Where in the brain does consciousness originate? Theories abound, but neuroscientists still haven’t coalesced around one explanation, largely because it’s such a hard question to probe with the scientific method. Unlike other phenomena studied by science, consciousness cannot be observed externally. “I observe your behavior. I observe your brain, if I do an intracranial EEG [electroencephalography] study. But I don’t ever observe your experience,” says Robert Chis-Ciure, a postdoctoral researcher studying consciousness at the University of Sussex in England.
Scientists have landed on two leading theories to explain how consciousness emerges: integrated information theory, or IIT, and global neuronal workspace theory, or GNWT. These frameworks couldn’t be more different—they rest on different assumptions, draw from different fields of science and may even define consciousness in different ways, explains Anil K. Seth, a consciousness researcher at the University of Sussex.
To compare them directly, researchers organized a group of 12 laboratories called the Cogitate Consortium to test the theories’ predictions against each other in a large brain-imaging study. The result, published in full on Wednesday in Nature, was effectively a draw and raised far more questions than it answered. The preliminary findings were posted to the preprint server bioRxiv in 2023. And only a few months later, a group of scholars publicly called IIT “pseudoscience” and attempted to excise it from the field. As the dust settles, leading consciousness researchers say that the Cogitate results point to a way forward for understanding how consciousness arises—no matter what theory eventually comes out on top.
“We all are very good at constructing castles in the sky” with abstract ideas, says Chis-Ciure, who was not involved in the new study. “But with data, you make those more grounded.”
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