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posted by martyb on Friday March 16 2018, @02:44PM   Printer-friendly
from the Moog-want-spear...-Gork-want-axe? dept.

Signs of symbolic behavior emerged at the dawn of our species in Africa

More than 320,000 years ago in the Rift Valley of Africa, some early innovators adopted a new technology: They eschewed the clunky, palm-size stone hand axes that their ancestors had used for more than a million years in favor of a sleek new toolkit. Like new generations of cellphones today, their Middle Stone Age (MSA) blades and points were smaller and more precise than the old so-called Acheulean hand axes and scrapers.

These toolmakers in the Olorgesailie Basin in Kenya chose as raw materials shiny black obsidian and white and green chert, rocks they had to get from distant sources or through trade networks. In another first, they chiseled red and black rocks, probably to use as crayons to color their bodies or spears—an early sign of symbolic behavior. "This is indicative of a gear change in behavior, toolmaking, and material culture," says evolutionary psychologist Robin Dunbar at the University of Oxford in the United Kingdom, who studies social networks.

A trio of papers released online in Science today documents this remarkable technological transition. Although other sites have yielded MSA tools, the new, securely dated chronology nudges the transition back by at least 20,000 years, matching when our species, Homo sapiens, is now thought to have emerged. By analyzing artifacts over time at one site, the papers also show that these behaviors developed as climate swings intensified, supporting the idea that environmental variability drove innovation.

Related:

Environmental dynamics during the onset of the Middle Stone Age in eastern Africa (DOI: 10.1126/science.aao2200) (DX)

Chronology of the Acheulean to Middle Stone Age transition in eastern Africa (DOI: 10.1126/science.aao2216) (DX)

Long-distance stone transport and pigment use in the earliest Middle Stone Age (DOI: 10.1126/science.aao2646) (DX)


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  • (Score: 2) by Arik on Friday March 16 2018, @06:49PM (4 children)

    by Arik (4543) on Friday March 16 2018, @06:49PM (#653737) Journal
    "On what exactly?"

    The loss of technology thing.

    Why would a population bottleneck necessarily result in loss of technology? Of course it's *possible* something is lost but typically the entire population would be expected to have nearly the entire existing skillset; it's not like there was this one hunter that made all the arrowheads and everyone bought from him. Every hunter knew how to make scrapers and points and how to repair them in the field. Specialization would have been a disadvantage, and impractical. So there's no necessary loss of technology in population bottlenecks that far back. The most recent population bottleneck may have had the opposite effect - there was an article to that effect I read recently but I can't seem to find it again easily.
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  • (Score: 0) by Anonymous Coward on Friday March 16 2018, @10:25PM

    by Anonymous Coward on Friday March 16 2018, @10:25PM (#653832)

    Actually, that's pretty much exactly how it worked (specialization). Pretty much everyone learned the basics, but mastery was generally left to the most skilled. When a bad arrow can make the difference between food or starvation, you let the best fletcher fletch and let the best hunters hunt. Everything took a lot of time and effort and considerable skill and knowledge, though it doesn't seem like much from a modern perspective.

  • (Score: 2) by JNCF on Monday March 19 2018, @04:47PM (2 children)

    by JNCF (4317) on Monday March 19 2018, @04:47PM (#654990) Journal

    One well documented example is Tasmania. I think I read this whole paper (direct PDF) [harvard.edu] a few years ago, but it might have been a similar one. Here's the abstract (emphasis added):

    A combination of archeological and ethnohistorical evidence indicates that, over an approximately 8,000-year period, from the beginning of the Holocene until European explorers began arriving in the eighteenth century, the societies of Tasmania lost a series of valuable skills and technologies. These likely included bone tools, cold-weather clothing, hafted tools, nets, fishing spears, barbed spears, spear-throwers, and boomerangs. To address this puzzle, and the more general question of how human cognition and social interaction can generate both adaptive cultural evolution and maladaptive losses of culturally acquired skills, this paper constructs a formal model of cultural evolution rooted in the cognitive details of human social learning and inference. The analytical results specify the conditions for differing rates of adaptive cultural evolution, and reveal regimes that will produce maladaptive losses of particular kinds of skills and related technologies. More specifically, the results suggest that the relatively sudden reduction in the effective population size (the size of the interacting pool of social learners) that occurred with the rising ocean levels at the end of the last glacial epoch, which cut Tasmania off from the rest of Australia for the ensuing ten millennia, could have initiated a cultural evolutionary process that (1) kept stable or even improved relatively simple technological skills, and (2) produced an increasing deterioration of more complex skills leading to the complete disappearance of some technologies and practices. This pattern is consistent with the empirical record in Tasmania. Beyond this case, I speculate on the applicability of the model to understanding the variability in rates of adaptive cultural evolution.

    Consider that without writing, a culture's technology is limited by human memory. Insisting on replication of all data in all humans limits the growth of technology considerably. The less replication we insist on, the more technology we can have. We just also risk losing it if the population declines. One human can not remember all useful skills to the same degree of precision that a hundred humans can.

    • (Score: 2) by Arik on Monday March 19 2018, @07:16PM (1 child)

      by Arik (4543) on Monday March 19 2018, @07:16PM (#655070) Journal
      That's a good example to show that it *can* happen but it's a bit sparse to prove it *must* happen which I think was the assertion I was challenging.

      "Consider that without writing, a culture's technology is limited by human memory."

      Which is why we developed poetry and all the other memory-enhancing technologies that moderns too often forget about.

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      • (Score: 2) by JNCF on Friday April 06 2018, @12:21AM

        by JNCF (4317) on Friday April 06 2018, @12:21AM (#663202) Journal

        How many examples does it take to show that something *must* happen? It's not a possible task, obviously. No number of measurements can prove that an apple must drop downwards. What would you need to probabilistically convince you that this is a real effect?

        On poetry and other mnemonics, you're totally correct that they increase the amount of information an individual can store, but that doesn't change the fact that a group of people using those techniques to store overlapping-yet-different sets of information can record more than a group of people using the same techniques to store the exact same set of information in every individual. Increasing bytes-per-capita doesn't change this dynamic.