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Brain size intelligence fallacy

(2016-Feb-28, 22:23:17)General-Factor analyst Wrote: This is exactly why your papers get nowhere. Good luck publishing your low quality garbage on sites like these while getting rejected by peer reviewed journals year after year.

What is "this"? My impatience with your inability to understand basic stats? My next three papers are going in Mankind Quarterly. One will be the target paper for the March edition and another is the reply to the 9 well published researchers who commented on it. But, yes, ad hominems are the arguments of last resort.
(2016-Feb-28, 22:03:18)General-Factor analyst Wrote: The problem as to why many racialists like you fear.

The brain size/head circumference arguments for racial differences are problematic. For one, contrary to the predictions of Rushton and others, some large admixture mapping studies have found no negative associations between African ancestry and head circumference in Latin American populations. Had you simply said, "These race-brain size-IQ arguments are dubious...", I likely would have agree and explained why I felt so too. But instead, you made a bizarre statistical argument regarding inter-individual differences and then doubled down on it after I patiently detailed the errors.
What is the most up to date brain size difference estimates between blacks and whites?

Is it still that old Rushton piece?

I recall seeing something with closer brain sizes in 2013 or so, cannot find it at all.
It's difficult to find a representative sample for this sort of thing. One can see brain size differences in the PING dataset. This was the dataset that the authors accidentally leaked with that "poverty shrinks the brain" paper. This sample is not very representative since they basically just sampled children around universities.

Quote:The PING Data Resource is the product of a multi-site project involving developmental researchers across the United States including UC San Diego; the University of Hawaii; UC Los Angeles; Children’s Hospital of Los Angeles of the University of Southern California; UC Davis: Kennedy Krieger Institute of Johns Hopkins University: Sackler Institute of Cornell University; University of Massachusetts; Massachusetts General Hospital at Harvard University; and Yale University.
The Data Resource includes neurodevelopmental histories, information about developing mental and emotional functions, multimodal brain imaging data, and genotypes for well over 1000 children and adolescents between the ages of 3 and 20.

Still, there is a variable for cortex total area ("cort_area.ctx.total") which has a d=.58 (W/B). The familiar gender pattern is also there.

I attach a plot.

The Black children were somewhat older, so this makes the difference smaller. Mean ages W/B 11.32 vs. 12.16. Age has non-linear effects so correcting for it requires a flexible model. I used LOESS, and after correction total cortical area d=.61. For comparison, the gender d is 1.12.

N's 203/973 for B/W.


Did you look at the Connectome dataset? Looks like they will oversample siblings and release genomic data too. So good for many analyses. I don't have the dataset or have the time to pursue it. Send it to me if you can get a hold of it.


Attached Files Thumbnail(s)
Sorry for extremely long reply time, I don't have time.

Thanks for info. Even though that was not what I was looking for, it was another article with (I think) MRI scans of brain volume between African Americans and whites, Chuck was in the comments section of that... Maybe I was imagining it.

I will post whatever I find of use, if I find anything.

Also, thats some massive variation within group in that ping sample, shees. It would be very interesting to see what IQs those extreme ends have.
PING dataset has total volume too. The differences are the same: .62 and .1.10 d for race/gender. Cortex x total volume is .89, hence the similar findings.
Ah ok.
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