February 8, 2011

And more Neanderthal-Sapiens subtle differences

David Sánchez of Noticias de Prehistoria, has today a very nice review (in Spanish language) of several papers which have come out in short term, most of them already mentioned here, on subtle anatomical differences between Neanderthals and Homo sapiens.

However one was not known to me yet:

Qin Zhu and G. P. Bingham, Human readiness to throw: the size–weight illusion is not an illusion when picking the best objects to throw. Evolution and Human Behavior, 2011. Pay per view. (doi:10.1016/j.evolhumbehav.2010.11.005)

Abstract

Long-distance throwing is uniquely human and enabled Homo sapiens to survive and even thrive during the ice ages. The precise motoric timing required relates throwing and speech abilities as dependent on the same uniquely human brain structures. Evidence from studies of brain evolution is consistent with this understanding of the evolution and success of H. sapiens. Recent theories of language development find readiness to develop language capabilities in perceptual biases that help generate ability to detect relevant higher order acoustic units that underlie speech. Might human throwing capabilities exhibit similar forms of readiness? Recently, human perception of optimal objects for long-distance throwing was found to exhibit a size–weight relation similar to the size–weight illusion; greater weights were picked for larger objects and were thrown the farthest. The size–weight illusion is: lift two objects of equal mass but different size, the larger is misperceived to be less heavy than the smaller. The illusion is reliable and robust. It persists when people know the masses are equal and handle objects properly. Children less than 2 years of age exhibit it. These findings suggest the illusion is intrinsic to humans. Here we show that perception of heaviness (including the illusion) and perception of optimal objects for throwing are equivalent. Thus, the illusion is functional, not a misperception: optimal objects for throwing are picked as having a particular heaviness. The best heaviness is learned while acquiring throwing skill. We suggest that the illusion is a perceptual bias that reflects readiness to acquire fully functional throwing ability. This unites human throwing and speaking abilities in development in a manner that is consistent with the evolutionary history.

Arguably this subtle ability of intuitively evaluating objects for their throwing characteristics was not extant among Neanderthals or was less developed. Or at least that is what co-author Bingham argues based on size of cerebellum and posterior-parietal cortex in both species (more developed in ours).

Also, as complement to all this digression on the various Homo sp. hunting techniques and biological abilities, David includes a beautiful documentary on Bushmen hunting, narrated by David Attenborough. In it we can follow how a group of Bushmen track and hunt a kudu in some eight hours and the rather unexpected advantages of our species in the hunt (long term resistance and sweat specially):


See also:

7 comments:

  1. Maju Greetings!

    Thanks for the link!

    The video was impressed, the end is simply wonderful: we can see the true human nature: an animal consumes another, but it shows respect and thanks him.

    Just the two, human and animal: not gods, prejudices, nothing.

    I have to admit I was get emotional to see the end of the video.

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  2. Besides a visit to Santimamiñe cave when I was a kid, I think that what really got me enamored with the Paleolithic and huntergatherer lifestyle was reading Richard Leakey on human evolution and almost invariably using Bushman examples. I also fell in love with the Bushmen in general then.

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  3. I think William H Calvin was the first to suggest that the advances of human inteligence owed a lot to brain adaptations for throwing.

    It is amazing how efficient human are; they can run down a four legged animal.

    The Bushmen are presumably well adapted to spend all day in the African sun. Not all that dark skinned are they ?

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  4. The Bushmen are "Mediterranean" (subtropical) by climate, mind you. They have therefore Mediterranean type of skin tone, more or less.

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  5. Also, I do not know if the Bushmen have it or not but East Asians' pigmentation bio-strategy includes something (not yet known) highly protective of skin cancer other than mere melanin. East Asians have very low rates of skin cancer for all the pigmentation clade. However I do not know if Indonesians, who are tropical but quite white, have folate-related issues or how have they managed to circumvent them.

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  6. The Kalahari is a vast plateau, 1650 - 5000 feet above sea level,there is almost zero humidity.

    Because of these factors there is a LOT more UV than in the Med

    "during the last 17 years main solar radiation parameters have been measured at the University of Botswana main campus, Gaborone. It was observed that instantaneous direct-normal radiation at Solar-Noon can be very high, in fact it can exceed 1000 W/m2; and that half an hour before sunset, it can be greater than 500 W/m2. At sunset (or sunrise) moment it can be up to 100 W/m2."

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  7. You are describing the conditions of the Kalahari now, not in the Ice Age. Second, the "Khoisanid race" certainly did not coalesce in the Kalahari but the much more fertile lands of South Africa, where AMH inhabitation is documented from at least 70 Ka ago (and more in the case of Mazambique).

    Whatever the case it's not Gabon, Congo nor Tanzania. In such cases, very close to the Equator, you do have "primitive" peoples to analyze and they are all highly melanic (even if they practice serial monogamy).

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