("epicycles") around the main orbit were devised to account for the discrepancy. Finally Johannes Kepler showed that all this silliness could be avoided by [[OccamsRazor dropping the insistence on perfectly circular orbits]] and moving to a more elegant model of elliptical orbits.
* [[http://www.funnyjunk.com/Vaccines+Cause+Autism/funny-gifs/5216011/ this gif]], taken from a Website/CollegeHumor video, involves a woman searching Google (who is in the form of a regular guy) about vaccines causing autism. Google comes up with hundreds of results that they don't, and one source that says they do. The woman snatches the positive result with a smarmy "I knew it!"
* Similar to the planetary orbits example above, one of the many (regarded by several mathematicians as crackpot) ideas about the "golden ratio"[[note]]which is an ironic misnomer; it's actually an algebraic irrational number[[/note]] phi (or "tau" as some mathematicians, wishing to disassociate themselves from such beliefs, prefer to call it) is that the "perfect" rectangle as far as human psychology is concerned is one whose sides are in the golden ratio. One psychologist did an experiment exploring this, and claimed that the results he got "proved" the idea; but others, attempting to repeat the experiment, were able only to conclude that the ideal rectangle for most people lies somewhere between 1:1 and 2:1. When this is mentioned to phi supporters, they tend to dismiss this inconvenient fact.[[note]]Interestingly, aspect ratios for visual formats have moved ''away'' from the near-golden 4:3 (TV/old movies) or 3:2 (35mm full-frame) to 16:9, which is nearly 2:1; many movies nowadays are in even more extreme ratios, ''wider'' than 2:1. So much for "the perfect rectangle".[[/note]]
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