Ecology cannot explain divergent cultural traits among neighboring Amazonian groups

Evidence

Demographically, the Machiguenga live in individual family-based houses, whereas Yora live all together in larger malocas. The Yora have a well-defined tradition of raiding, and they frequently raid Machiguenga communities. The Machiguenga have no parallel tradition and never raid Yora communities. Moreover, both male and female Machiguengas wear cushmas (long cotton ponchos), where Yora females wear short skirts (called samas) and Yora males wear monkey tooth belts to which they tie their penises. The Yora have personal names, whereas traditionally the Machiguenga do not (Snell 19674). Further Glenn Shepard (1996, personal communication), who has worked extensively with both of these groups, has found that the Yora and Machiguenga possess fundamentally different traditional medical systems, including their concepts of illness classification and causation. The list goes on and on. The local ecology cannot account for the substantial differences maintained between groups inhabiting adjacent and often overlapping regions. — Joe Henrich and Robert Boyd, The Evolution of Conformist…, 110

Categorization

• XREF: Connects to the reader’s interest in transmission models versus environmental explanation — this contrast motivates cultural-evolution frameworks like Henrich’s. — connects to: Environment alone cannot explain cultural differences between groups — Joe Henrich and Robert Boyd, The Evolution of Conformist…, 112; Explaining intergroup cultural variation requires analysis at two coupled levels — Joe Henrich and Robert Boyd, The Evolution of Conformist…, 12; Evolutionary and neurological accounts cannot fully explain cultural patterns — W. David Marx, Status and Culture: How Our Desire for…, 807 (+1 more)
• QUESTION: Worth checking whether these Yora/Machiguenga contrasts appear in Henrich’s own work as canonical examples of conformist transmission vs. ecology.

Broader Connections

• Environment alone cannot explain cultural differences between groups #expands (0.95) — Joe Henrich and Robert Boyd, The Evolution of Conformist…, 112
• Explaining intergroup cultural variation requires analysis at two coupled levels #expands (0.85) — Joe Henrich and Robert Boyd, The Evolution of Conformist…, 12
• Ecology explains why individualist societies form depersonalized symbolic group identities #complicates (0.80) — Roderick M. Kramer, Geoffrey J. Leonardelli, Robert W. Livingston, Social Cognition, Social Identity, and…, 1650
• Evolutionary and neurological accounts cannot fully explain cultural patterns #corroborates (0.78) — W. David Marx, Status and Culture, 807