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His Brain Measured Up

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June 24, 1999, Section A, Page 27Buy Reprints
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People have long wondered about the source of genius. Last week three neuroscientists claimed to have found it using a pair of calipers. After examining the brain of Albert Einstein, they said it had large and unusually shaped inferior parietal lobules, a seat of mathematical and spatial reasoning.

The effort to reduce brilliance to bulges in the brain may smack of 19th-century pseudoscience. Phrenologists at that time pinned traits like ''acquisitiveness'' and ''conjugality'' to swatches of the cortex and assessed those qualities in different people by measuring bumps on their heads. Vain Victorian intellectuals bequeathed their brains to craniometers, but their ghosts would be disappointed; we now know that brain size is only weakly related to intelligence. These fiascoes would seem to confound any attempt to measure giftedness in centimeters.

But the elegant study on Einstein, published in the medical journal The Lancet by Sandra F. Witelson, Debra L. Kigar and Thomas Harvey, is consistent with the themes of modern cognitive neuroscience. Every aspect of thought and emotion is rooted in brain structure and function, including many psychological disorders and, presumably, genius. The study confirms that the brain is a modular system comprising multiple intelligences, most nonverbal. Contrary to widespread belief, we do not think exclusively in language.

Indeed, Einstein said he reasoned by combining mental images of a ''visual and muscular type.'' Only after he could reproduce a crucial episode of mental play at will did he ''laboriously'' seek words and symbols to convey the insight to others.

For example, from imagining himself riding on a beam of light and looking back at a seemingly frozen clock tower, he developed the theory of special relativity -- that time, length and mass vary with the relative motion of an event and an observer. From imagining himself inside a plummeting elevator and seemingly weightless, he developed the theory of general relativity -- that gravity and acceleration are the same. The theory of relativity depends on conceptualizing time as a dimension like height, width and depth, and on visualizing the universe as a curved four-dimensional space, which may be characterized precisely in complex equations.

The neuroscientists who studied Einstein's brain had good reason to focus on his parietal lobes, the top rear quadrant of each hemisphere. Situated between the primary areas for vision and body sensation, the parietal lobes are the home of spatial sense, how we locate real and imagined objects in front of us.

The inferior lobule, or lower bulge of the lobe, in particular supports abstract mathematical and spatial reasoning. Presumably that is because the core of number sense is an intuition about spatial extent; people reason about numbers as if they were places along a line.

The difference between the inferior parietal lobules of Einstein and of us mortals is not subtle. Our lobules are deeply cleaved by a branch of the Sylvian fissure, the horizontal Grand Canyon of each cerebral hemisphere. Einstein's fissure veered sharply upward, skirting the lobule and leaving it undivided.

Also, the inferior parietal lobule is ordinarily smaller in the left hemisphere, perhaps because it is crowded by adjacent areas involved in language. Einstein's left lobule was as large as his right, and both were larger than normal. But his brain as a whole was no heavier than average for a man of his age and height.

The neuroscientists speculated that Einstein's parietal lobes expanded early in prenatal development, giving him larger, undivided lobules that accommodated richer and more tightly integrated circuits for mathematical and spatial reasoning. This may help explain Einstein's other famous cognitive trait: he did not speak until he was 3 years old. Many late-talking children grow up to be engineers, mathematicians and scientists, including the physicists Richard Feynman and Edward Teller. Perhaps this is because different mental functions compete for real estate as they develop in the cerebral cortex.

No one can claim to have explained Einstein's genius. For all we know, a person with big inferior parietal lobules could just as easily have become a great home builder or billiards shark as the man who changed our conception of the universe.

For Einstein did more than manipulate mental images. He sought and found images that captured the fundamental aspects of physical reality, and converted them into appropriate mathematical equations and empirical predictions. These gifts surely lie in the microcircuitry formed by trillions of synapses in many parts of the brain, and we are not going to work out that wiring diagram in Einstein or anyone else any time soon.

Still, it is strangely fitting that the brain that unified the fundamental categories of existence -- space and time, matter and energy, gravity and motion -- should now be helping us unify the last great dichotomy in the conceptual cosmos, matter and mind.

A version of this article appears in print on  , Section A, Page 27 of the National edition with the headline: His Brain Measured Up. Order Reprints | Today’s Paper | Subscribe

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