Einstein's Brain: What Studies Found and Why Scientists Are Cautious

What Studies of Einstein’s Brain Found, and Their Limits

Was Albert Einstein's brain really different? Studies of his preserved brain have reported a few unusual features: an unusually well-connected corpus callosum, the bundle of fibres that links the two hemispheres; an atypical pattern of folds in the parietal lobes; and a higher ratio of support cells to neurons in one region. What they have not shown is that any of these features explains his genius. The evidence comes from a single brain, compared with small control groups, often using decades-old photographs.

Here is how Einstein's brain came to be studied at all, what each major study found, and why scientists remain cautious about the conclusions.

How Einstein's Brain Ended Up in a Jar

Einstein died in Princeton, New Jersey, in April 1955, at the age of 76. During the autopsy, the pathologist on duty, Thomas Stoltz Harvey, removed the brain and weighed it at 1,230 grams, which is within the normal range for an elderly man.

Whether Einstein would have agreed is disputed. Einstein asked to be cremated, and more recent research suggests the brain was taken without prior permission from him or his close family. His son Hans Albert later gave his approval after the fact, on the condition that the brain be used only for serious research published in respected scientific journals.

Harvey photographed the whole brain from many angles, then cut it into about 240 blocks, preserved some of them on microscope slides and sent samples to researchers. For years the pieces sat in jars in his possession, until journalist Steven Levy tracked them down in 1978. In 2010 Harvey's heirs passed his material, including fourteen previously unseen photographs, to the National Museum of Health and Medicine. The Mütter Museum in Philadelphia holds 46 small portions and has displayed slides of brain tissue.

What the Major Studies Reported

Glial cells (Diamond, mid-1980s)

Neuroscientist Marian Diamond and colleagues at the University of California, Berkeley, compared tissue from four areas of Einstein's brain with samples from 11 men who had died at a younger average age. Einstein had more glial cells, which support and nourish neurons, per neuron in every area studied. However, the difference was statistically significant only in one region, the left inferior parietal area.

The parietal lobes (Witelson, 1999)

Sandra Witelson's team at McMaster University in Canada analysed Harvey's 1955 photographs and published the results in The Lancet. They reported that his parietal lobes were about 15 percent wider than those of the comparison group, that part of a groove called the Sylvian fissure was missing, and that a region called the parietal operculum appeared to be absent. The parietal lobes are linked with spatial and mathematical reasoning, which made the finding a tempting match for a thinker who described his ideas as visual. Even at the time, other scientists said a definite link to his abilities was a step too far.

The cortex in detail (Falk and colleagues, 2012)

Anthropologist Dean Falk of Florida State University led a study of the fourteen newly released photographs, published in the journal Brain in November 2012. The team described an extra ridge in the frontal lobe, unusual patterns in the parietal lobes and a feature of the motor cortex that they speculatively tied to his violin playing. They also found that the overall size and shape of the brain were normal.

The corpus callosum (Men and colleagues, 2013)

This is the study behind the "superhighway" headlines. Physicist Weiwei Men of East China Normal University, working with Falk, used a new technique to measure the thickness of the corpus callosum along its length in Harvey's photographs. In a paper published in Brain in September 2013, they compared Einstein's brain with 15 elderly men and 52 men aged 26, the age Einstein was in his "miracle year" of 1905. In most sections, his corpus callosum was thicker, which the authors interpreted as a sign of more extensive communication between the hemispheres.

Other findings

In 2001 psychologist Dahlia Zaidel reported that neurons in two slices of Einstein's left hippocampus were larger than those on the right, an asymmetry not seen to the same degree in controls. Like the others, this result rested on a very small amount of tissue.

Why Scientists Urge Caution

Each of these studies is interesting, but none can show that a brain feature caused Einstein's achievements. The main problems are familiar to anyone who reads research critically:

A sample of one. Every brain is unique. Finding something unusual in one person's brain is almost guaranteed if you look hard enough, and there is no way to know whether the same feature appears in many ordinary people.
Mismatched comparisons. In Diamond's study the control brains came from younger men, and glial cells keep dividing with age, so Einstein's age alone could explain part of the difference.
Knowing whose brain it was. Researchers were aware they were studying Einstein, which risks unconscious bias in what they looked for and how they interpreted it.
Photographs, not tissue. Several studies relied on 1955 photographs of a preserved brain, which limits precision.
Publication bias. Studies that find differences are more likely to be published than those that find nothing special.

Psychologist Terence Hines of Pace University has been one of the sharpest critics. He argues that claims linking these features to genius go far beyond the evidence and that it would be more meaningful to study the brains of many accomplished scientists than the brain of one. Some critics also note an uncomfortable echo of nineteenth-century phrenology, which tried to read character from the shape of the skull.

Myths About Einstein and the Brain

"Einstein had a bigger brain." He did not. At 1,230 grams his brain was average or slightly below average for his age.

"We only use 10 percent of our brains, but Einstein used more." The 10 percent idea is a myth. Brain imaging shows activity across virtually the whole brain over the course of a day, and the quote is not traceable to Einstein.

"Left-brained people are logical, right-brained people creative." The hemispheres do specialise in some tasks, such as language, which relies more on the left side in most people. But complex thinking uses both, which is exactly why the corpus callosum matters. There is no good evidence that people can be sorted into left-brain and right-brain personality types.

"Einstein failed maths at school." Another popular myth. He excelled at mathematics from a young age; the story probably grew from confusion over a Swiss grading scale.

What This Means for the Rest of Us

If a thick corpus callosum is not a recipe for genius, what is? Einstein's own life points to things anatomy cannot capture: intense curiosity, years of sustained work on a small set of hard problems, a habit of thought experiments and a network of friends and colleagues to argue with.

Brain research does offer one encouraging lesson. Throughout life, the brain changes in response to how it is used, a property known as neuroplasticity. Learning an instrument, a language or a demanding skill can reshape connections. Whatever Einstein was born with, the brain that Harvey studied was also the product of decades of thinking hard.

The short video below covers the 2013 corpus callosum study in a few minutes.