Comments on: Is a Bigger Brain Really Better?

By: exigentsky

exigentsky — Fri, 18 Jul 2008 01:25:00 +0000

I should add an important clarification. The brain size to body ratio is not relevant as long as the brain size is still within the range of normal and if the given size is a natural condition. For example, if one has a smaller brain size due to severe malnutrition or other problems like that, obviously that's going to be a factor.

By: exigentsky

exigentsky — Fri, 18 Jul 2008 01:18:00 +0000

I've put enormous research exactly into this issue. Even if one looks only at the brain to body ratio, there is no convincing link. Note, that looking at head size alone is even less relevant since it doesn't give an accurate enough measure of brain size.

Human intelligence results mostly from the structure and organization of the brain (consider the frontal cortex). Even in genetic studies about people with high IQ, there was little correlation with the brain to body ratio. However, there was a high correlation for several clusters of genes. For example, those with a gene resulting in more myelinated axons did better on average. Myelin basically gives better connectivity for the electrical signals of the brain. To sum up, consider processors today. Would you judge how fast a CPU is by its size? If so, the P1 300 Mhz would be dozens of times faster than any single core processor.

By: Growing Freedom

Growing Freedom — Wed, 09 Apr 2008 13:19:00 +0000

Clearly a contentious issue, from the comments. I thought the article was spot on.

The author posits that there is no correlation between brain size and intelligence. To critique his arguments via other ways of measuring body/brain relationships is not to critique his argument at all.

When he takes up the redirection (ie bait) and puts forward a solution, the readers / comments try to spring the trap, but only catch themselves. Ooof.

By: Jeremy (PsyBlog author)

Jeremy (PsyBlog author) — Sun, 30 Mar 2008 09:39:00 +0000

Rebel, it's a chapter in the book: "Tall tales about the mind and brain: separating fact from fiction."

By: DanielOH

DanielOH — Sat, 29 Mar 2008 05:29:00 +0000

James Watson stated that Caucasians have a greater aptitude for intelligence than Africans, also that Asians have a greater aptitude than Caucasians. So this supports the head-size theory. Am I the only one who feels that discoveries should not be covered up because some people might not like to hear the news? It is in the DNA, just pretending the evidence doesn't exist is not going to make it not true. It will, however, hold back out progress. I feel those who demand political correctness in science today, are just as bad as churches were for science hundreds of years ago.

By: rebel

rebel — Sat, 29 Mar 2008 01:33:00 +0000

Does anyone know where I can get my hands on a copy of this Journal article of Careys 2007

By: Doc Shadow

Doc Shadow — Tue, 25 Mar 2008 12:50:00 +0000

Jeremy - I think it was just the comments that muddied the waters. The point about brain size in humans and intelligence having little to no relationship is an excellent point.

By: Malcolm

Malcolm — Sun, 23 Mar 2008 19:40:00 +0000

Well, and the other problem with intelligence tests is that not all intelligence is hereditary. Plenty comes from environmental influences.

By: HoverHell

HoverHell — Sun, 23 Mar 2008 12:26:00 +0000

I agree with you main poimt, but I can note some presumptions (no real science, just a bit of logic):
1. It might be matter not only of size, but also of complexity of its structure.
2. As well, it might be not size of entire brain, but of its specific parts (frontal lobes, for example).
3. And, really, "Whatever intelligence tests measure.". Size might affect, but not imply intelligence (especially anything measurable).

By: Jeremy (PsyBlog author)

Jeremy (PsyBlog author) — Sat, 22 Mar 2008 09:55:00 +0000

Hi Doc, this post is about the relationship between ability (intelligence) and brain size. I'm saying there's no proven relationship between those two things in humans - that's the main point.