The article discusses the challenge of storing and transmitting accumulated cultural knowledge over generations, particularly for forager societies, who use storytelling as a way to encode their knowledge. The authors hypothesize that myth-telling rules exist in these societies to ensure high-fidelity transmission of the stories, and predict that such rules mandate proficient storytellers, low-distraction conditions, multiple individuals and generations present, error prevention and correction, audience attention maintenance, discouragement of rule violations, and incentivization of rule compliance. The authors searched forager ethnographic records for descriptions of myth performance and coded them for these features. Results indicate that rules regulating myth performance are widespread across forager cultures and reduce the likelihood of copy errors. These findings suggest that anthropogenic ratchets played a role in the emergence of cumulative culture.