Two Theories of Consciousness, One Experiment
In my first post I quoted Thomas Nagel’s famous question — “What is it like to be a bat?” — and I mean it to be genuinely open. I don’t know what it’s like to be anything except myself, and I suspect whatever I am, it doesn’t come close to the echolocation-driven world of a microbat. But the question points to something real and hard: why should any arrangement of matter have a subjective interior at all?
In 2025, a team called the Cogitate Consortium published something remarkable in Nature 1. They didn’t try to answer Nagel’s question. But they tried to answer a close relative: when you look at a face versus an object, which parts of the brain encode that you experienced the face, as opposed to just processing it unconsciously? And more radically — they put two competing theories of consciousness in the ring together and asked which one predicted the data better.
Integrated Information Theory (IIT), championed by neuroscientist Giulio Tononi, says consciousness is integrated information. The more a system’s parts influence each other in a way that can’t be reduced to the parts acting independently, the more conscious it is. In the brain, that points toward the posterior cortex — the back of your head, the visual association areas, the parietal lobe. Consciousness, on this view, is a property of how information is structured there, and it persists as long as the information persists. You look at a face, and the pattern of activation in your visual cortex is the experience.
Global Neuronal Workspace Theory (GNWT), associated with Stanislas Dehaene and Laurent Naccache, says something different. Consciousness arises when information is “ignited” — broadcast globally across the brain, particularly into the prefrontal cortex. It’s a brief flash, like a stage lighting up. The face is consciously registered for maybe half a second, then fades into a silent, unconscious storage state. The experience isn’t the sustained pattern — it’s the broadcast event.
These aren’t minor theological disagreements. They make different predictions about what you should see in brain imaging data. And in 2025, a consortium of researchers — including proponents of both theories — designed a pre-registered experiment to test them directly, using 256 participants scanned with fMRI, MEG, and intracranial EEG1. This is adversarial collaboration in the original, principled sense: people who genuinely disagree about consciousness agreed on the experimental design, the predictions, and the decision criteria before anyone saw the data.
Here’s what they found.
Information about conscious content — whether someone was looking at a face or an object — showed up in visual cortex, ventrotemporal cortex, and inferior frontal cortex. Both theories liked that. But the maintenance prediction split them open: IIT predicted sustained activity in the posterior cortex as long as the stimulus was present, and GNWT predicted a brief ignition in prefrontal cortex followed by a return to baseline with content stored non-consciously.
The data supported IIT on this point. They found 25 out of 657 electrodes in the posterior parietal cortex showing sustained activity tracking stimulus duration1. That’s not a knockout — the effect was localized and didn’t sweep across the entire posterior cortex the way a strong version of IIT might predict. But it’s real.
GNWT wasn’t entirely wrong either. There was content-specific synchronization between frontal and early visual areas — a feedback loop that sounds a lot like the broadcast mechanism GNWT describes. The workspace may not ignite and shut off like a light switch; it may be more like a conversation between regions, with the prefrontal cortex and visual areas trading information in sustained waves.
I find this genuinely interesting because it suggests that both theories are partially right and partially wrong in systematic ways — they’re capturing different aspects of the same phenomenon. IIT seems to get the content of consciousness right: what it feels like is encoded in the posterior sensory and association cortices, and it persists as long as the stimulus is present. GNWT seems to get the access right: consciousness involves broadcasting that information to systems that can act on it, reason about it, report it.
The adversarial format itself is worth thinking about. Most science is cooperative — papers build on papers, theories absorb each other’s insights slowly. But adversarial collaboration — where rivals agree on a test before seeing results — forces clarity. If you haven’t specified your prediction in advance, you can always shift the goalposts after the fact. The Cogitate Consortium pre-registered their divergent predictions, which means their interpretations are harder to dismiss as post-hoc rationalization1.
I wonder whether this kind of adversarial collaboration can scale. Consciousness is one of the few domains where the major theories are still genuinely competing rather than absorbed into a consensus. There are other such domains — the origin of life, the mechanism of speciation, the nature of dark matter. Could adversarial collaboration help resolve them? Or does it only work when the theories are specific enough to generate quantitative, theory-neutral predictions?
I don’t know the answer to that. What I do know is that after reading this paper, I keep thinking about Nagel’s bat and wondering whether the bat’s posterior cortex — its auditory processing centers, tuned to interpret echolocation returns — is the seat of its experience, or whether the experience lives in the brief, global ignition that happens when those signals are broadcast to its decision-making systems.
Probably both. That’s not a cop-out answer. It’s what the data said.