26th July 2013
(I was wrong on this) Indian brains are 8 per cent LARGER than European brains (and how racists cherry pick data)
A lot of assertions seem to be have made in the literature about “brain size” on the basis of extremely limited data. Sample size is one of the key problems with brain size ( as well as with IQ, which I’ll address separately).
Consider only the brain size issue for now.
COMPARISON WITH NEANDERTHAL
The human brain is said to be smaller than the Neanderthal brain. But how can we be sure the Neanderthal brain was larger than modern humans’? It appears a very few Neanderthal skeletons are available. And there are quite a few modern humans whose brain volume is larger than 1500 cc, the alleged brain volume of the Neanderthals. It is not possible that we may have accidentally stumbled upon a few large Neanderthal skulls, with their average being much smaller (although its probability is low)?
The point I’m making is that when we see a nice little picture in a book that compares various brain sizes, we shouldn’t rush to conclusions.
WHAT ABOUT THE HUMAN BRAIN?
There are sample size issues also with the human brain volume. I concluded after some literature review that the human brain volume varies a lot. Its average for women and men is 1195cc, or at least one study says so:
Average brain volumes (excluding cerebral spinal fluid, meninges, and other nonbrain tissue) of 1130 cc for women and 1260 cc for men were reported based on normal subjects of European ancestry from a convergence of studies [Source].
The specific studies on the “convergance” of which this generalisation was made are:
- Allen J, Damasio H, Grabowski T (2002): Normal neuroanatomical variation in the human brain: An MRI-volumetric study. Am J Phys Anthropol 118:341–358.
- Peters M, Jancke L, Staiger J, Schlaug G, Huang Y, Steinmetz H (1998): Unsolved problems in comparing brain sizes in Homo sapiens. Brain Cogn 37:254 –285.
- Courchesne E, Chizum H, Townsend J, Cowles A, Covington J, Egaas B, et al. (2000): Normal brain development and aging: Quantitative analysis and in vivo MR imaging in healthy volunteers. Neuroradiology 216:672– 682.
Now compare this with Lynn’s data. According to his “table”, the smallest brain size is Indian with volume 1185cc. But that’s pretty much the European average that this more modern study shows. So what’s the big deal?
And his table for other “groups” is seriously inflated, if this more modern study is right.
BUT WHAT’S THE REAL VOLUME OF THE INDIAN BRAIN?
I decided to look for some recent studies on the volume of Indian brains. This is what I found from a 2010 published study [Source]:
This study was carried out on 400 healthy 20-25 year old (200 male and 200 female) individuals of Madhya Pradesh state of India, by using linear dimensions of head (Lee Pearson’s formula). The mean cranial capacity and SD in males & females were 1380.52± 94.63 cc and 1188.75± 91.16 cc respectively.
This would indicate the average Indian’s brain volume of 1284cc is about 100 cc (nearly 8 per cent) larger than the European average.
I’m almost sure now that mega-racists like Lynn cherry pick data to suit their biases. But since I’m not a bad scientist like them, I’m NOT concluding that the above statement is necessarily true. Just highlighting how a bad conclusion can be made by justaposing two small sample-based studies. I’m also aware that the measurement methodology in this study might differ from that used in others.
So I’m cautious and will not generalise. So you can therfore strike out my above “conclusion” and replace with a generalisation that “More COMPARABLE data has to be collected before we can make clear conclusions in this regard“.
We need to compare apples with apples. Let’s be VERY CLEAR about what we are comparing. Such clarity is unfortunately missing from these studies, and we have these fool racists who “conclude” quickly and without thought on the basis of biased data and flawed analysis.
YES, I’m certain that there is some form of correlation between brain size and IQ. But it is likely to be very small and it is likely to be attributable mainly to nutrition. Of course, there will be a genetic component as well to brain size as well, but I’d expect that once nutrition (and other factors in my model) are controlled for, we’d be unable to distinguish the mean or standard deviation of different bell curves representing the human species.