“…This phenomenon occurs in other aspects of culture as well. In a study of projectile points from eastern North America that immediately postdate Clovis, including a large sample from the northeast, Gingerich et al 74 found increasing variation in bifacial flake-scar symmetry, which was not the case in the Clovis-only study of Sholts et al 47 The resulting regionalization in the east 31,42,71,73,113,118 shows up in morphologically distinct, fully fluted, basally thinned, and unfluted forms, with subregional variants, including types such as Barnes, Beaver Lake, Bull Brook, Crowfield, Cumberland, Dalton, Debert/Vail, Quad, Redstone, San Patrice, Suwannee, Simpson, and some lanceolate shapes that resemble points from the Great Plains. In contrast, design and manufacture in the east were tied to two tiers of social learning, one tied to conformist transmission of ancestral tool-making processes-flake removal-and the other a product of drift and, perhaps to some extent, regional adaptation-shape.…”