The mortar and pestle, technologically linked to intensive acorn economies, appeared initially in low frequencies over a large portion of California ca. 4000-3500 B.C. Three sites on the Big Sur coast of central California illuminate the circumstances surrounding the advent of this new technology, which initially supplemented hand stones and milling slabs. Excavation results suggest that ca. 3500 B.C. production of hunting-related flaked-stone tools increased relative to ground stone, and hunted resources became more important, as part of a transition from a highly mobile, selective use of the coastal resources, heavily focused on gathering, to a less mobile, more intensified lifeway. Obsidian hydration profiles indicate that interregional exchange increased at the same time. Evaluation of alternative mussel collection techniques further indicates that shellfish-harvesting strategies became less efficient at this juncture, promoting the emergence of a processing specialization, concomitant with increased hunting intensity. These transitions apparently mark the appearance of lineal descent organization and the system of gender-specific task appropriation observed at European contact.