Since the early years of cinema, film-makers have shown how we might one day create – and be supplanted by – artificial intelligences.
Samantha, the sentient Siri-style OS at the heart of Spike Jonze's new film Her, is the latest attempt to depict an AI on screen – a machine consciousness so advanced, she can form a relationship with a human being.
AIs crop up throughout cinema, housed in clever computers or rogue robots. But whether they're antagonists or heroes, they can all be separated into one of four categories: artificial helpers, implacable machines, mad computers and (most interesting of all) learning intelligences.
So which are the most iconic? We've rounded up the 25 finest machine brains from cinematic history.
Helpful intelligences ("More tea, sir?")
In the future, we'll all have robot butlers. Or we will if science fiction cinema is to be believed. Oddly, many of these automated manservants are endowed with human (or near-human) intelligence, which seems rather cruel. Why create a robot slave and then make it aware that it's a slave, when it's unnecessary?
C-3P0 and R2-D2 (Star Wars, 1977-)
Star Wars' comic-relief duo were loosely based on a pair of bumbling peasants from the Akira Kurosawa film The Hidden Fortress; the gag being that we're seeing an mundane tale of empires, princesses and warriors through the eyes of the lowest members of society.
The Star Wars saga takes a similar tack; the droids may be humble servants, but they're our introduction to the Star Wars universe, and the focus of much of the action. Indeed, at the end of the final prequel, Revenge of the Sith, it's revealed that the one character who's aware of everything that's going on – all of the secret identities and hidden plans – is R2-D2. Who can't speak.
In the original script for Star Wars, C-3PO was meant to be a sleazy used-car salesman type; it was actor Anthony Daniels who created the sniffy, camp droid we all know and love. R2-D2's bleeps and bloops, meanwhile, were provided by sound design wizard Ben Burtt, who later went on to provide the voice for WALL-E.
JARVIS (Iron Man, 2008)
Tony Stark's ultra-efficient digital manservant began life in the comics as a flesh-and-blood butler – which explains the frankly daft acronym that is his name ("Just A Rather Very Intelligent System"). Ably voiced by Paul Bettany, he's a look at the future of Siri – controlling all your home automation, managing your life, and just a little bit sarcastic. The best bit? You can download JARVIS for your iPhone now.
Bettany looks set to be rewarded for his perseverance, too. After six years of waiting on Tony Stark hand and foot, it's been announced that he'll be playing the android superhero The Vision – an evolved version of JARVIS – in the upcoming Avengers sequel.
Robby (Forbidden Planet, 1956)
On the poster for 1956 sci-fi mundane Forbidden Planet, Robby the Robot is depicted spiriting away a scantily-clad maiden, like some sort of mechanical Frankenstein's Monster. He's nothing like as aggressive in the film itself; the film's (loosely) based on Shakespeare's The Tempest, with Robby playing the captive spirit Ariel to Dr Morbius' Prospero. Robby's more of a well-spoken (if somewhat smug) butler, who can speak 187 languages, knock up a designer miniskirt and produce food from his torso on command.
An enduring sci-fi icon, Robby's popularity stretched beyond Forbidden Planet; he's appeared in everything from The Twilight Zone to The Addams Family. Want your very own Robby? You can buy a full-scale version here, for a mere US$17,0000 (S$21,560).
Gigolo Joe (A.I. Artificial Intelligence, 2001)
Jude Law's sexbot won't just bring you tea, he'll bring you the whole service. Soundtracked by Dick Powell and choreographed by Fred Astaire; Law based his character on Astaire and Gene Kelly, taking dancing lessons to get the moves down pat.
The standout star of Steven Spielberg's AI: Artificial Intelligence, Joe was originally intended to be a soldier before sci-fi author Ian Watson suggested making him a robot prostitute. “I guess we lost the kiddie market," said original producer Stanley Kubrick, "but what the hell.” It's an unsettling look at a future in which humanity's outsourced all of its needs to robots, from emotional connection in the case of the robot boy David, to Joe's more physical services.