“There’s two kinds of people in the world: Those who think people

can be divided up into two types, and those who don’t.”

Groucho Marx


There are two types of creativity theories: those that divide the brain into dual modes and those that don’t.  And then there those who don’t, then do anyway.  As Chuck Berry sang, “sometimes I think I will, then again I think I won’t.”

The most familiar duality is the myth of right brain/left brain: the right brain is open, creative and fun while the left brain is closed, logical and serious.  You should pack one of each in your lunch box, so you can switch back and forth as needed.  Except, none of these functions are limited to one side of the brain.

There are other dualities in thinking about how the brain thinks:

Top-down/bottom-up, global/local, spontaneous/deliberate, conscious/unconscious, internal/external, intrinsic/extrinsic, automatic/controlled, implicit/explicit.

Maybe we should add cat and mouse, night and day, and beans and corn bread.

Why do we have a love/hate relationship with duality in the brain?  Is it because the normal body is anatomically symmetrical: two hands, two ears, two eyes and one head?  And inside that head are two nearly identical hemispheres—just like earth herself.

Human beings love to make complexity seem simple and to make the simple needlessly complex.  And you can’t get more simple than binary operations: yes/no, true/false.  Unfortunately, the human brain doesn’t fit into simple duality, especially during idea generation.

How does the brain generate ideas?  Neuroscientists in creativity are trying to pull back the curtain on this:  Is there a part of the brain devoted to revolutionary thought and another dedicated to choosing lunch?  Is there a brain region charged with brilliance ready to surprise you with insight?

Using sophisticated technology, neuroscientists can measure brain structure, track alpha waves, and monitor blood flow in the brain.  These powerful tools can determine disease like a tumor, but also assign brain functions to regions of the brain.  For example, the amygdala is part of the limbic system which processes emotions, survival instincts and memory. The amygdala (from the Latin for almond) is said to coordinate the infamous fight or flight instinct. The amygdalae (there are two, one in each hemisphere) are said to be the center of fear.  But, it is also active during decision making.

As powerful as they are, brain scans are like looking at a house from a satellite in space.  We can lift the roof and see the rooms.  We think we know where the dining room is, but we don’t know who’s in there or what they’re eating.  We may consider that part of the brain as a dining room, but it also serves as a card room, game parlor, home work desk and uses we haven’t imagined yet.

Neuroscientists are moving away from a localized letter box theory of the brain: as in all the memory mail goes to the hippocampus.  Instead, neuroscientists have identified networks of brain regions, like tracing a letter from the neighborhood mail box to the substation to the central hub and out to its destination across the country.

The central executive network and default mode network set up a seesaw duality.  The central executive network rallies the neuronal armies to accomplish tasks, invoke rational thought and logic.  You can picture the central executive network with a button-down shirt, loose tie and sleeves rolled up: ready to get the job done.

The default mode network, however, is sometimes described as “task negative,” more mission “forget about it” than mission impossible. It was dubbed the default mode network because it comes to the fore during periods of rest when the central executive network is taking a break for lunch.

This duality—the seesaw between central executive and default mode—is too simple; it fails to represent what the brain does.  The default mode network is not idle but is the home of internally directed thinking, episodic memory, self-perception, meta-cognition, visualization, and imagination.

The two networks are not even comprised of independent brain regions.  For example, the precuneus—episodic memory retrieval, visual-spatial imagery and self-related thoughts—is often linked into the default mode network.  Yet, during moments of task performance, the precuneus connects to the central executive network.

The hippocampus is also known for preserving and retrieving episodic memory.  But, it joins the default mode network generating flexible cognition and some operations of imagination.  Recent studies suggest that the hippocampus plays a role in determining whether an idea fits into the needed context.

A core region for the central executive network is the basal ganglia which inhibits and controls cognition and action.  However, in one study, larger gray and white matter volumes in the basal ganglia correlated with better performance on some creativity tasks.  Another study found the opposite.

At least three brain regions are switch hitters, hopping between the default mode network and the central executive network.

Even neurons don’t comply with duality.  Computers function with an on or off signal duality, 0 or 1.  People assume that the brain is merely a biological computer.  However, neurons send a variety of messages to each other: some messages activate, and some inhibit.  But, some neurons ignore the messages, others need multiple messages to activate.

Identifying duality modes like the default mode network and the central executive network is still a useful exercise, serving as metaphors.  Each of the pairings above provide a critical way of thinking about what we cannot see.  For example, the top-down vs. bottom up duality suggests how the brain integrates conceptual observation from the “top” (how we anticipate events) with sensory information sent to the brain from the body’s senses—from the “bottom.” (how we experience events.)

The imagination in the mind that leads to creativity in the world draws on the default mode network but also on many other brain regions.

It would be nice if the brain were divided into regions by function, like rows of post office boxes.  It would be nice if the brain broke down into interconnected networks like a great railway.  But, it’s not that simple: the brain is changing by almost a million synapses per second.

However, you cannot command your brain like other body parts.  You can decide to raise your right hand and your body responds.  But, you cannot decide to use your hippocampus, or insert the amygdala into your thinking or call on the intraparietal sulcus to be more flexible.  The brain seems to run on its own, completely oblivious to our metaphors and dualities.

Someone once said, “I used to think that the brain was the most important organ in the body.  Then, one day, I realized—hey—who is telling me that.”