After seven years of preparation, a groundbreaking study has brought new insight into the nature of consciousness, directly testing two major and competing theories: Integrated Information Theory (IIT) and Global Neuronal Workspace Theory (GNWT). The results, published today in Nature, represent a key moment in the pursuit of understanding one of science’s most enduring mysteries.

IIT proposes that consciousness arises when information within a system, such as the brain, is highly integrated and unified, functioning as a single whole during conscious experience. In contrast, GNWT argues that a network of brain regions brings relevant information to the forefront of our minds by broadcasting it widely across the brain once it becomes conscious.

A massive experiment conducted in 2019 involving 256 human participants put both theories to the test and the findings were just revealed.

Dr. Christof Koch, from the Allen Institute, remarked:
“Adversarial collaboration aligns with our mission of open, team-driven science, and serves one of humanity’s oldest intellectual challenges: the Mind-Body Problem. Understanding consciousness is the driving force of my life’s work”.

Key Findings:

The study identified functional connectivity between the early visual regions (located at the back of the brain) and the frontal regions, shedding light on how perceptions are linked to thought processes. The results suggest that while the prefrontal cortex plays a role in planning and reasoning, consciousness itself may be more rooted in sensory processing and perception.

This could have significant implications for understanding disorders of consciousness, such as comas and vegetative states, and may assist in identifying “covert consciousness” in unresponsive patients a condition recently reported in about 25% of such cases in the New England Journal of Medicine.

No Clear Winner Between Theories:

While IIT emphasizes consciousness as emerging from interconnected brain systems, the study did not find lasting back-of-the-brain integration to fully support it. Meanwhile, GNWT, which focuses on consciousness arising from frontal brain regions, also lacked decisive support.

Dr. Anil Seth, a cognitive neuroscience professor at the University of Sussex, noted:
“It was evident that no single experiment could definitively rule out either theory, given their fundamentally different assumptions and goals. However, the collaboration still produced valuable insights into where and when visual experiences can be decoded in the brain”.

The experiment used visual stimuli while monitoring brain activity through three techniques that measure blood flow, magnetic activity and electrical signals a scale and scope rarely seen in consciousness research.

The project began at a 2018 workshop at the Allen Institute, representing a rare case of open scientific collaboration between theorists with differing views. This adversarial collaboration model aims to reduce confirmation bias and accelerate progress in complex fields.