Mariana Lenharo
Nature 625, 438-440 (2024)
Neuroscientist Lucia Melloni didn’t expect to be reminded of her parents’ divorce when she attended a meeting about consciousness research in 2018. But, much like her parents, the assembled academics couldn’t agree on anything.
The group of neuroscientists and philosophers had convened at the Allen Institute for Brain Science in Seattle, Washington, to devise a way to empirically test competing theories of consciousness against each other: a process called adversarial collaboration.
Devising a killer experiment was fraught. “Of course, each of them was proposing experiments for which they already knew the expected results,” says Melloni, who led the collaboration and is based at the Max Planck Institute for Empirical Aesthetics in Frankfurt, Germany. Melloni, falling back on her childhood role, became the go-between.
The collaboration Melloni is leading is one of five launched by the Templeton World Charity Foundation, a philanthropic organization based in Nassau, the Bahamas. The charity funds research into topics such as spirituality, polarization and religion; in 2019, it committed US$20 million to the five projects.
The aim of each collaboration is to move consciousness research forward by getting scientists to produce evidence that supports one theory and falsifies the predictions of another. Melloni’s group is testing two prominent ideas: integrated information theory (IIT), which claims that consciousness amounts to the degree of ‘integrated information’ generated by a system such as the human brain; and global neuronal workspace theory (GNWT), which claims that mental content, such as perceptions and thoughts, becomes conscious when the information is broadcast across the brain through a specialized network, or workspace. She and her co-leaders had to mediate between the main theorists, and seldom invited them into the same room.
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Here's what the article highlights:
- Divisions abound: Researchers disagree on the very definition of consciousness, making comparisons between theories difficult. Some focus on subjective experience, while others look at the brain's functions.
- Testing head-to-head: New research projects are directly comparing competing theories to see which one explains experimental data better. This could be a step towards finding a unifying explanation.
- Heated debate: The recent critique of one prominent theory, Integrated Information Theory (IIT), shows the depth of the disagreements. Some question its scientific validity, while others defend it as a viable framework.
- Hope for progress: Despite the disagreements, there's optimism. New research methods and a younger generation of researchers focused on collaboration could lead to breakthroughs in understanding this elusive phenomenon.
