Articles to 2014-09-26

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First the link to this week’s complete list as HTML and as PDF.

Looking at Boëda et al. I see several caveats. All the supposed tools were found near the tops of gravel layers of similar grain sizes. During excavation the fine grained layers are carefully scraped away, so it is the top of any gravel layer that emerges prominently and catches the eye. Lower down the need to remove stones leaves an irregular surface, where single stones stand out much less. Secondly one should not underestimate the discriminatory power of human vision. A set of stones selected for some distinctiveness or other will probably prove to be different from a randomly selected one on objective criteria. This alone does not show them to be man-made. Like Knutsson I notice the lack of debitage flakes. So while this evidence is not easily dismissed entirely, it does not look as strong as the authors want to make out.

Buizert et al. fill a real need. The last time I counted there were eight totally different things, oxygen 18 was a proxy of, and all those effects were of the same order of magnitude. When measurements go across massive changes of world-wide climate, any assumption of "all else being roughly equal" is manifestly ridiculous. So the extraction of temperature from ice core 18O data alone has always seemed a somewhat questionable exercise to me.
    That said their new method too raises more questions than it answers. Although different gases differ widely in their solubility in water, any differential diffusion has always been denied and the fraction of CO2 in old bubbles taken as an exact measure for its original concentration in ambient air. Everything else in ice has also been taken as highly conserved, only heavy nitrogen is now supposed to get fractionated so strongly, it can be used as a valid thermometer.

Two psychological studies this time and both methodologically squeaky clean as far as I can tell. Rietveld et al. find 69 different genetic markers for intellectual attainment. Two results stand out: Each genetic variant isolated so far only has a tiny effect. Genetic engineering for intelligence seems further off than ever. Second, although frequently chosen, years of schooling are a poor proxy for intellectual capability. Several of the genes found nudge it and measured intelligence in opposite directions.

Fleming et al. on the other hand seems rather trivial. All Chinese not only look but also sound alike and I believe everyone finds it noticeably harder to tell two speakers with identical foreign or strong regional accents apart than two speakers from the listener’s familiar home region. Still, it seems the question has been in dispute and is now resolved.

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