Rethinking Consciousness: When Science Puts Itself to the Test
What is consciousness? For centuries, scientists and philosophers have tried to understand how the brain creates our inner world—how neural activity translates into the taste of coffee, for example, or the sting of pain. Now, an international, theory-neutral research consortium, led by the Max Planck Institute for Empirical Aesthetics (MPIEA) in Frankfurt am Main, Germany, has put two of today’s most studied theories of consciousness to the test. The results, published in Nature, challenge core assumptions of both models and propose a new way to study complex scientific questions.
Digital illustration by Ana Perez Hernández (commissioned by Lucia Melloni)
Bernstein member involved: Lucia Melloni
The study was carried out by the Cogitate Consortium (Collaboration On GNWT and IIT: Testing Alternative Theories of Experience), which set out to rigorously test the Global Neuronal Workspace Theory (GNWT) and the Integrated Information Theory (IIT). Both theories aim to explain how conscious experience arises from neural activity, but offer starkly different answers. GNWT suggests that consciousness emerges when information is globally broadcasted across the brain, particularly in prefrontal and parietal regions. IIT, by contrast, places consciousness in the posterior cortex, where information is integrated into unified experiences.
Rather than working in isolation, theory leaders joined forces with an international team of researchers to design a study that would provide an objective, falsifiable test of their predictions. This adversarial collaboration—an approach first championed by Nobel laureate Daniel Kahneman—is a radical departure from the status quo in neuroscience, where confirmation bias and methodological silos have long hindered progress.
All hypotheses, analyses, and interpretations were preregistered in advance. Independent research teams conducted the study across seven laboratories worldwide. Using three complementary neuroimaging techniques—functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and intracranial electroencephalography (iEEG)—they tested a total of 256 participants. All researchers agreed beforehand to accept the outcome, whatever it may be.
“The strength of this approach is that we put the theories on the line—together,” says Lucia Melloni, co-senior author of the MPIEA. “This isn’t about crowning a winner. It’s about raising the bar for how we test scientific ideas.”
The results show that both theories were challenged. IIT’s key prediction, that conscious perception depends on sustained synchronization in posterior brain regions, was not supported by the data. In the case of GNWT, although some conscious information appeared in the prefrontal cortex, key features were missing, and the predicted “ignition” at the offset of the conscious experience could not be confirmed.
“This is a humbling reminder that even our most established ideas need to be rigorously tested. If we’re serious about understanding consciousness, we have to let the data lead,” Melloni continues.
Building on its previous work, the Cogitate team is already finalizing a second large-scale experiment to further probe GNWT and IIT. In a further commitment to transparency, the team is making the dataset freely available to researchers around the world.
“There are over twenty theories of consciousness out there. We’ve tested two,” concludes Alex Lepauvre, co-author of the MPIEA. “Now we invite others to take this rich dataset and help push the field forward.”
The paper was co-authored by 41 researchers, including nine co-first-authors. A full list of authors and contributions can be found on the consortium’s website.
