02 July 2025
How a British AI pioneer helped to make the 1983 sci-fi classic "WarGames"
There aren’t many sci-fi movies as cleverly written and executed as the 1983 Hollywood classic WarGames, directed by John Badham and written by Lawrence Lasker and Walter F. Parkes. But it might not have been as good as it is if not for the input of the British AI scientist Donald Michie (1923-2007) and his knowledge of game-learning machines, especially computers that can play noughts and crosses.
Who was Donald Michie?
Donald Michie was a codebreaker at Bletchley Park (BP) during the second world war; after the war, a geneticist and later an artificial intelligence (AI) pioneer who founded the first department for machine intelligence in the world at the University of Edinburgh. He made significant contributions to all three fields that he worked in and was instrumental in institutionalising AI and machine learning (ML) research in the UK, and abroad.
A major part of his AI research focused on machines that could play games. However, one of his most famous achievements in this subfield of AI is MENACE (Machine Educable Noughts and Crosses Engine), a mechanical computer made of matchboxes and beads that could learn to play noughts and crosses. MENACE is now considered one of the first working examples of, what ML researchers call, reinforcement learning. This eventually led to the development of the BOXES algorithm by Michie and R. A. Chambers for learning of dynamic systems.
Therefore, it is no surprise that Universal Studios reached out to him when working on WarGames.
Dangerous games
If you haven’t seen it, be warned that there will be spoilers ahead.
WarGames tells the story of a young computer hacker, David Lightman (Matthew Broderick) who accidentally gains access to a US military supercomputer that controls the launch of nuclear warheads. He starts playing games with it thinking that it’s a game-playing machine, which makes the supercomputer run real war-game simulations and almost launch the nuclear warheads. Fortunately, Lightman, along with Prof. Stephen Falken (John Wood), the scientist who designed the supercomputer, makes it play a game of noughts and crosses against itself, which leads the machine to conclude that a Third World War involving nuclear warheads cannot be won, thus stopping it from launching the missiles.
It might be an exaggeration to call it sci-fi as it hits a little too close to reality than most sci-fi movies would. Although there is no public record of any supercomputer malfunctioning and almost launching nuclear warheads to start a world war, there have been a few mishaps in United States alone that have almost caused nuclear detonations, and one incident in 1983 when a Soviet early warning system gave a false alarm of a missile launch by the US.
The fear of the Cold War escalating to a direct nuclear war was alive and well when WarGames was released. However, that was only a part of the reason why the movie became a box office success and a cult classic. It was the presence of an ‘intelligent’ supercomputer that could play games and treat global thermonuclear war as a game, and act on its own to potentially end the world as we know it, that made WarGames such a compelling film.
Michie’s concern
WarGames tapped into a real concern that was prevalent at that time, regarding the increasing inscrutability and influence of large computers that were being used by big companies and government organisations for various purposes. This was something that Michie too was very concerned about and he points out in his correspondence regarding the script consultancy with Universal Studios:
We are all in danger from the current emergence of super-computers inscrutable to man. Very few are yet alert to the seriousness and nature of the peril.
This is not surprising coming from Michie, who had already been discussing the social risks of AI for over a decade by this point. In fact, he was the one who organised the first global conference on the social impact of AI in 1972 at Serbelloni in Italy1. In the years since then, Michie had raised some of his concerns regarding increasingly complex and sophisticated computers in several publications despite being a pioneer in the field. It makes sense why he was enthusiastic to collaborate on this sci-fi movie project, which was initially titled The Genius.
Main suggestions
In his correspondence, Michie points out five pages worth of technical inaccuracies in the draft script. Most of them are small details regarding the terminologies that are spoken about and technical issues in how the technology is used in various scenes. Michie recommended a lot of minor changes, for instance using the term “printer” instead of “teleprinter,” which was no longer used among the computing community by the 1980s. However, he also pointed out major technical errors, such as that a program once terminated would not have a fragment of itself accidentally re-animated when the computer goes online as was shown in one of the scenes in the draft script.
Although some of Michie’s minor suggestions have been taken into account by the scriptwriters, we can see that most of the technical inaccuracies he pointed out are still there in the final cut of the movie. This includes the premise of Michie’s main suggestion: to consider changing the climax sequence where the machine is self-playing a 3-in-a-row noughts and crosses to “learn” that it’s a game that cannot be won. Michie recommended changing it a game called 5-IN-A-ROW (sometimes called Peggity) as it would take much longer for the computer to self-learn how to play compared to noughts and crosses, which can be learned by a fast computer within seconds. This, in his view, would make the long climax sequence where the computer is learning to play the game more realistic. Moreover, Michie pointed out that the supercomputer “would try to establish the ‘no win’ property by logical proof,” rather than brute-forcing through various playing strategies as is shown in the movie. He states that a computer as sophisticated as the one shown in the movie would not use a ‘try everything’ strategy to learn how to play a game.
Crucial contribution to the script
However, one key suggestion of Michie’s that was taken into account by the studio and the scriptwriters was the technique by which David and Prof. Falken make the computer play itself. In the draft script given to Michie, the computer “somehow” starts self-playing, presumably without a prompt. Michie suggested changing the number of players to “zero” to make the computer play itself. This is what happens in the movie.
Michie also recommends changing the way the supercomputer abruptly stops trying to guess the launch codes of the missiles, as it was in the draft script. He instead suggests that the filmmakers show the computer generalise from the self-play sequence that ‘nuclear wars are not winnable’ and apply this to terminate the war game it was playing. He recommends David or someone else instructing the computer to do this, although this was not taken into account. In the film, the computer automatically generalises from the noughts and crosses self-playing that various real-world nuclear war-game simulations all end up with no winners.
Although Michie’s main suggestion to change the 3-in-a-row game to 5-in-a-row was ignored by the filmmakers, he himself points out in the correspondence that it is not necessary to fix this as ‘there is a risk of distracting from the gripping simplicity of the ending by fussing over side-issues.’ It shows his concern for how well laypeople could receive the movie and its main theme of the futility of nuclear war, rather than focusing too much on the technical inaccuracies or inconsistencies in the script.
Aswin Valsala Narayanan
The Donald Michie Papers at the British Library comprise two separate tranches of material gifted to the Library in 2004 and 2008. They contain correspondence, notes, notebooks, offprints and photographs and are available to researchers.
Aswin Valsala Narayanan is as PhD student at the University of Leeds and the British Library. He is on an WRoCAH Collaborative Doctoral Award researching the Donald Michie Archive, exploring Michie's work as an artificial intelligence researcher in post-war Britain.
[1] Rosamund Powell, “The ‘Artificial Intelligentsia’ and Its Discontents: An Exploration of 1970s Attitudes to the ‘Social Responsibility of the Machine Intelligence Worker,’” BJHS Themes, September 19, 2023, pp.1–15, https://doi.org/10.1017/bjt.2023.8.