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The evolution of thought

Interdepartmental collaboration aids research on earliest behavior of modern humans


Over the past four years, I have been excavating an archaeological site in rural South Africa, near the Lesotho border, to examine the origins of modern human thought and behavior. We know that the earliest anatomically modern humans originated in Africa. During the Middle Paleolithic in Europe, Neanderthals - or what we call "archaic Homo sapiens" (Homo sapiens neanderthalensis) because they were a subspecies apart from modern humans - were behaving in non-modern ways, producing small campsites, little to no art, and no ethnic markers.

During the same time period, what's called the Middle Stone Age in southern Africa, or the Middle Pleistocene among geologists, anatomically modern humans appear. Did these physically modern humans think like modern humans? In other words, did modern behavior co-evolve with anatomically modern Homo sapiens or did intellectual modernity lag behind, developing at a later time? The tantalizing information from my site, which I have collected and examined, thanks to the help of colleagues from two other ODU departments, thus far suggests that anatomically modern humans were practicing a range of modern and non-modern behaviors.

How does one differentiate modern behavior from non-modern behavior? The Department of Engineering Technology, thanks first to Joe Betit and now John Rand, has been helping to answer this question by lending a laser theodolite (a surveying instrument used to measure vertical and horizontal locations) and data collector that I take to South Africa each summer. The theodolite and data collector allow me to pinpoint the location of all artifacts uncovered at the site. These data can then produce site maps of all the artifacts that are within millimeters of accuracy of where they were found. The maps allow us literally to see past activity areas and the behaviors that produced them. The spatial analyses help us determine whether or not the people who produced the artifact patterning are intellectually modern by examining their use and organization of space.

Can plant remains reveal information about spatial patterning at the site? One person's trash is another's treasure, as can be seen at any weekend garage sale. At my Middle Stone Age site, the trash from eating wild plants or from using plants to make artifacts may be revealed through the identification of phytoliths, which are microscopic plant remains found in the soil. Jennifer Slate, assistant professor of biological sciences, is overseeing the identification of the phytoliths I have collected. So far, grass stems and grass shafts have been identified at the site. Once the plant remains of various units have been identified, we can obtain information on how space was used at the site, what plants were available in the environment, and what the climate was like during site occupation.

All modern humans, regardless of their culture, use space in very patterned ways. I studied the use of space among contemporary hunter-gatherers, the Bushman (Basarwa or San as they are also known) in the Kalahari Desert of Botswana, southern Africa. Every summer from 1987 to 1995, and then again in 1997 and 2000, I lived, ate and slept with a group of Kalahari foragers who were still hunting using traditional weapons of poisoned arrows, spears and traps, in addition to collecting wild plants. These people taught me much about hunter-gatherers, the use of space among non-Westerners, sharing, gender in a highly egalitarian society and much more. When the Botswana government forced them to relocate in a large government village where they were no longer able to hunt and gather, I decided to apply the information learned to understanding the beginnings of modern human thought and behavior.

Among modern hunter-gatherers, like those I studied in the Kalahari, sociality is one trait that stands out as the weft that weaves people together at a camp. I believe sociality is one of the most important behaviors to evolve because it is the basis of modern human societies, from kinship on. The presence of sociality at Middle Stone Age sites in Africa can be inferred from the way in which space was used. Intellectually and behaviorally modern humans use space in patterned ways that we call activity areas, and it is the activity areas that the theodolite maps by measuring the exact location of an object. Organizing behavior into discrete activity areas is, I suggest, one way to determine the presence of sociality at a prehistoric site.

There are other traits that also tell us about modernity. Intellectually modern humans are selective in the raw material they bring to their sites from which to make artifacts. Modern humans with modern behavior can tell from the outside of a rock whether it is likely to be useable for stone tools. This selection process does not appear to be present at the Middle Stone Age site I am excavating. Any piece of flint is brought to the site, resulting in many pieces of stone discarded as unusable after one or two flakes are removed. This example of non-modern behavior is striking in combination with the use of discrete activity areas. The mixing of modern and non-modern behavior is intriguing and may help us understand the evolution of the brain to what it is today.

The transition to behavioral modernity is one of the most challenging and interesting phases of human evolution. Through the continued collaboration of the departments of Engineering Technology and Biological Sciences, along with my own Department of Sociology and Criminal Justice, where anthropology is housed, we can begin to understand the transformation to intellectual modernity and its associated behaviors.





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