Our Dwindling Intelligence and Einstein's Brain

A recent duo of articles by Stanford professor Gerald Crabtree has sparked some controversy. In two parts, he discusses our ‘fragile intellect’.

In the first part, it is stated that our intelligence is based on the many, many genes, and, as such, is very fragile.

In the second part, he argues that, during much of human history, intelligence was very important for survival (you had to be smart enough to avoid getting killed). However, so the argument continues, since we settled down, this selection pressure relaxed. Lots of food, lots of support, and so on, would mean that even those not ‘intelligent’ enough to survive ‘out in the wild’ could have their ‘happily ever after’ (wow, quotation mark overload. Apologies to those who get annoyed by it).

With regards to the first part, there doesn’t seem to be too much of a fuss, many genes underlie intelligence, nobody’s really going to argue otherwise.

Part two, however, did cause a bit of a fuss. And here, I choose the easy way out: for more about that, go here and here. In short: sexual selection, survival doesn’t equate to reproduction, early days in settlements weren’t particularly easy, ‘street smarts’ needn’t equate to ‘book smarts’.

(Wikimedia Commons, Dan Smith)

And this last point leads to something worth stressing: intelligence is incredibly hard to define. The cognitive abilities that are very valuable among hunter-gatherers are probably not entirely identical to those that are important in a huge metropolis. Just think: finding your way from memory vs. GPS. What we consider intelligent depends on the historical era (kids in western communities learn more math than adults for most of human history), culture (hunter-gatherer vs. westerner), and other things.

So, it seems that, instead of talking about declines or rises in intelligence, it would surely prove more valuable to consider more specific cognitive abilities (spatial reasoning, working memory, …)?

And now, Einstein’s brain. Smooth transition, wasn’t it?

Albert Einstein, 1947.
(Wikimedia Commons, public domain)

Most will agree that Albert Einstein was quite intelligent (however, intelligence is a tricky thing, remember). Anyway, after his death, his brain was preserved for scientific study. It was photographed and cut into pieces. These pieces were subsequently spread across the globe to various researchers. This scattering of Einstein’s brain resulted in difficulty studying it in its entirety. Now, all research material from Thomas Harvey (who did the cutting), such as photographs from the whole brain and information about how and where the brain was sliced, has been transferred to the National Museum  of Health and Medicine.

This material has been analyzed and it suggests that his brain is remarkable in some ways indeed. Or, more accurate, it was complicated. While it’s only average in size, the cerebral cortex shows more convolutions and folds than in other brains (it was compared to 85 other blobs of grey and white matter). For more info, click here and read an interview with the lead researcher here.

Some brief thoughts:

• 85 brains to compare is good, more would be better (though, admittedly, availability might be an issue).

• Interesting to consider how much of this could be attributed to nature, how much to nurture, and how much to the interaction between both.

• Are there other ‘brilliant brains’ researchers can look at?

• It’s probably more than the folds and convolutions (relative size of certain regions, connectivity, glial cells,…).

• Genius comes in many shapes and forms…

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Crabtree, G. (2012). Our fragile intellect. Part I Trends in Genetics DOI: 10.1016/j.tig.2012.10.002

Crabtree, G. (2012). Our fragile intellect. Part II Trends in Genetics DOI: 10.1016/j.tig.2012.10.003

Falk, D., Lepore, F., & Noe, A. (2012). The cerebral cortex of Albert Einstein: a description and preliminary analysis of unpublished photographs Brain DOI: 10.1093/brain/aws295

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