Economic Principles and Pre-historic Man: Natural Selection and the Division of Labor

Here is a fascinating discussion from the October 2008 issue of National Geographic in an article titled "Last of the Neanderthals":

Neanderthal society may have differed in another way crucial to group survival: what archaeologists call cultural buffering. A buffer is something in a group's behavior—a technology, a form of social organization, a cultural tradition—that hedges its bets in the high-stakes game of natural selection. It's like having a small cache of extra chips at your elbow in a poker game, so you don't have to fold your hand quite as soon. For example, Mary Stiner and Steven Kuhn of the University of Arizona argue that early modern humans emerged from Africa with the buffer of an economically efficient approach to hunting and gathering that resulted in a more diverse diet. While men chased after large animals, women and children foraged for small game and plant foods. Stiner and Kuhn maintain that Neanderthals did not enjoy the benefits of such a marked division of labor. From southern Israel to northern Germany, the archaeological record shows that Neanderthals instead relied almost entirely on hunting big and medium-size mammals like horses, deer, bison, and wild cattle. No doubt they were eating some vegetable material and even shellfish near the Mediterranean, but the lack of milling stones or other evidence for processing plant foods suggests to Stiner and Kuhn that to a Neanderthal vegetables were supplementary foods, "more like salads, snacks, and desserts than energy-rich staple foods."

Their bodies' relentless demand for calories, especially in higher latitudes and during colder interludes, probably forced Neanderthal women and children to join in the hunt—a "rough and dangerous business," write Stiner and Kuhn, judging by the many healed fractures evident on Neanderthal upper limbs and skulls. The modern human bands that arrived on the landscape toward the end of the Neanderthals' time had other options.

"By diversifying diet and having personnel who [did different tasks], you have a formula for spreading risk, and that is ultimately good news for pregnant women and for kids," Stiner told me. "So if one thing falls through, there's something else." A Neanderthal woman would have been powerful and resilient. But without such cultural buffering, she and her young would have been at a disadvantage.

Of all possible cultural buffers, perhaps the most important was the cushion of society itself. According to Erik Trinkaus, a Neanderthal social unit would have been about the size of an extended family. But in early modern human sites in Europe, Trinkaus said, "we start getting sites that represent larger populations." Simply living in a larger group has biological as well as social repercussions. Larger groups inevitably demand more social interactions, which goads the brain into greater activity during childhood and adolescence, creates pressure to increase the sophistication of language, and indirectly increases the average life span of group members. Longevity, in turn, increases intergenerational transmission of knowledge and creates what Chris Stringer calls a "culture of innovation"—the passage of practical survival skills and toolmaking technology from one generation to the next, and later between one group and another.

Whatever the suite of cultural buffers, they may well have provided an extra, albeit thin, layer of insulation against the harsh climatic stresses that Stringer argues peaked right around the time the Neanderthals vanished. Ice core data suggest that from about 30,000 years ago until the last glacial maximum about 18,000 years ago, the Earth's climate fluctuated wildly, sometimes within the space of decades. A few more people in the social unit, with a few more skills, might have given modern humans an edge when conditions turned harsh. "Not a vast edge," Stringer said. "Neanderthals were obviously well adapted to a colder climate. But with the superimposition of these extreme changes in climate on the competition with modern humans, I think that made the difference."