Baars’s and Dehaene’s Global Workspace Theory

Proposed originally by Bernard Baars (Baars, 1988, 1997, 2002), extended with neuroimaging and computer modeling by Stanislas Dehaene (Dehaene & Naccache, 2001), along with Jean-Pierre Changuex, Lionel Naccache, and others, Global Workplace Theory (GWT) posits that brain-wide presence and broad accessibility of specific multi-sensory, multi-cognitive information is what constitutes conscious awareness.

GWT is founded on the concept of an inner “theater of consciousness,” where the mental spotlight of awareness shines on sequential sets of integrated perceptions that are dominant, at least momentarily. (The global workspace “Theater of Consciousness” is said not to contradict Dennett's rejected “Cartesian Theater,” because the former is not dualistic and does not reside in only one location in the brain; rather, the Theater of Consciousness is passive, not active, and is spread across much of the brain.)

Global Accessibility and Competition

GWT holds that conscious mental states are those which are “globally available” to a wide range of brain processes, including attention, perception, assessment, memory, verbal description, and motor response. Which sets of integrated perceptions become dominant, move to center stage, and thus leap into conscious awareness? It's a competition. Diverse data flows originating both within the brain (e.g., memories) and from external stimuli (i.e., sensory information) are in constant competition, such that the “winner” is broadcast broadly (i.e., globally) in the brain and becomes accessible throughout the brain, which is how we become aware of it as the content of our consciousness.

This brain-wide focus on a particular phenomenological package integrates all the relevant sensory and cognitive streams by recruiting all the relevant brain areas into an organic whole—while inhibiting other, extraneous, conflicting data flows—such that what resides in the global workspace is perceived as consciousness “snapshots” in continuous, movie-like motion. This means that while our conscious awareness may seem unified and seamless, in fact it is neither.

Empirical Framework of GNW

According to neuroscientists Stanislas Dehaene and Lionel Naccache, the hypothesis of a global neuronal workspace (GNW) should synthesize three major empirical observations (which, they say, any theory of consciousness should incorporate) to build the GNW’s theoretical framework: “(1) a considerable amount of processing is possible without consciousness, (2) attention is a prerequisite of consciousness, and (3) consciousness is required for some specific cognitive tasks, including those that require durable information maintenance, novel combinations of operations, or the spontaneous generation of intentional behavior” (Dehaene & Naccache, 2001).

Dehaene and Naccache then build their case for the GNW theory of consciousness. “This framework postulates that, at any given time, many modular cerebral networks are active in parallel and process information in an unconscious manner. An information becomes conscious, however, if the neural population that represents it is mobilized by top-down attentional amplification into a brain-scale state of coherent activity that involves many neurons distributed throughout the brain. The long-distance connectivity of these ‘workspace neurons’ can, when they are active for a minimal duration, make the information available to a variety of processes including perceptual categorization, long-term memorization, evaluation, and intentional action. We postulate that this global availability of information through the workspace is what we subjectively experience as a conscious state” (Dehaene & Naccache, 2001).

Substrate Neurobiology

Neuroscientist Jean-Pierre Changeux puts it this way: “The conscious compartment, the global workspace, processes information from non-conscious processors and in turn broadcasts that information from one system of processors to all the other processors—but in a certain way, a ‘theater’ kind of ‘stock exchange’ of processors, where these specialized processors interact, coordinate, and control each other in competition or cooperation.”

Regarding the substrate neurobiology, Changeux says that the GNW theory “privileges a subset of interconnected cortical pyramidal cells with long-range excitatory axons, particularly dense in prefrontal, temporoparietal, and cingulate regions, that, together with the relevant thalamocortical loops, forms a horizontal ‘neuronal workspace’ interconnecting multiple, specialized, automatic, and nonconscious processors. The conscious content of a given sensory input (seeing, hearing, etc.) is assumed to be encoded by the sustained and amplified activity (termed ‘ignition’) of a subset of neurons from the GNW, the rest being inhibited, which ultimately leads to a report of conscious experience” (Changeux, 2025).

Global Workspace Dynamics and Revisions

Whereas GWT started in the 1980s as a purely psychological theory of conscious cognition, it has become a “family” of theories adapted to today's far more detailed understanding of the brain. The brain-based version of GWT is called Global Workspace Dynamics because the cortex is viewed as a “unified oscillatory machine.”

GWT, therefore, according to its advocates, joins other theories in taking consciousness as the product of highly integrated and widespread cortico-thalamic activity, including evidence that the prefrontal cortex participates in the visual conscious stream. Cortex is extraordinarily flexible in its dynamic recruitment of different regions for different tasks. Therefore, an arbitrary division between prefrontal and other neuronal regions is said to be misleading. Consciousness requires a much broader, more integrative view (Baars et al., 2021).

In a pioneering set of “adversarial collaboration” experiments to test hypotheses of consciousness by getting rival researchers to collaborate on the study design,^[1] preliminary results did not perfectly match GWT's prediction that consciousness arises when information is broadcast to areas of the brain through an interconnected network. The transmission, according to GWT, happens at the beginning and end of an experience and involves the prefrontal cortex, at the front of the brain.

But independent “theory-neutral” researchers found that only some aspects of consciousness, but not all of them, could be identified in the prefrontal cortex. Moreover, while they found evidence of brain broadcasting, the core of GWT, it was only at the beginning of an experience—not also at the end, as had been predicted. Further experiments are to come, but revisions to GWT are believed likely (Lenharo, 2023a, 2023b, 2024).

Footnote

[1]. The adversarial experiments are envisioned and sponsored by the Templeton World Charity Foundation.