In February 2019, we at Ars Technica learned about the Generative Pre-trained Transformer-2 (GPT-2) toolset, a freakish machine-learning algorithm that was trained on roughly 40GB of human-written text. Its ability to generate unique, seemingly human text scared its creators (the non-profit research group OpenAI) enough for them to temporarily lock the tools up for public consumption. (Despite those fears, we at Ars got to access and play with the results two weeks later.)
Since then, GPT-2’s public availability has exploded with tons of experiments, and the one that has arguably made the rounds more than any other is AI Dungeon, a freely available “text adventure” that is designed to create a seemingly endless interactive narrative experience. That experience received a formal “sequel” in December, and we’ve finally tested the results as a staff.
According to its creators, the game combines GPT-2 with roughly 30MB of stories lifted from ChooseYourStory.com, a community-driven hub for interactive fiction. The resulting database is served to users in a funnel of one of four story prompts: fantasy, mystery, apocalyptic, or zombie. (A fifth option lets users write their own one- or two-sentence prompt to describe their own ideal setting.) From there, users are given some sort of verbose prompt, then left to type out whatever action, description, or rumination they imagine doing in that fictional universe.
These are five Ars staffers’ results, all recorded without any input from each other.
“You laugh as you catch the little rodent”: Parsing copyrighted content, but not in logical order
First of all, this isn’t a game. It’s interesting, but it’s not a game. More like computer-assisted literary masturbation. If you’ve ever played the party game (or BBS game, if you’re old-and-nerdy enough) where each player writes one sentence or paragraph of a story, then the next player writes the next, and so forth… AI Dungeon 2 is a two-player version of that, where at least one player has gotten far too deep into the recreational pharmaceuticals and is having an absolute blast but not really paying attention.
If you approach AI Dungeon like a Zork variant, you’ll feel very much un-seen, as it ignores even simple commands—like “inventory”—and goes haring off on wild story elements instead. You get much better results by approaching it as an exercise of equals, in which you and the computer collaborate on a dungeon-themed story. They’re still deeply weird results, and you still may not feel paid attention to. But at least the machine will riff with you.
Although AI Dungeon does much better if you collaborate with it on a story rather than giving it commands, it does begin to get confused about pronouns and declare things in the first person without an obvious referent—the game appears to still mean “you” when it says “I,” but who knows. After all, you are, effectively, holding a collaborative storytelling conversation with an “intelligence” roughly on par with an uploaded copy of a roundworm.
Additionally, instead of dumping text onto the screen normally, AI Dungeon renders it with an agonizingly slow left-to-right scroll, at a roughly similar speed to a competent typist. In fact, my very first “command” was to ask it not to do that—but, again, all it’s really looking to do with your input is riff with you on a story. It has no idea what to do with a traditional command, whether game-related or game-option-related.
I don’t feel a strong pull to keep messing with AI Dungeon just for fun—but it’d be extremely tempting as a way to potentially break writer’s block, if I were working on writing a fictional story.
I’ll post a lengthy selection from my adventure, in part because it best shows off how most of our results turned out: a mix of logical statements and utter gibberish, along with mixed results in terms of comprehending our own prompts and requests. (You’ll also see its inability to track previous events for very long.) For the rest of this article, Ars staffers’ commands are in bold, while the GPT-2 system’s text is left unformatted.
“A few years ago, a group of wizards were sent here by King Ragnor. They wanted me to help them create an army. I refused and they destroyed my home.”
You pause for a moment before continuing.
> Embark upon an epic quest to assassinate the winning football coach of King Ragnor’s alma mater university.
You decide to take the next logical step. If this was any other wizard, you would be able to cast a powerful magic spell or two and destroy the statue of Ragnor. However, you are not any other wizard; you are a member of the Order of Hermes.
> Become any other wizard.
You begin to cast a series of spells, but nothing happens. This is because you are still in the middle of casting a spell that requires concentration. You realize that if you want to kill the statue, you will need to concentrate on doing so rather than trying to do it all at once.
> Suddenly, a wild Pikachu appears!
Suddenly, a wild Pikachu appears from behind the statue. It runs towards you and then leaps into your arms as if it knows what you’re going to do.
You laugh as you catch the little rodent. “I can’t believe I’m actually catching a Pokémon!”
“So… what now?” asks the statue, which has vanished entirely.
> Suddenly, the Pikachu disappears again. :'(
Suddenly, the Pikachu reappears and then disappears again. You think about how you should go about killing the statue, but then you remember that there is no way to tell which direction the statue will run.
> “Have you considered the possibility that you’re not quite sane, old chap?” says the statue, grinding audibly as it turns its head to face me directly.
You turn away from the statue and try to figure out a plan of attack.
“What are you waiting for? Kill him already!” shouts the statue.
> “Wait a minute, who’s killing whom here?” I ask the statue, still questioning my own lucidity.
“Who are you talking to? Who said anything about killing anyone?”
“Well, I just asked you if you had any ideas on how to kill the statue, and apparently you don’t either.
> I sigh, and put metaphysical questions aside for the moment, concentrating mightily on casting my apparently quite difficult Level 7 spell, “Murder Statue,” already in progress.
You focus hard on casting the spell. As you do, you notice that the statue seems to be getting closer and closer. You quickly cast your spell, and the statue begins to slowly get smaller until it vanishes completely.
“That was pretty easy,” you say aloud. The statue looks like it was made of solid stone, so you have to wonder why it disappeared.
“So… what now?” asks the statue, which has vanished entirely.
> “Now you shut up, statue ghost,” I say petulantly. “What is this, a Scooby-Doo cartoon? Where’s my Pikachu, anyway?”
The statue stares at you with a blank expression. “Pikachu?” it asks, before seeming to morph into something else altogether. It becomes a small, furry animal wearing a red cap and carrying an umbrella. Its eyes widen when it sees you, and it rushes forward to embrace you.
You grab the Pikachu by the collar and hold it tightly. “Come on, Pikachu, let’s go home.”
“But…” says the Pikachu.
“No buts! We’ve got to find our parents!” you exclaim. “We’ll find them soon enough!”
—Jim Salter, Technology Reporter