Their inner life is completely inaccessible to archaeology.

What the dental evidence shows is the behavioral and physical signature of continued use despite harm: the teeth were being destroyed by the habit, and the habit continued.

The exposure of the pulp in CPL-R2a’s most severely damaged teeth meant that the pain produced by the habit created a specific form of pharmacological trap: the substance that caused the pain also provided temporary relief from it, making cessation of the behavior directly painful in the short term.

This is a situation that modern clinical researchers would recognize immediately as one of the structural features of addiction — the way in which a substance becomes self-reinforcing through the harm it causes, as much as through the pleasure it produces.