Lenin's Brain
The project of teasing intelligence out of a floppy wet mass of fat, water, carbohydrates, proteins and salt
This Sunday will mark hundred years since the death of Vladimir Lenin, something I definitely realised and thought about before I started writing this piece.
For as long as people have thinking about the brain, they’ve been trying to see if the number of spongy bits correlates with intelligence. Erasisstratus, one of the purported founders of neuroscience working in the 3rd century BC, suggested humans were the most intelligent animals because they had the most complex cerebral hemispheres.
Galen, a Roman physician in the 2nd century AD, argued that was wrong. Donkeys had complex cerebral hemispheres, and Galen believed they were among the stupidest animals on the face of the Earth, so clearly Erasisstratus was wrong.1
Skipping forward a few thousand years, we arrive at the 19th century, where brain analysis became a lot less about donkeys and a lot more about reinforcing prejudicial cultural narratives. People like Samuel George Morton and Gustave Le Bon promulgated theories about how the cerebral capacities of different races varied, and pushed the idea that Caucasians had the largest brain capacity, in line with their supposedly superior intellect.
This was also much easier to believe when their best tools for measuring cranial volume was to take an empty skull and fill it with millet or mustard seed, and then see how much that weighed. If you wanted to, you could give Caucasian skulls a greater brain capacity by ramming more millet in. Millet also changes size in response to things like fluctuations in water vapour, so it’s a great tool for measuring brains if you’re more interested in the conclusions than the method.
In 1855, Rudolph Wagner, a professor at the University of Göttingen, was able to obtain the brain of Carl Friedrich Gauss. Wagner was initially excited, because while Gauss’ brain weighed only slightly above average, he had a much more complex pattern of fissures than the typical brains being studied. However, Wagner had obtained the brains of a number of other professors at his institution (presumably after they had passed on), and they lacked these patterns.
There was one possible explanation for this. Paul Broca, who has the part of the brain responsible for speech production named after him, drily remarked, “A professorial robe is not necessarily a certificate of genius; there may be, even at Göttingen, some chairs occupied by not very remarkable men.” Perhaps these fissure-less professors were not up to much, intellectually speaking, and Gauss’ fissures were still a hallmark of his evident intelligence.
This turned into a competition, and by that I don’t mean that Wagner challenged Broca to pistols at dawn. Great men set their brains aside to have them weighed against each other, in order to determine their genius scientifically. This process was somewhat unreliable.
Firstly, you had to be dead in the 19th century to get your brain weight accurately measured - unless you just wanted them to drill a hole in your skull and just pour two kilograms of millet in. This made the bragging rights somewhat superfluous. Secondly, the brain tends to waste away in the last years of life, particularly if you live a long time, so this undermined those same bragging rights in the afterlife.
One of the most significant brain anatomists of the turn of the twentieth century, Edward Spitzka, promising to scientifically explore genius, was able to get his hands on the brains of men from all walks of life (as far as I can tell they were mostly men). These included Ludwig von Beethoven, Abraham Lincoln, William Thackeray, and Louis Agassiz (who had done some racist brain profiling before his own brain was put in a jar), to name a few.2
Cranial Capacities
Before we really get into this, some context. The average brain size is around 1,328 (±145) units of cranial capacity (cc), or around 1262 (±138) grams.3
Spitzka found that people from “the exact sciences”, or what we would now call “the sciences”, generally had the heaviest brains. The heaviest brain in his sample was Ivan Turgenev, the Russian author of Fathers and Sons, whose brain had a cranial capacity of 2,118cc, around 68% larger than the average European brain. There you have it folks, the man with the largest brain in our collection is also associated with nihilism, thus proving the nihilists were right and life has no meaning. Or rather, it proved that all brains submitted were subject to significant variation, and that Turgenev had a really big number next to his name.
Don’t get me wrong - there is a correlation between brain size and intelligence, and brain size has been reported as explaining anywhere between 9% and 16% of the variance on intelligence tests.4 Whether the relationship is causal is still being debated. But it doesn’t inherently mean that having a large brain is a prerequisite for being a genius. Albert Einstein’s brain had a cranial capacity of around ~1,291cc, slightly smaller than Walt Whitman’s ~1,317cc, and both of those are below the average cranial capacity I cited above (although that average has likely increased over time with better nutrition).
Nonetheless, according to Spitzka, the brains of those considered geniuses usually tended to weigh more than the typical brains they were compared with. Incidentally, Franz Joseph Gall, the inventor of phrenology, had a brain that weighed 1,198 grams (or 1,261cc).
Spitzka then took the very nineteenth century next step of comparing Gauss’s brain, an average bushwoman’s brain and a gorilla brain. He also took the brain of Hermann von Helmholtz, a pioneer in psychology, and compared it to a person from Papua New Guinea, and a chimpanzee. You can see the results below. Note that both of the European men were much physically larger, and brain size correlates strongly with body size:
Meanwhile, Vladimir Bechterev had found that Dmitry Mendelev’s brain had exceptional development in the frontal lobes, and other anatomists went on to try and establish this relation in all the brains of geniuses, with limited success.
In 1904, Robert Bennett Bean performed a study where he arbitrarily concluded that the brains of black people weighed less than those of white people. From that he went on to make a series of subjective jumps, deciding that this meant white people were more objective, and had better aesthetic senses, and a lot of other random stuff he seemingly just made up.
The problem? His own study said that the brains of black and white people weighed similar amounts. How did Bean get out of this one? He just decided that the people in his study were high-class black people and lower-class white people.
Franklin Paine Mall, an American anatomist of the early 20th century, attempted to replicate this study and got nowhere. He wrote: “It certainly would be important if it could be shown that the complexity of the gyri and the sulci of the brain varied with the intelligence of the individual, that of genius being the most complex, but the facts do not bear this out, and such statements are only misleading. I may be permitted to add that brains rich in gyri and sulci, of the Gauss type, are by no means rare in the American negro.”
This didn’t stop other brain scientists from pursuing their own racist agendas. Bean continued to publish as if Mall hadn’t written anything, and others reprinted his results without much consideration, as if they were scientific fact.
The complexity of gyri and sulci actually do correlate with intelligence (not that this has relevance to Mall’s research), but only in specific regions such as the temporo-occipital lobe, as opposed to across the whole brain. Nonetheless, scientists in the early days of brain mapping were focused elsewhere, and women also suffered from this erratic and blinkered approach.
While this is all fascinating, it doesn’t really allow you to determine who will be a genius from their brain. You can estimate that someone with a larger brain might perform higher on an IQ test, but there are plenty of people with high IQ scores who are not Einstein. The collection of circumstances required to produce great minds is complex and clearly culturally influenced.
This didn’t stop a lot of people from taking the brains of great people, finding any abnormal quantity of any brain mush, and assigning it as a prerequisite for genius. Einstein, whose poor brain in recent years has been continually investigated, supposedly had a larger than average amount of glial cells (which provide support for neurons), and more extensive connections in his corpus callosum, and alternative features in his primary motor cortex that gave him greater musical ability. At some point, people have argued that any of these different features allowed Einstein to think in the way he did.
Lenin’s Brain
As a result of this furore about the brains of great men, when Lenin died in 1924, the Soviet High Command decided to prove that he was a genius via brain analysis. To do this, they asked the preeminent anatomist of the time, Oskar Vogt, who was based in a Berlin laboratory, to examine Lenin’s brain.
The information about this program is conflicting. Multiple sources differ on whether Vogt had access to the entire brain or a tiny slice of frontal cortex, and how exactly he performed his analysis. He seems to have been shown the entire brain in Moscow, but then only been allowed to take one cortical slice back home to Berlin. One source notes that Vogt and his wife were protected by the wealthy Krupp family and at one point they used this protection to kick Joseph Goebbels down the stairs when he tried to interfere with their work.
The Soviets were certainly anxious that Vogt wouldn’t come to the right conclusions. To quote the Head of the Culture and Propaganda Department of the Central Committee: “Vogt’s presentations are of a questionable nature; he compares Lenin’s brain with those of criminals and assorted other persons. Professor Vogt has a mechanical theory of genius using an anatomic analysis based on the presence of a large number of giant cortical pyramidal cells. In the German encyclopaedia of mental illness, a German authority (a Professor Spielmaier) claims that such pyramidal structures are also characteristic of mental retardation.”
You can almost feel the paranoia emanating from the final statement: ‘a different neurologist has an alternative theory of what Vogt has found, and the western press are going to use it to call Lenin an idiot!'
Vogt didn’t do that. His main conclusion was this:
"In the third cortical layer, particularly in its deep portions, of several brain areas, I found pyramidal neurons of extraordinary size and number never previously observed by myself .... The anatomical findings allow us to identify Lenin as a brain athlete and association giant".
Again, these results are somewhat suspect, because we don’t know how much access Vogt had. However, his conclusions were broadly right. Recent research shows larger dendrites do seem to correlate with higher IQ scores.5
Dendrites are the section of a neuron that receive electrical excitation from other neurons - the axon synapses onto dendrites. Large dendrites can hold larger pools of current, allowing for faster changes of neuronal membrane potential. This speed allows for quicker generation of action potentials, and better tracking of synaptic inputs.
Testa-Silva et al. (2014) show that human synapses in pyramidal neurons, partly by virtue of being larger, can transfer information about 4-9 times faster than mouse pyramidal neurons.
Goriounova et al. (2018) expand on this and argue that all of this comes from the ability to generate action potentials quickly. Larger dendrites result in faster action potentials, and neurons which generate action potentials faster can encode more changes in synaptic membrane potential, and thus encode more information. In the same manner, reaction speeds often correlate with IQ scores. Small differences in dendrite size at the neuronal level could result in very large changes in information processing power across the brain, which contains ~86 billion neurons.
So Lenin probably was a brain athlete and an association giant, although you’d expect that a man capable of writing complex philosophy would be.
The Future
What does all this tell us? Even if they are not the whole story, we are becoming better able to determine neural correlates of intelligence accurately. This should produce strong ethical concerns, especially given the history of brain measurement and intelligence testing.
We are going to have tools in our hands in the near future that present an excess of neural information, which needs to be strictly regulated. Rafael Yuste, among others, has been warning for some years now about the dangers of new neural technologies. They stress the dangers of neuromodulatory technologies, but information about the brain will also become more dangerous as we understand the mechanisms of thought and intelligence better.
Such tools and information may be useful - if we can determine how different diets or educational strategies impact the brain’s development, that is beneficial. But such tools also could easily create problems - a system that triages people for jobs based on a neural profile, say, sits ill-at-ease with our current system of morality.
We need to find a system that enables the first of those two possibilities without enabling the second. We’re still near the beginning of the process of drawing intelligence out of the brain, and we have the mistakes of past generations to draw on as we move forward.
This claim is made here, although Finger gives no reason why Galen believed that donkeys were so stupid. Maybe Galen just thought donkeys were dumb. I once sponsored a one-eyed donkey called Seamus in a sanctuary, and then watched him run headfirst into a wall. Then again, I have done the exact same thing, and I have one more eye than Seamus did.
As an aside, Spitzka’s father testified to the insanity of Charles Guiteau, who assassinated President Garfield, at his trial, while Spitzka himself performed the autopsy on Leon Czolgolz, who assassinated President McKinkey. Disappointingly, none of the Spitzka family seem to have been involved in the autopsy of Lee Harvey Oswald, a major lapse on the part of the Spitzka granchildren.
See this article for various calculations and estimates. To get the grams from the cranial capacity, I used Hofman’s equation: Brain mass (g) = cranial capacity(cc) × 0.95.
The amount of intelligence variation explained by brain size is also debated, but the correlation is fairly robust.
Yes, we’re relying on IQ scores again. They’re the best resource we have for measuring intelligence, and map to a lot of positive life outcomes, but you have to put them in context.