Neuro-sama is a VTuber who streams Minecraft and the rhythm game Osu! on Twitch. But unlike most anime avatars, she’s controlled by an artificial intelligence program rather than a human being. That makes her catnip for the denizens of Twitch chat, who can prompt her to respond with all sorts of questions ranging from innocent inquiries to 4chan trolling. Within the first few streams, someone had already asked Neuro-sama about the Holocaust. “I’m not sure if I believe it,” she said.
That was one of the more infamous clips that went viral online near the end of last month. Asked what she thought of women’s rights, she said they didn’t exist. How would she solve philosophy’s famous trolley ethical conundrum? Throw a fat person on the tracks. Often, however, she’ll go for long stretches without getting tempted by the chat into controversial or hateful remarks. In that way she’s an impressive simulacrum of a Twitch streamer straddling the chasm between repetitive banter and edgelord antics.
“The controversial things she says is due to the fact that she tries to make witty and comical remarks about whatever is said in chat, aligning AIs with human values is an ongoing area of research,” Neuro-sama’s creator, a game programmer named Vedal, told Kotaku. “To counter this, I’ve worked hard since the first few streams to improve the strength of the filters used for her. Data that she learns on is also manually curated to mitigate negative biases. We now also have a team of people moderating twitch chat who check everything she says.”
Neuro-sama isn’t Vedal’s first AI. In fact, a version of her was first created years ago with the explicit purpose of learning to play Osu!, a long running free-to-play rhythm game where you click shapes on a screen to the beat of anime music. While those sessions were also streamed, there was no avatar or interactive personality. Following last year’s surge of big-name VTubers, Neuro-sama builds on the Osu! skills of the original project with a fully-voiced Twitch performance that can riff with the audience.
It’s perfect timing given the internet’s recent love affair with the OpenAI-powered ChatGPT chatbot, where users could submit hyper-specific text prompts and receive uncannily artful responses in return. Vedal wouldn’t go into detail about how Neuro-sama learns and communicates, other than to confirm she relies on a large language model, which has been “trained on a large amount of text on the internet.” While not as sophisticated, the effect has been convincing enough to net Neuro-sama thousands of viewers per stream.
She also recently defeated the top-ranked Osu! player, Mrekk, on December 28, though some fans of the game debate whether the human opponent was ill-served by the song selection. Neuro-sama has since moved onto Minecraft, a much more complex game with far more possibilities for unexpected moments as players ask whether Melee is the best Super Smash Bros. and whether she’ll step on them. The moderation tools are apparently better now too.
“She picks what to respond to within a limited window,” Vedal said. “However it should be noted that she will not talk about the Holocaust as the filters have been improved.” Instead, she’s currently trying to learn how to sing.