I’ve been meaning to blog about the really awesome news that Afarensis first broke on the blogosphere for a couple days now. The news he shared is of an upcoming Journal of Archaeological Science paper authored by R. Lee Lyman, Todd VanPool and Michael O’Brien, all of the University of Missouri Anthropology Department, evaluating the selection and optimization of projectile points.
I’ve tracked down the paper. It is currently more or less an accepted draft and titled, “Variation in North American dart points and arrow points when one, or both, are present.” Yesterday, Afarensis supplemented his news coverage with a little questionnaire he asked one of the authors, Dr. Lyman specifically. Dr. Lyman answered the questions and provided a little bit more information than the initial press release provided.
To give you a quick digest, Lyman, VanPool, and O’Brien analyzed over 1,000 projectile points from three archaeological sites; Verkamp Shelter in Missouri, Gatecliff Shelter in Nevada, and Mummy Cave in Wyoming. The collection of points span at least 3,200 years of time and all include the date the bow and arrow were introduced and used in these regions. Upon the introduction of the bow and arrow about 1,7000 years ago, Lyman et al. were able to see that people experimented to find the optimum point. They did that by synthesizing cladistic analysis, which O’Brien specializes in and concluded that there was
“initial burst[s] of variation in projectile points… and that prehistoric [people] experimentally sought arrow points that worked effectively. Following that initial burst, less-effective projectile models were discarded, causing archaeologists to see a reduction in variation.”
So these people tested many different projectile points. The ones that were functionally more effective were the designs that were selected and further optimized, kinda like punctuated equilibrium. Diversity was lost once the best points were identified. Sounds right in line with other models of cultural selection, such as the 60,000 year old tool kits Sibudu Cave that also showed those people experimented with tool design to accomplish a variety of tasks.
I believe I have a good understanding of the archaeological record and I think it is really safe to say that humans have always experimented with tools, selecting ones that were functionally superior to tools that weren’t. That is optimization, to make the best or most effective use of a tool.
You can see for yourself, some of the first examples of stone tools are classified as Oldowan type. They first appear in the record about 2.5 million years ago, also known as the Lower Paleolithic. They were very simple. About 1.5 million years ago, a new type, Achulean tools appear. They are much more refined and optimized for special tasks compared to Oldowan tools.
Following Achulean stone tools, the Levallois, Aurignacian, and Magdalenian techniques succeeded into the Upper Paleolithic becoming more specialized with time than its predecessor. I’ve posted examples of each typology in chronological order, from Oldowan tools to specialized Solutrean blades, for you to see how tools have been refined over time. Optimization of tools did not end with the Neolitihic revolution. In fact, tools have been constantly revised to fit the new tasks that came about as humans began to adopt sedentary lifestyles over nomadic ones.
So I’m really disappointed, shocked even, to read from Martin, an archaeologist… someone who is supposed to specialize in studying material culture, commenting on this topic and writing that cultural selection is irrational, arbitrary, and does not optimize. He cites face painting as an example about how cultural selection is full of ‘null mutations.’ Based off of his choice of comparisons, I don’t think he understands the difference between functional and symbolic traits in cultural memes. And this is alarming.
A very recent paper, authored by two biologists from Stanford, evaluated the differences in the rates of change between functional and symbolic traits in Oceanic canoe design. I recommended Martin read up on it, if he hasn’t already, because in the paper Ehrlich and Rogers clearly distinguish the difference between symbolic and functional traits… Something that Martin did not with his example. Symbolic ones, as Martin pointed out, are highly variable — but functional traits, ones that affect the survivability of the user are rapidly revised and selected.
Adding to his foolish comparison, Martin also stated that once upon a time pre-scientific humans existed. While trained scientists haven’t been around until relatively recently, people have always been experimenters. The inquisitive nature of humans has been a fundamental aspect of our evolution, both biological and cultural. Furthering this idea, he writes that, ‘he is convinced that both people in the lo-tech past and people of the present are largely ignorant non-optimisers who mainly do things with no adaptive significance.’ Without ‘scientific,’ adaptive minded optimizing humans, we would not have had cave art, fire, agriculture and animal domestication… we’d be still eating tubers out of the ground.
I really hope people see beyond Martin’s comparison. Let me remind you that he’s comparing apples to oranges, literally. Symbolic things, like face painting, trinkets on a fishing pole, adornment on a canoe, offer little functionality. Projectile points are functional elements, that directly correlate to a successful hunt and survivability. The are selected in different operant realms. Also, this is not the first time example of Martin’s asininity… in the past he’s spun this mindless mantra and wondered if genetic evidence is relevant in the peopling of the Americas.
LYMAN, R., VANPOOL, T., OBRIEN, M. (2008). Variation in north american dart points and arrow points when one, or both, are present. Journal of Archaeological Science DOI: 10.1016/j.jas.2008.05.008