Forget dated ideas about the left and right hemispheres. New research provides a more nuanced view of the brain.
Author and neuroscientist Stephen Kosslyn talks to WSJ
editor Gary Rosen
about the practical implications of new brain
research.
Are you a Mover, Stimulator, Perceiver or Adaptor?
Photo:
Getty Images
Who hasn't heard that people are either left-brained or
right-brained—either analytical and logical or artistic and intuitive,
based on the relative "strengths" of the brain's two hemispheres? How
often do we hear someone remark about thinking with one side or the
other?
A flourishing industry of books, videos and self-help
programs has been built on this dichotomy. You can purportedly
"diagnose" your brain, "motivate" one or both sides, indulge in "essence
therapy" to "restore balance" and much more. Everyone from babies to
elders supposedly can benefit. The left brain/right brain difference
seems to be a natural law.
Except that it isn't. The popular
left/right story has no solid basis in science. The brain doesn't work
one part at a time, but rather as a single interactive system, with all
parts contributing in concert, as neuroscientists have long known. The
left brain/right brain story may be the mother of all urban legends: It
sounds good and seems to make sense—but just isn't true.
The origins of this myth lie in experimental surgery on some very
sick epileptics a half-century ago, conducted under the direction of
Roger Sperry,
a renowned neuroscientist at the California Institute of
Technology. Seeking relief for their intractable epilepsy, and
encouraged by Sperry's experimental work with animals, 16 patients
allowed the Caltech team to cut the corpus callosum, the massive bundle
of nerve fibers that connects the two sides of the brain. The patients'
suffering was alleviated, and Sperry's postoperative studies of these
volunteers confirmed that the two halves do, indeed, have distinct
cognitive capabilities.
But these capabilities are not the stuff
of popular narrative: They reflect very specific differences in
function—such as attending to overall shape versus details during
perception—not sweeping distinctions such as being "logical" versus
"intuitive." This important fine print got buried in the vast mainstream
publicity that Sperry's research generated.
There is a better way to understand the functioning of the brain,
based on another, ordinarily overlooked anatomical division—between its
top and bottom parts. We call this approach "the theory of cognitive
modes." Built on decades of unimpeachable research that has largely
remained inside scientific circles, it offers a new way of viewing
thought and behavior that may help us understand the actions of people
as diverse as
Oprah Winfrey,
the
Dalai Lama,
Tiger Woods
and
Elizabeth Taylor.
Our theory has emerged from the field of neuropsychology,
the study of higher cognitive functioning—thoughts, wishes, hopes,
desires and all other aspects of mental life. Higher cognitive
functioning is seated in the cerebral cortex, the rind-like outer layer
of the brain that consists of four lobes.
Illustrations of this wrinkled
outer brain regularly show a top-down view of the two hemispheres,
which are connected by thick bundles of neuronal tissue, notably the
corpus callosum, an impressive structure consisting of some 250 million
nerve fibers.
If you move the view to the side, however, you can see the top and bottom parts of the brain, demarcated largely by the Sylvian fissure, the crease-like structure named for the 17th-century Dutch physician who first described it. The top brain comprises the entire parietal lobe and the top (and larger) portion of the frontal lobe. The bottom comprises the smaller remainder of the frontal lobe and all of the occipital and temporal lobes.
Our theory's roots lie in a landmark report published in 1982 by Mortimer Mishkin and Leslie G. Ungerleider of the National Institute of Mental Health. Their trailblazing research examined rhesus monkeys, which have brains that process visual information in much the same way as the human brain. Hundreds of subsequent studies in several fields have helped to shape our theory, by researchers such as Gregoire Borst of Paris Descartes University, Martha Farah of the University of Pennsylvania, Patricia Goldman-Rakic of Yale University, Melvin Goodale of the University of Western Ontario and Maria Kozhevnikov of the National University of Singapore.
This research reveals that the top-brain system uses information
about the surrounding environment (in combination with other sorts of
information, such as emotional reactions and the need for food or drink)
to figure out which goals to try to achieve. It actively formulates
plans, generates expectations about what should happen when a plan is
executed and then, as the plan is being carried out, compares what is
happening with what was expected, adjusting the plan accordingly.
The
bottom-brain system organizes signals from the senses, simultaneously
comparing what is being perceived with all the information previously
stored in memory. It then uses the results of such comparisons to
classify and interpret the object or event, allowing us to confer
meaning on the world.
The top- and bottom-brain systems always
work together, just as the hemispheres always do. Our brains are not
engaged in some sort of constant cerebral tug of war, with one part
seeking dominance over another. (What a poor evolutionary strategy that
would have been!) Rather, they can be likened roughly to the parts of a
bicycle: the frame, seat, wheels, handlebars, pedals, gears, brakes and
chain that work together to provide transportation.
But here's
the key to our theory: Although the top and bottom parts of the brain
are always used during all of our waking lives, people do not rely on
them to an equal degree. To extend the bicycle analogy, not everyone
rides a bike the same way. Some may meander, others may race.
Beyond
what is required by a particular situation (your reaction, say, to a
car speeding toward you), all of us can use each system in optional
ways. You can use the top-brain system to develop simple and
straightforward plans, as required by a situation—or you have the option
to use it to develop detailed and complex plans (which are not imposed
by a situation).
For example, instead of just catching dinner in
an unfamiliar city by finding the nearest restaurant, you might
formulate a more detailed and complex plan that involves coordinating
schedules with a friend, finding the best way to reach different parts
of town, discovering which restaurants have tables at specific times and
so on. And you can use the bottom-brain system to get a quick sense of
what you perceive—or you can use it in optional ways to go "deeper,"
interpreting even the subtleties of a situation. For example, instead of
just noticing the type and size of a restaurant, you might check out
how many other people are dining there, the types of cars in the parking
lot and so on.
Our theory predicts that people fit into one of
four groups, based on their typical use of the two brain systems.
Depending on the degree to which a person uses the top and bottom
systems in optional ways, he or she will operate in one of four
cognitive modes: Mover, Perceiver, Stimulator and Adaptor.
Mover mode
results when the top- and bottom-brain systems are both highly utilized
in optional ways. Oprah Winfrey, who overcame a difficult childhood to
create a formidable TV and publishing empire, illustrates such behavior.
According to the theory, people who habitually rely on Mover mode are
most comfortable in positions that allow them to plan, act and see the
consequences of their actions. They are well suited to being leaders.
Others
who seem to typify the Mover mode include: the Wright Brothers, who
incorporated lessons from their many failures into designing the
successive models that finally led to the first airplane;
Franklin Delano Roosevelt,
who brought the U.S. out of the Great Depression and led the
country during World War II; and the late Nascar chairman Bill France
Jr., who began by parking cars and working the concession stands at his
father's speedway and eventually grew the sport into a
multibillion-dollar business.
Perceiver mode
results when the bottom-brain system is highly utilized in optional ways
but the top is not. Think of the Dalai Lama or
Emily Dickinson.
People who habitually rely on Perceiver mode try to make sense in
depth of what they perceive; they interpret their experiences, place
them in context and try to understand the implications.
But they
don't make and execute grand plans. By definition, such
people—including naturalists, pastors, novelists—typically lead lives
away from the limelight. Those who rely on this mode often play a
crucial role in a group; they can make sense of events and provide a
bigger picture. In business, they are key members of teams, providing
perspective and wisdom but not always getting credit.
Then there is Stimulator mode,
which results when the top-brain system is highly utilized but the
bottom is not. According to our theory, people who interact with the
world in Stimulator mode often create and execute complex and detailed
plans (using the top-brain system) but fail to register consistently and
accurately the consequences of acting on those plans (using the
bottom-brain system). They don't update or correct their plans when
events unfold in unexpected ways.
Such people may be creative and
original, able to think outside the box even when everybody around them
has a fixed way of approaching an issue. At the same time, they may not
always note when enough is enough. Their actions can be disruptive, and
they may not adjust their behavior appropriately.
Examples of
people who illustrate Stimulator mode would include Tiger Woods, who
clearly makes ample use of his top-brain system but does not always
respond well to the consequences of carrying out his plans, and the late
social activist
Abbie Hoffman,
who effectively organized major protests in the 1960s but reacted
poorly when some of his plans went off track.
Finally, there is Adaptor mode,
which results when neither the top- nor the bottom-brain system is
highly utilized in optional ways. People who think in this mode are not
caught up in initiating plans, nor are they fully focused on classifying
and interpreting what they experience. Instead, they become absorbed by
local events and the immediate requirements of the situation. They are
responsive and action-oriented and tend to "go with the flow." Others
see them as free-spirited and fun to be with.
Because they can
easily embrace the plans of others, those who typically operate in
Adaptor mode can be valuable team members. In business, they often form
the backbone of an organization, carrying out essential operations.
The
New York Yankee slugger
Alex Rodriguez
and the late Elizabeth Taylor show evidence of often functioning
in this mode. Coming to the Yankees in 2004 from the Texas Rangers,
where he played Gold Glove-winning shortstop, Mr. Rodriguez agreed to
switch to third base to accommodate his new teammate Derek Jeter—"the
ultimate team move," as Mr. Rodriguez himself called it. But his ongoing
troubles over his alleged use of steroids suggest that Mr. Rodriguez
has not learned from his experiences. As for Taylor, she was a great
actress—and fun to be around, by all accounts—but her eight marriages
suggest that she had difficulty understanding her experiences and making
detailed plans.
In applying this new way of looking at the brain
at work, it is important to avoid the pitfalls of the
left-brain/right-brain story. The top-brain and bottom-brain systems
should not be seen in isolation. The key is how they interact—both
within individuals and in groups where individuals tend to favor one
mode over another.
Individuals who operate in different modes can
complement each other to form a successful team. Consider, say, a mayor
who has an efficient staff. Her policy experts may be people who
habitually operate in Perceiver mode; the person answering phone calls
from constituents perhaps habitually uses Adaptor mode; the chief of
staff might be someone who often operates in Mover or Stimulator mode
(but, if the latter, someone will need to exert quality control on the
ideas). All the while, the mayor could be operating in Mover mode. She
is at the center, drawing on help as needed.
No one mode is
"better" than the others. Each is more or less useful in different
circumstances, and each contributes something useful to a team. Our
theory leads us to expect that you can work with others most
productively when you are aware not just of the strengths and weakness
of their preferred modes but also of the strengths and weakness of your
own preferred mode.
The injunction to "know thyself" is not
exactly news, but science is regularly advancing toward this ancient
goal—and we hope that our new theory proves to be a step forward.
#Πηγή:
A New Map of How We Think: Top Brain/Bottom Brain
By Stephen M. Kosslyn and G. Wayne Miller
Messrs. Kosslyn and Miller are the authors of "Top Brain, Bottom
Brain: Surprising Insights Into How You Think," which will be published
by Simon & Schuster on Nov. 5. Dr. Kosslyn was a cognitive
neuroscientist and professor of psychology at Harvard University for
over 30 years and now serves as the founding dean of the Minerva Schools
at the Keck Graduate Institute. Mr. Miller is an author and filmmaker.
Oct. 20, 2013 8:31 a.m. ET#
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου