Babel's Dawn

A New Account of Human Origins?

The latest issue of Science, just published, devotes several papers to a consideration of Australopithecus sediba, a species identified in southern Africa and dated to between 1.95 and 1.76 million years ago. When the species was identified in 2008 I wasn't much interested because the genus Homo was already perhaps a million years old by then, so this finding seemed to outside the human lineage. There were many bipedal apes three million years ago and even after the emergence of Homo bipedal apes persisted. The new Science issue considers the possibility that A. sediba led into Homo as we now know it.

Why Did Neanderthals Die Out?

Whenever I read a story like this one inThe Guardian I wonder what it implies about Neanderthal speech. I'm sure they spoke, spoke pretty well, but what did they talk about? Feelings, ideas, or did they stick to practical things? They cooked food. Fire is older than the split between our lineage and theirs, so the proof that they cooked food is not too amazing. But they are a mystery. So like us and yet gone.

Neanderthal Cousins Bred with Homo Sapiens

I know I'm on vacation, but you've got to read this story. The study of DNA has become as revolutionary as geology was two centuries ago.

Neanderthals Wasted No Time Growing Up.

There are two  life phases that are found in Homo sapiens and not in Neanderthals. One is the period between weaning and the loss of baby teeth. My father used to call that plateau, reaching the age of reason. After it, there were no excuses. We were supposed to knnow the difference between right and wrong. The second  period begins at puberty and ends  with the halt some years later of skeletal growth. Neanderthals grew up much quicker, so there three year olds look like our five year olds and their thirteen year olds look like our eigteen year olds.

Neanderthal Genome

Science magazine announces progress in putting together the Neanderthal genome, apparently confirming the presence of the mutated FoxP2 gene. The Economist has some more details.And AAAS has an online presentation about the work.

New Australopithecus Species

Science magazine reports the discovery of a new Australopithecus species: sediba.Two skeletons in reasonably good condition have been found in South Africa's Malapa Cave. The skeletons are dated from 1.95 to 1.78 million years ago, making them contemporaries with early Homo erectus. Its pelvis and teeth are said to be more like early Homo than its presumptive ancestor, Australopithecus africanus. On this blog I have assumed that the human lineage moved through the Homo genus right from the beginning. That would put sediba on a collateral line, but these taxonomies are all imperfect and we never know what surprises tomorrow will bring.

Ardi Is #1

Science magazine has declared the work on "Ardi"  "the scientific breakthrough of 2009" (see: New Details on 4.4 Million Year Old Hominid). In an editorial, the editor in chief at Science writes, " This breakthrough “changes the way we think about early human evolution."

Division of Labor — Pre Homo sapiens style

The same magazine reports that Israeli archaeologists, led by Nira Alperson, have explored an 800,000 year old site near the Dead Sea and found evidence that work in a hominid settlement was divided by type. Flint was worked in one location, shell fish cracked open in another, and vegetable remains found in another.

Early Sorghum Working

The same issue reports that evidence of sorghum residue on hundred thousand year old stone tools have been found in a cave in Mozambique. Sorghum is a grain that is still widely consumed in Africa. Seed (grain) eating is usually dated much closer to an 11 thousand year old date. 

None of these stories directly relates to language, but each of them pushes back the date of other features thought peculiarly human, implying that the date for language in some form should probably be pushed back as well.

I might add as a personal note, during my teaching years in an African village I was very familiar with the sight of women pounding grain to break it open, so I feel it is easy for me to imagine a world in which the Mozambique cave dwellers did such work.

How Old Is Language?

Rene Descartes was probably the last great thinker to try to explain the universe on the basis of definitions and logic alone, but he was not the last savant to explain the mind that way.

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I had thought I would skip reporting on Bart de Boer’s presentation in Torun. I have already covered his work on the loss of air sacs (see: Fossil Evidence of Speech?) in the human lineage. In Torun he presented experimental evidence that strengthens his case for the idea that as precision of speech sounds became more important, the air sacs used for ape vocalizations became a problem, but much of the presentation matched the one given in Barcelona. I changed my mind about reporting, however, after I began looking at the new online issue of Biolinguistics.. One of the papers directly contradicts de Boer’s conclusion, so I thought this might be a good time to take a look at the different approaches.

One of de Boer’s slides (available here) said:

Hypothesis: —Neanderthals could speak, Australopithecines not —(proto) speech is at least 500,000 years old.

Meanwhile a Biolinguistics paper by Dennis Ott (available here) proposes:

It therefore seems reasonable to assume that the human I-language trait is at most 100,000 years old, its emergence having facilitated the ‘Upper Paleolithic Revolution.’ [257; italics author’s]

We seem to have a disagreement of, at a minimum, 400,000 years.

New Details on 4.4 Million Year Old Hominid

Notice anything dubious about this screen-capture of the Discovery Channel's "Ardi" page? Ardi's eyes have white sclera. What is the evidence for that? Primate eyes tend to have black sclera. Having whites of eyes is a peculiar human trait, one that means we make redirecting attention easy. Could Ardi do that? I've seen no reason to think so. (Check out this webpage here.)

A team of scientists have announced in a special issue of Science magazine new details resulting from the extensive study of a series of Ardipthecus ramidus fossils from 4.4 million years ago. The centerpiece of the new report concerns a skeleton of a female the team has nicknamed "Ardi." Although not complete, the skeleton includes the skull, teeth, arms, hands, pelvis, legs, and feet. All in all, it makes for a bad day to be defending creationism. The project's co-director, Tim White, said, "It's not a chimp. It's not a human. It shows us what we used to be."

Ardipithecus lived long before speech in any form is suspected to have evolved, but the report does have implications for language-origin theory. In particular, Ardipithecus seems to have had a completely unexpected social arrangement. Ardi is estimated to have weighed about 110 pounds (50 kg), making her more or less equal in size to her male conspecifics. The difference in sizes for the diferent sexes that is found in chimpanzees and especially gorillas does not appear to have been found in ramidus. Sexual dimorphism (as sex-based size differences are called) commonly reflect strong competition among males for sexual access to females. A lack of dimorphism suggests a lack of competition. This finding raises new questions for Terrence Deacon and his theory that symbolism developed in response to a need to limit competition between males over females. If the competition disappeared two million years before the first Homo, it is  hard to credit Deacon's account of language origins.

I asked Deacon for a comment and he replied:

My argument is NOT that low sexual dimorphism is a correlate of symbol use, in general, it is only a correlate of minimal male-male competition. So my argument is only that that a *reduction* in sexual dimorphism from our more immediate ancestors the australopithecines (which we can now assume must have increased in sexual dimorphism since ardipithecines) indicated a reduction in overt male-male competition (over compulatory access). The ardi data is in this respect no more relevant than the gibbon data.

 The press kit had an astonishing speculative account of behavior:

Ardipithecus probably had a social structure unlike that of any living primate—one in which multiple males and multiple females lived together, but without strong male-male conflicts. Males were probably pair-bonded to specific females, and may have aided females by gathering rare and valuable foods that they would regularly share with them.

Among the other surprising findings:

• The species is not much like a chimpanzee, suggesting that chimpanzees and bonobos have evolved quite considerably since the last common ancestor with humans. We can no longer assume the last common ancestor was much like a chimpanzee in behavior or anatomy.
• Although Ardipithecus was bipedal, it was as well adapted to climbing trees as to walking on the ground.
• Its foot retained the grasping toe of a chimpanzee, indicating that it did not have the arched foot of an Australopithecus.
• The face was neither flat and massive as the later Australopithecus, nor projecting like a modern ape.
• The hand shows no signs of specialization for knuckle walking (like chimps and gorillas) and no signs of having evolved from a hand that ever knuckled walked. This detail indicates that the knuckle walking of chimpanzees and gorillas evolved twice along separate, convergent lines.
• The brain was about 300-350 cc, just slightly smaller than a modern chimpanzee.

UPDATE: John Hawks' Weblog found a nice little zinger on the idea of monogamous Ardis here. Poloygamy and serial relations are so common today, I wonder how all that could flow from a monogamous past.

Hamjambo, Arusha

I see Tanzania is today beginning a celebration of the Leakey discovery of the “Zinjanthropus“ fossil (now called Paranthropus). The find occurred 50 years and 1 month ago, on July 17, 1959. It’s a little hard to figure out the excitement today, remembering that Australopithecus had been known for 30 years. Maybe it was the proof a few years earlier that “Piltdown Man” was a forgery, or maybe Louis Leakey was a genius at publicity. At any rate, the finding triggered the interest in humanity’s African origins that persists to this day. I was still a school kid in those days, but I remember the news breaking. In one of the world’s most remote places, a human ancestor had been found that was well over a million years old. The thought conjured up quite romantic images in my imagination, and I was quite pleased to find myself twenty years later on the edge of Olduvai Gorge having tea with Mary Leakey. It was Mary by the way who actually found the fossil and ran to report her discovery. So I’m honoring the festivities in Tanzania today by pretending I’m in Arusha, drinking a cold Tusker, and joining the festivities.