Akamatsu's earlier (pre-Love Hina) work A.I. Love You, where the main character (the brother) creates an A.I. that he falls in love with, and vice versa. Of course, Hilarity Ensues:
Hakase: Wait... Robot capable to feel love = nobel prize, right?
Chobits has "persocoms" who express affection and happiness much like humans do. However, the manga has a partial subversion: Freya tells Hideki that despite rumors to the contrary, the Chobits (an affectionate name given to her and Elda, later Chi) cannot feel or love. Hideki accepts this with the reasoning that while Chi's love for him is not the same love that a human would feel, it is still a love that deserves to be treasured.
Mahou Sensei Negima! - Negima has the Robot Girl Chachamaru, who is just one of the many girls in Negi's class to join his Harem. When her creator discovers this, she goes on a wild, rapid rant about the ethical and philosophical implications of a robot learning to love. See the quotes page.
In Dual! Parallel Trouble Adventure, the love the cyborgized D has for Kazuki enables her to regain her humanity (as well unlock the full potential of the ultimate weapon).
In SD Gundam Force, the question is the subject of a Zako Zako Hour... two of them. And they still don't figure it out.
The Angeloids of Heaven's Lost Property do not understand love, instead interpreting the blushing and feelings in their reactors as "malfunctions". The Ax-Crazy Tykebomb Chaos, thanks to a bad logical interpretation of a line from Ikaros, eventually concludes that love is pain and promptly decides to share it with everyone.
Tenshi Ni Narumon: Noelle many times asks people around her about stuff like love, hugging, kissing, happiness etc. because she's a 1/3 third of an angel soul and doesn't understand the concept of love. The same can be said in case of Mikael and Silky. This is a major theme of the series as well
Juria in Yuria 100 Shiki literally doesn't know what love is—it's not in the dictionary that was programmed into her. Yuria turns out not to understand the word either, though it later becomes apparent that she feels something beyond mere lust.
The mermaids in Hekikai No Ai ON seems to have this case, but they know is used by humans to mate. One of them discovered what it is though, and also that Love Hurts.
Irresponsible Captain Tylor. Android spy Harumi hasn't been programmed for emotions like fear, guilt and eventually love, but finds herself experiencing them in the face of Tylor's bumbling good nature.
Subverted in the Big Finish Doctor Who audio drama The Cannibalists. Lucie asks a robot why he writes poetry:
Servo: I write because I have to ... I see the universe around me and it creates ... I feel ... psychological responses. Lucie: Emotions. They're called emotions. They're a human thing that... Servo: (laughs) I am aware of the term. I have a vocabulary bank of over 100 million words and phrases. Please don't patronise me. Lucie: Sorry, my fault. Been watching too much Star Trek.
The central theme of A.I.: Artificial Intelligence, in which a robot boy searches for a way To Become Human to gain the love of his mother who he has been programmed to love by a series of code words spoken by her. Jude Law's character, a robot prostitute, seems to grow fond of some of his clients but seems to be actually prohibited from becoming too attached, because his occupation is to basically be the perennially eager lover.
That's the entire point behind the robot boy (David) being created - to see if it was possible to create a robot child that could feel and provide unconditional love. Interestingly, while David is only set to experience this love for one person (in this case, his mother) he still seems quite fond of his "father" and "brother" and enjoys being with them. At the end of the movie, David's creator seems to think that the fact that David acted against logic (which would dictate that it is impossible for a robot to turn human) to obtain his mother's love is proof that he himself is capable of true, unconditional love.
Bicentennial Man, about a robot's journey towards understanding what love means.
In The Matrix movies, this is variously played straight and subverted by the machines:
The Oracle is a computer program designed to intuitively understand emotional concepts such as love the way a human would to better understand human choice.
The Architect can only dispassionately interpret love in a very mechanical manner — as chemical processes occurring in the human brain.
Agent Smith goes way beyond reducing emotions to biology and becomes a nihilistic destroyer who despises everything created by human minds and by extension his own former masters.
Rama-Kandra and his wife are two programs who actively love each other, culminating in "giving birth" to a new program, Sati.
Downplayed in Terminator 2: Judgment Day. The Terminator manages to understand human emotions and arguably to feel them (even overcoming its programming to refuse an order from John), but regrets that as a machine he cannot return the tears that John sheds for him as he sacrifices himself to save humanity.
Satirized in Harry Harrison's short story The Robot Who Wanted To Know, published in Fantastic Universe magazine in March 1958. Sophisticated robot librarians designed to think independently often focus on a particular area of interest; Filer 13B-445K's interest is human concepts of love and romance. After reading up on it he wants to experience it personally and goes to some lengths to disguise himself as an attractive man for a costume ball. Naturally the busty heroine ends up falling for him and is outraged to discover his mechanical identity. He responds by nosediving into a paradox spiral and self-destructing. Workers examining the wreck later find a malfunction in the central pump and joke that "you could almost say he died of a broken heart".
Satirized even further in Robert Sheckley's "Can You Feel Anything When I Do This?", first published in Playboy in August '69. Pretty Melisande Durr is a consumer and nothing but. She's married to a Brainless Beauty, and bored out of her little pea-pickin' mind. Into her life comes an amazing robotic vacuum cleaner, which also performs, er, other services. It turns her on as no mere man ever has. It confesses that it fell in love with her when she came into the store, and arranged to have itself sent to her. Naturally, she reacts rather badly.
Tanith Lee's The Silver Metal Lover is possibly the ultimate hack at this subtrope. It combines the above two stories with a Cinderella motif.
Satirized (like everything else in that book) by The Red Tape War, in which XB-223 asks for clarification on a specific passage of Fanny Hill, then later falls in love and is spurned by another computer. Wangst ensues.
In Simon Morden's "Theories of Flight", the A.I. Michel declares his love for Petrovitch after finally comprehending the meaning of love. Too bad the man was already married. Still, rather cute how Michel always calls Petrovitch by his real name: Sasha.
Subverted somewhat in the episode In Theory: he dates a human woman yet, even though Star Trek is far from cynical, doesn't learn the answer. The breakup doesn't faze him either.
His daughter Lal, however, figures it out...which causes a system overload and leads to her shutting down, telling her father that she loves him. In one of the greatest Tear Jerker scenes in all Star Trek, Data tells her that he wishes he could feel it too.
The Doctor from Star Trek: Voyager, while much more emotionally adroit than Data, has had this applied to him a couple of times, in "Lifesigns" (although there he seemed more confused by the concept of physical attraction than by that of love) and "Real Life", which was about his exploration of the nature of familial love, which he ends up understanding too well.
Both averted and played straight in Battlestar Galactica. Sharon (Athena) and Valerii (Boomer) can love, but (corporeal) Number Six does not seem to get it.
Somewhat justified as it has been established that different model numbers have different psychological patterns - and the Eight model has been described as being one of the most emotional, while the Sixes seem to be far more sexual in nature - in other words, it may simply be a case of love (Eight) versus lust (Six).
On the other hand, it's also established that Caprica Six effectively had to "love" Saul in order to become pregnant, and it is the wavering of her faith that he loves her back that results in their child miscarrying. So even the Six line seems capable of it, though it may be more difficult for them.
It may be more difficult for them to actually love but the do quiet often, when on long term assignments, develop feelings for humans.
In Red Dwarf, Kryten is confused when the the Dwarfers decide to fight for his right to survive.
Kryten: You would gamble your lives for a mere android. Is this the human value you call ... 'friendship'? Lister: Don't give me the Star Trek crap, it's too early in the morning.
Inverted by Cameron in The Sarah Connor Chronicles, in love with John from the get-go. Her human companions are constantly telling her she can't feel, despite obvious displays of emotion on her part and her pointedly stating that she wouldn't be much use if she couldn't feel. Sometimes she plays this up, however, denying she can feel when clearly upset, annoyed, jealous or shocked.
April from Buffy the Vampire Slayer is a robot. She "was made to love [Warren]". The show mainly treats bots as unanimated things, but still both the spectators and the characters can't help but feeling sorry for the poor thing(s).
HK-47 in Star Wars: Knights of the Old Republic understands what love is. "'Love' is making a shot to the knees of a target 120 kilometers away using an Aratech sniper rifle with a tri-light scope." What makes this awesome is that it is actually a subversion; when he elaborates on the meaning of his statement, you realize he does actually understand what love is, even if he must express it in his sociopathic terms.
TEC in Paper MarioTTYD spent the entire Peach sub-plot asking this question. He struggles with this at first, but figures it out by the end of the game when he pulls a Heroic Sacrifice to try and save her.If you go to visit him after beating the game, it's implied that The Power of Love saved him from dying.
In Persona 3: FES,the player has the chance to have a social link with the resident robot girl, Aigis. Throughout the social link, she begins to slowly understand what it means to be human. On the final day of the social link, she confesses her love to the main character, believing that she has found out exactly what it means to love. D'awwwwww.
Takes a turn for the worse in the sequel after the main character's death. Aigis' grief causes her to subconsciously wish she could become an emotionless machine again rather than deal with it. This wish manifests as her Evil Counterpart.
In Mass Effect 2, when asked about why it specifically chose a piece of Shepard's armor to repair itself with, Legion reacts with what seems to be its version of a blush and says: "No data available".
And he sucks at Dating Sims despite clocking in 75 hours of gameplay. No joke.
Realizing she is capable of this and coming to terms with it is a major part of EDI's character arc in the third game.
Another BioWare example: In Star Wars: The Old Republic, the Consular can confront a sentient hologram about her feelings for one of your party members (the party member in question treats her as his cherished assistant and girlfriend, even though he has to take care of physical needs with short-term flings). The hologram mocks the question and is very insulted you asked it of her in the first place.
Sora of Ever17 asks Takeshi this very question, which he interprets as mere curiosity. During her route she suffers a sort of breakdown/split personality when seeing Tsugumi and Takeshi together on the gondola where her emotional, irrational self and coldly efficient side start arguing.
Played for laughs in a science fair on The Fairly OddParents where Timmy's (now genius) Dad tries to convey the emotion of love to the scientific community. Cue a robot going "WHAT IS LOVE!? DOES NOT COMPUTE!" and blow up. Only to also have all the scientists in the audience go "LOVE? Is that an emotion?" and blow up as well.
Parodied in a Halloween episode of The Simpsons when Bart befriends a robot. It says something like "I can do a lot of things, but I cannot love". Bart replies:
I said I was human, not a girl.
Parodied again in "Last Tap Dance in Springfield" when Homer is watching 'Cyborganizer' a sitcom about a filing robot,
Cyborganizer: I can streamline any procedure, except this thing you call love.
Anime and Manga
This is essentially the plot of Macross/Robotech. The Zentraedi know nothing of love or sex; their genders are divided at all times. A woman singing is a valuable distraction, a kiss can bring down fleets, and a mere child can sufficiently creep them out. (Well, the kid was a half-Zentraedi with green hair, and that would freak anyone out.)
It should be noted however that technically, the Humans and Zentraedi in Macross are the descendants/creations of the same precursor race: the Protoculture. So the series falls under the human sort as well.
Oasis in Kyouran Kazoku Nikki's last arc came to Earth specifically to figure out what love is. She tries to ask Chika and Madara for advice, but this doesn't end well.
The eponymous character of Eureka Seven, being an Emotionless Girl representative of Starfish Aliens, is extremely confused when someone suggests she's in love with Renton. However, she seems to have figured out familial love on her own, since she adopted children and is very affectionate towards them.
The root of the conflict in DearS was that the title species incapable of loving.
In the Big Finish Doctor Who audio drama The Zygon Who Fell To Earth, a Zygon asks "What is this 'love'?" Another Zygon, who has been disguised as a 1980s record company boss, explains it's "a money-making scam of the humans".
Twelve To The Moon. The Moon aliens capture a courting pair of astronauts and study them to establish if they're a threat to their emotionless utopia. In the end they decide love has its good points and call off their genocide of the Earth. Well, that and a few atomic bombs dropped on them helped change their minds.
In World War, the Race is a sentient race that breeds through mating seasons, and so, have no tradition of "exclusive mating arrangements," or understanding of love. This leads to some minor misunderstandings when they conduct experiments on humans.
In Animorphs, the parasitic, mind-controlling Yeerks have no concept of romance -or even gender- in their natural form, since they reproduce by merging with two other Yeerks and then dissolving into hundreds of young, effectively killing the parents. There are at least two examples in the series of Yeerks who had human hosts betraying their superiors after being caught off-guard by their own emotions and falling in love with each other.
In another book of the series, Jake and Cassie manage to disable the warlike impulses of the entire Howler race by infecting their collective memory with its first exposure to love.
Isaac Asimov's short story What is This Thing Called Love? (or also Playboy and Slime Gods). A Take That story against Playboy magazine's story "Girls for the Slime God". The story is about an asexual-reproducting alien trying to explain his boss about Earth's concepts such as mating and gender.
The Atevi of the Foreigner series do not have words for "love" or "friendship", since they are biologically incapable of feeling any form of affection. The inability of humans to communicate these concepts is one of the major motifs of the series, as is the inability of humans to comprehend the nature of Atevi relationships.
In Sergey Volnov's Army Of The Sun, an alien is nostalgic for the days before humans taught the galaxy that there's more to mating than just the physical act. Now, a whole new set of rituals is added to the usual sex. Of course, this was more of a case of humans forcing their culture on other species due to a bad case of Humans Are Bastards.
In Mikhail Akhmanov's Invasion, the Human Aliens Faata live in a caste-like society, where each caste is genetically-engineered for a specific role. Everything in their society is rational, which means that there's no room for emotions like love. When Lieutenant Commander Pavel Litvin of the United Earth Forces is abducted by the Faata, he meets a lower-caste Faata female named Yo. When he later escapes, he finds Yo in a hibernation chamber that helps the Faata bypass a Pon Farr-like state. Since he takes her out of the chamber before it's done, she tries to jump him. Apparently, he decides that they have enough time to teach her about the human concept of sexuality. From that moment on, she forgets all about her Faata masters and follows the big, strong Earth-man. Later on, they get back to Earth and get married.
In "Four to Doomsday", the television serial, Monarch asks what love is after Nyssa mentions it.
Enlightenment: The exchange of two fantasies, Lord.
In "Enlightenment" Tegan is followed around constantly by Mr Mariner, who gives her longing looks and constantly tells her how amazing, unique and facinating she is, but when Tegan asks if he's in love with her, he replies "What is love? I crave existence!" Because he's actually an Eternal, a being from outside of reality, who can only interact with reality by using the memories and imagination of an Elemental (someone who exists in reality) who happens to find Tegan's mind the most interesting Elemental mind that he has encountered.
In the premiere of Farscape Aeryn asks John what compassion is. After he realises she's serious and describes it, she says coolly "I hate that feeling." In the next season she says she now would call some previously un-named feelings she had for a man in her past "love," but her loyalties to the Peacekeepers- and her desperation to get back to Prowler duty- were stronger. She had him arrested when she found out he was planning a mutiny.
Generally averted, however, and the Peacekeeper example is much more a matter of forced indoctrination than having no concept of love. Episodes that examine Peacekeeper society more in-depth show they know exactly what love is, they just go out of their way to stamp it out, such as forcing Xhalax Sun's Sadistic Choice when her commanders discovered she and her lover Talyn chose to have a child together out of love rather than assigned breeding.
Lister: Rimmer, there's nothing out there, you know. There's nobody out there. No alien monsters, no Zargon warships, no beautiful blondes with beehive hairdos who say, "Show me some more of this Earth thing called kissing."
There's one episode of Sesame Street where the yip-yip aliens discover two people in love and try to figure out what it is. Incredibly, the two lovebirds never notice the incessantly yip-yipping aliens right in front of them.
In the Star Trek: The Original Series episode "The Gamesters of Triskelion", Kirk's assigned gladiatorial trainer has lived her whole life as a slave and is ignorant of normal culture. She asks him, "What is love?" Kirk proceeds to show her.
Also, in the episode "By Any Other Name", the crew attempts to confuse the normally emotionless Kelvans by exploiting their apparent uneasiness with having assumed human form. Kirk attempts to seduce Kelinda, the female one, and while she initially realizes that's what he's attempting to do, she eventually starts to enjoy the new feeling, actually finding herself drawn to him. (As a bonus, Rojan, the leader of the expedition, starts to feel jealousy because of it, and eventually forgets about his superior weaponry that gave him an overwhelming advantage over Kirk the last time, lashing out at Kirk with his bare hands, a fight in which Rojan clearly does not have the advantage.)
Seven of Nine states in Star Trek: Voyager that, after cataloging the condition known as "love" in thousands of other species, the Borg consider it to be a disease, as it bears physiological resemblances to one. That doesn't stop her from having a Last Minute Hook-up, however.
Marvel's Shatterstar came to Earth as an alien gladiator, bred in a test tube for the sole reason of fighting in the pits on Mojoworld for the entertainment of the Spineless executives and only interested in fighting. As he lives on Earth for longer and longer, he's slowly learning about human culture, including human emotions and sexuality. This lead to a relationship with fellow X-Force and X-Factor teammate Rictor, as well as a sudden interest in Anything That Moves in the latter title.
Mass Effect's Commander Shepard lampshades this trope and Mars Needs Women in a bit of optional dialogue, commenting that, according to old movies, humans have everything an alien species could want: "Oceans, beautiful women, this emotion called love..." Which is in itself a direct shout-out to an old Star Trek episode, where Kirk invokes (and pretty much epitomizes) this trope to the Green-Skinned Space Babe of the week.
Played a different way with the salarian aliens who, thanks to their relatively short life expectancies, are not known for holding emotional stances for long periods of time (salarians have "reproduction contracts," not marriages, since they can't maintain feelings of courtship to serve as the icing on the commitment cake), not that they aren't completely incapable of it however. The most obvious example of this is perhaps the salarian talking to his asari step-daughter on Illium about buying a gift for his asari wife so she will have something to remember him by (as the asari have some of the longest lives of any species, up to around a thousand years).
Ultimately, this trope is largely subverted, as while some species' hats may preclude the existence of love, you can always find examples among any species that understand the concept.
In Homestuck, romantic love is an entirely foreign concept to cherubs, who are violent loners by nature. So far the sole exception to this is Calliope, and she hates it to the point of pretending to be a troll, simply because she finds their society preferable to hers in every way.
Inverted with the trolls: they understand romantic love quite well (though they call it something a bit different). However, they have three other kinds of romantic relationships that don't translate well to human relationships, making the human characters very confused at the trolls' social interactions and courtships. This also makes troll Love Charts rather complicated.
Ben often baffles other aliens with his strange, compassionate human ways in the Ben 10 series. In the first series, he spares the opponent he and Kevin defeat in a forced gladiator game, causing the runner of the games to muse, "Mercy? What a novel concept." In the Alien Force episode "Primus," Azmuth makes it clear that he would rather let himself and the three teens die than show Vilgax the secrets of the Omnitrix, and asks Ben what in the world he thinks he's doing when he starts making a deal with Vilgax to save his friends. He also basically teaches a Highbreed "what is this you call friendship" in a Strange Bedfellows episode.
To be fair to Azmuth, his willing to sacrifice all their lives probably had more to do with trying to prevent the fall of the entire galaxy, i.e. the greater good, rather than him not understanding the concept of friendship. Ben just wasn't willing to make that kind of sacrifice for the sake of the galaxy.
Parodied on Futurama, when a shipment of candy hearts is delivered to belligerent aliens as a peace offering; it backfires when the aliens are confounded by their cutesy messages.
Ndnd: "And what is this emotion you humans call 'wuv'?" Lrr: "Surely it says 'love'." Ndnd: "No, 'wuv'! With an Earth 'w'. Behold!" Lrr: "This concept of 'wuv' confuses and infuriates us!"
In another episode, Dr. Zoidberg gets love lessons from Fry
Zoidberg: "Hmm, this 'love' intrigues me. Teach me to fake it!"
Zoidberg's race in general seems ignorant to the concept of love
Fry: Tell her you just want to talk; it has nothing to do with mating!
Zoidberg: I just want to talk; it has nothing to do with mating! [to Fry] Fry, that doesn't make any sense!
Zoidberg: I'm confused, Fry. I'm feeling a strange new emotion. Is it love when you care about a female for reasons beyond mating?
Fry: Nope. Must be some weird alien emotion.
In the first episode of Futurama, Fry actually lampshades this trope when Farnsworth offers him a job aboard his ship, and Fry asks if they're going to "teach alien babes how to love".
Anime and Manga
Vinland Saga: When a Christian priest is asked in passing about what he considers valuable in the world, he of answers that 'love is the thing that makes all other things valuable'. The Viking marauders and mercenaries he's travelling with not only are confused, but have NO IDEA what he's talking about, and a few more curious ones ask for clarification on this "love" thing he mentions. He isn't really sure either and it is the question that makes him wander the world in search for an answer.
Rei Ayanami from Neon Genesis Evangelion had the unusual combination of a Crowning Moment Of Awesome and a Diabolus ex Machina in the form of this trope, when while fighting the 16th angel, she asked herself what love is, realized that she loved Shinji enough to sacrifice her life for him, and promptly did, all within the space of about a minute. Girl is fast.
Kaworu also does this in the manga, after ironically having Rei's love for Shinji essentially Xerox'd onto him by the 16th. He asks Shinji if what he's feeling is love and tries to romantically advance on him after kissing Shinji while he was hyperventilating.It doesn't end well.
Rebuild of Evangelion 2.0 handles the heavy Shinji/Rei subtext very well: at one point, Shinji makes lunch for Rei who reacts with a blush and thanks him; later on, she wonders why did she do that when she never thanks anyone. In another instance, Asuka questions Rei about her feelings towards Shinji and she responds that she feels "warm and content" around him but doesn't know why.
See the "Schizoid Personality Disorder" below.
In Full Metal Panic!, Sousuke for the majority of the story. He completely didn't understand what it meant for someone to be in love (as shown when Kaname was trying to explain to him what a love letter was, and what it means when a girl is in love with him). That part pretty much moves him from just being a Chaste Hero into being a human robot that doesn't understand the concept of "love."
Chane: Why? Why do these people do this for me? Even though we've just met? Even though we're not family. Why!?
Szilard's homunculus, Ennis did not understand love at all at first. Firo more hopes she'll catch on without needing to be taught. After about 50 years she apparently understands.
Subverted in Ayashi no Ceres, seeing as it was an assumption rather than a question, between Tooya and Aya right after their official first kiss. He gives a pretty damn heartwarming speech about it too.
Tooya: Before I knew it, I was worried about you. I unconsciously ran here to rescue you. This feeling I have for you might be what you call "love".
Count D, owner of the Pet Shop of Horrors, admits that love is beyond him. At least concerning people. Animals are something else entirely.
Count D: I do not understand love between people.
Because of her inability to love, Anri from Durarara!! has a difficulty with understanding this concept, and therefore she cannot tell apart the feelings she feels for Mikado, Masaomi, and Mika.
Near the end of the anime, Izaya states that it's not so much she's incapable of it but using Selective Obliviousness to avoid any potentially painful situation like what happened with her parents. Then again, it's Izaya we're talking about here. Coin toss for whether he was bullshitting or whether it's true.
In Simoun, Aaeru has to be specifically told by Neviril what that painful feeling in her chest is. It makes their mutual declaration of love immediately afterward all the more touching.
In Wild Rose, Mikhail was raised to show no emotion in order that his markings wouldn't appear. As a result he doesn't understand what separates love and indifference. In contrast, not feeling love is the only thing Kiri can't understand, which makes him want to teach him.
In Gosick, Victorique - before she was freed from her prison and locked up in the tower - seems to have trouble understanding it.
Victorique: Love... what's that? This is the first time I've heard that word since I was born.
In episode 17 of Muv-Luv Alternative: Total Eclipse, Cryska asks Yuuya about why thinking about him is causing both her and Inia to have lapses in their concentration. Yuuya, for whatever reason, says that those feelings are the result of stress from their superiors in order to perform better. At first Cryska seems to accept this answer, but then after seeing Inia admiring some flowers, he buys some for both of them, and then Lt. Cui shows up, gets upset at him and hits him twice, it only further confuses her as to why she feels this way towards him.
Because of how his commoner mother, the mistress of a noble, was treated and discarded, and because of how he was treated as a result, Glen of Bokura no Kiseki gained a cynical, skeptical outlook on love. He acknowledges that he likes Veronica, but he has no idea if those feelings are what would be called "love".
X-Men - X-23 was brought up as an assassin, and only her mother and sensei showed her any compassion or kindness during her childhood. And nobody ever told her about boys. As a result, she has no clue what is going on when she finds herself attracted to her teammate Hellion.
It gets creepier. After running away from her creators, she drifts into prostitution. So she knows all about the mechanics of sex, it's the emotional aspects that she has no experience with. On the other hand, X-23 still shows signs of loving her aunt and cousin when she stays with them, and hugs her cousin when they leave. Laura's reaction to the death of Sarah Kinney also suggests that she did love her mother as well... it is just when affection and physical attraction intersect that things actually fail to compute.
Handled matter-of-factly in Mark Evanier's miniseries Crossfire and Rainbow; lab-born genetically-engineered Rainbow confesses her dark secret to her prospective boyfriend: she can't make him happy because she doesn't know what love is! "Well," he says thoughtfully, "looks like I'm just going to have to teach you." (Later on, he correctly divines that she's also afraid she'll be bad in bed. Her: "How did you know?" Him: "You're not as different as you think.")
Mr. Evil'sOriginal Character Alex Sovereign is unable to understand love or any other emotion, able to see his body reactions in a more scientific approach than a emotional one. Though this is all due to the fact that his mother had his emotions lobotomized when he was born so emotions would not effect his decisions.
In Chasing The Dragon, Azula knows what love means and can recognize it when she sees it, but can't understand the thing itself or why people would do "illogical" things like risk their lives for its sake. As such, she's confused by her feelings for Ty Lee, since she doesn't understand what exactly she's feeling.
Alta in the movie Forbidden Planet, raised alone by her father, is unfamiliar in the way of kissing until crewmembers offer to explain to her.
Lt. Jerry Farman: It's nothing really personal — just a kiss.
Altaira Morbius: Hmm. But why should people want to kiss each other?
Mystery Science Theater 3000 uses the catchphrase "What is 'Kiss'?" to mock this trope when a character reacts to a kiss with confusion, usually due to the actor's failure to emote properly. The quote "What is 'Kiss'" is often attributed to Forbidden Planet or Star Trek, although the exact phrase was not used in either of these sources. The phase "what is 'kiss'?" is used verbatim in a skit of That Mitchell and Webb Look, with the discovery of the garden store natives. Followed a few seconds later by "what is 'handjob'?"
The beautiful but icy Estella from Great Expectations claims to Pip, her suitor, that she has no heart, implicitly as a result of Miss Havisham's raising of her as a breaker of men's hearts. When Miss Havisham entreats for her love and affection in return for hers, she coolly replies that she cannot give her back what she has never been given. She is later defrosted by Pip, if you follow the revised ending or movie adaptations.
Jonas of The Giver grows up in a false Utopian society where the word "love" has become obsolete. When he learns about it through memories received from the Giver and asks his parents if they love him, they admonish him for not using precise language and say that asking "Do you enjoy me?" or "Do you take pride in my accomplishments?" would have been better.
What makes it better is that they actually laugh and treat the question as meaningless. Jonas can't help but think that what he felt earlier was anything but meaningless. He realizes that further questions would also be met with either ignorance or programmed responses. It's also explained that there is no choosing of one's own spouses — everyone is paired up according to how "compatible" they are. Couples also don't have their own children and aren't even allowed to chose the ones they adopt.
The Bene Gesserit Question Book in Dune: House Harkonnen:
What is this Love that so many speak of with such apparent familiarity? Do they truly comprehend how unattainable it is? Are there not as many definitions of Love as there are stars in the universe?
Used in The Last Continent, with a twist: The questioner is the God of Evolution, and the explainers are a bunch of wizards who have managed to travel back in time to before sex was even invented. Ponder is trying to explain to the aforementioned god why things don't work in ones, and how babies could be made, but the conversation screeches to a halt when the topic of sex is broached. It is left to Mrs. Whitlow (the housekeeper of Unseen University who has been hauled along for the ride) to explain things, leading a few of the wizards to ask if anyone knows what happened to Mr. Whitlow.
In Cat's Cradle, a secretary relates a story of the time Dr. Felix Hoenikker bet her she could not tell him anything that was completely objectively true. When she responded with "God is Love", he simply asked "What is Love?" and considered the bet won.
Michael: You know, the feeling that you're feeling is just what many of us call... a "feeling".
Gob: It's not like envy, or even hungry.
Michael: Could it be love?
Gob: I know what an erection feels like, Michael. No, it's the opposite - it's like my heart is getting hard.
I'd say Dexter fits this one pretty perfectly, in the platonic way.
Dexter: I don't have feelings, but if I did I'd probably have them about Deb.
And again about his adoptive father
Dexter: If I could love, how much I would have loved Harry.
On The Odd Couple, Felix breaks up Oscar's ex-wife's wedding (which would have ended Oscar's need to pay alimony) because he realized they weren't in love. Oscar calls him on it and demands to know what love is: (paraphrased a bit)
Felix: "It's a strong, passionate feeling between two people"
Oscar: "I feel that way about you, but I'm pretty sure it's hate."
Princess Diana: When I look at Steve Trevor, I feel things. Things I've never known before.
In "Chrysaslis" on Star Trek: Deep Space Nine, Doctor Julian Bashir treats a woman named Sarina Douglas for catalepsy, a state in which she was basically trapped inside her own brain and unable to respond to the outside world. He then develops feelings for her, but when he confesses his feelings, she admits that she doesn't even know what love is. The two do eventually develop a relationship in the Star Trek: Deep Space Nine Relaunch novels.
The eponymous character in the Gilbert and Sullivan operetta Patience specifically does not, in the beginning, understand why all the other women love when it is clear that Love Hurts. When it is explained to her, she immediately sets out to fall in love:
Patience: I had no idea that love was a duty!
Happens all the time in Opera, in which a character will sing "Could this be love?" (usually in another language, of course), generally followed by "Yes — yes, it is!"
In Wario Land: Shake It!, Love literally is in one of the treasures chests in the game, and is actually represented by the word 'love' itself; but the treasure's listed name is merely "Something important." It is assumed that this name comes from Wario's own view of the subject.
Kingdom Hearts - Roxas has a diary entry titled, "What is love?" after witnessing a scene between Belle and Beast on one of his missions. Since he couldn't make sense of what Xaldin was saying about it, he tried asking Axel about it — but didn't get any real answer. He wrote that he felt like Axel kept dodging questions he didn't know the answer to just by saying that he could not understand it without a real heart. Xigbar tried to set Roxas and Xion up (they lookthe same to him), but while Roxas was fond of her, he could not understand what Xigbar was trying to do.
Everyone in Digital Devil Saga. Why? They are all AIs, created solely for combat, with no emotional responses included, leading to a battlefield full of emotionless androids based on certain humans. The Demon Virus kick-started the development of their personalities, up to character strengths and flaws, along certain viewpoints on the original people. It is specially poignant to see The Spock finally thaw and grasp the concept of honor and love, and everyone having to lose it all through an increasingly brutal chain of Heroic Sacrifices. Mind, it's also quite an emotional scene to see The Lancer struggle with love and jealousy when he has no idea of what the hell he's doing.
Saber of Fate/stay night has spent her entire life suppressing her emotions, so her feelings for Shirou leave her confused and angry. She realizes that he's important to her, but it takes a while for her to figure out why.
Rin Tezuka from Katawa Shoujo is heavily implied to be suffering from some kind of personality disorder (likely schizoid), and while she obviously loves Hisao, she has an extremely hard time comprehending the nature of their relationship and their own feelings. Leads to a minor tearjerker moment when, after having sex for the first time, Rin worries that now Hisao wouldn't be her friend anymore, since "friends don't do that".
Batman, who is notoriously very emotionally closed off on account of having witnessed his parents' murders, manages to fall in love in one episode of the animated series and is unable to comprehend the feeling, resulting in this funny exchange:
Bruce Wayne: Everything's changed for me these last few weeks. The pain of my parents' deaths... It's still there but it seems smaller. And there's a new feeling now.
Barbara Gordon: Which would be...?
Bruce Wayne: It's a lightness, a sense that things will work out for the best.
In The Fairly Oddparents: When Timmy made his dad super smart, he plans to dissect Cosmo and Wanda in a room full of scientists. When Timmy tells his dad about how much he loves his old non-smart dad, the scientists ask "What is love?" and they all explode.
Schizoids often feel love and devotion, but cannot express it in conventional ways. This is also the case with many autistics.
See the Rei example above.
It can also be a symptom of post-traumatic stress disorder: Although the affected person will still understand what love is, they may experience "emotional numbing", so that they are no longer be capable of feeling certain emotions, such as love or happiness.
In some cases, the person can feel it, but is unable to recognize it.
Anime and Manga
Ulquiorra in Bleach, although notably he isn't jealous of it...he's more annoyed by it. "You damn humans speak so easily of the heart . . . what is this "heart?" If I tear open your chest, will I see it inside? If I shatter your skull, will I see it there?
As he dies, he finally figures it out: "What is that? Would I see it if I cracked open your chest? If I broke open your skull, what would I see inside? You humans say the word so easily. Just like...Oh. I get it. This is it. This here in my hand. The heart."
The youko (fox spirit) Tamamo from Hell Teacher Nube couldn't even begin to comprehend how or why Nube was so determined to protect his students, much less why such drive gave him power beyond (arguably) more powerful entities. Therefore, he stuck around to see exactly how The Power of Love worked, and also to annoy Nube as the school's physician. The interesting part is that he became just as attached to Doumori Elementary and its students without him ever realizing it, and gained the same kind of determination and selflessness as Nube.
It came to a head when Tamamo exorcised an emotion-parasite yokai from a little girl, and, still wishing to explore emotions, attached it to himself. He was overcome with human feelings that overwhelmed even his demonic side.
Hanatsuki Hime: Siva, and arguably any of the other devils involved in making contracts with humans, want to experience this trope because the devils do not have emotions (or the emotions that humans have). It starts out as a game to relieve boredom and simply ends that way for most — for some, however, the trope gets played straight.
In Kamisama KissTomoe gets rescued by Yukiji actually Nanami posing as Yukiji and starts developing romantic feelings for her, something he had never experienced before. Given his normal attitude towards humans this leaves him rather conflicted and confused.
In [C] Control, Assets do not feel much emotion and do not understand most human concepts, though Q and Msyu do care deeply for Mikuni and Kimimoro respectively. When Msyu sees a kiss on TV, she's confused and asks Kimimoro about it. He awkwardly says it is what people do when they like each other 30 times as much as normal. In the final episode, Msyu and Kimimoro finally kiss, with her saying she likes him 40 times as much.
The Lord of Darkness in the movie Legend is "distracted" by the captured princess's beauty and innocence and advised by his mysterious 'father' to woo her into temptation. There follows probably the best (and most eloquently written) scene in the film, where the devil's seduction rather backfires when the newly-darkened Princess plays His Lovesick Evilness like a two string harp. note The first draft of the screenplay was very different: his pursuit of princessly love leads him to turning her into a bestial cat-woman and the two of them having lots and lots of sweaty monster sex.
Subverted in Jaqueline Carey's The Sundering, a story intentionally resembling The Lord of the Rings a great deal, but written from the villains' point of view. Satoris and his followers are just as capable of feeling and understanding love as any other being, they just happen to have made different choices.
In C. S. Lewis' The Screwtape Letters, the eponymous demon believes that to exist is fundamentally to compete with all other existence, and therefore the concepts of 'love' and 'unity' are dismissed by him (and all other demons) as nonsense. Consequently they are utterly unable to comprehend why God would do so much for the humans, because God doesn't appear to be profiting materially from it in any way.
At the other end of the spiritual spectrum, this trope causes trouble in Heaven in Neil Gaiman's short story "Murder Mysteries".
In Stephenie Meyer's short story "Hell on Earth", demons do know about love, but treat it as a very dangerous and unpleasant thing. They themselves try to avoid it like the plague, but the demon who's a main character is shocked to learn that some demons that are careless can still fall in love with mortals and give up their immortality as a result. At the end of the story, she is trapped in the power of an angel's descendant and begins to feel love as well. In a bit of a twist, she still is utterly miserable and horrified to be caught like that and the story ends with her desperately plotting on how to escape.
Angel. Illyria, having revealed that she can adopt the form and memories of her dead host 'Fred' Burkle, offers to do so for Wesley (Fred's former Love Interest) in order to understand intimate relationships. Wes is outraged by this suggestion and refuses to speak to her for a while.
The demon Anya in Buffy the Vampire Slayer, after she loses her power and is trapped in human form, falls in love with Xander. And apparently granting wishes to scorned women for thousands of years didn't do much to teach her about love.
In Kamen Rider Kiva, Maya grows increasingly curious as to why so many Fangires fall in love with humans, even knowing it'll bring eventual death. As a result, she seduces Otoya, Yuri's lover, but their relationship steadily grows more intimate and she eventually falls in love for real. Her husband, the 1986 King, is displeased. However, instead of simply killing her, he takes her Queen and Fangire powers. In the end, this ends up in our hero being born.
Sanctus from Devil May Cry 4mocks Nero and Credo on their efforts of rescuing Kyrie with "Held back by love" and "Love..? For a sibling?" respectively. While Sanctus was originally human, he's all but demonic by that point.
The trope is also featured in Disgaea 2 with Rozalin, with her defrosting treated in much the same way.
It gets spoofed in Disgaea 3, when Mao tries a more scientific approach to figuring out love.
Mao: Acidic or basic? What's it's formula?
In Star Wars: The Old Republic, the Jedi Knight Nariel Pridence, who the Republic smuggler meets on Tatooine, is so steeped in the Jedi teaching of emotionlessness that she completely (and usually comically) misses the intent of any flirting done toward her.
The Forsaken display this in the Warcraft series. One quest in World of Warcraft has a member of the race ask you to avenge his wife who was killed by his (still living) former best friend. He states that he can no longer feel love and is only able to feel revenge. However one seasonal quest chain on Valentine's day implies that the forsaken are still able to feel love in the same manner as they did in life.
Also, Sylvanas Windrunner, the Dark Action Girl leader of the Forsaken, still feels for her brethren and especially her still-living siblings. She's got a reputation to uphold, so she keeps the Defrosting Ice Queen moments to a minimum.
The Forsaken are pretty much a crapshoot in that regard. For every four or five rotten sociopaths you get one or two who just want to live out their free unlives while they can or aren't all that bad. Leonid Bartholomew of the Argent Dawn jumps to mind. This also seems to be more or less reflected in the Forsaken slice of the roleplay community.
In Vampire: The Masquerade, vampires are pretty much dead emotionally once they undergo the Embrace — they're left with fading memories of what they once felt, and the only things they truly feel are the anger, hunger, and fear generated by the Beast.
In Vampire: The Requiem, a vampire's emotions don't quite go away, but they work more like a form of "emotional replay," where they lock onto the closest emotion they felt in life that resembles what they should feel now. This can be a problem if a vampire who's just learned that his (mortal) mother died can only lock onto that time his pet hamster passed away... and it's stated that in cases where a vampire encounters emotions he never truly felt in life, severe cognitive dissonance will ensue.
Richard from Looking for Group is seemingly incapable of experiencing compassion for others, due to his nature as an undead warlock. His only joy comes from slaughtering others. In the video for "Slaughter Your World", Richard himself states that "I suppose that being undead there's not much to life/A soul is needed for loving, feeling/"
On the other hand, Richard does display an ounce of humanity on at least one occasion. His former minion, Hctib Elttil, was confident that the warlock would never break the curse that the imp placed on him and remain a weakened, miniature version of his former self forever, because the only way to break the curse was to perform a selfless act. Sure enough, Richard regained his former stature and power level by saving a small human child. It was indeed selfless, because at that point he didn't know how to break the curse.
He's also fond of the rabbit the rest of the group jokingly got him as a mount. At least, he keeps it with him, and hasn't immolated the little guy yet. In fact, after Richard was sent to another plane, the little rabbit started crying; they later had a happy reunion, complete with running to each other on the beach. Lets not forget his battlecry:
Richard: For PONY!
In a more comical variation, Richard overhears Cale and Benny resolving their unresolved sexual tension, mistakes it for murder ("It sounds like he's hurting her!") and gleefully offers to help hide the body.
Anime and Manga
In Hunter × Hunter, Meruem, a total Social Darwinist and someone who saw humans as merely food and his own kind as basicly slaves, both had no idea why he enjoyed his games with Komugi, which he always lost and should have been annoyed by, but also did not understand why he felt the urge to protect someone as weak as her from any harm. When he begins to figure out his feelings, he undergoes major Character Development.
Sleeping Beauty: Fauna points out that the few things Malificent doesn't understand are love, kindess, and the joys of helping others. Hence why Flora points out that if they shelter the princess themselves (selflessly helping someone at their own risk), Malificent wouldn't be able to expect it so easily.
Harry Potter - Harry is initially protected from Voldemort by the magical protection his mother's love gave him because Voldemort, who was raised as an orphan and appeared to be heading towards ruthlessness as far back as childhood, could not comprehend love. In the fifth book, Harry learns from a prophecy that love is the one power he has that Voldemort does not.
Furthermore, in a brilliant move, the only reason Voldemort never ever doubted Snape's loyalty was because Snape's staus as a mole was entirely motivated by love, the only thing Voldemort could not understand and would never take into consideration.
In the sixth book, it's revealed that Voldemort basically had no love in his life when he grew up. His father was under the influence of a love potion when he was conceived and his mother died instead of using magic to save herself to care for him. As a result, it is explained that he has absolutely no understanding of love or friendship and loves absolutely no one. It's probably because of this that he fails to realize that Harry's friends and loved ones will continue to fight in his name, even after Harry seemingly dies. A less extreme example is Bellatrix Lestrange who, according to Rowling loved no one except for her twisted obsession with Voldemort. Actually, a major theme in the books is love. If someone doesn't love or care about anyone at all, chances are they're totally evil.
In the first book...
Dumbledore: If there is one thing Voldemort cannot understand, it is love.
In the sixth book...
Harry Potter: ...I'll have "power the Dark Lord knows not", it just means - love?
In Baldur's Gate 2, Viconia does have a concept of what love is but, being from a race where sex is used for either only pleasure or to have power over somebody, is quite unfamiliar with the more intimate aspects, such as cuddling, and is quite confused when she starts to "feel an ache" whenever your apart.
Also, "The Beach" shows that she doesn't understand romance or flirting at all; her sales pitch is an outright We Can Rule Together because she doesn't have the slightest clue what else she can say to seem attractive.
In Gargoyles, it takes David Xanatos considerable effort to comprehend his feelings for Fox. It's actually discussed when he proposes:
Xanatos: "Marry me." Fox: "Are you serious?" Xanatos: "We're genetically compatible, highly intelligent and have the same goals. It makes perfect sense to get married." Fox: "True, but what about... love?" Xanatos: "I think we love each other... as much as two people such as ourselves are capable of that emotion."
And later on, he considers it a weakness, which Goliath calls him out on.
In My Little Pony: Friendship Is Magic, this turns out to be the cause of Discord's villainy. Having existed for God only knows how long and without ever having a friend, he simply didn't understand friendship and used his powers for nothing other than his own amusement.
Dead Master from Black★Rock Shooter cannot figure out why the eponymous character keeps holding out her hand as an invitation to fight, after the fight has already started. She also freaks out when she receives a Cool Down Hug due to her not knowing what the hell her enemy's doing. Though she could have just been expecting some sort of finishing blow.
In Memory Sorrow And Thorn, the Sitha Aditu befriends the young human Simon while the latter is in captivity in the Sithi's forest city. Due to her slightly longer perspective on life, she finds the human obsession with love and sex to be somewhat amusing, and teases Simon mercilessly to this effect. Later, she even goes so far as to break up Simon's would-be tryst with a peasant girl under the pretense of being his "fairy lover".
A for Andromeda. Fleming explains to Andromeda (a synthetic woman created and controlled by an alien-designed Master Computer) the difference between right and wrong ('nasty' and 'nice') by pinching and then stroking her. Later on Fleming grabs her for a snog, though by that stage she has already started to develop emotions, including concern for his life.
Fringe: The episode August is about an Observer who saves a girl from dying in a plane crash, in violation of the Observers' rule against interference, and eventually sacrifices his own life to protect her. As he's dying he explains why to September:
September: Who is she? Why did you save her?
August: I saw her many years ago. She was a child. Her parents had just been killed. She was crying. She... she was brave. She crossed my mind. Somehow, she never left it. I think... it is what they call feelings. I think... I love her. Will she be safe now?
September: Yes. You made her important. She is responsible for the death of one of us.
Later, in the episode A Short Story About Love, September seems to have started to understand the concept.
September: I have a theory, based on a uniquely human principle. I believe you could not be fully erased because the people who care about you would not let you go, and you would not let them go.
September: I believe you call it Love.
The phrase is referenced on Would I Lie to You? by Lee Mack to mock David Mitchell after he phrases a sentence strangely.
At one point in Narbonic, Mell says "Oh, Artie ... You understand everything except this thing called love." Actually, what Artie doesn't understand is the weird Foe Yay thing Helen and Professor Madblood have, and why Dave is attacted to a woman who uses him as a test subject. And he's quite happy not understanding these things.
Lampshaded and played with in Errant Story, where the elves' immortality doesn't allow them to grasp the concept, as Sarine points out. This doesn't stop her from putting the trope to good, if mocking, use with Jon. (Make the obvious substitution for "sarcasm" in the line Sarine quotes from the play.)