David Chalmers (left) and Christoph Koch. Photo: Jesse Winter/Nature
Neuroscientist Christoph Koch of the Allen Institute for Brain Science in Seattle and philosopher David Chalmers of New York University (NYU) announced the resolution of a 25-year-old scientific dispute about the nature of human consciousness. According to the journal Nature, at the annual meeting of the Association for the Scientific Study of Consciousness, the neuroscientist admitted defeat, but said he was ready to double down and make the same bet for the next 25 years.
In June 1998, Koch and Chalmers had a bet on a case of wine about whether scientists in the next 25 years will be able to scientifically explain how brain neurons "form" consciousness, or not? The neuroscientist Koch insisted they could, while the philosopher Chalmers was skeptical. The dispute was resolved experimentally.
Koch worked early in his career in the 1980s with Francis Crick, one of the discoverers of the structure of DNA. Scientists have set themselves the task of finding out whether consciousness can be reduced to a simple "neural correlate" in the same way that heredity was reduced by Crick and James Watson to a simple sequence of nitrogenous bases?
In order to scientifically settle the bet, scientists chose two of the most popular and influential hypothetical theories of consciousness and developed experiments that would have to disprove or confirm these theories. These were " integrated information theory " and " global workspace theory ".
The first assumes that the "quantity" of consciousness in the system can be measured, and it will be the higher, the faster and more efficiently specialized modules interact. In terms of this theory, consciousness is “a structure in the brain formed by a specific type of neural connectivity that is active as long as a certain sensory experience continues.” Such a structure is anatomically connected to the posterior cortex, in particular because the measure of neuronal connectivity in it is considered to be higher.
The second theory suggests that different processes in different parts of the brain compete with each other for access to the "workspace". The signal that wins this competition is "sent" throughout the brain through a system of distant connections, which means that we are aware of this signal. According to the global workspace theory, "consciousness arises when information is transmitted to different areas of the brain over a multiply connected network", and "information transmission occurs at the beginning and at the end of sensory experience." The theory assumes that the transmission of relevant information occurs through the prefrontal cortex, that is, in the front of the brain.
Scientists have developed a protocol for experiments to test these theories. Six independent laboratories performed measurements according to the protocol. Both theories were not entirely satisfactory.
The theory of integrated information predicted that there should be a stable synchronization between different areas of the brain, but it was not possible to observe it. The global workspace theory predicted that both at the beginning and at the end of sensory experience, the brain "notifies" its parts; in practice, scientists managed to fix the beginning of sensations, but not the end. Also, the experiment failed to reproduce some of the phenomena in the prefrontal cortex that this theory predicted.