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THE HOMININ CORRIDOR DEMOGRAPHIC ABSORPTION MODEL A Unified Mathematical Framework for the Rapid Global Replacement of Archaic Hominins by Homo sapiens Author: Hollis Black (Matthew Dominik) Year: 2025 Abstract Homo sapiens dispersed out of Africa with unprecedented speed, reaching Europe, Asia, Oceania, and the Americas within a geologically short window. Existing models attribute this expansion to cognitive revolutions, climate shifts, or competitive superiority. I propose a different mechanism: earlier hominins had already mapped the Old World, establishing long-distance movement corridors, ecological knowledge networks, and resource pathways. When Homo sapiens encountered these preexisting structures, the species expanded along them with higher reproductive rates, greater social plasticity, and larger kin networks. This model describes replacement not as violent conquest, but as demographic absorption. Limited interbreeding occurred, but population-math ensured the archaic gene contribution diluted into the much larger Homo sapiens pool. I formalize this mechanism through a unified differential-equation framework capturing: (1) exponential population growth, (2) logistic competition, (3) spatial diffusion along inherited corridors, and (4) admixture with dilution. The resulting collapse timescale (~900–1,200 years per region) aligns with archaeological disappearance rates of Neanderthals and Denisovans. This model reframes human origins as a phase transition in an already-developed hominin world: not exploration, not supremacy, but demographic amplification along ancient routes laid down by others. 1. Introduction For over a century, explanations for the swift global rise of Homo sapiens have oscillated between cognitive, technological, and climatic causation. However, none fully explains the speed of our dispersal or the tempo of archaic hominin decline. This paper proposes a new integrative perspective: earlier hominins (Homo erectus, Neanderthals, Denisovans) built the world first. Humans expanded into their networks. The model rests on four empirical pillars: 1. Archaic hominins occupied Eurasia for over a million years, creating stable travel corridors, mapped landscapes, and ecological habits. 2. Homo sapiens remained in Africa for ~200,000 years, with little demographic pressure to migrate outward. 3. Upon contact, Homo sapiens exhibited higher reproductive rates than archaic groups. 4. Replacement occurred through demographic takeover with limited admixture, not systematic conflict. 2. Earlier Hominin Corridor Systems Evidence from Dmanisi, Denisova Cave, Atapuerca, and Southeast Asian Homo erectus sites suggests repeated long-range dispersal, raw material transport, seasonal migration routes, shared hunting territories, and stable landscape memory over hundreds of millennia. These corridors formed a pre-human mobility scaffold. Thus, when Homo sapiens migrated, they entered an inhabited, mapped world, not an empty continent. 3. Differential Growth Rates as the Replacement Engine Homo sapiens reproduced faster. Let: dH/dt = r_H * H dA/dt = r_A * A with r_H > r_A. The population ratio: H(t)/A(t) = (H0/A0) * exp((r_H - r_A) * t) Replacement occurs when this ratio approaches infinity. 4. Spatial Diffusion on Inherited Corridors To model movement across archaic-built landscapes: ∂H/∂t = D_H ∇²H + r_H H(1 - (H + A)/K) ∂A/∂t = D_A ∇²A + r_A A(1 - (H + A)/K) Where D_H > D_A because Homo sapiens exploit established corridors more efficiently. 5. Admixture and Genetic Dilution Interbreeding occurred, but low archaic population sizes meant their genes were absorbed. dH/dt = r_H H + mA dA/dt = r_A A - mA Tracking archaic ancestry as p(t): dp/dt = m(A/H) - p r_H As A/H → 0, archaic ancestry stabilizes at a small constant. 6. Collapse Timescale Local archaic disappearance time: t_collapse = ln(A0/H0) / (r_H - r_A) For realistic frontier ratios and growth rates: ≈ 36–45 generations ≈ 900–1,200 years. 7. Discussion This model avoids problematic narratives of supremacy and instead emphasizes inherited landscapes, demographic mathematics, admixture followed by dilution, and phase-transition population dynamics. Homo sapiens did not conquer the archaic world. They amplified into it.
8. Conclusion The Hominin Corridor Demographic Absorption Model provides a unified explanation for rapid Homo sapiens expansion, consistent with archaeological timelines and genetic evidence. Acknowledgments This framework grew from iterative conceptual refinement and mathematical synthesis by Hollis Black.
