I've
been puzzled ever since I posted "Intuition
and Expertise" about a month ago. If you read it, you may remember a
central postulate of Daniel Kahneman's book Thinking, Fast and Slow: people use two distinct mechanisms in
thinking. These are a fast and
intuitive "System 1" and a slow and analytical "System
2." It's a model that left me
with nagging questions, unaddressed by Kahneman. Are the two systems merely metaphors that don't have
discrete neurological counterparts?
Or is each system instantiated at a specific neurological site?
I
was therefore excited to hear an interview
on NPR in which Jonah
Lehrer discussed his new book Imagine:
How Creativity Works. He talked not only about intuitive and
analytical thinking in creativity, but also about particular neural circuits
that are their loci.
Thankfully,
Lehrer is a journalist, not a scientist like Kahneman, so his book is short and
relatively crisp. (Good! I thought. I didn't want to plunge into another tome
like Kahneman's.) The book has two
parts, "Alone" and "Together," which respectively address individual
and communal creativity. Just the
first part is concerned with the details of neural activity, so I will confine
myself mostly to it. But the other
part is of sufficient interest to warrant a brief outline.
Together. Lehrer
asks why such places as fifth century BCE Athens, fifteenth-century Florence,
late sixteenth-century London and today's Silicon Valley came to have
"clots of excess genius"—rare agglomerations of creative people. He maintains that they have in common a
vital combination of ingredients: a dense population, relative affluence, and
civic and social institutions that encourage creativity. Together, these
ingredients foster frequent interactions among imaginative individuals,
resulting in their interchanging ideas.
Each individual's creativity, the "alone" kind, is stoked by
bumping into other creative individuals at random. The environment in turn attracts still more of the brightest
and most original, driving a positive feedback loop.
For
example, late sixteenth- and early seventeenth-century London had one of the
densest populations on earth; a relative lack of censorship; an amazing
near-50% literacy rate nurtured by the English Reformation's rendering of the
Bible into the vernacular; ardent and supportive theater-goers; and a plethora
of coffee houses, which acted as milieux for chance meetings. The result was a "clot of excess
genius" containing the likes of Jonson, Marlowe, Shakespeare, Milton, Kyd,
Spenser and Donne. English
literature has never again seen an efflorescence like that in such a short time
period.
Many
modern companies try to mimic this clotting phenomenon. At the insistence of Steve Jobs, for
instance, all of the most-frequented spaces at Pixar and Apple—cafes and
cafeterias, mailboxes, meeting rooms, even bathrooms—were clumped together
centrally, so that people would be forced by happenstance to bump into each
other, chatter and exchange ideas.
It seems to work, for Pixar and Apple are among the most creative
companies ever established.
Alone. Still,
while people can be prodded into creative acts by their surroundings, the act
itself is usually individual.
That's where System 1 and System 2 thinking come into play. Lehrer provides a fine insight into how
these two forms of thinking occur in the brain. Here are some of the facts he presents, with a few of my own
comments interpolated.
As
I argued in my posting on intuition and expertise, System 1 leads to the Aha! moments that we all experience. Finding the part of the brain where
those epiphanies are generated has recently been made possible by using
functional MRI (fMRI) measurements, which perceive increases in neural activity
as surges in blood flow to those neurons.
Such measurements show that the anterior superior temporal gyrus (aSTG),
a small fold of brain tissue above the right ear, becomes especially active a
few seconds before an insight. The
aSTG functions subconsciously, apparently by obsessively searching for
relationships among the myriad pieces of data that are stored in the
brain. When it finds a significant
relationship, it "lights up" in the fMRI scan, like the light bulb
above a cartoon character's head indicating an intuitive flash. We may trigger an aSTG search because
we are stumped in the analysis of a particular problem, probably because we are
looking at the wrong data, or it may happen autonomously. Interestingly, the aSTG seems to be
most active when we are relaxed, possibly daydreaming. That may be why Archimedes got his Eureka! moment while in a bath.
On
the other hand, System 2 thinking, the analytical kind, is in our conscious
mind all along; we know that it is happening because it is effortful,
concentrated work. That work takes
place in the prefrontal cortex (PFC), located behind the forehead. The PFC has associated with it a short-term
working memory that allows it to
focus on the very pieces of data it presumably needs to solve a problem—akin, I
think, to a computer's RAM.
By not paying much attention to the vast amounts of other data in the brain (data "on
disk" so to speak), the PFC emphasizes the fine-tuning of an emerging
solution, but doesn't provoke epiphanies. We gain incremental understanding from its activities, piece
by piece.
Part
of the PFC may actually inhibit our full creativity: the dorsolateral
prefrontal cortex (DLPFC), which is most closely associated with impulse
control. It constrains our
thoughts and actions so that we don't make fools of ourselves or violate social
norms—a sort of straitjacket that the mind places on itself. It can therefore prevent us from
thinking "out of the box."
Tellingly, it is one of the last areas of the brain developed by
children, which may explain both their relative lack of social inhibitions and
their as-yet unbridled creativity.
fMRI studies of jazz musicians while they are improvising show their
DLPFC activity to be suppressed, as if they are purposely inhibiting their
inhibitions so as to be able to jam; this suppression doesn't occur when they
are merely playing a set piece.
Another
connection, or actually lack of one, between creativity and the PFC is quite
amazing. When we are asleep, the
PFC shuts down! Our analytical
abilities and our inhibitions—our sanity checkers—are gone. The brain is then free to run amok,
dreaming uninhibited thoughts and making "insane" connections among
its memories. Occasionally
connections that do make sense occur in this maelstrom. Perhaps that is why we sometimes decide
to "sleep on it" when we are trying to solve a particularly vexing
problem.
These
few facts about the neurology of thinking are of course not the whole
story. No matter. They are the
beginning of an answer to the "nagging questions" Kahneman left me
with. My inner scientist is very
pleased. I love it when observational data can be understood in
terms of underlying physical phenomena!