Read an Excerpt
HOW THE LEFT SIDE OF YOUR
BRAIN WORKS FOR YOU
This book is the second in the new Brainwaves(r) series. Like the first, Building Mental Muscle, this book offers synopses of current brain research that can be practically applied to real-word situations. The interactive exercises provide opportunities to apply the research findings and, simultaneously, to stimulate and strengthen targeted skills controlled by the left hemisphere of the brain. Recent invention of technologies to measure how the brain works have released a torrent of research on how learning takes place. This is proving that the "Use It or Lose It" principle applies to our brains as well as our biceps, and that idle brain cells can be re-activated by enticing them to go back to work.
The left hemisphere evolved to draw comparisons between new incoming data and old data already known
Moreover it arranges abstract symbols into patterns that represent reality. This equips the brain to plan ahead by visualizing the future. ("Six coins this size and five that size would buy a nanny goat whose milk will make enough cheese to buy another nanny goat three moons from now.") It allows people to agree that certain sounds and marks can be strung together to describe what happened somewhere else at some other time. ("Language saves time. Now I can walk over the mountain and tell the other tribe: `Big flood yesterday. Many fish.' Otherwise, I'd have to to drag all of them over to my side of the mountain and point to the mess.")
And, best of all, your left brain LOVESits job!
Back in the early 1960's a research team at the University of California, Berkeley led by Mark Rosenzweig and Marion Diamond took a few of their genetically identical, very young, lab mice out of their comfortable cages and put them into much larger comfortable cages. They left other mice of the same age alone in their smaller cages. Every few days they put another new piece of tiny mouse-gym equipment into the larger cages running wheels, tunnels, climbing platforms and such. Both groups of mice had a great life with plenty of food and water and clean cages. But the "enriched environment" group that got lots of new stuff to figure out and play with every day were constantly experimenting and always actively engaged.
After several weeks, well through adolescence in mousetime, the brains of all the mice in the old and new test cages were measured, weighed and compared. As predicted, Rosenzweig and Diamond found that the brains of the mice with the frequent new challenges to meet had grown heavier and had more connections, with higher levels of neurotransmitters to stimulate or inhibit mental activity. The researchers couldn't tell which group was happier, but the challenged group certainly didn't lie around looking bored. They were all over their toys all the time inventing ways to use them. That mental activity constantly stimulated the development of new cells in their young brains and provided increased physical exercise, which also stimulates brain growth.
What's more, the research group at U.C. Berkeley and later a research team at the University of Illinois, confirmed that mentally active mice not only grew brains more densely packed with neurons but also took less time to solve problems such as learning how to find their way through a maze. Of course, they were only mice but it is amazing how little human DNA differs from a mouse's. And, vive la difference! Most of the difference between the human brain and the brains of other animals which have evolved along different lines those uniquely human skills that include language, math, conscious recall of past data to plan future goals are processed in the left hemisphere and prefrontal areas.
Popular myths about brains are contradicted by research
Until very recently, the accepted dogma in the brain sciences has been that, once you're born, all your brain has to look forward to is a long and steady loss of brain cells (also known as neurons). Many of life's little events, routine and otherwise mini-strokes, drinking a glass of wine, holding your breath, the very fact of living would pick off the neurons in your cerebral cortex like ducks in a shooting gallery. And, it was also once thought, no new brain cells would grow to take the place of the extinguished ones, since nerve cells in your brain and spinal cord could not regenerate. But current research is showing clear evidence that "stem" cells in the human brain can create new neurons and that relatively idle neurons will begin to extend their branches to carry signals to and from other neurons.
Even the widespread belief that we use only a tiny fraction of our brains has never been supported by facts. It's a bit of a mystery how the idea took hold in popular culture in the first place. As neurologist Oliver Sacks points out, the brain is an organ that uses a lot of energy and a lot of blood. Our bodies simply can't afford the luxury of allowing large unused portions of any organ to continue to draw off energy from the body's limited supply of nutrients in the blood. If neurons dedicated to perform a given skill are not being used they will either atrophy or be co-opted to some other function.
Through all the debates about the respective roles of nature and nurture in shaping human behavior, the notion has persisted that intelligence is fixed from birth. If we really believe this, it might not matter what we do with the brain we're born with, since (according to folk wisdom) nothing can change the inherent abilities and limitations with which our genes endow us. But it does matter. Everyone knows the brain can acquire facts. The good news is that we can sharpen our ability to sort them, interpret them and use these facts. In other words ...
Uncultivated mental skills can be regained with use
Outdated beliefs have helped make us complacent about our brains. We spend huge amounts of money and time keeping our bodies in shape at health clubs, but how time much is spent on mental fitness? When we retire, we imagine that it's our just reward to rid our lives of all mental challenge. And yet, anybody who's had a friend or family member succumb to Alzheimer's knows that an active brain contributes to the quality of life.
When the infant laboratory animals described above were exposed to an enriched environment of lots of playmates and toys, the extra stimulation literally made their brains larger and their neurons send out more and longer branches, called axons and dendrites. In fact, mice in the enriched environment showed an increase of 4000 new neurons in the hippocampus compared to 2400 in the control group without toys and playmates. This fit well with existing research showing that young brains can call on a large bank of neurons to start filling the need to develop new skills. What surprised the researchers was that the same results occurred when old mice (three years is old for a mice) were transferred from a life-long impoverished environment to an enriched one. Their brains got bigger and better, too, and quite quickly in fact, just as elderly people who begin to exercise can rebuild muscle mass surprisingly quickly.
These findings have been known in the research community for many years, and yet very few laypeople are familiar with them. They point to a very important conclusion. We may have been misguided all along in our preoccupation with the number of neurons in our brains. More important than number may be the quality of our brain cells. Simply put, a higher-quality brain cell is one that has a rich system of dendrites reaching out to make contact with other brain cells. Diamond and Rosenzweig's work showed that challenging mental exercise and social contact can give even older mice bigger, better brains by improving brain cell quality even if not quantity.
More recent work has shown that improved neuron quality may not be the only reason brains can get bigger and better late in life. Two bodies of independent research reported in March 1999, out of the Salk Institute in San Diego and Princeton University, add to other new evidence that adult animals do indeed grow new brain cells. (A Purdue researcher, Joseph Altman, actually offered evidence for this 30 years ago, but most scientists simply dismissed his findings.) Even more exciting are the factors that the studies show how to promote such growth. In the Salk study, mice that exercised regularly on a running wheel grew twice as many new brain cells as other mice. The new cells appeared in the hippocampus, a part of the brain crucial for memory and learning. In the Princeton study, led by psychologist Elizabeth Gould, the apparent cause of the mice's doubled braincell growth was mental exercise. Her research proved that challenging mental tasks not only spurred the production of new hippocampal brain cells, but helped maintain existing ones. As Gould herself put it, "It's a classic case of `use it or lose it.'"
Since you're not a laboratory mouse do these findings apply to you?
A Swedish-American team led by the Salk Institute's Fred Gage recently found that adult human brains can and do grow new neurons throughout life. This fits well with another recent study of U.C. Berkeley professors which showed that cognitive abilities that usually decline with age planning, organizing, and manipulating new information in terms of prior knowledge are preserved in older professors who continue to challenge themselves with demanding intellectual activity.
So it's time we accepted the fact that one of the most fundamental claims of 20th-century brain science that adult brains can't grow new neurons is false. Adult brains do grow more new brain cells and connections between existing cells in several ways. One is physical exercise. Another is good diet. Another is to enrich your environment with social contact and mental activities that are both fun and challenging.
Common misunderstandings about the "good" right hemisphere and the "bad" left hemisphere
In the late 1970's, art teacher Betty Edwards wrote a very popular book called Drawing on the Right Side of the Brain that was based on her experiences with young art students. Her "right-brain" approach to teaching how to draw an accurate likeness emphasized learning to see the whole form rather than focusing on component parts, and on learning to render literally what you see by ignoring the left-brain's tendency to view a subject in terms of what it has seen before. One of Ms. Edwards' tricks to help students do this was to turn a photo upside-down before drawing it. This trick encouraged the untrained artist to allow the "literal" right brain to view, say, eye glasses seen from the side, as oval shapes and prevented the left hemisphere from "seeing" them as idealized eye glasses with round lenses. Many people who were influenced by such techniques of art instruction came to think of artistic, holistic, or spiritual people as "right-brained," or as "left-brain" if they were practical, logical or unimaginative.
But, brain researchers began to point out that the human brain cannot be divided up neatly, or even roughly, along those lines. In fact, some stereotypically male skills, such as the spatial visualization involved in, say, map-reading or construction, are more right- than left-brain, while some "female" ones such as verbal skill are predominantly left-brain. Musical skills are distributed across both hemispheres, with more left-brain involvement as the skill level rises. Current brain research clearly shows how interconnected our internal neuronal ecosystem is and how wrong it is to claim that a single label such as "female" or even "music" matches up with a single part of the brain.
The "happier" hemisphere. Recent research reveals how left vs. right hemisphere dominance affects mood
For a long time, neurologists and other medical practitioners have noted that people who have suffered damage only to the right side of their brains whether caused by stroke, tumor, or injury -- tend to suffer from depression. Something in their left hemisphere, then, must help to maintain a happy, motivated outlook on life. As far back as 1982 Harold Sackheim's research, based on observations of patients with emotional disorders arising from brain injury or disease, posited a right-hemisphere specialization for crying, and a left-hemisphere specialization for laughing.
More recent studies using brain imaging technology have confirmed the left brain's role in positive emotions, and the right's involvement in negative emotions. PET scans show that the front part of the right hemisphere is activated when a person feels negative emotions, such as depression, fear, disgust, or anger, and many depressed patients have overactive regions in the right front part of their brain. Breakthrough research by leading neuroscientists including Drevets and Damasio, clearly reveals that a depressed mood is associated with underactivity in prefrontal regions of the left hemisphere. If the same area is overactive, the result may be extreme happiness, even mania. Most people feel a sense of positive satisfaction when their left brain is busy.
More recent studies by Australian researcher Jack Pettigrew at the University of Brisbane, propose a "sticky switch" explanation for bipolar disorder, also known as manic depression. Normally, humans process positive emotions in the left hemisphere, and negative ones in the right. Normally, too, the two hemispheres constantly exchange impulses at a high rate of speed. Thus, we can feel a mix of emotions or have good or bad moods, as some mechanism in our brain switches activity from one hemisphere to the other. What makes bipolar patients different is that their switch is slow, and tends to get stuck in one setting or the other. When the switch is stuck in the left-hemisphere setting, the patients are manic; when it's stuck in the right-hemisphere setting, they're depressed.
The two domains are mutually reinforcing, with each hemisphere's specializations helping the other's to develop. As brain researcher Robert Ornstein has put it in a recent book, "The right-hemisphere specializations develop to their fullest when informed by a fully developed left side." Conversely, of course, neither do you help a child to learn how to read by denying her the opportunity to express her creativity.
What happens if the right and left sides of the brain can no longer communicate to each other what they know?
Dramatic insights into differences between the left and right hemispheres have come from studies of people who've had the neurons that connect the right and left sides, or hemispheres, of their brain severed. This operation splits the brain into two independent halves by cutting through the corpus callosum, the main bundle of nerves binding the brain's left and right hemispheres together. Doctors started performing these split-brain operations in the 1940s to reduce the severity of epileptic seizures by preventing a seizure that starts on one side from spreading to the other side of the brain. Oddly, such split-brain patients appear to function like everybody else, moving normally through everyday lives until their behavior is examined closely and tested professionally. For example: medical literature tells of a split-brain patient whose two hands (each of which is controlled by a different hemisphere) fought with each other while he was getting dressed in the morning. One hand would try to pull on the pants while the other struggled to pull them off. Another patient was awakened by a hand her own slapping her across the face. The half of her brain controlling that hand had woken up, realized the other half of the brain was oversleeping, and decided to remedy the situation.
Since each half of the brain controls the opposite side of the body's movements and sensations, a split-brain patient who is holding a pencil out of his own sight in his left hand receives that information with his right brain. Because his corpus callosum is severed, the right side of his brain can't communicate with the left. Since the left brain commonly controls speech, he simply can't tell you the fact that he has a pencil in his left hand.
The right side of his brain knows the pencil is in his left hand, even if the left does not. If you then show him a selection of pictures, and ask him to point out the object he'd been holding in his hand, his left hand will point to a picture of a pencil. This tips off the left brain visually where the pencil is, so it can now tell you in words what the right brain knew but couldn't say.
Even though communication from one side of your brain to the other across your corpus callosum is virtually instantaneous, it isn't perfect. The brain hemisphere that gets information directly from your senses has an advantage over the one that gets it indirectly across the corpus callosum. In carefully designed experiments, it's easier to read written words flashed to the right visual field, connecting directly to the left hemisphere. On the other hand, faces are easier to recognize when flashed to the left visual field. Also, each one of your ears sends information to both brain hemispheres, but cross-connections from left ear to right brain, or right ear to left brain are stronger than same-side connections. The difference is unimportant except when there's competition for access to your left-hemisphere language centers. For example, when you're trying to listen to a single voice in a noisy bar you might unconsciously tilt your head so that you listen with your right ear. You can try a simple experiment right now to test the hypothesis that you'll favor your right ear for sounds that are hard to hear. Pretend that you want to eavesdrop on a conversation on the other side of a wall. When you approach the wall, which ear do you press against it?
You may not be able to feel it happening, but while you are engaging in the following tasks, activity will be increasing in either your left or you right hemisphere
What is odd about the shapes shown on the preceding page? The kind of task, that requires you to rotate or manipulate visual figures in your mind's eye is typical of the sort of test designed to gauge your visual or spatial intelligence. One reason puzzles like these serve well to isolate right-brain visual skills is that it's virtually impossible to translate them into a verbal mode. The demands placed on your brain are about as purely visual as you can get, unlike, say, the demands made by a spatial task requiring metric distance judgments, and you can therefore be sure that people who are good at tasks like these aren't falling back on their language skills to get themselves to the right answer.
Next, take a look at the pairs of words below, another game similar to what you'll find on some standard intelligence-test batteries. Here, the trick is to figure out what features the paired words have in common.
Tree - Fly
Orange - Banana
Happiness - Anger
Praise - Punishment
Promise - Disappointment
It makes sense that the sort of reasoning involved here would be left-brain because it is language-based. The parallel concepts are not visual; the similarities have little to do with what the meaning of the word looks like. They are related to function or are abstractly symbolic, so it would be very difficult to express what the similarities are in anything other than words. Studies of split-brain patients and of stroke patients, as well as PET scan studies of "normal" brains, back up the hypothesis that tasks like these typically involve the left hemisphere far more than the right.
The right and left hemispheres offer different strategies for solving problems, and cooperate in that endeavor, though one side may be more specialized in a given skill
To get an idea how different strategies can be applied to yield possibly different results, examine the photo below. It is a painting by the 16th-century Milanese artist Giuseppe Arcimboldo. What do you see? A face? Lots of fish? Of course, you can see either, and you can switch rapidly back and forth between the two. Like "the forest or the trees" the difference corresponds to a left-brain vs. right-brain approach.
It's not so much that a well-developed left hemisphere interferes with the full development of the right brain, or that the left and right hemispheres are antagonists in a competition for finite resources or energy allocations. All our brain's skills are valuable and mutually supporting. To the extent that they can be viewed separately, the two hemispheres give us different perspectives to problems and offer complementary approaches to solve them. Sometimes, a sequential, verbal, linear approach works best; other times, a configurational or visually-based strategy might point to the best results.
Why are the uniquely human skills monitored by the left-hemisphere worth building up?
In brief, there are three reasons: those skills improve career opportunity, emotional outlook and quality of life in later years. Noted neuroscientist Michael Gazzaniga goes so far as to assert that "years of split-brain research informs us that the left hemisphere has many more mental capacities than the right. The right hemisphere's level of awareness is limited; it knows precious little about a lot of things." Most researchers would concede that the sorts of abilities housed in the left brain analytical problem-solving, language, computational skills, logic are ones that most people think of as demonstrations of intelligence. In fact, they largely define what it means to be human.
Left-brain injuries tend to destroy speech, a skill loss that can be easily and dramatically observed. Curiously, injuries to the right hemisphere tend to be ignored or belittled by those who suffer them even though they produce irrational, anti-social behavior bordering on monomania. President Woodrow Wilson continued several years in office after a right-brain stroke. The highly-respected Justice William O. Douglas also suffered serious stroke-damage to his right hemisphere, but continued to participate in the deliberations of the Supreme Court for months, unaware of his cognitive limitations and dismissing the paralysis of the left side of his body. In both cases the right-hemisphere damage had spared their speech but no longer enabled them to update their self-awareness. And here's bad news for men: they suffer more left-hemisphere strokes than women do, in general, and take longer to recover speech afterward. One reason for their slower recovery is that men tend to be more right-hemisphere specialized and the corpus collusum fibers connecting their two hemispheres are not as dense as women's are. Hence, women can more easily transfer language functions from damaged areas in the left side to their undamaged right side. However, left-handed people in general tend to show more differences from right-handed people in which hemisphere is dominant than between sexes.
Left-brain skills tend to be identified with competence in professional and academic pursuits
Carl Sagan identified human, right-brain abilities as those we share with other animals, and left brain skills as those that tend to be more specific to our species. That is one reason why it may be that left-brain subjects are stressed in our educational system. Left-brain skills are also less "intuitive" than the crisis-management reaction to new data that the right hemisphere is set up to trigger. But your left side is fiercely determined to seek out how newly-introduced data may share something in common with other discreet data it has already composed into meaningful arrays. It is a great tool for spotting trends, solving algebra problems and composing clear, step-by-step instructions for assembling a barbecue grill the skills that must be learned and practiced in order to succeed.
Demands placed on you may shift with time or circumstance, so it's good to have many strategies at your disposal to deal with new challenges that may arise. Whether you do or don't criticize teenagers for larding their speech with such imprecise colloquialisms as "you know" and "I'm, like, I dunno!", the inescapable fact is that most people need logical thinking and the ability to express them selves precisely to get and hold a job and maintain their professional edge. The fact that people do have an understanding, in a face-to-face interaction at least, of what a teenager means when she says, And "I was all, like, [facial expression]", doesn't mean that she can get away with that kind of language when she's delivering a report at a staff meeting or writing one up afterward.
The happy jolt-of-recognition that comes from suddenly realizing just how This-is-like-That! ranks high among the joys given to humankind
Those who protest that they're just not good at math or writing are suffering not so much from innate disability as from negative attitude and habit. The Germans have the word Funktionslust (Pronounce it aloud for full impact.) to refer to the kind of pleasure you get from doing something you're good at. For your pet cat, that pleasure may come from hunting voles on a warm summer night. For you, with your multitalented brain, with all your neural redundancies and your lack of hard-wired instinctual commitment to one specific task or one specific strategy, does pleasure come from otherwise complex hunting expeditions -- hunting for an answer to a crossword puzzle clue, for example? To make the most of the mental capabilities you were born with you need to exercise them all. That is why this book presents such a wide variety of exercise formats targeted to specific mental skills.
Since either kind of hunt may require learned strategies to get the prey, we've taken pains to try and clearly describe the techniques you may need to work out the exercises in this book. You may well find better ones. Our goal is to give you a taste of success. Most of us don't tackle new, potentially rewarding activities because there's nobody around to show us how easy it is to be good at them. If the only approach available is trial and error the left-brain skills you were born with are completely wasted. Everyone has heard of the notion that if a hundred monkeys poke randomly at the keys of a hundred typewriters, sooner or later one of those monkeys will come up with the complete works of William Shakespeare. Random trial and error can eventually lead to the right answer, but it's not very satisfying. Also it takes too long to come up with an answer to be competitive with problem-solving strategies your left hemisphere can cook up.
How this book is organized
You can dive into this book anywhere. You needn't read it from beginning to end. Everybody's mind works differently, but most people will find that the formats of the exercises in the chapters toward the beginning of the book are easier to solve than the ones near the end. Within each chapter the exercises progress from easier to harder, as shown by the thermometer-like difficulty scale at the top of each right-hand page.
A wide range of exercise formats maximize the excitement of acquiring new skills and honing old ones
Easier puzzles are at the beginning because we know how frustrating it can be to dive into a difficult puzzle in an unfamiliar format. Our goal is to get you started working in an unfamiliar skill area and allow your own sense of satisfaction take over as you begin to master it. The left brain excels not so much at sorting through completely new information, but at applying well-practiced, routinized codes and strategies in a quick and efficient way. But first, you have to learn the routine. (one major aspect of what's called "intelligence" reduces to nothing more than this kind of familiarity, developed through practice.) We've tried to set things up so this learning process will be maximally enjoyable and minimally frustrating.
Instructions on how to solve each of the 14 different exercise formats makes new challenges manageable
At the beginning of each chapter, you'll find an explanation of how that specifically targeted mental exercise works and demonstrates strategies for solving them. In these chapter introductions, you'll also find interesting facts about the parts of your brain you'll be challenging when you work on the exercises.
Some exercise formats provide clues as crossword puzzles do. To help you get started if you're stuck an optional "Starter" will help with strategies. For further help getting started (with an interlocking exercise especially) a small piece of the answer appears in a hint. We have made these hints particularly easy to ignore by printing them in small type, upside-down at the bottom of the page. The full solution to each exercise appears in the back of the book.
We have also included a test in some of the chapters. You can try them by yourself or with another person to take the measure of a skill related to the subject of the chapter. Some measure aptitudes and some temperament.
Information on how your brain solves problems and learns new techniques is written in non-technical language
The "Brain Bite" you'll find in almost every puzzle gives you a nugget of interesting information about the left hemisphere's skills and abilities, or about left-and-right-hemisphere differences. Often, this information is drawn from research reported in academic and scientific journals that we've listed in the reference section at the back of the book. That way, if you want to learn more, you can match the name of the researcher cited in the Brain Bite to an entry in the reference section, and look up the primary source.
Everybody's stupid at something. Try the exercises you think you will enjoy most, but sneak a look at the others
Everybody's brain is different, as are everybody's skills and abilities. The person who shies away from the word-skill exercises in the "Analock" chapter may have an easy time with "Codebreakers," while the relative difficulty may be reversed for someone else. We hope, though, that you will take advantage of this opportunity to sneak a look at the stuff you don't think you're good at. We all have a tendency to settle into fixed patterns of behavior, either out of laziness, fear of failure or habit. Problem-solving strategies can be learned and reinforced through practice. The broad array of exercises in this book let you get started stimulating some of your precious, though temporarily idle neurons. The process is really quite a lot of fun, the hints and starters are there to give you a boost, and the solutions are in the back.
We hope your left hemisphere will thrive on the diverse engagements we have devised for it in the following pages. And, when you have worked out a solution to an exercise that looked daunting at first, we hope you will savor the private kind of joy that comes from applying your mental tools effectively to complete an unfamiliar task.