Culture does, in fact, optimize

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

14 thoughts on “Culture does, in fact, optimize

  1. Tim: first and foremost, your “Magdalenian” blades are actually Solutrean – I’m no PhD but it’s patently obvious. ;-)

    Magdalenian tech is more like a refined Aurignacian actually. Solutrean is pretty much unique, at least in Europe.

    On the rest, I would rather agree with you in making that distinction between symbolic culture (art, magic, religion) and technological culture. The latter obviously does tend to incorporate the most effective design available. You see pygmies hunting nowadays with homemade crosbows and using steel knives, while the rest of their culture remains about the same as before the penetration of other peoples. They would surely use firearms if that was practical to them, as many other hunter-gatherers do.

    Just a but: not always there is a single best way of doing things. So in case of such clear advantage he normal trend will surely be to preserve the tradition. And certainly in some cases unfounded feelings of overall superiority may prevent people from incorporating better stuff maybe out of disdain. Sometimes the improvement is too obvious to ignore but in other cases it requires certain mindset to appreciate the qualities of some tech or usage. If you despise or just ignore that mindset, then you are surely unable to understand and therefore to appreciate the quality of “foreign” designs and usages, even if they actually present improvements. You won’t just understand that they do because you choose to remain blind.

  2. Thanks for catching the Solutrean blades typo, Luis. I appreciate it. Also, it’s cool about the Tim reference… I figured that was a typo.

    I’m a bit confused with the tone in last paragraph. Are you addressing me or are you using you to refer to any person in general? I believe its the latter because you write,

    “Sometimes the improvement is too obvious to ignore but in other cases it requires certain mindset to appreciate the qualities of some tech or usage.”

    Not too sure, though. On that point though, often improvements, optimizations, refinements in any cultural meme that provides better functionality are under heavy positive selection.

    Razib just commented on Martin’s thread, a very logical and clear distinction:

    “i do think that the distinction between arrowheads and head-gear is important. if you don’t want to concede the distinction i simply ask that you not eat for 1 week and not wear a hat for 1 week and note that there is a physical difference.

    Often times, people can’t arbitrarily design arrow heads and ignore the added functionality of an improved, functional arrowhead…


  3. I’m a bit confused with the tone in last paragraph. Are you addressing me or are you using you to refer to any person in general?

    In general, of course.

    On that point though, often improvements, optimizations, refinements in any cultural meme that provides better functionality are under heavy positive selection.

    What I meant is that the benefit may not always be so obvious.

    For instance, sometimes one technology or way of doing things may be more productive in the short run but deplete resources in the mid or long run. It would still be positively selected because its short term benefits but it may not be so positive when looked at it holistically, from a historical perspective.

    We are not out of the natural selection process, be it biological or cultural, but unlike most other species we don’t have almost any predators and we can very much alter the enviroment before the unavoidable malthusian/selective forces are felt.

    Often one way is sufficient for survival and certain prosperity but it’s not competitive enough. A more destructive way of doing things can be more efficient in the short run but less so in the long run. This is a tragedy we seem bound to fall into repeatedly, I suspect, because percieving the whole thing, being balanced and sustainable, does not give the competitive edge normally.

    In other cases, a tech my be just as good as the other. Or better for certain type of economy/ecology and not for another. What I mean is that there is not always necesarily a better way – sometimes things are just different, with pros and cons of their own.

    Consider pottery for instance: it’s been argued that pots are burdensome for hunter-gatherers, while useful for farmers. It’s not like they are always positive: it depends on your particular circumstances. Even agriculture as such: in arid enviroments it can be impracticable, even if some kilometers away, at an oasis or a riverine enviroment it can be very succesful.

    But overall I agree that there is fundamental difference between an bow and a hat (unless the first is a musical bow and the scond a helmet, I guess).

  4. Certainly the LEAST variable tool ever invented is the hand ax, which lasted an unimaginable million and half years virtually unchanged. This has been used as an example of the limited imagination of homo erectus, but I go along with Professor William Calvin that it was not only optimized for its purpose, but that purpose was as a thrown weapon, not being used as a “Swiss Army knife.”

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