Too Dumb to Fool

""Well, he can't outsmart me, 'cause I'm a moron!""

- The Giant, Jack-Wabbit and the Beanstalk

""We're going to die because he's too dumb to outsmart!""

- Forgath, Goblins

You've got the perfect plan to escape blame for your latest misdemeanor. You've come up with a logical explanation for all the events that shows you're innocent while the culprit has vanished. The argument is patently false, but it's so long, convoluted, and confusing that it can't be disproven. Even when they catch a hole in your story, you have a half-dozen backup stories and another imaginary culprit to pin it on. By the time you've finished weaving your tale, you've convinced the authorities and even the witnesses that you're just a victim in all of this and even deserve compensation for your suffering.

Except for that fellow over there, who never paid attention to what you said in the first place. He's still looking at the blatantly obvious evidence of what you actually did.

This is a man who's completely immune to logic traps and fallacies because he ignores anything that he can't understand in favor of what he can. It's not his only advantage. He also doesn't manage to fool himself. If something is too simple to be seen, count on him seeing it. Cutting the Knot is frequently suggested by such a character. And it's really, really, really hard to sucker him with ideological explanations.

Trying to Break Him By Talking is a bad idea. He probably won't understand your attempts to undermine his confidence or self-esteem, and will merely tell you to Shut UP Hannibal His best counterargument is to make you Talk to The Fist.

Often The Fool is actually mentally disabled, though he may merely be Book Dumb. Children can also fall under this; when the Constantly Curious child comes up with an Armor Piercing Question, this often comes into play. Frequently the Spanner in The Works and the Only Sane Man who can detect the Devil in Plain Sight. Sometimes he does not detect the sarcasm in the Sarcastic Confession.

Sometimes produces the Fearless Fool and Achievements in Ignorance. It is not unknown for them to be able to ignore Schmuck Bait.

May be impossible to distinguish from Obfuscating Stupidity. Often a Foil to Too Clever By Half. See also Dumbass Has a Point and Your Brain Won't Be Much of a Meal.

The concept derives from the idea that the simple-minded are Closer to Earth, and the conviction that Cutting the Knot is an excellent solution to most complex problems. In certain circumstances this trope relies on the idea that a certain kind of simplicity allows one to circumvent the need to figure things out in favor of knowing what things actually are, even when this really ought to require some kind of metaphysical super-senses. This is one major way in which idiocy is turned into a Disability Superpower; sometimes found in the case of the actually mentally disabled, as well. See also Disability Immunity for where a character is similarly unaffected, but has an actual, recognized disability.

Anime & Manga
"Sasuke: You'd have better luck teaching it to a hamster."
 * The revelation that  from Slayers is actually a Mazoku comes as a shock to everyone -- except Idiot Hero Gourry, who noticed from the beginning and didn't say anything because he thought it was so obvious, surely everyone else had noticed too.
 * In an early Dragonball, a ninja tells Goku to close his eyes and count to thirty while he hides under a fake rock. This actually works... until Goku forgets what comes after seventeen.
 * In Bobobo Bobobobo, Poet's Circle of Memory Destruction doesn't work on Don Patch, 'cause he's stupid!
 * In Darker Than Black, the Wrong Genre Savvy, none-too-bright Clueless Detective is one of the only people to notice that that cute Chinese exchange student, Li, keeps showing up. Additionally, the only person to figure out the Black Reaper's identity was a Loony Fan who was more interested in stalking the hot guy than anything else.
 * Naruto
 * Something like this occurs during the Chunin Exam arc, when Sasuke comes up with a plan to figure out if somebody is infiltrating the group using a transformation jutsu. His plan was to come up with a very, very, long password. Later, when someone does come disguised as Naruto (Orochimaru) and gets the password right, Sasuke realizes that it's an impostor because he knew Naruto would never be able to remember the whole thing.


 * Also comes to Naruto's aid during the first part of the Chunin Exams. The ninja candidates are given an insanely difficult written test, with the implicit understanding that what's really being tested are their covert information gathering skills (i.e. being able to cheat on the test without getting caught). However, the way the test is set up is that anyone who lasts the entire testing period without being caught cheating passes automatically. This means that Naruto, who was too dumb to answer the questions or realize he was supposed to cheat, gets a passing grade despite having a completely blank answer sheet.
 * Comes to his aid again later during the exact same test. This test involves telling the class that there is one final question, and anyone who fails it will lose the chance to ever become a Chunin, with no option to retest. You can quit ahead of time, at which point you'll fail and be allowed to retest again at some point in the future. Furthermore, if anyone in your 3-person cell quits, you automatically flunk with them. Everyone expected Naruto to quit, because he couldn't even answer one question before now. But, Naruto not only refuses to quit but inspires everyone who was thinking about it to stay as well. It later turns out that this was another Secret Test of Character, as ninjas are expected to bravely accept missions even when they have no guarantee of success--or, indeed, when failure is almost assured.
 * In Durarara, manipulative sociopath Izaya names this as the reason why he hates Heiwajima Shizuo -- the guy is just too thick (and too angry) to fall prey to Izaya's mind games.
 * In The Law of Ueki, BJ starts off trying to win fights by claiming to be Robert Haydn, which causes people to run in fear. While Mori falls for this, Ueki just remembers that BJ introduced himself as BJ earlier that day, and just can't seem to understand BJ's claims that his name is really Robert Haydn... and keeps insisting that he's really BJ. The fact that he doesn't even know who Robert Haydn is probably helps.
 * In Eyeshield 21, Riku of the Seibu Wild Gunmen realizes, to his horror, that Rikiya Gaoh of the Hakushu Dinosaurs is too single-minded to fall for his feint, on top of being too big and strong to have to worry about it.
 * Although Gaoh isn't dumb at all- he's just too unsubtle, blunt and single-minded to be tricked.
 * Yasuri Shichika from Katanagatari isn't exactly dumb -- but he has No Social Skills, with his only human interaction being his father and his sister until Togame came along and the series started. As such, he is barely able to distinguish between people, and when a ninja used an impressive technique to impersonate Togame, Shichika immediately punched him even when he didn't know who it was yet.
 * Shichika has been on the receiving end of this as well. His first major defeat was against a super-strong little girl named Konayuki who had no understanding of combat and who just swung her sword around wildly. Shichika practices a martial art that focuses heavily on feinting and predicting your opponent’s moves, neither of which worked on her.
 * Gon Freecss from Hunter X Hunter is too childish and naive to fool. In a game where he and his opponent had to light candles and keep them burning, he was presented with two choices. Pick the long one or pick the short one. His friends speculate that the long one could be a trap but the short one could also be a trap. He picks the long one because it would obviously burn longer. However, it turns out that it doesn't burn longer because the candle he picked was special and burned three times as quickly as the shorter one. His opponent eventually reveals to us that he hid several booby-trapped candles under his shirt and would've given Gon a booby-trapped candle no matter which candle he picked.
 * And despite all the deceptions and trap-laying, Gon realizes that his booby-trapped candle is burning so fiercely that there's no way it could be extinguished short of running out of wick. He then puts it down and uses his superior speed to move in and blow out the enemy's candle himself.
 * Adachi Hana from Flunk Punk Rumble proves to be this. When a bunch of creepy monsters start scaring Student Council members while they're doing work at school overnight, and they sneak up on Adachi and Shinagawa, she simply assumes they're Shinagawa's friends because they're following him.
 * Pirate Captain Monkey D. Luffy has displayed this sometimes, although he's also been fooled a lot. On one occasion his crew actually lamented that he was 'just the kind of idiot who would fall for that,' and were right, but when the chips are down, or just when he already knows the bad guy is a bad guy, he has used this trope. He's more often just Too Dumb To Confuse or To Distract, though.

Board Games

 * Many a chess grandmaster has lost games to beginners in simultaneous exhibitions (that is, when they're playing against several people at the same time) by setting traps whose bait goes unnoticed.

Card Games

 * In Poker, there's the saying "Never bluff a monkey". While experienced players will fold if they think their hand isn't strong enough to call a high bet, a beginner will call almost any bet with a hand he likes, even if this hand is just strong enough to beat a bluff, if nothing else.
 * On one episode of Celebrity Poker Showdown, Michael Vartan commented that Amber Tamblyn, the least experienced player at their table, might actually be the toughest to play against, "because people who don't know how to play at all will call anything." Indeed, many experienced poker players have felt that beginners can make the most difficult opponents, because there is no way to ever predict what they will do, and, perhaps as a result, they are the hardest to manipulate.
 * In Magic : The Gathering, a player keeping two Islands untapped implies that he/she has a Counterspell in his/her hand. Similarly, a player tapping all of his/her Forests except one implies that he/she is holding a Giant Growth. Sometimes, players will attempt to bluff their opponents by keeping those lands untapped even when they don't have the necessary cards in hand. This tactic works best against intermediate players, because beginners don't yet know enough about the game to know what two untapped Islands or one untapped Forest signifies, and expert players are usually able to see through their opponents' bluffs. Many a Magic : The Gathering player has seen a bluff fail completely because they didn't realize that their opponents were, ironically, too inexperienced to fall for it.

Comics
"Pointy Haired Boss: Why should I care? The year 00 is before I was born.
 * Nextwave has Forbush Man trap the team in illusionary realities that exist entirely within their own minds... only to realize too late that Tabitha escaped the ploy because she has no mind to control. One explosion later, Tabitha claims she got out of it because she's "smart and stuff."
 * Groo the Wanderer has had his bacon saved by this on several occasions. In The Life of Groo, a comic special that covered his early years and first adventure, he was
 * In a 1996 Dilbert comic strip, Dogbert tries to sell his services, updating the company's computers to make them Y2K compliant, explaining that if something isn't done, then massive problems will occur when the computers think it's the year 00. Dogbert then says that his work is guaranteed for one year. It's here.

Dogbert: Amazing. You'd actually have to be smarter to do something stupid."

Fairy Tales

 * In "The Emperor's New Clothes," all the adults in the crowd convince themselves that they can see the Emperor's non-existent outfit. Only the child is simple and uninhibited enough to realize, "The Emperor has no clothes!"
 * A staple of fairy tales is that the youngest son of the family is also considered a complete idiot, yet he still is able to solve the puzzles or win the contests that his older brothers can't.

Films -- Animation

 * In The Emperors New Groove, Yzma tries too rationalize to Kuzco why she's doing his job, but he doesn't listen because he has the attention span of a goldfish.
 * This is shown by her dialogue not being audible to the audience either, replaced by Kuzco's internal monologue about Yzma's ugliness.

Films -- Live-Action

 * Fletch. When he's caught red-handed trespassing by a guard with a shotgun, the title character tries to bamboozle him with a line of patter: claiming to be Don Corleone, saying he's with the mattress police, etc. The guard (who's obviously not too bright) isn't impressed, and insists on calling the cops. Since it's one of the few times where Fletch's wit fails him, it takes a well-timed Groin Attack to get him out of hot water.
 * Star Wars: The Jedi mind trick doesn't work on four groups of sentient beings: skilled Force users, species that are naturally immune (including Droids, but their sentience is debatable), exceptionally smart individuals, and exceptionally dumb ones.
 * Good Burger; Carmen Electra's attempts to seduce Edd into giving her the secret sauce fails because he is too dumb to realise she's hitting on him. Also he is too dumb to understand insults aimed at him.
 * The title character of Forrest Gump
 * Played with in the 2007 adaptation of Hairspray, when Velma Von Tussle tries to seduce Wilbur Turnblad. She assumes that he is not responding to her advances because he's an idiot, but it's implied that he knows what she's trying and is deliberately ignoring her.

Literature

 * Ford Prefect tries to con the Vogon Guard in Douglas Adams' The Hitchhikers Guide to The Galaxy by appealing to his pride. The guard is too dimwitted to fall for it and is perfectly happy being a low-level grunt, stomping around, shouting and tossing people out of airlocks. He hopes one day to be promoted to "Senior Shouting Officer".
 * In David Brin's The Uplift War, a subplot has one alien ambassador trying to scam another by faking evidence of a massive coverup. The victim appears too simple-minded to spot the planted clues, (and too stolidly indifferent to be psychically induced to be curious), causing the hoaxster to wonder whether this is true idiocy, or a sign of deep wisdom.
 * The target of the scam does pick up on the evidence that someone else seems to be shadowing their movements: the ambassador's confederate who is planting the false clues.
 * At the end of Graham McNeill's Warhammer 40000 Ultramarines novel Dead Sky Black Sun, the Lord of the Unfleshed tells Uriel and Pasanius that they should leave. They point out there are no passageways. He points out.
 * In Sandy Mitchell's For the Emperor, Ciaphas Cain is trying to deliver tau to their embassy; having gotten through the hostile city, they find it surrounded by crowds. His aide Jurgen points out that the crowds are not hostile, so they could just ask them to move and go in the front door.
 * In Dan Abnett's Gaunts Ghosts series, "Try Again" Bragg seems like this at times, once replying that he would go over a cliff if ordered by Gaunt, and asking if it was supposed to be a trick question. However it may be something of a subversion, as Gaunt points out that Bragg may actually be the smartest of the Ghosts.
 * Terry Pratchett likes to describe characters this way in Discworld. Detritus the troll, Fred Colon, and the Palace Guards in Guards! Guards! have all been characterized this way at some point.
 * Commander Vimes actually takes advantage of Detritus' nature to prevent people getting where he doesn't want them.
 * The Palace Guards have actually been stated to be hired for precisely this trait.
 * Subverted and parodied in Thief of Time, where the story of the Emperor's New Clothes is mentioned, and the book then points out that the story ended before it got to the bit where the kid was beaten for being rude to royalty.
 * Also seen in Making Money, where Moist tests his paper currency on particularly "slow" shopkeepers (although he does distinguish between "slow" and "stupid", with the implication he can persuade a stupid man of anything). If he can convince them, he can convince anyone. "Slow" here refers to mental inertia. These are men to whom new ideas are very dodgy. Not stupid (they can make wrong change as quick as you can blink), but set in their ways.
 * A related concept is that children on the Discworld don't have a Weirdness Censor, because they don't know they're not supposed to be able to see the Grim Reaper.
 * An especially terrifying example is the Hiver in A Hat Full of Sky It cannot be tricked, it's too stupid.
 * In The Fifth Elephant, it is suggested that one reason the Clacks is so efficient that it can function as a Bamboo Internet is that it employs Discworld's gargoyles, who are good at watching and too uncreative to make mistakes.
 * The picture taking imps are the same way; they're only intelligent enough to paint what they see, very fast. They can't paint what isn't there.
 * Banjo from Hogfather is far too clueless to follow the criminal gang's plotting, yet he notices that the bar suddenly has a waiter . He also proves Too Dumb to Corrupt, as.
 * Throughout Interesting Times, whenever someone says they would rather die than betray the Emperor, Cohen kills them. When the Silver Horde encounters a guard by the name of One Big River and ask him whether he'd rather die than betray the Emperor, One Big River (who isn't bright enough to see in terms of metaphor) answers, "I tink I rather live." The Horde, seeing value in a man too dumb to think in the empire's strict mental paths, bring him along.
 * Apparently, it takes at least five minutes to explain Mustrum Ridcully anything. His subordinates consider this an advantage, because it means that people will only ever bother him with really important matters. Of course, there are many hints in the books that this may be Obfuscating Stupidity, so it might be deliberate on his part for the very same reason... It's been stated that Ridcully doesn't start paying attention for a few minutes, because if someone's still trying to explain something to him after that long, it must be worth listening to.
 * Note that it is for this precise reason he gets on with Ponder Stibbons: the young lad is always trying to explain stuff to him. So Ridcully will often listen to Stibbons more often then not.
 * Tom Cullen from The Stand is mentally handicapped, which makes him immune to the villain's array of mind powers.
 * One of the murder victims in "East is East" by Emma Lathen qualifies.
 * Heinrich von Kleist's essay On the Marionette Theater: A top class fencer finds his master in a bear. The bear parries all the fencers thrusts because it cannot be fooled by feints and tricks due to its lack of consciousness and understanding. In a number of similar examples, the essay laments human consciousness (a consequence of the Fall of Man) as imperfect - as opposed to the perfect consciousness of God and the nonexistent consciousness of animals. The imperfect consciousness stands in Mankind's way to beauty, grace and happiness, which both God and the Animal can acieve (for different reasons).
 * In L. Jagi Lamplighter's Prospero Regained, receives the staff with the spirit of evil wisdom in it because he's too stupid to be corrupted by it; it only manages to raise him to a high normal intelligence.

Live-Action TV
"Jack Carter: I pay attention sometimes!"
 * This is essentially the premise of the show Eureka. Jack Carter is a regular guy surrounded by supergeniuses, some of them a little evil. However, even when the bad guys have the entire town fooled, Carter always spots the detail that they missed. Carter also likes to apply common sense solutions to uncommon problems. And he isn't afraid of using SCIENCE! to get it done.

"Announcer: I'M TRYING TO TORMENT YOU!!!!!! DON'T YOU WATCH THE SHOW!!??!???!""
 * Subverted in The Tenth Kingdom. The village idiot repeatedly mentions that the dog Prince reminds him of someone, implying that he can sense the dog is actually the shape-shifted prince. Later when Tony asks him, it turns out he was thinking of a dog he knew when he was a kid, completely unrelated to the prince.
 * Related: In an episode of 30 Rock, Kenneth turned out to be an ace poker player since "you can't read his thoughts 'cause he doesn't have any."
 * In the US version of The Office, Kevin, who had made it to the world series of poker, correctly infers when they are playing poker that Phyllis thinks her hand isn't great, but loses because she actually had a flush she didn't notice.
 * In another episode, Michael Scott proves he's too dumb to fool when Andy is trying to convince Michael that Dwight is an incompetent boob. Every time Andy makes an attempt to talk negatively about Dwight, it goes right over Michael's head, including when Andy says that when someone does something dumb in the office, they say they "Schruted it." When Michael doesn't catch on, Andy points out that this is probably because of Dwight Schrute. Michael disagrees and says they're probably unrelated.
 * Subverted when Michael clearly states in his interview at the end of the show that he prefers Dwight to Andy because Andy is just a general suck-up while Dwight sucks up because he really believes Michael is special.
 * Comes up for Michael again in the episode "Did I Stutter?". Early in the episode, Dwight strong-arms Andy into selling him his car for an absurdly low price. He tries the same thing on Michael later on to convince him to give Dwight "emergency power" over everyone in the office; the attempt completely goes over Michael's head.
 * In an episode of The IT Crowd, Moss and Roy feed Jen a bunch of laughably incorrect techno-babble to say in her company presentation as a practical joke. To their horror, the rest of the company is just as tech-ignorant as she is, and the speech is met with resounding approval, even though she presents a small blinking box as "the internet."
 * In one episode of All That, the guy who tries to degrade celebrities fails when the guy he's mocking is so stupid that he fails to realize he's being insulted. Cue an extremely hillarious Villainous Breakdown.


 * In an episode of Smart Guy, T.J. found himself competing in a chess tournament he really wasn't qualified for, and in desperation asked Marcus to help him practice. Marcus was limited to moves that were so stupid T.J. didn't know how to respond to them, and in the middle of telling him this, he realized he'd found his strategy.
 * In The Increasingly Poor Decisions of Todd Margaret, a terrorist family tries to con Todd into refusing payment for a large purchase by implying that it won't leave them with enough money for the mother's medication. They all turn to Todd expectantly, waiting for him to suggest that he accept payment later, but he just stares blankly back at them, too socially inept to read the unspoken request. After an awkward pause, they give up and try a second tact, which Todd is dumb enough to fall for.
 * Gentaro Kisaragi, the protagonist of Kamen Rider Fourze, is a self-admitted Idiot Hero who tries to befriend everyone. However, when Ryusei Sakuta tries to join the Kamen Rider Club, Gentaro shocks everyone by refusing. He says that Ryusei isn't showing his real face, and he doesn't want to be friends with someone who can't be honest -- and he's 100% correct. Later on, Ryusei becomes enraged with Gentaro and punches him, nearly breaking his cover, but Gentaro just smiles and says now they can be friends because that punch gave him a glimpse of the real Ryusei.

Sports

 * Prior to an exhibition game against the Red Army hockey team in 1976, Bobby Clarke of the Philadelphia Flyers is said to have claimed of his Soviet opposition: "They're always trying to play with our minds. But that won't work with our club. We've got 20 guys with no brains."

Tabletop Games

 * GURPS has the disadvantage Clueless, which (as well as, naturally, some flaws) gives you bonuses against attempts to seduce you, among other things.
 * Rogue Trader's Navigators all have a power called The Lidless Stare. If mastered, it can instantly kill people who look into the Navigator's Warp Eye -- unless they have less than Intelligence 20...
 * Note that the lowest human intelligence possible during character generation is 27, but that's only the player character minimum, and the PCs are high-powered in Rogue Trader.
 * Exalted has Paralyzing Contradiction, a spell in which caster tells a Koan, and everyone nearby who hears it has to come up with a personal interpretation before they do anything. Unless they have intelligence 1 or less, in which case they're too stupid to realize there's a puzzle.
 * Some compulsion spells in Dungeons and Dragons have as a condition that the target must have a minimum amount of Intelligence (usually 3) to understand what you're trying to compel them to do. However, that isn't quite this trope because less than that is animal intelligence. It'd be like trying to hypnotize a cat.
 * Though some other powers will affect only a stricter range of intelligence, sparing those who are either too smart or too stupid. For example, the 2nd Edition psionic devotion "post-hypnotic suggestion" only works on a subject with a score between 7 and 17.
 * The Orks of Warhammer 40000 fit this trope. They cannot be fooled with a cunning tactical ruse, they won't attack an enemy's command structure or supply chains, they'll simply charge at whatever is right in front of them.
 * In Call of Cthulhu, losing a certain amount of sanity in one go - as caused by say, seeing an Eldritch Abomination or reading a Mythos book can cause temporary insanity... unless the Investigator fails an Idea roll... essentially, meaning they're too dumb to realize the full enormity of what they're just experienced and are thus saved some of it's horror.

Video Games
"Konishi: No analysis could ever plumb the depths of your fatuity.
 * The Wizardry series of RPGs uses this trope with characters of low intelligence (like Lizardmen). Characters with low intelligence aren't as prone to mental conditions or psionic (mind-based) attacks and effects.
 * Played straight and then inverted with the idiot mutant Harry in the Fallout 1 game. If you're at all intelligent, nothing you can say will fool him into letting you past him. If you happen to be playing a stupid character (whether naturally so or temporarily so through abusing drugs) however, your answer to his question will be "Huh?" to which he will reply "Huh?" and after several repetitions of this exchange, the "conversation" will decay into idiotic grunts of laughter and then he'll let you pass.
 * Beat from The World Ends With You is like this. He doesn't get offended when people make fun of him... because he's too stupid to realize he's being made fun of.

Beat: Heh heh. Damn right!

Neku: Uh, dude... She's making fun of you.

Beat: WHAT!?"

"Neku: ... you thought you could predict what he does?!"


 * In Baldurs Gate II: Shadows of Amn, your party encounters a con man who attempts to sell him a planar sphere that's just materialized spontaneously in the Slums. While the dialogue varies between NPCs, Minsc has one of the best: he declines because according to Boo (his pet miniature giant space hamster), the sphere is not a good buy, because -- get this -- it's too big to fit in even Minsc's pocket.
 * Also, if a mage casts maze on a party member, a really dumb character will escape the spell before a moderately intelligent character.
 * In Portal 2, GLaDOS attempts to

Web Animation

 * In Homestar Runner, it was revealed that Homestar is the only character that realizes that The Thnikkaman is just Bubs in a Paper Thin Disguise... although this doesn't stop him from inexplicably idolizing him like everyone else.
 * Hadouken Dude's 4 Swords Misadventures 6 had a moment in which Green Link and a drunken Red are attempting to answer a series of questions. The last one, 'What's the quickest way to a man's heart?' was answered by Red as 'Chuck Norris's fist' Surprise surprise, it's the right answer! When Green asked him how he came up with the answer, Red replied 'Dude, Chuck Norris is everywhere...'

Web Comics
"Horribus: Why can't we use his fears against him?
 * Sluggy Freelance:

Psyk: The long of it is, he does not explore consequences in depth, so he has no unknown fears to confront. And his memories are limited, so he has no fears from his past. The only things he seems to "fear" stem from simpler things we would not ever regard.

Torg: Hey, are you saying I'm too stupid to be afraid?

Psyk: That's the short of it."

"Forgath: Minmax, look up.
 * Elan from The Order of the Stick.
 * Mega Man and Bass in Bob and George.
 * The title character in The Inexplicable Adventures of Bob! is made of this. Perhaps most notably here.
 * Bikke of Eight Bit Theater has earned this title. When Sarda tries to taunt the Dark Warriors with the fact they don't know how to actually use the Orbs, Bikke responds by chucking his at Sarda's head.
 * Mind you, this does end up working in his favor. Sarda is so amused by his pluck that he promises You Will Be Spared. Or at least suggests it...
 * Similar thing occurred when Black Mage tried to use his hypno-vision on Fighter. It didn't work, and Fighter hardly noticed that he attempted it. Fighter comments that trying to hypnotize him won't work because he isn't smart enough to be hypnotized.
 * Fighter even says at one point, "It may not be possible to fool me, 'cause of how smart I am." While his teammates discuss how best to fool him. And succeed. With the plan that he was listening to.
 * Minmax of Goblins has his moments. It's especially funny when his teammates are trying to confuse him (It Makes Sense in Context) and failing, leading to the page quote.

Minmax: Okay. *looks up*

Forgath: No, no, the other up.

Minmax: Sorry. *looks down*"


 * This trope takes a serious turn with Izza from Elijah and Azuu, who is too stupid to understand the concept of lying (despite being a demon), and as such is wholly immune to optical illusions.

Western Animation
"Leela: Now when you say "special"..."
 * In Futurama, Fry is immune to the effects of the Brain Spawn because of his "special" mind. Special because he's his own grandfather, thanks to Time Travel shenanigans.

"Conngressman: We need to get government out of government!"
 * Rocky and Bullwinkle: Bullwinkle's own natural stupidity makes him immune to "Goof Gas," an IQ lowering drug. Later in the same arc, Boris and Natasha attempt to use it to attack the US Congress, but inanity of the politicians political debates cause them to think someone already "goofed" congress.

"Early: .38 Special? How the hell you boys doin'!
 * Bullwinkle is this trope. Another example when he enters an elevator that says "out of order" only that he falls in the empty shaft, but happened to contain the hidden stash of counterfeit boxtops.
 * The Simpsons
 * Homer resists the most powerful persuasion techniques of a cult thanks to his negligible IQ and attention span. Until they change the lyrics to the 1960's Batman score from "Batman" to "Leader".
 * There was also Mr. Burns' numerous attempts to negotiate with Homer when he became head of the union for the Power Plant. The situation got too disturbing for Homer to the point where he thought that Mr. Burns was hitting on him.
 * Lisa tries to deliver the classic Koan of "What is the sound of one hand clapping?" to Bart. He simply slaps the fingers and palm of one hand together.
 * From Squidbillies, when Early walks in on his wife naked with the band .38 Special, and they try to convince him nothing is going on:

Larry: Uh, we're just hanging out...

Early: Well, it says here on this shirt you're supposed to be playing up in Pittsburgh tonight.

Don: That shirt's from 1984.

(long pause)

Early: Hell, that ain't this year! What's goin' on here?!"


 * Luanne from King of the Hill tops this trope by being too dumb to brainwash when she accidentally joins a cult.
 * In an episode of The Weekenders, dimwitted Bluke figures out the answers to the clues for the scavenger hunt because he doesn't bother to think they're cryptic and complicated, as the main cast assumes... and nets them second place and a pizza -- which he similarly correctly realizes is a better prize than the first-place pool table, since the game was played by five-person teams, and you can't "split" a pool table.

Real Life

 * Many magicians don't like having children in the audience, because they often don't pay attention to the nonverbal cues magicians use to distract the audience and notice what they're actually doing.
 * There's a saying that goes "The best swordsman in the world only needs to fear the worst, because he has no idea what that idiot will do."
 * In martial arts, we say the most dangerous belt is a white belt. God only knows how they could hurt you or themselves.
 * The two above examples translate into the sport of fencing as well as historical swordsmanship. The idiot with no idea how to use his weapon is more dangerous to an excellent swordsman if only because the idiot is unpredictable.
 * This is also why the Drunken Boxing trope exists, since someone who's behaving erratically is much harder to predict.
 * This is also a concern in matters military. Several of the greatest innovations in warfare were the result of amateurs making war without the baggage that professionals had acquired over centuries.
 * According to The Other Wiki one possible explanation for what is commonly called "beginner's luck" is that beginners are not limited in their thinking to what is the "right" way to win, and explore wider possibilities.
 * During World War I, the Germans tried to lure a French force into attacking, whereupon they would be isolated and massacred. To accomplish this, they faked a hole in their security. This might have worked, had the French commander in charge of the area not been too dim to notice the weak point.
 * During the second world war, MI 5 did a deliberately botched operation on a German spy so that he would report back to his masters with false information about British interrogation techniques. The plan failed as German intelligence never even realized the spy had been discovered.
 * The idea behind it was to make him look so obviously and incompetently subverted that they'd think that he must be the only one who had compromised -- they had actually captured or bribed most or all of the German spies, but they figured if the Germans assumed they were that incompetent, they'd think the others weren't compromised, as they weren't giving such blatantly false information. It wasn't a total loss, as they did indeed fail to realize that the others had been compromised... but since they didn't even realize the decoy had been, the operation was simply a waste of time and money.
 * Asperger Syndrome sometimes results in this, since a lack of ability to read social cues means that attempts to diminish the appearance of deception aren't picked up on. Notably, many are less susceptible to hypnosis of any form, due to having to interpret subtle signals consciously. A study that came out a few years ago (but seems to have vanished from search engines) found that people on the Autism Spectrum (including Asperger's) were less vulnerable to certain kinds of emotional manipulation (specifically, they were less likely to change their decisions in game scenarios when a move was presented as "avoiding a loss" vs. a "gain"). The abstract of the paper seemed to be going to great length to frame their results in terms of "too dumb to fool" and ensure that no one mistook the traits they were describing for a strength, insistently describing subjects with Asperger's at some length as "failing" to integrate certain kinds of (objectively and rationally irrelevant) information into the decision-making process.
 * Poor eyesight can also cause this, not being able to read non-verbal cues and thus harder to mislead. Athough it works like that in the negative too.