I have been following this thread but keeping quiet because neuroscience is not my field. However language is. Now forgive me if this is way off-field...but couldn't speech have in influence on the size of the human brain as compared with other mammals?

Rather than an ability to detect poisonous snakes - which of course we now know is not limited to humans - is there a possibility that our larger brain size has something to do with our unique possession of vocal chords? It is this which differentiates us from the larger primates (though presumably the makers of Planet of The Apes chose to ignore this)and even from our remote ancestors. Erectus and Neanderthal did not possess the power of speech, did they? So, although Neanderthal had a larger brain it did them no good...a failed experiment, perhaps?

The possession of vocal chords having led to the formation of words and speech; the evolution of abstract thought; and ultimately philosophy, the arts, technology and science, is it not feasible to posit that our larger brain size may be connected with functions related to these skills? As I said, this isn't my field so perhaps this is easily shot down in flames?

As to the relation of this to the original topic? I think it is germane as, without some glimmering of an idea of how our brains function it is impossible to make a decision on which side to come down on in any debate about a rationale for increasing the size of our offsprings' brains.

Romany,

I think you have made very valid comments.

Homo habilis, also known as transition man, is currently the earliest known species of genus Homo, that is the first of the human species, and which used a variety of tools. H. habilis, existed from over to 2 million years to some 1.6 million years ago (the date varies according to whom is writing the paper, however, the range is within this “ball park”). A brain cast found evidence of the bulge of Broca’s area essential for speech. There is speculation that this species may have had rudimentary speech. The brain of this species ranged from 680 cc to 800cc.

Regarding Neanderthal, they had cave art, flutes and were the first to bury their dead with flowers - so it would appear that they were capable of “abstract” thought. However, scientists, basing their findings on computer modeling, think that physicality of Neanderthal speech was actually poor, which gave them a disadvantage in communication and resultant organisational skills. This link povides fuller information
http://www.bbc.co.uk/worldservice/sci_tech/highlights/010710_neanderthal.shtml

A neuroscientist confessed that what they knew about the development of the human brain could be written on a postcard. He may have been exagerating, of course ...

Romany, I too, am waiting to be jumped on from a great height ...

Sadly I am forced to interupt you once more.

I must clarify no connection to peta= Although we support all groups and and members of the public fighting to stop cruelty to animals.
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pale has no connection to peta.

Bugsy why not allow the others to go on with their debate.

Thank You all for your patience

Danielle,

thanx for the great link - kept me happy for hours. Still no further towards solving the larger brain dichotomy - but neither did my theory fall completely flat on its face either, I suppose. At least on a superficial level.

Another thought which has has stuck for years in my own (large) brain is that our brain may have had even more capabilities, the use of which our more sophisticated life-styles have now rendered redundant. These do still manifest from time to time in certain "gifted" individuals and may even have links to autism. However, this is not the time or space to go into that.

Suffice to say, however, that I personally would therefore not choose to have my own child's brain size increased as I already hold the view that significant capabilities already present are no longer utilised. Thus to my way of thinking this would not necessarily prove advantageous.

But if we could somehow learn to utilise our brain to the full extent of its latent capabilities? Ah, that would interest me greatly.

Danielle, my interest lies mainly with human IQ at this stage, largely because of my daughter whose emotional "intensity"(for lack of a better word), advanced language ability, and general vagueness prompted her teacher to organise an IQ test recently. To see what we were really dealing with.
Speaking from experience, having a child with a high end IQ is not something I'd be genetically/chemically manipulating a child to achieve. Fitting in with children their own age is difficult, and can often lead to underperformance in order to conform, negating that extra ability. We've only begun the journey, and as you've said high IQ is no guarantee of success along the way.

wizofaus, steven brought up animals in the first place.
I don't doubt the importance of brain size on intelligence either, except that there are large variations of intelligence within the size we currently have, so size is not the limiting factor for 99.5% of the population. On rereading steven's posts he may have a goal in mind of exponentially raising intelligence levels, where I was thinking along the lines of being ahead of the bunch not lapping them.

I'm not completely sure if it's true, but I've read that we are born with all the braincells we'll have, and that we'll loose half of them by age 5. And all those cells within a brain mass 1/3 of an adults.
I say I'm unsure because the hippocampus is supposed to be able to make new neurons.

Look, brain size in and of itself has nothing to do with the level of cognitive abilities human beings have, this has been demonstrated. It's the number of neuronal connections that matter. Rojo, that brain cell deal is a myth, as I said it's about neuronal connections. The brain is extremely dynamic. Babies are born with a great many neuronal connections and they are then worked upon by the environment the baby lives in. Many connections are lost through disuse and many are strengthened through activity. This is the way neurons and synapses work. It's not how many you have, honeybees only have a fraction of what mammals have and yet are able to communicate, navigate, learn and orient themselves to food sources and threats extremely effectively.

It's all in the organisation of the brain and neuronal connections, not the number of cells there are. However, an increase in the number of neuronal cells can increase the potential number of connections, but not necessarily. It very much depends on the environment in which the developing brain lives.

Ok, all that aside, what I believe Steven was driving at was, humans can now take charge of their offspring's potential, which I personally disagree with because we don't really know much at all about how the brain develops, what the major genetic factors are, or how they work. Steven thinks we are at the cusp of understanding this, and yet I believe we are at the start of just understanding what the major non-genetic factors are, let alone what the genetic factors are how they interact and so I think that his "brave new world" screening embryos for intelligence and whatnot is far, far in the future. And if it can happen, let it, it will only be a drop in bucket of humanity and the human gene pool and won't be a major determinant leading to a GATTACA type scenario.