Interesting that the correlation is lower for children. Extrapolating, this means that the C-sections aren't that effective intelligence enhancers as one may be led to think based on the adult data alone.

That is interesting, because Sandra Witelsen, in Deep, Dark Secrets of His and Her Brains, claims that this is not true.

"Einstein, she was convinced, had been born with a one-in-a-billion brain. "

Lets clone Einstein!!!

I don't see how one can claim Einstein had a one-in-a-billion brain without examing anywhere near that many. OTOH, if he did, there are half a dozen Einsteins in the world today.

From I can determine, she said Einstein had little or no divide between the left and right hemispheres - so his brain would be too exceptional to include in any statistical test.

My interpretation of the low child correlation was that, given growth still in progress, the researcher was trying to measure a moving target - that is, essentially comparing apples to oranges. Once the targets reach maturity they may in fact have the higher adult correlations.

Here’s my pet theory: males have larger brains not because they can reason better, or are smarter, etc. but rather so they can visualize better (read maps, become artists and architects). The extra grey matter is devoted to this ‘’video memory’’ – and computer folks know very well how much memory is required to display and manipulate visual images. Males developed this (energy- and resource-draining) skill so as to be better hunter gathers, soldiers, etc. Females didn’t need to drag around such excessive brain mass – so hence the ‘’smaller’’ brains – but according to Sandra smaller only in grey matter. The amount of grey matter in the male – if it is highly variable- may also be a reason for the difference in male-female correlations. For example, males with smaller brains but with even less amount of grey, visualizing matter, could in fact, have more of the other types brain functions (the kind that make females as intelligent as males – in spite of having smaller brains).

It's possible that the sexual dimorphism in male and female brains is part of an evolutionary legacy that goes farther back than our recent large brain-ed-ness. Maybe the differences don't even make sense context of anatomically modern humans. They are just there because of the starting points.

So, if an approximately 0.40 correlation exists between brain size and intelligence, what does this mean in the real world?

If 'intelligence' is measured by IQ scores, then, I suppose, predicting a person's IQ score could be accurate 40% of the time based on brain size (and therefore inaccurate 60% of the time).

Or, perhaps, 40% of the probable range, especially the upper limit, of a person's IQ score is accurately determined by brain size. Or perhaps...

As an aside, I understand some current research correlates intelligence/smarts/IQ scores with the SURFACE AREA of a brain. Actual surface area is increased by a brains convolutions and folds.

Any help here would be appreciated.

Are the brains of men bigger on average than the brains of women?

>>So, if an approximately 0.40 correlation exists between brain size and intelligence, what does this mean in the real world?

It means that there is a statistically significant amount that is predictable by brain size but the relationship is small. (about 16%) In other words, 16% of the diffrence in IQ in populations are predicted by head/brain size.

>>Are the brains of men bigger on average than the brains of women?

Men tend to have bigger just about everything.

"In other words, 16% of the diffrence in IQ in populations are predicted by head/brain size."

16 % is small? :/

"It means that there is a statistically significant amount that is predictable by brain size but the relationship is small. (about 16%)"

Please explain how 0.40 correlates to 16%.

Being a male visualizer, I'd sure like to see some scatter grams of the data used.

Yes male brains are bigger (in volume) by 10-15% - according a quick google. However, Aristotle believed that women were only born with 28 teeth. So everyone could be wrong - but just looking around I would say no. Btw, Sandra says the smaller brains seem to have more densely-packed neurons.

The size difference is actually acknowledged indirectly by feminists, who point out that the female brain is not smaller if you account for body size. Regardless, my hypothesis is that the extra male brain mass is there largely to enhance visualization abilities. We males don't like to stop and ask for directions because we enjoy problem solving, plus we're confident that our inborn navigational skills will come though. Sometimes they do, ladies, but okay, not always.

R-square, the square of the correlation estimate ''r'', is usually referred to as the variable's ''explanatory power.

(.4)(.4) = .16

"We males don't like to stop and ask for directions because we enjoy problem solving..."

Oh, just give it up, raise the white flag up.

You can solve problem both ways, endure the experience or learn from someone else's experience, which is usually the faster route.

:)

>>Please explain how 0.40 correlates to 16%.

.40^2 is .16 or 16%.

I am guesing they used the usual method (linear) to measure stat corrleation. If it was in vivo, I would think they got MRIs or something from people and measured their IQs. They then ploted it. A .40 corrleation and the Pearson Product Moment Coefficient just means that the scatter plot is somewhat linear, i.e. blob-bunched up in a "linear" fashion. They then got a stat average of these points on the graph taht is called a regression line. 16% of the variance in these point differences from the average are predicted by the regression line.

>>They then got a stat average of these points on the graph taht is called a regression line. 16% of the variance in these point differences from the average are predicted by the regression line.


Or if it was ploted in deviational units, they just needed the slope of the regression line.

"Btw, Sandra says the smaller brains seem to have more densely-packed neurons."

The usual obfuscation when faced with unpleasant facts?

What's the evidence?

Is that only for smaller female brains or smaller brains in general?

Is that only for smaller female brains or smaller brains in general?

''So among female brains, the cortex is constructed differently, with neurons packed more closely together," she said.

from

http://www.latimes.com/news/scie...-home- headlines

Btw, Liv, being surrounded by females at home, I would observe that some ladies enjoy communicating so much, they'll stop to ask for directions even if they're pretty sure they already know the way.

At odds with the research that gave rise to this post, Sandra talks about how she believes that brain size has nothing to do with intelligence, citing Einstein's normal size brain as evidence.

http://www.latimes.com/news/scie...s/scie...-home- headlines

Women do have smaller brains on average (~9%) but the cortical gray matter is thicker and the folding pattern is more complex. For references, see paper #351 (and #95, #113) here:
http://www.loni.ucla.edu/ ~thomps...mpson_pubs.html
It is not clear whether this has any functional significance, as these structural differences may also be found in small male brains (e.g. you could look at brains of men who are shorter than average height and see the same differences). Also - note that the correlation of IQ with total brain volume is true within each gender but not across genders :)

There are some theories that men have better visio-spatial abilities that developed because of their role in hunting and that this caused bigger male brains.

Regarding Einstein, what always baffled me was that early on his career always appeared very unremarkable academically, before he suddenly published his theory of relativity and other work.

I believe that Einstein's early problems are something of an urban legend. Figure he was Jewish (and had to deal with the anti-Semitic German academia), could have had mild autism (Asperser’s). Any number of things could have slowed his rise to the big leagues. But he showed evidence of genius (was reading Euclid) at a very early age.

Does this mean Dee Dee Ramone http://www.thesmokinggun.com/arc...ve/ deedee4.html
was smarter than Einstein? http://answers.google.com/answer...dview& id=232621

About big Al, he was slow to speak and did badly in some subjects but showed the usual trajectory of the great conceptual thinkers: unusual mathematical ability from early on, a remarkable growth spurt around puberty, frenetic energy in early manhood...then decline.

Kind of like athletes.

Einstein was not slow to speak, and was an excellent pupil at school. Although this excellence is most marked in his early school years, he was by no means ever a mediocre student. For reference, see any book length biography of Einstein.

Oh really? I thought he didn't speak until age three (that is about a year after the normal age), but I'm not gonna fall on my sword over it. There's a lot of folklore about him. And you are right: the AIP website sez he was a good student. http://www.aip.org/history/einst...tein/ early1.htm

Oh wait, on the next page it says that he had a "hesitant" style of speaking as a child. Perhaps this gave rise to a lot of lore.

http://www.aip.org/history/einst...in/ einbrain.htm

Regarding the male/female brain size/IQ conundrum, Dienekes had a post regarding a study that seems to put it all in perspective.

Thomas Sowell is certainly under the impression Eistein was late to speak, he even titled his book on late speaking children the Einstein syndrome! Haven't read it, don't know if it's any good.

The earliest documented reference to Einsteins verbal ability is a letter from his maternal grandmother to a relative. It is dated a few months after Einstein's second birthday, and describes the young Einstein as charming and full of amusing ideas. No mention is made of retarded development.

Francis, aren't you confusing Cro-Magnons with Neanderthals?

I think whales have the largest brains in the animal world.

BTW, here from the Einstein website you quoted

http://www.aip.org/history/einst...tein/ early3.htm


"After Einstein graduated with an undistinguished record, he made a number of efforts to get a university job, and failed. He found only occasional jobs on the periphery of the academic world. He felt he was a burden on his none too prosperous family, and wondered if he had been mistaken in trying to become a physicist."

Well, since English isn't your first language, I suggest you make sure you know what the word "correlation" means, because your post seems to indicate that you don't.

Not that this is of any relevance for the subject at hand, but I read somewhere that Paul Allen scored 1600 on the SAT while Gates only had a score of 1595.

I think Paul Allen is jewish, by the way.

e3bdc3 54ebd5e15d