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South Asia and the Dawn of Modern Thinking In our June issue I wrote about the origins of modern human behavior--that is, when humans started thinking like we do. This question has long vexed paleoanthropologists, who observed that whereas humans that looked like us had evolved by nearly 200,000 years ago, art, language, trade and other sophisticated practices flowered only around 40,000 years ago. For years, the prevailing theory was that our species underwent a behavioral revolution around 40,000 years ago in Ice Age Europe--perhaps the result of contact between the resident Neandertals and the invading Homo sapiens. More recently, it has been proposed that this revolution began in Africa 50,000 years ago, sparked by a genetic mutation that kicked our ancestors' cognitive powers into high gear. But for as long as these sudden origins theories have been around, there has been evidence against them in the form of fancy tools, symbolic jewelry and putative artwork that are older than they should be if these hypotheses are correct. Arguably the greatest blow to the revolution scenarios is the material from a South African site known as Blombos Cave, where Chris Henshilwood and his colleagues have unearthed the mother lode of advanced artifacts, including shell beads, engraved iron ore (ochre), ochre crayons and a bunch of modern-looking implements--all at least 75,000 years old. These finds and others suggest that human behavior changed gradually, starting long before 50,000 years ago. Fresh insights into the nature of the behavioral shift appear in the December issue of Current Anthropology, in which graduate student Hannah V. A. James and Michael D. Petraglia of the University of Cambridge review the evidence from South Asia. The paper contains many more details than I can recount here, but I found the following particularly interesting. The authors note that explicit symbolism, such as art and jewelry, shows up later in the record there than in Africa or Europe. And it emerges gradually, as it does in Africa, rather than in a big bang like the one evident in Europe 40,000 years ago. They contend on the basis of that evidence as well as the more utilitarian aspects of the local material culture, such as the stone tools, that anatomically and cognitively modern humans from Africa arrived in the region at least 70,000 years ago with so-called Middle Paleolithic technology. Over time, James and Petraglia surmise, the more advanced Late Paleolithic traditions evolved from the Middle Paleolithic ones. That is, South Asians arrived perfectly capable of modern thinking, but only expressed that potential in archaeologically visible ways later in time. Perhaps, the researchers offer, fluctuations in population size played a role in this cultural change. For example, symbolic behavior may have been advantageous only during times of intense competition for resources. The climatic oscillations of the Late Pleistocene, when these folks lived, would have surely impacted population size, and hence, competition. This, in fact, is the same explanation some experts have proposed for why early symbolism didn't "stick" in Africa: when population size diminished, these behaviors disappeared, either because their practitioners died out, or because they did not pay off. As it stands, the South Asian paleoanthropological record has its limitations: a paucity of hominid specimens, for one, and of solid archaeological dates for another. But James and Petraglia state that ongoing research in the region may help to elucidate the picture. It seems certain that South Asia will figure importantly in future discussions of how we became human. Posted by Kate Wong
