How to Detect Consciousness in People, Animals and Maybe Even AI

In late 2005, five months after a car accident, a 23-year-old woman lay unresponsive in a hospital bed. She had a severe brain injury and showed no sign of awareness. But when researchers scanning her brain asked her to imagine playing tennis, something striking happened: brain areas linked to movement lit up on her scan.

The experiment, conceived by neuroscientist Adrian Owen and his colleagues, suggested that the woman understood the instructions and decided to cooperate — despite appearing to be unresponsive. Owen, now at Western University in London, Canada, and his colleagues had introduced a new way to test for consciousness. Whereas some previous tests relied on observing general brain activity, this strategy zeroed in on activity directly linked to a researcher’s verbal command.