Early Brain growth in H. erectus

[Daryl Habel]

 According to an article in this week's issue of NATURE, early brain growth in Homo erectus follows an ape-like trajectory that differs from growth in extant Homo sapiens.
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Nature 431, 299 - 302 (16 September 2004); doi:10.1038/nature02852  
 
Early brain growth in Homo erectus and implications for cognitive ability

H. COQUEUGNIOT(1), J.-J. HUBLIN(2), F. VEILLON(3), F. HOUËT(1) & T. JACOB(4)

1 UMR 5199-PACEA, Laboratoire d'Anthropologie des Populations du Passé, Université Bordeaux 1, avenue des Facultés, 33405 Talence cedex, France
2 Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04130 Leipzig, Germany
3 Service de Radiologie I, Hôpital Hautepierre, avenue Molière, 67200 Strasbourg, France
4 Department of Physical Anthropology, Gadjah Mada University, College of Medicine, Yogyakarta, Indonesia

Correspondence and requests for materials should be addressed to J.J.H. (hublin@eva.mpg.de).

Humans differ from other primates in their significantly lengthened growth period. The persistence of a fetal pattern of brain growth after birth is another important feature of human development. Here we present the results of an analysis of the 1.8-million-year-old Mojokerto child (Perning 1, Java), the only well preserved skull of a Homo erectus infant, by computed tomography. Comparison with a large series of extant humans and chimpanzees indicates that this individual was about 1 yr (0–1.5 yr) old at death and had an endocranial capacity at 72–84% of an average adult H. erectus. This pattern of relative brain growth resembles that of living apes, but differs from that seen in extant humans. It implies that major differences in the development of cognitive capabilities existed between H. erectus and anatomically modern humans.
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© 2004 Nature Publishing Group

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Dar

[trehinp]

Thanks Dar,

This is fascinating (even with just the abstract).

If this analysis means what I think it does, there was a very big qualitative jump between Erecus and AMM. This could explain the acceleration of tool making technique by AMM.

But given the same type of technology acceleration also happened with Neanderthals, the brains of our "cousins" must have had also a big qualitative difference with that of Erectus.

To your knowledge, have there been similar comparisons made between Erectus and Neanderthal, or between Neanderthal and AMM ?

Paul

[Dale Hoogeveen]

Hi Paul,

A little caution is called for here.  There seems to be a lot made out of a single very ancient specimen.  The specimen comes from very near the beginning of the erectus period with a huge amount of erectus history following it.  Erectus type humans are not static during that period (of what some 700,000 to over a million years depending on what you consider erectus).

While there probably was significant difference in cognition between the earliest erectus types and current humans, the specimen seems to me more to suggest (and no more than just suggest) that the base out of which Homo emerged was more likely to have been Panish in type of development than that erectus maintained that pattern over its entire history, or even for very long during its stabilization. 

The Dmanisi fossils demonstrate very clearly that the earliest erectus types were extremely variable, expecially in cranial capacity;  so I would caution against getting too fancy with that kind of percentage even when dealing with the earliest erectus specimens.

Of course, since the child died very young, it might not even have been a viable individual in the first place.  The possibility there is that this typification was developed from a pathology.

There are too many loose ends to hang one's hat on this.   More samples from more perods are needed before a conclusion with this much speculative generalization begins to be warranted. 

The technology is fascinating and certainly holds some promise, but I think the conclusion should not have made it past the jury. 

Dale

Thanks Dar,

This is fascinating (even with just the abstract).

If this analysis means what I think it does, there was a very big qualitative jump between Erecus and AMM. This could explain the acceleration of tool making technique by AMM.

But given the same type of technology acceleration also happened with Neanderthals, the brains of our "cousins" must have had also a big qualitative difference with that of Erectus.

To your knowledge, have there been similar comparisons made between Erectus and Neanderthal, or between Neanderthal and AMM ?

Paul

[Robert Henvell]

  The age of the child is highly conjectural.Estimates vary between six months and eight years.If the "true"age is closer to the latter estimate,the variation between Homo erectus and Homo sapiens would be considerably less than the article suggests.

[Daryl Habel]

  The age of the child is highly conjectural.Estimates vary between six months and eight years.If the "true"age is closer to the latter estimate,the variation between Homo erectus and Homo sapiens would be considerably less than the article suggests.

First, my apologies to Paul Trehin for not addressing his question about whether similar studies had been made on Neanderthal juveniles, but I've been vacationing in Wyoming for the past two weeks and really don't have an answer, anyway.  Simply put, there aren't really very many samples of juvenile pre-modern humans to study, so, in any case even if there have been studies, I doubt if it has been possible to arrive at definitive conclusions.

Secondly, I've now had the chance to read the Coqueugniot et al. article in Nature, as well as to compare it to another related article in my files:

Anton, S. (1997). Developmental age and taxonomic affinity of the Mojokerto child, Java, Indonesia. American Journal of Physical Anthropology 102: 497-514.

As Robert Henvell says in the quote above, the estimated age at death for the Mojokerto child is the key to whether the pattern of relative brain growth resembles that of living apes and differs from that of modern humans.  Coqueugnoit et al. seem to rely heavily on their measurement of the scanned image of the morphology of the Mojokerto subarcuate fossa (see Figure 2) to arrive at their age estimate of 0-1.5 years.  However, Anton (1997), using several other criteria, arrived at an age estimate of 4-6 years for Mojokerto.

It seems to me, that using Anton's age estimate of 4-6 years for Mojokerto would reverse the conclusion arrived at by Coqueugniot et al., who estimate the age as ~1 year , but in my ignorance of juvenile human anatomical development  I'm not about to jump in here and offer an armchair opinion as to which estimate is likely to be more accurate.

Dar  

 

[trehinp]

Thanks for your answers Dale, Robert and Dar.

The abstract of the article that started the discussion was making some quite strong statements. It was those who got me exited.

The question remains of the difference between Homo Erectus and AMM brain size, and here of its growth in infancy.

I was also wandering if there had been a relatively richer skull sample to compare Neandertalian brains to AMM brains than there were Erectus available skulls.

Interestingly enough, a rather recent research has shown a significant difference in infant brain growth between "normal" children and autistic children.

<<Dr. Eric Courchesnes, a neurologist from California, revealed that the brains of children with ASD(1) grow unnaturally quickly  from six months after birth and reach mature size when a child is between three and four years old. This is far too early as neurotypical(2) children’s brains do not reach mature size until early adolescence.>> Source
(1) ASD : Autistic Spectrum Disorders
(2)Neurotypical : nickname given by autistic self advocates to non autistic people. The term is now widely used in the domain of autism.

More on the subject

This explains why I was so intrigued by the paper on different brain growth in Erectus and AMM.

Paul

[Daryl Habel]

I was also wandering if there had been a relatively richer skull sample to compare Neandertalian brains to AMM brains than there were Erectus available skulls.

Without  making an exhaustive search of the number of Neanderthal infants of an age that would be applicable to a study of this nature (0-2 years age?), a glance at the messages posted by thurr khan in the recent Palanth thread discussing Neanderthal pelvis size:

http://www.palanth.com/forum/index.php?topic=572.0


will show that there seems to be fewer than about a half-dozen known Neanderthal neonates.  Of these few, not much of anything specific has been published concerning brain size and development.

Qualifying this last sentence with:  "as far as I know" (which doesn't necessarily mean a whole lot).

Dar

[Dale Hoogeveen]

Hi Dar, Paul,

Dar has put that very well.  I might add that not only is there very little published of this nature on the few Neanderthal infants found, there are far fewer erectus level infants to do any kind of analysis on.    Really I think too few to pattern.

From the very few that I have heard about, however, they seem to be close enough to modern that modern variation has some correlation to what little has been found.  I would think that certainly cautions against over-emphasising distinction, especially in such tiny samples as are present in the relevant fossil record.

Dale

Without  making an exhaustive search of the number of Neanderthal infants of an age that would be applicable to a study of this nature (0-2 years age?), a glance at the messages posted by thurr khan in the recent Palanth thread discussing Neanderthal pelvis size:

http://www.palanth.com/forum/index.php?topic=572.0


will show that there seems to be fewer than about a half-dozen known Neanderthal neonates.  Of these few, not much of anything specific has been published concerning brain size and development.

Qualifying this last sentence with:  "as far as I know" (which doesn't necessarily mean a whole lot).

Dar

[lagarvelho]

Dar and Dale:

Quite frankly, I can't recall anything about neonatal Neandertal development, so I would concur with both of you on this. What I *have* read seems to suggest that , overall their growth and development is similar, though.  This is based largely on what I've read about the Dediriyeh child.
Anne G