Scientists have been divided for centuries by the question of what consciousness is. The two major theories have now been put to the test by a group of researchers, including neuroscientists Floris de Lange and Yamil Vidal from the Donders Institute at Radboud University, and have been found to be partly incorrect.
What transforms neural activity into seeing a face, hearing a melody or feeling the warmth of the sun? What consciousness is and where it is located, for example, remains a mystery. A group of scientists, the Cogitate Consortium, has now subjected two influential and contradictory theories about consciousness to empirical testing: the Global Neuronal Workspace Theory (GNWT) and the Integrated Information Theory (IIT). Neuroscientist De Lange: ’These are two leading theories that have mainly been studied separately, until now. The aim of this study was to try to compare them directly.’
Conscious experiences
250 participants were subjected to a whole set of advanced neuroimaging techniques, including functional MRI, MEG and intracranial EEG recordings from epilepsy patients. The researchers wanted to test various predictions of the theories, including where in the brain content of conscious experiences is represented and how different brain regions communicate to generate conscious experiences. De Lange: ’GNWT assumes that conscious experiences arise from activity in a network of "higher" areas (the "workspace"), including the prefrontal cortex. IIT, on the other hand, suggests that areas in the rear part of the brain are essential.’
One of the most important predictions of IIT failed. The research showed no sustained synchronisation between areas in the posterior part of the brain, the ’posterior hot zone’. GNWT was also seriously challenged: while some features of conscious experience were evident in activity in the prefrontal cortex, critical aspects of experience were absent. Moreover, a predicted burst of neural activity at stimulus offset, known as ’ignition’, was not found. De Lange: ’What I personally found surprising was that both theories were partly wrong. These experimental data therefore provide an impetus to go back to the drawing board to develop better theories.’
What now?
Rather than viewing these results as a setback, the researchers see them as a springboard for the future. The Cogitate Consortium is now analysing the results of a second large-scale experiment to further test GNWT and IIT. In addition, they are releasing their entire dataset to the scientific community, ensuring that researchers worldwide can retest, refine and expand their findings.
Literature referenceFerrante, O., Gorska-Klimowska, U., Henin, S., Hirschhorn, R., Khalaf, A., Lepauvre, A., Liu, L., Richter, D., Vidal, Y., Bonacchi, N., Brown, T., Sripad, P., Armendariz, M., Bendtz, K., Ghafari, T., Hetenyi, D., Jeschke, J., Kozma, C., Mazumder, D. R., ... Melloni, L. (2025). Adversarial testing of global neuronal workspace and integrated information theories of consciousness. Nature, 1-10. https://doi.org/10.1038/s41586-025-08888-1
