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.
