Consciousness may become a mystery, but that doesn't mean that neuroscientists have not explained anything about it. And it's far from there.
“There are already many theories in the field of consciousness, so no more theory is needed,” says Oscar Ferrante, a neuroscientist at the University of Birmingham.
If you are looking for a theory that explains how our brains produce subjective and inner experiences, you can check out adaptive resonance theory. Or consider dynamic core theory. Don't forget about the theory of primary expression, not to mention the theory of semantic pointer competition. The list continues: A 2021 survey identified 29 different theories of consciousness.
Dr. Ferrante belongs to a group of scientists who want to reduce that number. However, they face a sudden challenge thanks to the way scientists often study consciousness. They devise theories, carry out experiments, build evidence, and claim they are superior to others.
“We are not encouraged to kill our ideas,” said Lucia Meloni, a neuroscientist at the Max Planck Institute for Empirical Aesthetics in Frankfurt, Germany.
Seven years ago, Dr. Meloni and 41 other scientists embarked on a major study of consciousness that they wanted to break this pattern. Their plan was to bring together two rival groups to design an experiment and see how well both theories worked in predicting what would happen in the brain in a conscious experience.
A team called the Cogitate Consortium released its results in Nature magazine on Wednesday. But in the process, this study became the subject of the same sharp low-bowed conflict they wanted to avoid.
Dr. Meloni and a group of like-minded scientists began planning their research in 2018. They wanted to try an approach known as hostile collaboration in which scientists with opposite theories join forces with neutral researchers. The team chose two theories to test.
One called the Global Neuronal Workspace Theory was developed in the early 2000s by Collège de France of Paris and fellow cognitive neuroscientist Stanislas Dehaene. Their theory argues that when the main areas in front of the brain broadcast sensory information across the brain, we consciously experience the world.
Another theory developed by the University of Wisconsin and his colleague Giulio Tononi is based on the name Integrated Information Theory. Instead of doing certain things to assign consciousness to specific parts of the brain, this theory begins with a fundamental feature of conscious experience. For example, they feel unique to themselves, and are rich in details that form a consistent, complex, unified whole, like Marcel Proust's memory experience crushing Madeleine.
The researchers then asked what physical networks (such as the brain) could produce the experience. They concluded that a large amount of information must be processed in many different compartments, and that it must pass the information to other compartments and create an integrated experience.
The Cogitate Consortium mapped experiments that could test both theories. The two theories champions supported it.
“It was especially good because it was the first time these people tried to resolve differences rather than doing this parallel play,” Dr. Meloni said.
But she and her colleagues knew that hostile collaboration would be a big job. They recruited many young researchers, including Dr. Ferrante, and then spent two years designing experiments and placing lab equipment through test execution. Since the second half of 2020, they began scanning the brains of 267 volunteers and worked in eight labs in the US, Europe and China.
Researchers have forced volunteers to play video games designed to measure their conscious perception of seeing things. In one such game, participants caught a colored disc when they became striped. Sometimes, blurry faces drifted across the screen, and the volunteers pressed buttons to indicate what they had noticed.
For maximum understanding, researchers used three different tools to measure brain activity in volunteers.
Some volunteers who had undergone epilepsy surgery agreed to temporarily insert electrodes into their brains. The second group scanned the brain with an fMRI machine where the brain measured the flow of the brain. The researchers studied a third group with magnetic EEGs that record the brain's magnetic field.
By 2022, researchers had moved to analyzing data. All three techniques provided the same overall results. Both theories made some accurate predictions about what was happening in the brain as subjects consciously experienced the photograph. But they also made predictions that turned out to be wrong.
“Both theories are incomplete,” Dr. Ferrante said.
In June 2023, Dr. Meloni presented the results at a meeting in New York. And Cogitate Consortium submitted the results online and submitted them naturally, hoping that the journal would publish the paper.
Hakwan Lau, a neuroscientist at Sungkyunkwan University, was asked to serve as one of the reviewers, but made a negative judgment. He felt that the consortium did not carefully lay out where in his brain it would test the predictions of each theory.
“It's difficult to make a compelling claim that the project is testing theories in a truly meaningful way,” Dr. Lau wrote in a July review.
Dr. Lau, who pioneered his own theory of consciousness, posted his assessment online that August. He later helped write an open letter criticizing both Cogite's experiments and integrated information theory. A total of 124 experts signed the work.
The group called “IIT agreed” and directed much of its criticism towards integrated information theory. They call it pseudoscience, citing the withered attacks scientists have made in recent years on theories.
These critics pointed out that integrated information theory is more than just a theory of how our brains function. If a system that can integrate information is conscious, the plant may at least be a little more conscious.
Critics argued that Cogitate Consortium's experiment did not test the underlying aspects of the theory and therefore did not respond to its claims. “As researchers, we have an obligation to protect the public from scientific misinformation,” wrote Dr. Lau and his colleagues.
Their letter, posted online in September 2023, led to a storm of debate on social media. The authors wrote commentary to explain their objections in greater detail. It appeared in Nature Neuroscience magazine last month.
Dr. Tononi and his colleagues responded with a retort in the journal. The concerning letters of IIT “had a lot of enthusiasm and little fact,” they wrote, and the new commentary “attempts damage control by adding a veneer of Polish and the philosophy of science.”
In the meantime, Cogitate Consortium Paper was still going on through peer review. When it finally came out on Wednesday, it continued to draw divided opinions.
Anil Seth, a neuroscientist at the University of Sussex, was impressed by the scale of the study and the discovery of shortcomings in each theory. “I'm happy to see that,” he said. “That's an incredible job.”
However, concerning critics of ITT were in their first opinion. The experiment was not a test for either test, as Joel Snyder, a psychologist at the University of Nevada in Las Vegas, argued that the predictions made by each team could have been generated from other theories.
“It's going to cause confusion,” Dr. Snyder said.
In the email, Dr. Lau observed that new research does not seem to narrow down the long list of consciousness theory. “Recent discussions have made me not the impression that these issues have done anything to the theory,” he wrote.
But Dr. Seth still saw the value of pitting opposing theories against each other, even if scientists were not led to kill their ideas. “The best thing we can expect from a successful hostile collaboration is that others may change their minds,” he said.
