Anthropic discovers J-space, a global workspace-like structure in Claude

Anthropic published a paper on a “global workspace” in language models.

Using a technique called the Jacobian lens (J-lens), the researchers found a privileged internal region in Claude called J-space that contains silently processed concepts before they are spoken.

The space appears to emerge naturally during training and is causally involved in multi-step reasoning, reportability, and flexible control. Removing J-space severely degraded complex reasoning while leaving fluent speech mostly intact.