It is common in all forms of animation, as well as in live-action media, for a character to tilt their head sideways in confusion. In anime, this is often accompanied by a "..." while it is more often accompanied by a "...huh?" in western animation. A raised eyebrow is common in every genre.
Common in Animal Reaction Shots, especially with dogs (although animals who behave like dogs may do it too), accompanied by a Quizzical (or Disapproving) Whimper. Also a common mode of silent expression for The Speechless or The Voiceless.
There's a good biological reason why this trope applies in Real Life: when listening to sounds, brains determine which direction they come from by which ear hears the noise louder and a tiny fraction of a second earlier than the other. If a sound's point of origin is hard to pinpoint, tilting the head and turning the neck moves both ears into new positions, providing additional data from which to triangulate and determine an ongoing or repeated sound's source.
- The old RCA Victor ad had a dog with its head tilted quizzically as it listened to a phonograph record play, with the title "His Master's Voice◊".
- The famous trademark image comes from a painting by English artist Francis Barraud, A.R.A. and titled "His Master's Voice". The original title of the painting was "His Late Master's Voice" (and this phrase appears on many of the original RCA Victor labels), but the concept was considered too depressing for most of the public's tastes, and certainly for an image used as a means to put the consumer in the mood to buy. It was acquired from the artist in 1899 by the newly-formed Gramophone Company.
- The logo remains in use today by the British music store HMV, whose name is an acronym of the slogan.
- One Piece:
- Luffy is incredibly fond of this, tilting his head whenever something even mildly puzzling occurs. Don't know which direction is south?
Luffy: Hm.... [quizzical head tilt] That way's warm, so it's south!
- Zoro even gets into it when Luffy and him meet up Helmeppo again.
- The Boa sisters do this when Luffy No-Sell Hancock's Mero Mero Merrow beam.
- Later seven other pirate captains pledge their crews to Luffy. When he refuses his explanation leads all seven to do it in unison.
- Luffy is incredibly fond of this, tilting his head whenever something even mildly puzzling occurs. Don't know which direction is south?
- Nia in Tengen Toppa Gurren Lagann tilts her head when she sees Lagann in a garbage heap.
- In Durarara!! Celty and Shizuo do a simultaneous version, which goes to show their Like Brother and Sister bond, in addition to being absolutely adorable.
- Used by Yuki in The Melancholy of Haruhi Suzumiya when Haruhi tells to use her "magic powers" to zap Mikuru during the production of their student film. Considering how Yuki is the epitome of the Emotionless Girl, this is her equivalent of a stunned gasp (particularly how she does have reality-warping powers of her own).
- Naruto does slight head tilts early on in the show when he doesn't understand a concept or isn't familiar with something (which, being Naruto, happens quite a bit). An example is when he first hears of the Chuunin Exams from Konohamaru.
- Pokémon: In "Mastering Current Events!", surprisingly, the usual happy-go-lucky Gliscor did one when the Air Battle Master accepted Ash's offer to battle him.
- In Welcome to Demon School! Iruma-kun, both Iruma and Ameri tilt their head to the side with a confused expression when Opera tells them they don't understand the concept of cooking.
Opera: Don't tilt your heads at me!
- Child of the Storm has Maddie pull this in the sequel, when Harry surprises her. Since her job title is literally 'Hound', and she has some dog-like personality traits (as well as some cat-like ones), it's strangely appropriate.
- Used several times in Kyon: Big Damn Hero:
- Tsuruya when Kyon received a greatcoat as a gift from Mikuru, and realized it's the same coat she saw him wearing some weeks ago.
- Mikuru when Haruhi is explaining her plan for a relationship between Kyon and the girls in the brigade.
- Observed as an intriguing, if foreign, gesture that humans often do in the Mass Effect fic, ''First Contact.'' The fact that it's almost ubiquitous amongst both dogs and humans is just one of many things that drives home the fascinating dynamic humanity has with dogs and cats (to the point of major coevolution that continues to this day).
- A frequent aspect of the writing in Pokémon Reset Bloodlines.
- Ash and Red in The Road You Choose tend to do this.
- Mune, the title character of Mune: Guardian of the Moon, quizzically tilts his head throughout the film, along with a chirping noise.
- Wild Wild West: A "blink and you'll miss it" Shout-Out occurs when "Bloodbath" McGrath is lying on the ground and a dog comes up and does the "His Master's Voice" bit while looking at McGrath's ear trumpet.
- Starman has Jeff Bridges' character tilt his head quizzically for most of the movie — but that's because he was a non-human life form from outer space learning about the human experience as he went along, so everything was new and confusing to him.
- Jurassic Park:
- The Lost World: Jurassic Park: During its rampage in San Diego, the bull T. rex tilts its head sideways when Ian and Sara use the infant T. rex to lure its daddy back to the docks. Its expression just screams "You two again?".
- In Jurassic World, Charlie the Velociraptor tilts her head when she encounters Parental Substitute Owen in the firefight. Until this point, it appears that the raptors have betrayed their alpha and sided with the I. rex, but Charlie is visibly conflicted and chitters at Owen instead of attacking him. It gets her killed by the mercenaries.
- The Fifth Element: Leeloo gives a tilt of her head to General Monro before breaking through her "unbreakable" container and taking from him the key to opening it.
- Detective Hoffman tilts his head towards Strahm while residing inside the glass box in Saw V.
- In Halloween (1978), Michael Myers tilts his head when he's examining Bob whom he has just pinned to a wall with a kitchen knife. It becomes a trademark habit, with practically every subsequent movie having him tilt his head at least once.
- Jason Voorhees several times throughout the Friday the 13th series.
- First instance comes in Friday the 13th, Part II when Jenny mimics Jason's mother and tilts her head in an effort to lower his defenses and then kill him.
- In Part IV he is confronted by Tommy who has made himself appear as Jason as a child.
- In Part VI when he sees some Don't Come A-Knockin'-business going on in an RV.
- In Part VIII when he sees a billboard for a hockey league which features a hockey mask similar to his.
- Jason tilts his head in surprise in Jason Goes to Hell: The Final Friday when he finds out that he can see his true self in a mirror while possessing some else's body.
- In The Mask, Stanley's dog Milo tilts his head the first time Stanley turns into cartoon Mask, the title character.
- Star Wars:
- A New Hope: Luke tilts his head when he finds Princess Leia in the Death Star detention center, and right before she asks him "aren't you a little short for a stormtrooper?"
- Return of the Jedi: The Ewok whom Princess Leia befriends headtilts at her when she tries to talk to him. The child actor (Warwick Davis, in fact) who played the Ewok stated that he purposefully modeled this behavior from his own pet pooch.
- The Force Awakens: Kylo Ren headtilts when he asks Rey "you still want to kill me?" after she wakes up in the Finalizer's interrogation room.
- Ripley gives a "Like hell you will!" variation in Aliens just before going berserk in the alien nest. And the Alien Queen does a version of it as well when confronted with an opening elevator door.
- In Terminator 3: Rise of the Machines, after the T-X is repeatedly hit in the head with a fire extinguisher (even doing a 360 spin), she tilts her head with a disapproving expression — in a clear homage to the T-1000's Finger Wag. The T-850's face afterwards just screams "Oh, Crap!".
- Trinity during the Club Hel fight in The Matrix Revolutions. When one of the Merovingian's gravity-defying guards dodges a kick by leaping onto the ceiling, she tilts her head — then does her signature midair pose and kicks him so hard he's embedded in the wall.
- One of the alien invaders tilts their head upon seeing Steven Hiller and David Levinson in one of their ships in Independence Day.
- Emma.: As Mr Elton reveals the elaborate frame of Harriet's portrait, Harriet and Emma tilt their heads sideways simultaneously, each in the opposite direction.
- Karou of Daughter of Smoke and Bone tilts her head frequently, in a manner described as a "quick birdlike tilt". It's one of the first things Akiva notices when he meets her, as it reminds him of his deceased lover Madrigal which makes sense, as thanks to Reincarnation they're the same person.
- In The Dresden Files, Harry's dog Mouse tends to tilt his head when Harry explains something to him. How much he actually understands is up for debate, since Mouse is smarter than your average dog.
- Game of Thrones: Jaime's reaction after seeing Brienne slay three soldiers without any effort.
- Star Trek: The Original Series: Spock makes considerable use of headtilting, as well as the Fascinating Eyebrow (and sometimes both at once).
- Star Trek: The Next Generation: Data quizzically tilted his head every ten seconds or so. It was so distinctive that Riker was able to notice it in a completely different individual thirty years later.
- Det. Goren tilts his head while interrogating a suspect, in the intro to Law & Order: Criminal Intent, and repeats the gesture fairly often through the series as well.
- There's an episode of Will & Grace where Jack says 'reluctant pivot, inquisitive head tilt' as response to Will.
- In Supernatural, this is Castiel's typical reaction to Dean (or others) not making sense from his angelic perspective. He may just have patented his version, actually.
- Teal'c from Stargate SG-1 typically paired it with a Fascinating Eyebrow when something about Earth culture confused him in the early seasons.
- Spike on Buffy the Vampire Slayer tilts his head very often. In fact, his head's default position seems to be tilted. He has the Quizzical Tilt, the intimidating tilt, the "I'm about to bite you" tilt, the arrogant tilt, the tilt of sexy... well they're all pretty sexy, so that should probably be renamed the tilt of "I'm going to shag you right now."
- Illyria on Angel seems to be doing this the entire damn time. Usually it signifies the person she's looking at is about to get Punched Across the Room.
- Kurt from Glee is good at these, but they tend to be somewhat less inquisitive and somewhat more interrogative. As in "we-have-ways-of-making-you-talk" interrogative. Especially when the frosty eyebrow lift and serial killer Death Glare get in on the act.
- The Observers in Fringe head-tilts a lot in response to human behavior. September's actor Michael Cerveris got the idea from watching his dog. The series later provided an in-universe explanation for it in the final season, the subject of an epic The Reason You Suck speech delivered by Nina to the Observer commander, Captain Windmark. The Observers are hyper-evolved Transhuman Aliens from 600 years in the future, whose brains have been enhanced to reality-warping levels by sacrificing the regions of the brain responsible for emotions. The Observers repeatedly say they feel that regular present-day humans are animals compared to them. As a final screw-you before he kills her, Nina points out that the Observers tilt their head in that way because it's an atavistic trait: reptiles and lower mammals have an instinct to tilt their head to change the angle at which sound hits their eardrum, when they hear a noise they are unfamiliar with. Modern-day humans evolved beyond this rudimentary trait. So for all of the Observers' talk about how they are superior to regular humans, they're just walking science experiments, who even accidentally spliced back in a few behavioral traits from junk DNA - and like reptiles, they also spliced out their capacity for love, wonder, or the ability to appreciate "beauty".
- The New Adventures of Old Christine: New Christine hurts her neck, but everyone just assumes she's just tilting her head, wondering at various stuff.
- In Season 2 of Luther, a woman walking down a dark alley realises there's someone following her; a man in a hoodie wearing a Punch mask. Punchface tilts his head as if sizing her up, then we cut to her being murdered on the sidewalk.
- The West Wing: on the third season episode "H. Con 172", a former staffer at the White House has written a tell-all book about his time there, and it's riddled with errors (though Sam, for reasons of his own, is treating it as Serious Business), and Larry reads an excerpt from the book out loud, C.J. has this reaction:
Larry: "Bartlet was playing a round of golf with Toby Ziegler, the prickly, mumbling Communications Director whose inner, bitter darkness spelled the breakup of the one marriage we know about."note
C.J.: It was miniature golf, wasn't it?
- Farscape: One of Chiana's frequent Character Tics is tilting her head from side to side. This actually arose due to Gigi Edgley trying to see out of the black contact lenses she had to wear which severely limited her vision. The lenses were eventually switched to a less restrictive pair but the movement was so firmly established that she kept doing it.
- The first episode of The Mandalorian has the title character do this when he sees The Child a.k.a. Baby Yoda. Since the Mando wears a Cool Helmet that completely covers his face it's a good way of expressing his curiosity about the tiny alien he's been hired to find.
- Bassist Charlie Haden can be seen tilting his head on the cover of Ornette Coleman's This Is Our Music.
- Dwayne Johnson: The Rock sometimes tilts his head. Though it's usually accompanied with getting someone else's ass kicked. He would also say it during interviews or when one of his promos were interrupted, usually followed by...
Rock: ...and just who in the blue hell are you?
- Kane tilts head when he wears a mask and doesn't have a voice, probably borrowed from Michael Myers of Halloween.
- Head-tilting seen here by the referee as two hockey players demonstrate some impromptu yoga. (San Jose at Phoenix, 4/15/13.)
- Mass Effect 2 includes a scene where Joker tilts his head after EDI cracks a hilarious, albeit very poorly timed, joke.
- In Kirby: Planet Robobot, Susie tells Kirby he'd never understand how great it is to work, followed by Kirby adorably tilting his head in confusion.
- Emperor Palpatine hilariously tilts his head when accessing Imperial security panels in LEGO Star Wars.
- In Kingdom Hearts coded, Data-Sora, Mickey, Donald, Goofy, and Jiminy all perform one together as Data-Riku explains the nature of his existence.
- Tales Series: When something about normal life confuses Sophie in Tales of Graces, she tilts her head sideways.
- Team Fortress 2's "Meet the Pyro" has him tilt his head to the enemy Sniper. In his mind, everything is a happy Sugar Bowl of rainbows and sparkles, so he just doesn't understand why the Sniper is begging for help just before he's burned to death.
- Done by multiple characters in Pokémon Mystery Dungeon: Gates to Infinity, but is most notably used by Hydreigon, who in a moment of Leaning on the Fourth Wall, seems to direct one at you (As in, you, the player). Having the 3D effects enabled makes the moment especially amusing, as he shoves his face in the camera before he does so.
- In Pokémon X and Y, Pokémon will imitate your facial expressions and head movements to a degree while in Pokémon-amie. This includes a tilt of the head, which can look comical and/or adorable depending on which Pokémon is doing it. Recreating the aforementioned Mystery Dungeon example is very much possible and no less amusing than before.
- In the opening cinematic to Diablo III's expansion Reaper of Souls, the rogue angel Malthael gives a slight one when he is confronted by Tyrael, who has turned from angel to human since they last saw each other.
- Characters in Animal Crossing do this accompanied by a sound effect and question mark visual.
- The Plain Doll in Bloodborne will sometimes give the Player Character a confused tilt of her head if they perform a gesture in front of her.
- Michael Myers' victory animation in Terrordrome the Game: Rise of the Boogeymen has him tilting his head to the side as he looks down on his opponent as a reference to the first Halloween film.
- As a reference to the films featuring him, Jason Voorhees from Friday the 13th in Mortal Kombat Xtilts his head as his post-round taunt, and after doing his Slasher throw, understandably confused that his opponent is getting back up after being violently impaled on a machete.
- The Warrior of Light in Final Fantasy XIV will do this with an interesting level of frequency, both during and outside of the main quest line. Despite this, it's not a user-accessible emote for now.
- In The Whiteboard the girls do this when it's revealed that Doc has The Star Wars Holiday Special on LaserDisc.
- Grrl Power: Lampshaded, of course.
Sydney: Hmm. Going to need a proper thinking tilt to figure this guy out.
- Hyperbole and a Half illustrates the Simple Dog's usual method of dealing with a confusing situation: she tilts her head at an increasing angle. She will do this until the head-tilt has solved the problem or until she tilts her head so far she actually flops on her back. (She usually flops on her back.)
- Florence Ambrose from Freefall often does a quizzical tilt whenever she's puzzled. Being a Bowman's Wolf, it's particularly fitting. And, given the amount of research put into the comic's scientific aspects, most likely intentional.
- Cute Overload calls tilting one's head sideways the "baroo", after the sound dogs (supposedly) make along with it.
- A disproportionate amount of Slenderman-related media portrays him as having his head habitually tilted to one side.
- When Linkara of Atop the Fourth Wall joined The Nostalgia Critic to review Superman IV, this was his reaction to Supes' "repair The Great Wall of China vision".
The Critic: Does Superman have wall-repairing ability?
Linkara: [quizzical tilt] ...not in any comic I've read.
- On the vlog Vlogbrothers, Hank composes a song from weird noises sent in by nerdfighters to get his brother's dog to tilt quizzically. It works
- The Simpsons, "Sweet and Sour Marge":
Marge: Don't you have any sense of corporate responsibility?
Garth Motherloving: [tilts head, confused puppy-dog whimpers]
Marge: Hey! [claps twice, and Garth snaps back to attention]
- Family Guy, Stewie's reaction to Brian's "this has turned his life upside down face" comment.
- In The Thief and the Cobbler, there's a scene where Tak and Princess Yum Yum do this to each other for several seconds.
- In the Adventure Time episode "The Chamber of Frozen Blades" Dr. Princess head-tilts sideways in reaction to Finn, Jake and the Ice King acting like ninjas.
Dr. Princess: What am I... looking at here, exactly?
- Mabel tilts her head in the Gravity Falls episode, "The Hand that Rocks the Mabel" complete with a dog like, "Aroo?"
- My Little Pony: Friendship Is Magic: In "Sounds of Silence", since Kirins don't talk and show little emotion, the one most common bit of body language they demonstrate is a curious head tilt.