Some people corner the market  on a trait so thoroughly that their name becomes synonymous with it.

Like, if you call someone a Benedict Arnold, you’re calling them a traitor. And Albert Einstein means  genius, sometimes sarcastically.

Scientists have been fascinated  by what made Einstein a genius for decades, and what it can tell  us about intelligence in general. So fascinated that in fact it led one of them to take his brain without permission, which opened the door to it becoming the most studied brain in history. You don’t need to be Albert Einstein  to understand how wrong that was.

But quite a few researchers really wanted to know: Was there anything special about Einstein’s brain? [♪INTRO] Einstein died in 1955 at the age of 76 from a ruptured abdominal aortic aneurysm. At the time he was living  in Princeton, New Jersey. He had technically retired 10 years before, but was still actively doing physics  research and humanitarian work.

Einstein told his doctors that he didn’t  want to prolong his life artificially, and made it known that he wanted to be cremated. And he was. Mostly.

After his aneurysm, he was taken to a  hospital in Princeton, where he died. At that point, his body was  wheeled away for an autopsy. But the pathologist on-call that  day removed his brain during the autopsy and saved it, thinking  it would be valuable to study, while the rest of his body  was sent on for cremation.

Einstein had never given consent for his brain to be used for scientific  purposes, and the pathologist didn’t get permission from  the family at first, either. When one of Einstein’s sons found  out, he was understandably angry. But the doctor was later able to  convince the son to give permission for the brain to be preserved,  so he and others could study it.

And boy, did they study it. The first paper was published in  1985, 30 years after Einstein died. Which seems like a really long time,  right?

We’ll get back to that later. The first paper focused on glia,  cells in the nervous system that aren’t neurons and don’t  send electrical messages. There are several kinds of glia, but  they’re all support cells for the neurons.

They hold neurons in place, form the coating that helps neurons send messages more quickly, bring neurons nutrients, and basically act as an immune system for the brain. The paper compared Einstein’s brain  to the brains of 11 other men, and reported that Einstein’s  had more glial cells compared to neurons in the inferior parietal  lobe than the controls did. This area of the brain is involved  in complex language skills, and may also be involved  with performing calculations.

So they proposed that Einstein  needed more glia per neuron in that area because his neurons  worked harder than most people’s. Working harder requires more energy, and therefore more glia to bring them nutrients. The paper reported that the control  brains averaged roughly one glia for every two neurons, while for Einstein,  the ratio was closer to one to one.

Today, neuroscientists believe that the ratio of glia to neurons in Einstein’s  brain was actually typical. Most brains have that one to  one ratio of glia to neurons. But what would it mean if Einstein  did have more glia than usual.

There’s some evidence that more  glia compared to neurons is related to the size of neurons, but  it’s not connected to intelligence. There were also some major issues with this study. Like, sure, they found a smaller neuron-to-glia ratio in the inferior parietal  lobe than in the controls.

But they didn’t only look  in the left angular gyrus. They saw no differences in neuron-to-glia ratio in the three other brain areas they looked in. They also didn’t just look  at neuron-to-glia ratio, and saw no differences in any of the  six other ways of counting cells.

In other words, they looked  at seven different factors in four different brain areas,  for a total of 28 comparisons, and only found a significant  difference in one of them. So there’s a decent chance this  finding was a false positive. Einstein was also 76 when he died, and the average age of the control brains was 64.

The control individuals were also patients who died at a Veterans Administration Hospital, and while none of them died  of neurological disease, military service historically  hasn’t been kind to brains. So it’s tough to say that  any differences between them were indicative of Einstein’s  smarts, and not some other factor. On top of all of that, a different  paper argued that not only was a different neuron-to-glia  ratio in his inferior parietal lobe not what made him a genius, it’s  actually what caused his dyslexia.

Those researchers referenced  work that shows that damage in this area is associated with the reading disorder. So if Einstein’s ratio of cells really was different than other people’s,  that could be related. Except we can’t say for sure that  Einstein actually had dyslexia.

He was never diagnosed, and the  belief that he was dyslexic comes from anecdotes he and his family  recounted later in his life. And memories aren’t always accurate. Even if he did have dyslexia,  the ties between this brain area and dyslexia aren’t as direct  as this hypothesis suggests.

So ok, it doesn’t seem like glia can  account for Einstein’s intelligence. The next thing researchers  looked at was his neurons. But before I tell you more about that, let's take a quick break.

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A second study in 1996 looked at a slice of Einstein’s right prefrontal cortex. This area of the brain is involved  in a lot of complex tasks, like emotional regulation,  understanding what other people are thinking and feeling,  and planning things out. This study did a little better  with the age of the controls, comparing Einstein’s brain to five  men with an average age of 68.

It found that while the samples  of Einstein’s prefrontal cortex had the same number of neurons as the controls, the cortex itself was much thinner. In other words, the neurons  were packed in more densely. Which was curious.

The brain sections were  preserved and prepared in the exact same way, so that probably  couldn’t explain the difference. The controls were also elderly men, which meant that any age-related effects  should be relatively equal. So the researchers suggested  that a higher density of neurons could lower the amount of time it  took to send messages between them, which might allow for faster processing.

And faster processing could mean more smarts. But there were a few issues with this  study and its interpretation, too. First, a study the next year looked at  a different part of Einstein’s brain, the superior temporal gyrus, and reported that there was no difference in  cortical depth in that area.

To be fair, given the tasks that the  prefrontal cortex is involved in, there could be something about it specifically when it comes to intelligence. It has a role in some pretty intense  cognitive skills, so the hypothesis that denser neurons gives you some  sort of advantage seems reasonable. Except, there’s no evidence that denser neurons in the prefrontal cortex boosts those skills.

In fact, there is evidence that people with schizophrenia may have  denser neurons in that area. Einstein didn’t have  schizophrenia, but you can see how hard drawing conclusions  from this kind of thing can be. So the density of neurons in his prefrontal cortex was probably not what made Einstein a genius.

Researchers then turned to the  shape and structure of his brain. In 1999, a group of them looked  at photographs of Einstein’s brain to determine whether there  were any differences in the gyri and sulci of his brain  compared to other people’s. Those are the bumps and valleys  that make our brains look wrinkly, and neuroscientists use them as the boundaries that define certain areas of the brain.

For example, the primary motor cortex,  for example, can be found on the ridge right in front of the central sulcus. These researchers reported that  Einstein’s brain had a larger inferior parietal lobule than  usual, and that his supramarginal gyrus didn’t have the typical  groove running through it. This particular gyrus is thought to be important in speech and language processing, and the researchers suggested that differences in this area could mean that a larger chunk of his brain was deeply connected.

And more connections could mean more intelligence. But other scientists looked at the  same pictures and thought Einstein’s brain looked exactly like everyone  else’s, going so far as to say that his parietal lobes were so normal, it  looked like a picture in a textbook. There was a lot of back and forth as researchers argued over who was looking at the brain wrong.

A decade later, a researcher on  “Team Yes It’s Different” proposed that his large parietal  lobes might have contributed to more ability to do  mathematical and spatial tasks. They also observed what they called a  “knob” in his right precentral gyrus. This area is involved with  processing the sensation of touch, but changes in this area have also  been associated with musicians.

And Einstein was an accomplished violinist. So while it seems unlikely that  Einstein’s gyri made him a genius in physics, there may be some  relationship with his musical talent. Undeterred by the lack of  success so far, one final group of researchers decided to focus  on Einstein’s corpus callosum.

This is the large bundle of nerves that connects the two hemispheres of the brain, allowing them to communicate and pass information back and forth. Einstein’s was bigger than that  of other men his age, and in some measures, it was even  bigger than men 50 years younger. The researchers interpreted it as Einstein having more connections  between his two hemispheres, resulting in unique  mathematical and spatial skills.

Now, there is some evidence that  having a larger back section of the corpus callosum correlates  with higher scores on IQ tests. We won’t get into the problems  with IQ tests as a measure of intelligence here, but  there is at least a connection between the size of that part  of the brain and those tests. Except in Einstein’s case, it wasn’t just the back portion of his corpus callosum.

The whole thing was bigger, and we  really don’t know what that means. If the whole thing is bigger, you’d  expect the back to be bigger, too. It’s possible that a bigger  corpus callosum allows for more information transfer between the two sides, so Einstein could have put  information from different areas of the brain together more  effectively.

But we just don’t know. So after all these studies, we  still don’t have many answers, and there are some serious issues  with the whole body of literature. First, none of the studies of  Einstein’s brain were blinded, so the observers knew whether they were looking at a control brain or Einstein’s.

That’s not great scientific practice, because bias can slip in and color the findings. And a lot of the results have been influenced by what we know about Einstein. For example, he once explained that for him, thinking didn’t just involve images and feelings, but was also experienced in his muscles.

Researchers brought this up in  light of findings of Einstein having a larger area of the motor cortex  associated with the face and tongue. But they didn’t go into the  study looking for something that might explain this  description of how he thought. Instead, they noticed a  difference, and then went through Einstein’s life to see if there was  something that difference could explain.

Some researchers argue that’s  also not great practice. Plus, we only have information about Einstein’s brain from when he was 76 years old. You’d expect there to be some  changes from when he was younger, so we don’t know which of  these features he always had, and which may have been special to  the 76-year-old version of his brain.

And the cherry on top of all of  this is that Einstein died in 1955, and the first study didn’t come out until 1985. Like I hinted earlier, that’s  a suspiciously long time. The pathologist who kept the brain  had been studying it that whole time, and didn’t publish anything because  he didn’t find anything unusual.

That’s a lot of negative results  before finally finding a difference. And it’s going to be really  difficult to ever draw conclusions about intelligence from one  brain, no matter how smart it is. With a sample size of 1, we can’t tell  what’s a feature of his intelligence, and what’s just a weird  thing about Einstein’s brain.

All brains have unique features,  not just those of geniuses. Intelligence is so complex that  scientists can’t even agree on what it is, much less boil it down to one anatomical feature that’s responsible  for one particular trait. That’s just not how brains work.

And even if we could find some bit of  Einstein’s brain that directly tied into his genius, it would probably  only tell us about specific skills that Einstein had, not  about intelligence as a whole. So it’s pretty safe to say that  the keys to intelligence probably aren’t hidden somewhere in the  structure of Einstein’s brain. But, I mean, the guy gave us general  and special relativity, so...

I think he’s done enough. [♪OUTRO]