From: Scott Chase (ecphoric@hotmail.com)
Date: Sun 03 Aug 2003 - 00:51:19 GMT
>From: "Scott Chase" <ecphoric@hotmail.com>
>Reply-To: memetics@mmu.ac.uk
>To: memetics@mmu.ac.uk
>Subject: technological bottlenecks and Movius line (was Memes and
>population size) Date: Sat, 02 Aug 2003 20:32:21 -0400
>
>
>
>
>
>>From: Keith Henson <hkhenson@rogers.com>
>>Reply-To: memetics@mmu.ac.uk
>>To: memetics@mmu.ac.uk
>>Subject: Re: Memes and population size was: Memetic trapping and wars.
>>Date: Mon, 07 Jul 2003 20:06:29 -0400
>>
>>At 06:00 PM 07/07/03 -0400, Scott wrote:
>>
>>>>From: Keith Henson <hkhenson@rogers.com>
>>
>>snip
>>
>>>>It is an interesting point that a particular set of technology memes may
>>>>(very likely does) require a population larger than some critical
>>>>number.
>>>And in smaller populations genetic drift becomes important.
>>
>>Right http://home.entouch.net/dmd/neantas.htm
>>
>>"According [to] Flood, "No other surviving human society has ever been
>>isolated so long or so completely as were Tasmanian Aborigines over the
>>last 8000 years." (p. 173) During this period of isolation, the Tasmanians
>>developed several physical traits which were unique. They had the widest
>>nasal index of any people ever recorded. Their heads were shorter and
>>broader than those of their ancestors, the Australians."
>>
>>>Due to sampling errors allelic frequencies may fluctuate wildly and
>>>either go to fixation or loss from a population, regardless of selection
>>>value.
>>
>>Re fixation, they are the only known exception for people living at such a
>>high latitude. They never lightened their skin, staying as dark as the
>>Australian Aborigines. Perhaps it takes a higher level of clothing
>>technology before you get selection for lighter skin from rickets, or
>>lighter skin mutations just didn't happen, or they were getting enough
>>vitamin D from their diet.
>>
>>>There could be instances, like with Tasmanians, of a cultural drift,
>>>where important technologies that aid survival of individuals of a
>>>population are lost from cultural memory (ie- forgotten). It would have
>>>been advantageous for individuals to have some memory of these practices,
>>>but if nobody that can pass the technologies to future population members
>>>survives, then these traditions vanish.
>>
>>Good point.
>>
>>In fact, there is a *dynamic* process here. Cultural elements are lost at
>>a certain rate and created at a certain rate. It makes sense that the
>>rate of creation would be so many per million people per unit of time. If
>>the people communicate these memes, useful (or at least fashionable)
>>cultural elements accumulate if the group is large. Memes are lost from
>>generation to generation if the group is smaller than the size where new
>>meme creation does not keep up with the rate at which cultural elements
>>are being lost.
>>
>>
>In reading Richard Klein and Blake Edgar's book _The Dawn of Human Culture_
>(2002. John Wiley & Sons, Inc. New York) I learned of something called the
>"Movius line" which is a putative boundary in Asia that demarks the
>apparent absence of Acheulean technology (ie hand axes) east of the line
>toward Southeast Asia. This technology is indexed west of the line, in
>Africa and Europe. Klein and Edgar have a map on page 111 that has an arrow
>pointing to this "Movius line". From the context it looks like this
>boundary (named after Hallam Movius) applies to *Homo erectus* and its
>migration into Asia.
>
>There are two possible explanations offered for this apparent absence of
>hand axes:
>
>1. the people migrating into Asia lacked the hand axes because they had
>migrated "before hand axes were invented" (Klein and Edgar, page 130)
>
>2. There was a "technological bottleneck" where these people migrated after
>the invention of hand axes, but lost lost this innovation from their
>cultural memory due to some cicumstance such as not having proper material
>resources to craft hand axes. The "technological bottleneck" hypothesis is
>attributed by Klein and Edgar to Nicholas Toth and Kathy Schick.
>
>The technological bottleneck explanation for the "Movius line" reminded me
>of this exchange between Keith and I and I'm glad I still have Keith's post
>saved. Maybe technological bottleneck events have impacted human cultural
>evolution from time to time. Keith's example of the Tasmanians losing
>memory of certain technologies sounds like a technological bottleneck
>associated with cultural drift. The Explanation for the Movius line could
>likewise be an example, but that would depend not only on cultural drift
>being a viable hypoteses for the loss of Acheulean traditions of hand axe
>manufacture (especially if it can compete with the hyppothess that the
>migration into Asia occurred *after* the emergence of this technology), but
>also would depend on the "Movius line being real nd not apparent.
>
>The info in these URL's could take some wind out of the sails of Movius and
>a technological bottleneck:
>
>http://www.sciencenews.org/20000304/fob1.asp
>
Seems I lost a dot on this one:
>
>http://www.mnh.si.edu/anthro/humanorigins/whatshot/2000/wh20002.html
>
That should work better. That's it! I'm buying new batteries for my
keyboard.
>
>Aside from this interesting tangent, the meat of Klein and Edgar's book
>rests on a contentious hypothesis for the dawn of human culture, that it's
>based on a neural event facilitated by some mutation 5000 years ago.
>
That should be *50,000 years ago*! Ooops :-(
They weren't that crazy. 50,000 sounds much better than 5,000. Typos are
getting the best of me. My apologies. The rest of my typos aren't that
critical, but I'll try to edit better next time (drats, drats, drats!)!
>
>They cite Gould and Eldredge earlier in the book yet this putative
>mutational event sounds more saltational than punctuational to me. They
>assume this shift allowed for language and mental modeling of the
>environment. They use a loss of function mutation seen in cases adversely
>impacting human speech as evidence for an assumed gain of function
>quasi-saltational event. I wouldn't look at a condition that impairs
>language processing due to a single gene mutation as providing evidence for
>a single mutational event that gave humans language *de novo*. Language
>processing probably involves many genes (perhaps a gene complex) and the
>evolution of language could have involved the cumulative co-option of
>several genetic factors that were involved in other processes. Sounds
>marginally better than some magical mutation mumbo jumbo and I'm neither an
>anthropologist, a linguist, nor a geneticist. Klein and Edgar's book has
>many good points and the hand waving about a mutational revolution
>underlying the dawn of human culture should not detract too much.
>
>[Klein and Edgar, page 270] (bq)"In our view, the simplest and most
>economic explanation for the "dawn" is that it stemmed from a fortuitous
>mutation that promoted the fully modern human brain."(eq)
>
>In their enthusiasm, they may have take things a litle too far.
>
>
But at least they didn't have such serious problems with editing their typos
before hitting the send button like I do :-)
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