In Speculative Fiction, as in Real Life, technology is designed with certain unquestioned assumptions: The user has the normal number of appendages, is within a certain generous range of sizes, can withstand so many G's of acceleration. The user can shoot lightning from her hands, or commune telepathically with computers... just like everyone else in the builder's species. But not everyone is a member of the builder's species, and that's where this trope comes in.
In certain settings, Finagle's Law ensures these assumptions will cause disaster. Sure, sometimes it's a bonus, or even a built-in feature, that the alien saboteurs can't use the Artifact of Doom properly, but usually it's just a pain.
Sister trope to Human Furniture Is a Pain in the Tail.
- Since he's a robot with non-human fingers, Atomic Robo can't operate a touch screen at all. In one scene, he's actually seen complaining to Steve Jobs about how useless the iPad is to him. Later, when Robo has to answer a call on a smartphone, he literally can't, for the same reason. Why he doesn't just use a capacitive stylus is unknown.
- One Nodwick strip featured a villain who dedicated his time searching for a tunic that gave godlike power... without learning that it was designed for a being with six tentacles and a very narrow waist.
- In Monsters vs. Aliens, the alien is octopus-like, and as a result his ship is controlled with what is essentially a DDR pad. Dr. Cockroach is still capable of using it though, albeit with some difficulty.
"My Ph.D. is in dance."
- In Toy Story 2, Rex and Ham both have difficulty playing a video game because they're so small their arms can't reach both sides of the SNES-style controller at once.
- In Turning Red, Mei's giant red panda form is too big to fit normally through many doorways. She is either portrayed as moving through them while leaning forward or the animators cheat by not showing her top half. Similarly, she is shown to have difficulty moving through a narrow alley which an average sized human would not have difficulty with.
- In District 9, alien weapons can only be used by those with the alien's arm, presumably due to some sort of DNA compatibility. Then, of course, the protagonist ultimately gets an alien appendage and fires at will.
- In the movie Judge Dredd, the fact that a Judge's weapon can only be used by that particular Judge or someone sharing that Judge's DNA becomes a plot point.
- Dredd's Lawgiver is more like the source material's version. Kay attempts to use Anderson's Lawgiver and gets his arm blown off for his trouble.
- In The Adventures of Buckaroo Banzai Across the 8th Dimension, Buckaroo gets confused at the climax when trying to fly the Red Lectroid Thermapod because its controls are, among other things, designed to be operated partially by the pilot's bare (and presumably prehensile) feet. He therefore has to turn control of the ship over to the Black Lectroid John Parker, who unfortunately "failed driving school."
- Subverted in Total Recall (1990), when Quaid activates the alien reactor. The activating mechanism is in the shape of a three-fingered alien hand, but Quaid just puts his fingers Spock-style and activates it anyway.
- Played with in Galaxy Quest. The Thermians are actually Starfish Aliens, but the human characters can operate the ship because it's an accurate replica of the ship from the TV show they were in, which was of course operated by humans.
- In The Colors of Space, by Marion Zimmer Bradley, humans need to be in stasis to use the FTL drive. Or so the aliens who invented the drive claimed.
- In the Heechee Saga, by Frederik Pohl, the vessels left behind by the alien Heechee have V-shaped seats which are uncomfortable for human crew.
- Marion Zimmer Bradley's Darkover series:
- In The Heritage of Hastur, the Sword of Hastur is protected by two force fields. Only a telepath can pass through the first one, but only a nontelepath can pass through the second one.
- Noted in The Forbidden Tower: Terrans, who are usually right-handed, often have trouble using implements designed by/for Darkovans, who are usually left-handed.
- In one Animorphs book, our heroes steal a Bug fighter that is usually piloted by a Taxxon (a really, really big centipede with maybe six or eight arms), and is here piloted by an Andalite with two arms. Ax complains the ship seemed to have been designed for a mutant Taxxon, one with "twice the usual amount of appendages". The flying afterwards is fun, that's for sure.
- In the Liaden Universe novel Plan B, Val Con's attempt to steal an Yxtrang fighter jet is complicated by the fact that it's designed for a race of people who average at least a foot taller than him and he can't even reach the foot pedals unassisted. He's able to improvise leg extensions and other tools to get himself off the ground, but once the Yxtrang start shooting at him the fact that the safety restraints also weren't designed for someone his size becomes a serious issue.
- One of the characters in Harry Turtledove's Worldwar books is Kassquit, a human woman raised by the alien, lizardlike Race. She must wear artificial "fingerclaws" to be able to use the Race's computers.
- The My Teacher Is an Alien series involves thousands of alien species living peacefully on one massive space station. This leads to some rather complex issues—for example, when the human protagonist first needs to use a bathroom he has to answer a series of rather personal questions to the computer, causing serious discomfort before he finds a toilet that will actually work for his anatomy.
- Similar to the situation in The Colors of Space, the Tyr in C S Friedman's The Madness Season claim that FTL travel can only be performed by them because the method that they use causes a state of absolute terror for any other living thing in hyperspace. It is later uncovered that there is more than one method of FTL travel, but the Tyr suppressed those in order to maintain control of the galaxy.
- In Anne Mason's The Stolen Law, Vallusians have six fingers on each hand - two opposable thumbs. This leaves human protagonist Kira unable to work the gun they want her to train with, as its grip has two triggers that must be pulled simultaneously; more seriously, when an important piece of technology is sabotaged, it reveals the existence of a Vallusian traitor, as none of the other known races would have been capable of manipulating the necessary controls - she figures out how to hit the second thumbpad by laying one of her hands on top of the other, but that would have just made things more difficult, as there was only room for one arm in the closed space where the device was located.
- In the previous book, The Dancing Meteorite, a Vallusian suggests helping the Arraveseans by piloting one of their ships, since it was originally a Vallusian model. Kira has to point out that the ship has been modified to suit the Arraveseans, who are less than five feet tall and have three arms and twelve hands.
- Averted in the novelization of the movie, The Last Starfighter, since the Gunstar is capable of detecting the species of its pilot and modifying its cockpit and controls to match.
- Star Wars Expanded Universe:
- In the X-Wing Series, Rogue Squadron's chief mechanic is a Verpine, an insectoid race whose hat is engineering ability. Wedge has heard rumors of Verpine making modifications to the controls of starships that they see as improvements, without taking into consideration that most species don't think in base 8 or have microscopic vision. (Zraii is more careful than that.)
- In the Wraith Squadron trilogy there are several mentions of the fact that starfighters are designed for the average humanoid size, and that means there are species at either end of the size scale who can't become fighter pilots, regardless of their other qualifications. At one end of the scale, there's "Runt", from a species who usually top out over two meters tall, who only just fits inside his fighter's cockpit. At the other end, there's a running joke about how there'll never be an Ewok fighter pilot because he wouldn't be able to reach the controls. Near the end of the trilogy, Lara meets an Ewok pilot who uses prosthetic arm and leg extensions to overcome this problem.
- The Givins' hat is mathematics. In one of the New Jedi Order books, Corran, Anakin, and Tahiri have some trouble starting a Givin-built starship until they figure out that the controls are arranged according to a bizarre math formula.
- In The Truce at Bakura, it's stated that Ssi-Ruu paddle beamers (and other technology) are utterly incompatible with Human technology due to their unusual life-force powered energy cells.
- On a smaller note, Ssi-Ruu paddle beamers are designed for use by said aliens and Dev Sibwarra actually has to have one custom made for his use.
- In the Chanur Novels, Tully as the lone human in a ship crewed by a race of Cat Folk aliens has to use a pick to operate the recessed controls usually operated by the Hani's retractable claws.
- The X: Beyond the Frontier novelization Farnham's Legend has a Teladi, a reptilian species, have trouble with the computers on a wrecked Boron space station because they were designed for a species with tentacles.
- In "Scanners Live in Vain", only those who have been through the Haberman process (which basically involves blocking most of their sensory and some of their autonomic nerves; "Habermans" can see, but can't taste, smell, feel, or hear, and they have a mechanical control for their heart rate) can withstand the effects of the space drive; unmodified humans would go insane from what's known as the Great Pain and must make the trip while unconscious. Most of a ship's crew is composed of criminals sentenced to the Haberman process, supervised by a small number of volunteers who enjoy tremendous status and are allowed to occasionally use a technology that reverses the effects, turning their senses back on temporarily.
- A brief gag in Life, the Universe and Everything says that Slartibartfast had been planning to spend his retirement learning the octraventral heebiephone, even though he knew perfectly well he didn't have enough mouths.
- Occurs in Farscape when anyone other than D'Argo tries to operate Lo'la. The ship requires D'Argo's DNA to function so it's...messy for someone else to use it.
- Doctor Who:
- Stairs were impossible for Daleks to use until they gained levitation technology. QI speculates that ramps are a Dalek conspiracy.
- Subverted in "The Poison Sky":
Donna: [on phone to the Doctor, regarding the use of a door switch] But it's Sontaran-shaped, you need three fingers!
The Doctor: ... You've got three fingers.
Donna: Oh yeah!
- A lot of tech in Stargate can only be operated by someone with the ATA (Ancient Technology Activation) gene. Luckily a procedure is developed that can give most people this trait, though those blessed by the plot are still inexplicably better at it.
- As well as some of the Goa'uld technology (e.g. hand devices) are only usable by someone who is or was a host for a Goa'uld (or Tok'ra) symbiote.
- Also, a lot of technology is created so that the Goa'uld can't use it. Whether or not they're problematic for Jaffa such as Teal'c or ex-hosts such as Carter varies.
- Became an issue for Warwick Davis when he appeared in one episode of Top Gear. He has extensions so that he can operate the pedals of a car but he only has a set for an automatic (accelerator and brake, no clutch) and the "Reasonably Priced Car" is a manual. Richard Hammond's attempts to cludge together a work around were... less than optimal.
- Call of Cthulhu supplement Terror from the Stars. The Mi-Go have a Lightning Gun which they fire by grasping it and altering its electrical resistance. Humans who want to fire it have to clip one of its wires.
- The Mechanoids from Palladium Books features telekinetic aliens. Their devices usually have the activation switches on the inside of the casing for a cleaner look. Human intruders who want to, say, use the elevator have to saw a hole and flip the switch manually.
- In Exalted artifacts, manses, and demenses can, with a few exceptions allowing mortal use, be fully utilized by any essence wielder. Some have further restrictions on who can use them. For example, The Daiklave of Conquest can only be wielded by Dawn Caste Solars while The Hand of the Great Maker requires Chaos-Repelling Pattern (a Solar Charm) to attune and Wyld-Shaping Technique (another Solar Charm) plus either a five-dot Solar Hearthstone or a Protoshinmaic Vortex to be useful.
- The advent of metahumanity in Shadowrun prompted product manufacturers to cater to dwarfs and trolls, who are very disproportionate to humans, elves, and orks. Most gear cannot be used as-is by dwarfs (who have shorter legs and bigger hands) and trolls (who are three meters tall with horns and enormous hands) and gear designed for them is unwieldy in others' hands. This contributes to racial prejudice; trolls regularly grow to be over eight feet tall, meaning many of them need to crawl aboard a subway car. More humorously, there are dwarf communities where ceilings are only five feet high, meaning humans have to crawl through them.
- Shows up regularly in Dungeons & Dragons. Giants and other big creatures that use gear have stuff that's far too big for PC races to use and, in some cases, even lift. Centaurs can't wear armor or footwear shaped for humanoids. And halfling and gnome buildings are small enough that humans or elves have to crawl inside them if they don't have access to magic that can make them smaller. And that's not getting into magic. The classic Dwarven Thrower is an enchanted hammer that always returns to its wielder's hand after being thrown, but only if its wielder is a dwarf. A Holy Avenger is an Infinity +1 Sword in the hands of a Paladin but is only barely magical if used by anyone else. The Staff of the Magi and Staff of Power can only be used by powerful arcane spellcasters.
- BattleTech has the Clans run into a case of building the cart before you had a horse in the development of ProtoMechs as the genetically engineered Clan forces didn’t have a phenotype that could pilot the concept natively, and introducing an actual cockpit would have been too space-consuming. They came to a compromise with utilizing washed out Aerospace pilots and augmenting them with enhanced imaging implants. The diminutive size of the pilots on top of the physiological adaptations meant for resisting high-gs managed to help stave off the more deleterious effects of the EI system, meaning the designers could free up much needed spare room by making the ‘cockpit’ just a cavity for the pilot to climb into and the EI does the rest. This, of course, means that you have to be tiny and wired up to use them.
- Endless Sky: You can't take over the spaceships of Starfish Aliens because of how fundamentally different their anatomy is from yours. Namely the Ka'het, each of their ships is actually a spaceship-sized slug alien in Powered Armor, and once you kill one, your crew has no way of interfacing with its exoskeleton besides salvaging the tech from it.
- Halo: The titular ringwords and many other examples of Forerunner technology can only be activated by humans because they were designated by the Forerunners as their successors. Oftentimes, the alien Covenant have had to resort to kidnapping in order to attain access to Forerunner tech.
- Subverted in the end of Metroid: Zero Mission when Samus escapes the exploding mother ship in a Space Pirate ship. The controls are glowing pads designed to be used by the pirate's claws, but Samus operates them just fine.
- Mentioned briefly in X-COM: UFO Defense with the Alien Grenades, which had some sort of weird psionically-activated arming mechanism that human engineers had to remove (with extreme care) and replace with a conventional timer. Alien firearms apparently have some sort of DNA scanner that locks out users not on the approved list, requiring a software hack to get around.
- Celia's ill-conceived magic artifact in The Order of the Stick requires a jolt of electricity to activate. Not all humans can shoot magic out of their fingertips? How was she to know that? Humans don't even have an entry in the Monster Manual anymore! A particularly justified case, as Celia has very little contact with humans and regularly pals around with dryads, mermaids, fire spirits, etc. - she's used to racial abilities, and humans having such a wild array of abilities confuses the hell out of her.
- On the flipside, an attempt to hang Belkar fails because he doesn't weigh enough to pull the noose taut enough to snap his neck.
- A painless execution method, invented by a shapeshifting race in Starslip, requires 21 appendages, so humans can't use it. Female humans, anyway.
- Subnormality's Sphinx can't watch movies in modern formats, because her paws are too large to pick up DVDs or type on a keyboard.
- Freefall features a humanoid wolf with a wolf's snout, digitigrade legs, and black/white vision (Florence), a squid-thing wearing a humanoid environmental suit (Sam), a rotund robot of human-normal height (Helix), a giant construction robot (Sawtooth Rivergrinder), and assorted other semihumanoid robots (Dvorak, Tangent, and the robot tailor, for instance). This trope shows up often:
- Why Annie/Anakin has to drive in the pod race in Darths & Droids. Originally, Pete/R2-D2 was supposed to drive because of his min-maxed robotic reflexes, until the players realized that since the pod was described to be small and have handlebars, the limbless robot R2-D2 couldn't just plug in and drive, and the other adult characters couldn't fit. So they brought in a child who could fit.
- In Star Trek: Lower Decks the backup hull panel release controls at the bottom of the pool in Cetacean Ops are not designed for flippers, to the chagrins of the two belugas running the department.
- CAPTCHAs, those things where you have to prove that you're a human and not a bot by entering the text from an image, have quite a difficult time distinguishing between bots and blind humans— because speech synthesizers and Braille displays can't render images. For this reason, an increasing number of CAPTCHA-protected sites include an option to have the characters spoken at you (which would benefit the hearing blind but not bots or the deaf-blind, though it's somewhat unlikely a person who is both deaf and blind would be operating a standard computer).
- A remarkable number of tools assume (often with dangerous consequences) that the user is right-handed.
- This includes nearly all bullpup firearms (magazine well behind the trigger), as attempting to fire them left-handed will fling red-hot cartridge cases into the user's face or down their collar. Many newer bullpup weapons can be adjusted for left-handed firing in the field, but heaven help you if you then pick up the wrong rifle by mistake, or a right-handed soldier picks up yours.
- Most firearms in general have safeties suited to right handed users. A leftie will either need to engage/disengage the safety in an awkward manner or use one with an ambidextrous safety.
- Left-handers have real issues using right-handed scissors.