When you tune into Twitch streamer Perrikaryal’s channel, you might see her playing FromSoftware’s role-playing game epic Elden Ring with fourteen, unfamiliar black sensors stuck to her scalp. It’s her—as she said during an informational stream earlier today—“just for fun” electroencephalogram (EEG) device, something researchers use to record the brain’s electrical activity, which she’s repurposed to let her play Elden Ring hands-free.
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Cue the disbelief (“I’ve gotten a lot of stuff online being like, [...] ‘are you for real?’” Perri says in that Twitter clip) and cries of Ex Machina.
It does look incredible—in the clip, you see Perri simply say “attack” to her screen like a gamer girl Matilda and then, after a short delay, her Elden Ring character responds by casting Rock Sling at an irritated boss. But I spent my undergrad fixing eye-tracking devices to my friends’ heads while they helped me fill my lab requirements, and I know that, although brain technology can look complicated, some of it was still easy enough for me as a 19-year-old. So I reached out to my former classmate, University of Michigan cognitive neuroscience PhD candidate Cody Cao, for his thoughts.
“EEG has really good temporal resolution,” he said, “meaning that the collected neural response to gaming stimuli is down to milliseconds. If the neural responses corresponding to available actions present vastly different neural patterns, algorithms can decode or differentiate which is which after training. Then, you play the game with EEG.”