delanceyplace.com 6/26/13 - left brain versus right brain

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In today's selection -- the two hemispheres of our brain have very different but complementary functions that work seamlessly together -- and our society is increasingly shifting from the influence of left-brained to right-brained thinkers:

"The two hemispheres of our brains ... play a role in nearly everything we do. ... Neuroscientists agree that the two hemispheres take significantly different approaches to guiding our actions, understanding the world, and reacting to events. ... With more than three decades of research on the brain's hemispheres, it's possible to distill the findings to four key differences.

1. The left hemisphere controls the right side of the body; the right hemisphere controls the left side of the body.

Our brains are 'contralateral' -- that is, each half of the brain controls the opposite half of the body. That's why a stroke on the right side of someone's brain will make it difficult for that person to move the left side of her body and a stroke on the left side will impair the functioning of the right. ...

2. The left hemisphere is sequential; the right hemisphere is simultaneous.

The left hemisphere [is] particularly good at recognizing serial events -- events whose elements occur one after the other and controlling sequences of behavior. The left hemisphere is also involved in controlling serial behaviors. The serial functions performed by the left hemisphere include verbal activities, such as talking, understanding the speech of other people, reading, and writing.

By contrast, the right hemisphere doesn't march in the single-file formation of A-B-C-D-E. Its special talent is the ability to interpret things simultaneously. This side of our brains is 'specialized in seeing many things at once: in seeing all the parts of a geometric shape and grasping its form, or in seeing all the elements of a situation and understanding what they mean.' This makes the right hemisphere particularly useful in interpreting faces. And it confers on human beings a comparative advantage over computers. For instance, the iMac computer on which I'm typing this sentence can perform a million calculations per second, far more than the fastest left hemisphere on the planet. But even the most powerful computers in the world can't recognize a face with anywhere close to the speed and accuracy of my toddler son. Think of the sequential/simultaneous difference like this: the right hemisphere is the picture; the left hemisphere is the thousand words.

3. The left hemisphere specializes in text; the right hemisphere specializes in context.

In most people, language originates in the left hemisphere. (This is true of about 95 percent of right-handers and 70 percent of left-handers. In the rest -- about 8 percent of the population -- the division of linguistic labor is more complicated.) But the right hemisphere doesn't cede full responsibility to the left. Instead, the two sides carry out complementary functions.

Suppose that one night you and your spouse are preparing dinner. Suppose, too, that midway through the preparations, your spouse discovers that you forgot to buy the dinner's most important ingredient. Suppose then that your spouse grabs the car keys, curls a lip, glares at you, and hisses, 'I'm going to the store.' Nearly everyone with an intact brain would understand two things about the words just uttered. First, your spouse is heading to Safeway. Second, your spouse is pissed. Your left hemisphere figured out the first part -- that is, it deciphered the sounds and syntax of your spouse's words and arrived at their literal meaning. But your right hemisphere understood the second aspect of this exchange -- that the ordinarily neutral words 'I'm going to the store' weren't neutral at all. The glare of the eyes and the hiss of the voice signal that your spouse is angry. ...

Many studies have shown that the right hemisphere is responsible for our ability to comprehend metaphors. If you tell me that José has 'a heart the size of Montana,' my left hemisphere quickly assesses who José is, what a heart is, and how big Montana is. But when the literal meaning of the sentence doesn't compute -- how can a 147,000-square-mile heart fit inside José's modest chest cavity? -- it calls in the right hemisphere to resolve the incongruity. The right hemisphere explains to the left that José doesn't have some bizarre cardiac condition but instead is a generous and loving person. 'Neither side of the brain ... can do the job without the other,' [Robert] Ornstein writes. 'We need the text of our lives to be in context.'

4. The left hemisphere analyzes the details; the right hemisphere synthesizes the big picture.

'In general the left hemisphere participates in the analysis of information,' says a neuroscience primer. 'In contrast, the right hemisphere is specialized for synthesis; it is particularly good at putting isolated elements together to perceive things as a whole.' Analysis and synthesis are perhaps the two most fundamental ways of interpreting information. You can break the whole into its components. Or you can weave the components into a whole. Both are essential to human reasoning. But they are guided by different parts of the brain. ...

The left converges on a single answer; the right diverges into a Gestalt. The left focuses on categories, the right on relationships. The left can grasp the details. But only the right hemisphere can see the big picture."