Behavioral differences between Middle and Upper Paleolithic Homo sapiens in the East Mediterranean Levant: The roles of intraspecific competition and dispersal from Africa

Archaeological, paleontological, and genetic evidence indicate that Homo sapiens originated in Africa around 200,000-150,000 years ago (200-150 kya). Behavioral differences between earlier and later Homo sapiens populations are clearly germane to research on the origins of uniquely derived (i.e., "modern") human behavior. This paper examines evidence for behavioral differences between Middle (MP) and Upper Paleolithic (UP) Homo sapiens in the East Mediterranean Levant. Levantine archaeological assemblages associated with Homo sapiens between 130 and 75 kya and again between 45 and 25 kya show contrasts in settlement, subsistence, technology, and social organization. Recent explanations for these differences include technological-social evolution, neurogenetic mutation, population growth, and interspecific competition. These hypotheses are each critically examined. None accounts for the particular timing of the MP-UP transition, ca. 45 kya. A new hypothesis explains Middle vs. Upper Paleolithic behavioral differences among Levantine Late Pleistocene Homo sapiens as the result of intensified intraspecific competition among African Homo sapiens populations who dispersed into the Levant after a period of rapid climate change, 50-45 kya. This hypothesis contradicts the long-standing assumption of biological and cultural continuity across the MP-UP transition in the Levant.