* John Hawks have flagged a number of interesting articles. One study, linking population size and technological complexity in Oceania at first contact with European sailors reaches a facinating conclusion:
Much human adaptation depends on the gradual accumulation of culturally transmitted knowledge and technology. Recent models of this process predict that large, well-connected populations will have more diverse and complex tool kits than small, isolated populations. While several examples of the loss of technology in small populations are consistent with this prediction, it found no support in two systematic quantitative tests. Both studies were based on data from continental populations in which contact rates were not available, and therefore these studies do not provide a test of the models. Here, we show that in Oceania, around the time of early European contact, islands with small populations had less complicated marine foraging technology. This finding suggests that explanations of existing cultural variation based on optimality models alone are incomplete because demography plays an important role in generating cumulative cultural adaptation. It also indicates that hominin populations with similar cognitive abilities may leave very different archaeological records, a conclusion that has important implications for our understanding of the origin of anatomically modern humans and their evolved psychology.* On the methodology front, someone has found a way to turn W.E.I.R.D. samples into a feature rather than a bug when doing genomics:
Although much is known about college students as a special sample in terms of their behavioral traits such as intelligence and academic motivation, no studies have examined whether college students represent a “biased” sample in terms of their genotype frequencies. The present study investigated this issue by examining the Hardy–Weinberg equilibrium of genotype frequencies of 284 SNPs covering major neurotransmitter genes in a sample of 478 Chinese college students, comparing these frequencies with those of a community sample (the 1000 Genomes dataset), and examining behavioral correlates of the SNPs in Hardy–Weinberg disequilibrium. Results showed that 24 loci showed Hardy–Weinberg disequilibrium among college students, but only two of these were in disequilibrium in the 1000 Genomes sample. These loci were found to be associated with mathematical abilities, executive functions, motivation, and adjustment-related behaviors such as alcohol use and emotion recognition. Generally, genotypes overrepresented in the college sample showed better performance and adjustment than under-represented or non-biased genotypes. This study illustrates a new approach to studying genetic correlates of traits associated with a socially-selected group—college students—and presents the first evidence of genetic stratification in terms of education attainment.* On the "to do" list, one of the projects at the top of list is to look into the circumstances that lead to language formation, which may or may not be distinct from "ordinary" language evolution. A number of examples and leads to research come to mind to get at it, but full fledged language formation is very rare and mostly prehistoric with the exception of certain creoles and a couple of other outliers.
There are creoles whose formation process is well documented, and short of creoles punctuated language evolution via intense language contact. There are instances of isolated communities of deaf people developing their own personal sign languages from scratch. There is a growing literature discussing how societies and subcultures that split off (e.g. the differentiation of the Romance languages, revolutionary Americans, gang members, mother-in-law languages and "women's languages", Urdu v. Hindi) deliberately differentiate themselves linguistically as a means of distinguishing between insiders and outsiders and developing cultural identity. There are lots of data points on what drives language shift, which language formation requires, but language formation also requires more.
There are purposefully constructed languages or linguistic constructs (e.g. pig latin) although very few of them seem to catch on. They are like third parties in a two party biased first past the post single member district electoral system. The viable ones form out of schism in existing ones or are driven by nationalism (e.g. reconstructed modern Hebrew), not to advance intellectually compelling ideas.
I think that the extent to which language formation and change is punctuated rather than evolutionary is greatly underestimated. But, I'm curious in particular about how more tightly integrated features of a language like phonetics and grammer change relative to less core features like non-core lexical change. For example, feminism has made some pretty significant changes in these kinds of features recently in English.
In particular, I'm curious about what circumstances might lead to the formation of a new viable language in the modern era.
"hominin populations with similar cognitive abilities may leave very different archaeological records, a conclusion that has important implications for our understanding of the origin of anatomically modern humans and their evolved psychology".
ReplyDeleteHmmmm. That has implications for someone we both correspond with. Or, I used to. This recent John Hawks post is also relevant:
http://johnhawks.net/weblog/fossils/neandertals/italy/riparo-mezzena-mandible-2013.html#gsc.tab=0
"In our view, this change in morphology among late Neanderthals reopens the debate on the 'more modern like' morphology of late Neanderthals and can lend support to the hypothesis of a certain degree of continuity with AMHs or a possible interbreeding with them".
And:
" Jim Ahern and colleagues (including me) have showed that the Vindija G3 Neandertals have morphological features that are not typical of classic Neandertals, and that are significantly different in the modern human direction"
To me it is almost impossible that 'parallel evolution' is the explanation.
* On the first point, I think the big point is that the MSA to UP break in AMHs could be due to larger social units facilitated by climate or a cultural development, rather than by evolution of cognitive function.
ReplyDelete* Rather than parallel evolution (which I think probably was happening as well, but not on that time scale), the more plausible possible alternatives to hybrids could include:
(1) Overlapping ranges of variability or abnormality in individuals due to some illness or defect.
(2) Deformation of samples between recovery and deposition.
In short, the hard issue is whether the morphological differences are clear enough to be definitive.
"I think the big point is that the MSA to UP break in AMHs could be due to larger social units facilitated by climate or a cultural development"
ReplyDeleteI have come to believe that to be so as well. The wider social connections allowed survival during tough times whereas until that period small isolated groups had become inbred (as a recent Dienekes post hints) and so become extinct.
"Overlapping ranges of variability"
But that overlap of variability would imply con-specificity. Interbreeding would be no problem at all.
"the hard issue is whether the morphological differences are clear enough to be definitive".
John Hawks claims exactly that although he tends very strongly to the interbreeding scenario. By the way, have you noticed he is offering a free course on human evolution next year? Would be very interesting to enroll.