The theater metaphor and the core claim
Baars introduced the theory in 1988 with a now-famous image: consciousness is like a theater. Most mental work happens backstage among unconscious specialists that handle vision, memory, language, and motor control. A spotlight of attention illuminates one item on the stage at a time, and whatever is lit gets broadcast to the whole audience of processors. On this account, being conscious of something just is having that information made globally available across the brain, rather than kept local to a single module.
From psychology to neurons: Dehaene's global neuronal workspace
In the late 1990s and 2000s the French neuroscientist Stanislas Dehaene, with Jean-Pierre Changeux and Lionel Naccache, gave the theory a neural form called the global neuronal workspace. They proposed that long-range neurons, concentrated in prefrontal and parietal cortex, link distant regions into a temporary shared network. When a stimulus crosses a threshold, activity does not just grow gradually; it triggers ignition, a sudden, nonlinear, brain-wide surge that sustains and shares the information. Below that threshold a stimulus can still be processed and even influence behavior while staying unconscious, which the theory uses to explain subliminal perception and the attentional blink.
Evidence and open questions
Global workspace theory is one of the most empirically productive theories of consciousness. Ignition-like signatures, including the late P300 brain response and widespread frontoparietal activation, show up reliably when people report seeing a stimulus. Critics argue that these signals may reflect the consequences of a conscious experience, such as reporting or remembering it, rather than the experience itself, a worry sometimes called the report confound.
The 2025 Cogitate study in Nature challenged the theory on this point. Prefrontal ignition at the moment a stimulus disappeared was weaker than predicted, and some conscious content could not be cleanly decoded from prefrontal cortex. Supporters note that the theory was never only about the front of the brain, and work continues on separating the neural basis of experience from the machinery of reporting it.