You are hardly alone if you believe that humanity is divided into two great
camps: the left-brain and the right-brain thinkers — those who are
logical and analytical vs. those who are intuitive and creative. For years, an
industry of books, tests and videos has flourished on this concept. It seems to
be natural law.
Except it isn’t.
Scientists have long known that the popular left brain/right brain story
doesn’t hold water. Here’s why. First, the sweeping characterizations of the two
halves of the brain miss the mark: one is not logical and the other intuitive,
one analytical and the other creative. The left and right halves of the brain do
function in some different ways, but these differences are more subtle than is
popularly believed. (For example, the left side processes small details of
things you see, the right processes the overall shape.) Second, the halves of
the brain don’t work in isolation; rather, they always work together as a
system. Your head is not an arena for some never-ending competition, the brain’s
“strong” side tussling with its “weak.” Finally, people don’t preferentially use
one side or the other.
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The roots of the left/right story lie in a small series of operations in the
1960s and 1970s by doctors working with Roger W. Sperry, a Nobel-laureate
neuroscientist at the California Institute of
Technology. Seeking treatment for severe epilepsy, 16 patients agreed to let the
doctors cut the corpus callosum, the main nerve bundle that joins the two halves
of the brain. They found some relief from these dramatic visits to the OR — and
when they left the hospital, they allowed Sperry and his team to study their
cognitive functioning.
Laboratory findings do not always make their way into the popular culture,
but these did, which provided an unfortunate opportunity for misinterpretation
of what was, in essence, a limited set of experiments. In 1973, the New York
Times Magazine published an article titled, “We Are Left-Brained or
Right-Brained,” which began: “Two very different persons inhabit our heads … One
of them is verbal, analytic, dominant. The other is artistic …” TIME featured
the left/right story two years later. Harvard Business Review and
Psychology Today jumped in. Never mind that Sperry himself cautioned that
“experimentally observed polarity in right-left cognitive style is an idea in
general with which it is very easy to run wild.” A myth spread.
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Intelligence)
Myths, of course, are a timeless way to make sense of experience. In the
search for meaning, people may create simplified narratives. This is a
reasonable strategy, but the right brain/left brain narrative introduced
misconceptions.
We have developed a new theory built on another, frequently overlooked
anatomical division of the brain, into its top and bottom parts. Among other
things, the top part sets up plans and revises those plans when expected events
do not occur; the bottom classifies and interprets what we perceive.
Based on decades of research, the theory holds that this distinction can help
explain why individuals vary in how they think and behave. We all use both parts
of the brain but differ in how deeply we use each part. The key is the way the
parts interact, not each part by itself. Depending on the extent to which a
person uses the top and bottom parts, four possible cognitive modes emerge.
These modes reflect the amount that a person likes to devise complex and
detailed plans and likes to understand events in depth. (You can determine your
own dominant mode with this test.)
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Have in Common)
This new approach avoids the pitfalls of the left brain/right brain story for
several reasons. The characterizations of what each part does are based on years
of solid research. We emphasize that the two parts always work together — it’s
the relative balance of how much people use the two parts that determines each
cognitive mode. And we stress that the parts of the
brain don’t work alone or in competition but seamlessly together. In some ways
this theory too is a simplification, but one that brings more understanding. If
there’s one thing we do know, it’s that as a species, we are continually
inclined to try to understand what we encounter, even something as complex as
the brain.
Kosslyn is a cognitive neuroscientist and was professor of psychology at
Harvard University for over 30 years; he now serves as the founding dean of the
Minerva Schools at the Keck Graduate Institute. Miller is an author, filmmaker
and Providence Journal staff writer. They are the co-authors of Top Brain, Bottom Brain: Surprising
Insights Into How You Think.
Time
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