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Brain Rules by John Medina

June 23, 2020


Rule #1: Exercise Boosts Brain Power

One of the greatest predictors of successful aging was the presence or absence of a sedentary lifestyle. The gold standard appears to be aerobic exercise, 30 minutes at a clip, 2 to 3 times a week. Add a strengthening regimen and you get even more cognitive benefits.

Your lifetime risk for general dementia is literally cut in half if you participate in leisure-time physical activity.  Aerobic exercise seems to be the key. With Alzheimer’s, the effect is even greater: such exercise lowers your odds of getting the disease by more than 60 percent.

Fluid intelligence, the type that requires improvisatory problem-solving skills, was particularly hurt by a sedentary lifestyle

Brain-activation studies show that children and adolescents who are fit allocate more cognitive resources to a test and do so for longer periods of time.

Exercise does not provide oxygen and food. It provides your body with greater access to the oxygen and the food. 

Imaging studies have shown that exercise literally increases blood volume in a region of the brain called the dentate gyrus. That’s a big deal. The dentate gyrus is a vital constituent of the hippocampus, a region deeply involved in memory formation. 


Rule #2: The Human Brain Evolved, Too.

The brain appears to be designed to (1) solve problems (2) related to surviving (3) in an unstable environment and (4) to do so in nearly constant motion.

There is an unbroken intellectual line between symbolic reasoning and the ability to create culture. And no other creature is capable of doing it besides humans.

Variability selection theory predicts some fairly simple things about human learning. It predicts there’ll be interactions between two powerful features of the brain: a database in which to store a fund of knowledge, and the ability to improvise off of that database. One allows us to know when we make mistakes. The other allows us to learn from them. Both give us the ability to add new information under rapidly changing conditions.

We try to see our entire world in terms of motivations, ascribing motivations to our pets, and even to inanimate objects. The skill is useful for selecting a mate, for navigating the day to day issues surrounding living together, for parenting. The Theory of the Mind is something humans have like no other creature. It is close to mind reading as we are likely to get.

Our intellectual prowess, from language to mathematics to art, may have come from the powerful need to protect our neighbor’s psychological interiors.

If someone does not feel safe with a teacher or boss, he or she may not be able to perform as well. If a student feels misunderstood because the teacher cannot connect with the way the student learns, the student may become isolated. This lies at the heart of the flight of student’s failure.


Rule #3: Every Brain is Wired Differently.

When people learn something, the wiring in their brain changes.

Whether examining toddlers or teenagers, different regions in different children develop at different rates. There is a remarkable degree of diversity in specific areas that grow and prune, and with what enthusiasm they do so.

We are born into this world carrying a number of preset circuits. These control basic housekeeping functions like breathing, heartbeat, your ability to know where your foot is even if you can’t see it, and so on.  Researchers call this “experience independent” wiring. The brain also leaves parts of its neural construction project unfinished at birth, waiting for external experience to direct it. This “experience expectant” wiring is related to areas such as visual acuity and perhaps language acquisition. And finally, we have experienced dependent wiring.

Learning results in physical changes in the brain and these changes are unique to each individual.

No two people’s brains store the same information in the same way in the same place.

We have a great number of ways of being intelligent, many of which don’t show up on IQ tests.


Rule #4 – We Don’t Pay Attention to Boring Things.

The more attention the brain pays to a given stimulus, the more elaborately the information will be encoded and retained.

The brain can be divided roughly into two hemispheres of unequal function, and patients can get strokes in either. The left hemisphere spotlight is small, capable of paying attention only two items on the right side of the visual field. The right hemisphere, however, has a global spotlight. Getting a stroke on the left side is much less catastrophic because the right side can pitch in under duress to a division.

Emotionally arousing events tend to be better remembered than neutral events.

Emotionally charged events persist much longer in our memories and are recalled with greater accuracy than neutral memories.

Emotionally charged events can be divided into two categories: those that no two people experience identically, and knows that everybody experiences identically.

Regardless of who you are, the brain pays a great deal of attention to these questions: Can I eat it? Will it eat me? Can I mate with it? Will it mate with me? Have I seen it before?

Studies show that emotional arousal focuses attention on the gist of an experience at the expense of the peripheral details.

If we can derive the meaning of the words to one another, we can much more easily recall the details. Meaning before details.

If you want to get the particulars correct, don’t start with details. Start with the key ideas and, in a hierarchical fashion, form the details around these larger notions.

We are better at seeing patterns and abstracting the meaning of an event than we are at recording detail.

Multitasking, when it comes to paying attention, is a myth. The brain naturally focuses on concepts sequentially, one at a time.

To put it bluntly, research shows that we can’t multitask. We are biologically incapable of processing attention–rich inputs simultaneously.

Studies show that a person who is interrupted takes 50% longer to accomplish a task. Not only that, he or she makes up to 50% more errors.

The brain processes meaning before detail. Providing the gist, the core concept first is like giving a thirsty person a tall glass of water.

Audiences check out after 10 minutes, but you can keep grabbing them back by telling narratives or creating events rich with emotion.


Rule #5 – Repeat to Remember (Short-Term Memory).

Declarative memories are those that can be experienced in our conscious awareness, such as this shirt is green, Jupiter is a planet, or even a list of words. Non-declarative memories are those that cannot be experienced in our conscious awareness, such as the motor skills necessary to ride a bike.

Research shows that the lifecycle of a declarative memory can be divided into four sequential steps: encoding, storing, retrieving, and forgetting.

Information coming into your brain is immediately split into fragments that are sent to different regions of the cortex for storage.

From a physiological point of view, encoding is the conversion of external sources of energy into electrical patterns the brain can understand. From a purely psychological point of view, it is the manner in which we apprehend, pay attention to, and ultimately organize information for storage purposes.

We remember things much better the more elaborately we encode what we encounter, especially if we can personalize it.  Making something more elaborate usually means making it more complicated, which should be more taxing to a memory system. But it’s a fact: more complexity means greater learning.

Most of the events that predict whether something learned also will be remembered occur in the first few seconds of learning. The more elaborately we encode memory during its initial moments, the stronger it will be.

You can improve your chances of remembering something if you can reproduce the environment in which you first put it into your brain

Learn something while you are sad and you will be able to recall it better if, at retrieval, you are somehow suddenly made sad. The condition is called context-dependent or state-dependent learning.

The more a learner focuses on the meaning of the presented information, the more elaborately encoding is processed.

How does one communicate meaning in such a fashion that learning is improved? A simple trick involves the liberal use of relevant real-world examples embedded in the information, constantly peppering main learning points with meaningful experiences.

Why do examples work? They appear to take advantage of the brain’s natural predilection for pattern matching. Information is more readily processed if it can be immediately associated with information already present in the learner’s brain.

If you are trying to get information across to someone, your ability to create a compelling introduction may be the most important single factor in the later success of your mission.

Rule #6 – Remember to Repeat (Long-Term Memory)

Most memories disappear within minutes, but those that survive the fragile period strengthen with time.

Alan Bradley a British scientist describes working memory as a three-component model: auditory, visual, and executive.

The process of converting short-term memory traces to longer, sturdier forms is called consolidation.

If consolidation is not a sequential one–time event but one that occurs repeatedly every time a memory trace is reactivated, it means permanent storage exists in our brains only for those memories we choose not to recall!

The passage of time inexorably leads to a weakening of the events and facts that were once clear and chock–full of specifics. In an attempt to fill in missing gaps, the brain is forced to rely on partial fragments, inferences, outright guesswork, and often (most disturbingly) other memories not related to the actual event. It is truly reconstructive in nature, much like a detective with a slippery imagination.

In fact, the memories you encoded as adolescents have very little resemblance to the ones you remember as adults.

The brain constantly receives new inputs and needs to store some of them in the same head already occupied by previous experiences. It makes sense of its world by trying to connect new information to previously encountered information, which means that new information routinely re-sculpts previously existing representation and sends the re-created whole back for new storage

Present knowledge can bleed into past memories and becomes intertwined with them as if they were encountered together. Does this give you only an approximate view of reality? You bet it does. This tendency, by the way can drive the criminal justice system crazy.

A great deal of research shows that thinking or talking about an event immediately after it has occurred enhances memory for that event, even when accounting for differences in type of memory.

Repeated exposure to information at specifically timed intervals provides the most powerful way to fix memory into the brain.

Deliberately re-expose yourself to the information if you want to retrieve it later. Deliberately re-expose yourself to the information more elaborately if you want the retrieval to be of higher quality. Deliberately re-expose yourself to the information more elaborately and in fixed, spaced intervals, if you want the retrieval to be the most vivid it can be.

Information must be repeated after a period of time has elapsed. If the signal is given only once by the cellular teacher, the excitement will be experienced by the cellular student only transiently. But if the information is repeatedly pulsed in discreetly time intervals, the relationship between the teacher neuron and the student neuron begins to change.

The interval required for synaptic consolidation is measured in minutes and hours, which is why it is called fast consolidation.

The last step in declarative processing is forgetting. The reason for getting plays a vital role in our ability to function is deceptively simple. Forgetting allows us to prioritize events. Those events that are irrelevant to our survival will take up wasteful cognitive space if we assign them the same priority as events critical to our survival. So we don’t. We insult them by making them less stable. We forget them.

Long–term memories are formed and it too – way conversation between the hippocampus and the cortex, until the hippocampus breaks the connection in the memory is fixed in the cortex – which can take years.

Rule #7 – Sleep Well, Think Well.

The neurons of your brain show vigorous rhythmical activity when you’re asleep – perhaps replaying what you learned that day.

Sleeping brains, like soldiers on a battlefield, are actually locked in vicious, biological combat. The conflict involves a pitched battle between two powerful and opposing drives, each made of legions of brain cells and biochemicals with very different agendas… This fight is sometimes called the “opponent process model.”

The body possesses a series of internal clocks, all controlled by discrete regions in the brain, providing a regular rhythmic schedule to our waking and sleeping experiences. An area of the brain called the suprachiasmatic nucleus appears to contain just act such a timing device.

One army is composed of neurons, hormones, and various other chemicals that do everything in their power to keep you awake. This army is called the circadian (C) arousal system. It is opposed by an equally powerful army, also made of brain cells, hormones, and various chemicals. These combatants do everything in their power to put you to sleep. They are termed the homeostatic sleep (S) drive.

About 1 in 10 of us are “early chronotype” or often referred to as Larks. In general, Larks report being most alert around Noon and feel most productive at work a few hours before they eat lunch. They don’t need an alarm clock, because they invariably get up before the alarm rings – often before 6 AM.

Larks are the mortal enemy of the 2 in 10 humans at the other extreme of the sleep spectrum: late chronotype or Owls. In general, Owls report being most alert around 6 PM, experiencing the most productive work times in the late evening. They rarely want to go to bed before 3 AM. Owls invariably need an alarm clock to get them up in the morning, with extreme Owls requiring multiple alarms to ensure arousal.

If mom or dad is a Lark, half of their kids will be, too. Larks and Owls cover only about 30% of the population. The rest of us are called hummingbirds. True to the idea of a continuum, some hummingbirds more Owlish, some are more Larkish and some are in between.

Some scientists think that a long sleep at night and a short nap during the midday represent human sleep behavior at its most natural. When you chart the process S curve and C curve, you can see they flatline in the same place – in the afternoon.

Mountains of data demonstrate that healthy sleep can indeed boost learning significantly, in certain types of tasks.

Sleep has been shown to enhance tasks that involve visual texture discrimination, motor adaptations, and motor sequencing.

Loss of sleep hurts attention, executive functioning, working memory, mood, quantitative skills, logical reasoning, and even motor dexterity.

When people become sleep-deprived, their ability to utilize the food they are consuming falls by about 1/3. The ability to make insulin and to extract energy from the brain’s favorite dessert, glucose, begins to fail miserably. At the same time, you find a marked need to have more of it.

The bottom line is that sleep loss means mind loss.

The data suggests that students temporarily shift to more of an Owlish chronotype as they transit through their teenage years.


Rule #8 – Stress Brains Don’t Learn the Same Way.

Not all stress is the same. Certain types of stress really hurt learning, but some types of stress boost learning. Second, it’s difficult to detect when someone experiences stress. Some people love skydiving for recreation; it’s other’s worst nightmare.

The body isn’t much help in providing a definition, either. There is no unique grouping of physiological responses capable of telling a scientist whether or not you’re experiencing stress. The reason? Many of the same mechanisms that cause you to shrink in horror from a predator or also in use when you’re having sex – or even while you’re consuming your Thanksgiving dinner. To your body, saber-toothed tigers and orgasms and turkey gravy looked remarkably similar. An aroused physiological state is characteristic of both stress and pleasure.

Scientists Jeansok Kim and David Diamond came up with a three-part definition the covers many of the basis of stress:

Part One: there must be an aroused physiological response to the stress, and it must be measurable by an outside party.

Part Two: the stressor must be perceived as aversive. This could be assessed by a simple question: “If you had the ability to turn down the severity of this experience, or avoid it altogether, would you?”

Part Three: the person must not feel in control of the stressor… The more the loss of control, the more severe distress is perceived to be.

Without a flexible, immediately available, highly regulated stress response, we would die.

Our stress responses were shaped to solve problems that lasted not for years, but for seconds. They were primarily designed to get our muscles moving as quickly as possible, usually out of harm’s way.

These days, our stresses are measured not in moments with a mountain lion, but in hours, days, and sometimes months with hectic workplaces, screaming toddlers, and money problems. Our system isn’t built for that. And when moderate amounts of hormones build up to large amounts, or when moderate amounts of hormones hang around too long, they become quite harmful.

Not surprisingly, people who experienced chronic stress have an elevated risk of heart attacks and strokes.

Over the long-term, stress ravages parts of the immune system involved in producing antibodies. Together, these can cripple your ability to fight infection. Chronic stress also can coax your immune system to fire indiscriminately, even at targets that aren’t shooting back – like your own body.

The brain is just as influenced by stress as the immune system is. The hippocampus, the fortress of human memory, is studded with cortisol receptors like cloves in a ham. This makes it very responsive to stress signals. If the stress is not too severe, the brain performs better. Its owner can solve problems more effectively and is more likely to retain information.

If the stress is too severe or too prolonged, however, stress begins to harm learning. The influence can be devastating. Stressed people don’t do math very well. They don’t process language very efficiently. They have poor memories, both short and long forms. Stressed individuals do not generalize or adapt old pieces of information to new scenarios as well as non-stressed individuals. They can’t concentrate

Specifically, stress hurts declarative memory (things you can declare) and executive function (the type of thinking that involves problem-solving).

Stress hormones can disconnect neural networks, the wedding of brain cells that act like a safety deposit vault, storing your most precious memories. They can stop the hippocampus from giving birth to brand-new baby neurons. And under extreme conditions, stress hormones can even kill hippocampal cells.

The brain seems to be aware of all of this and has supplied our story not only with a villain but also with a hero. Brain Deprived Neurotrophic Factor (BDNF) is the premier member of the powerful group of proteins called neurotrophins. BDNF in the hippocampus acts like a standing military armed with bags of Miracle Gro, keeping neurons alive and growing in the presence of hostile action. As long as there is enough BDNF around, stress hormones cannot do the damage.

Like a fortress overrun by invaders, enough stress hormones will eventually overwhelm the brain’s natural defenses and wreak their havoc. Insufficient quantities, stress hormones are fully capable of turning off the gene that makes BDNF in hippocampal cells.

One of the most insidious effects of prolonged stress is that it pushes people into depression. Depression is a deregulation of thought processes, including memory, language, quantitative reasoning, fluid intelligence, and spatial perception.

People who feel depressed also feel there is no way out of the depression. They feel that life’s shocks are permanent and things will never get better. Even when there is a way out – treatment is often very successful – there is no perception of it. They can no more argue their way out of depression than they could argue their way out of a heart attack.

Your body’s reaction to stress depends on the stress, on its length and severity, and on your own body. There’s a point where stress becomes toxic, and this is often referred to as the allostatic load.

One of the greatest predictors of performance in school turns out to be the emotional stability of the home. The simple fact is that children find unresolved marital conflict deeply disturbing… They are powerless to stop the conflict, and the loss of control is emotionally crippling.

Marital stress at home can negatively affect academic performance in almost every way imaginable, and at nearly any age… The stronger the degree of conflict, the greater the effect on performance.

Stressed employees tend to avoid coming to work at the slightest excuse, and they often show up late.

Three things matter in determining whether a workplace is stressful: the type of stress, a balance between occupational stimulation and boredom, and the condition of the employee’s home life.

The perfect storm of occupational stress appears to be a combination of two malignant facts: a) a great deal is expected of you and b) you have no control over whether you will perform well.

Control isn’t the only factor in productivity. Employees on an assembly line, doing the same tired thing day after day, are certainly in control of the work processes. But the tedium can be a source of brain-numbing stress. What spices things up? Studies show that a certain amount of uncertainty can be good for productivity, especially for bright, motivated employees. What they need is a balance between controllability and uncontrollability.

There’s no such thing as a firewall between personal issues and work productivity. That’s because we can’t have two brains we can interchange depending upon whether we are in our office are in our bedroom. Stress in the workplace affects family life, causing more stress in the family. More stress in the family causes more stress at work, which in turn gets brought home again. It’s a deadly self-feeding spiral…

The problem in today’s economy is that people are typically starting a family at the very time they’re supposed to be doing the best work. They’re trying to be productive at some of the most stressful times in their lives. Businesses also risk losing the best and brightest at this time, as talented people are forced to make a terrible decision between career and family. This decision is especially hard on women.

The biggest part of successful stress management involves getting control back into your life.

Rule #9 – Stimulate More of the Senses.

We absorb information about an event through our senses, translate it into electrical signals, disburse those signals to separate parts of the brain, then reconstruct what happened, eventually perceiving the event as a whole.

The brain seems to rely partly on past experience in deciding how to combine the signals, so two people can perceive the same event very differently.

Our senses involved to work together – vision influencing hearing, for example – which means that we learn best if we stimulate several senses at once.

The benefits of multi-sensory inputs are physical as well. Our muscles react more quickly, our threshold for detecting stimuli improves, and her eyes react to visual stimuli more quickly. It’s not just combinations of sight and sound. When touch is combined with visual information, recognition learning leaps forward by almost 30%, compared with touch alone. These improvements are greater than what you expect by simply adding up unisensory data. This is sometimes called supra–additive integration. In other words, the positive contributions of multisensory prep presentations are greater than the sum of their parts. Simply put, multisensory presentations are the way to go.

Rules for multi-media presentations:

– Students learn better from words and pictures than from words alone.

– Students learn better when corresponding words and pictures are presented simultaneously rather than successively.

– Students learn better when corresponding words and pictures are presented near to each other rather than far from each on the page or screen.

– Students learn better when extraneous material is excluded rather than included.

– Students learn better from animation and narration than from animation and on-screen text.

Smells have an unusual power to bring back memories, maybe because smell signals bypass the thalamus and head straight to their destinations, which include that supervisor of emotions known as the maglev.

Marcel Proust, the French author, talked freely 100 years ago about smells and their ability to elicit long–lost memories.

Odors appear to do their finest work when subjects are asked to retrieve the emotional details of a memory or to retrieve autobiographical memories. You get the best results if the smells are congruent. Odors are not so good at retrieving declarative memory. You can get smell to boost declarative scores but only if the test subjects are emotionally aroused – usually, that means stressed before the experiment begins.

Rule #10 – Vision Trumps All Other Senses

Visual processing doesn’t just assist in the perception of our world. It dominates the perception of our world.

Vision is by far our most dominant sense, taking up half of our brain’s resources.

We actually experience our visual environment as a fully analyzed opinion about what the brain thinks is out there.

What we see is only what our brain tells us we see, and it’s not a hundred percent accurate.

The visual analysis we do has many steps. The retina assembles photons into little movie – like streams of information. The visual cortex processes the streams, some areas registering motion, others registering color, etc. Finally, we combine that information back together so that we can see.

Far from being a camera, the brain is actively deconstructing the information given to it by the eyes, pushing it through a series of filters, and then reconstructing what it thinks it sees. Or what it thinks it should see.

Previous experience plays an important role in what the brain allows you to see, and the brain’s assumptions play a vital role in our visual perceptions.

The brain doesn’t really know where things are. Rather, it hypothesizes the probability of what the current event should look like and then, taking a leap of faith, approximates a viewable image. What you experience is not the image. What you experience is the leap of faith. Why does the brain do this? Because it is forced to solve a problem: we live in a three–dimensional world, but the light falls on our retina a two-dimensional fashion. The brain must deal with this disparity if it is going to accurately portray the world.

Researchers have historically used two types of memory in their investigations. The first, recognition memory, is a glorified way to explain familiarity. Working memory is the collection of temporary storage buffers with fixed capacities and frustratingly short lifespans. Visual short–term memory is a slice of that buffer dedicated to storing visual information. Most of us can hold about four objects at a time in that buffer, so it’s a pretty small place. Recent data shows that as the complexity of the objects increases the number of objects capable of being captured drops. The evidence also suggests that the number of objects and complexity of objects are engaged by different systems in the brain, charting the whole notion of short–term capacity, on its head. These limitations make it all the more remarkable – or depressing – that vision is probably the best single tool we have for learning anything.

The more visual input becomes, the more likely it is to be recognized – and recalled. The phenomenon is so pervasive, that it has been given its own name: the pictorial superiority of fact, or PSE.

If information is presented orally, people remember about 10%, tested 72 hours after exposure. That figure goes up to 65% if you add a picture.

One of the reasons that text is less capable than pictures is that the brain sees words as lots of tiny pictures. Data clearly show that a word is unreadable unless the brain can separately identify simple features in the letters. Instead of words, we see complex little art – museum masterpieces, with hundreds of features embedded in hundreds of letters.

Babies use visual cues to show that they’re paying attention to something – even though nobody taught them they could do that.

There are things we know about how pictures grab attention that are rock solid. We pay lots of attention to color. We pay lots of attention to orientation. We pay lots of attention to size. And we pay special attention if the object is in motion. Indeed, most of the things that threatened us in the Serengeti moved, and the brain has evolved unbelievably sophisticated trip – wires to detect it.

Pictorial information may be initially more attractive to consumers because it takes less effort to comprehend. Because it is also a more efficient way to glue information to a neuron, there may be strong reasons for entire marketing departments to think seriously about making pictorial presentations their primary way of transferring information.

We learn and remember best through pictures, not through written or spoken words.

Rule # 11 – Male and Female Brains Are Different.

The X chromosome that males have one of and females have two of – though one acts as a backup– is a cognitive hotspot, carrying an unusually large percentage of genes involved in brain manufacture.

If you get 2X chromosomes, you are going to the ladies’ locker room all your life; and X and Y put you forever in the men’s. This sex assignment is controlled by the male. The Y can be donated only by sperm, so the male determines sex.

Gender differences can be divided into three areas: genetic, neuroanatomical, and behavioral.

Labs headed by scientists of both sexes have found differences in the front and prefrontal cortex, areas of the brain that control much of our decision–making ability. This cortex is fatter, in certain parts, in women than in men. There are sex-based differences in the limbic system, which controls our emotional life and mediates some types of learning.

Prominent differences lie in the amygdala, controlling not only the generation of emotions but also the ability to remember them. Running counter to current social prejudice, this region is much larger in men than it is and women. At rest, female amygdalas tend to talk mostly to the left hemisphere, while male amygdalas most of their chatting with the right hemisphere. 

Brain cells communicate via biochemicals, and these have not escaped sex differences, either. The regulation of serotonin is particularly dramatic. Serotonin is key in regulating emotion and mood. Males can synthesize serotonin 52% faster than females.

Mental retardation is more common in males than females in the general population. Many of these pathologies are caused by mutations in any one of the 24 jeans within the X chromosome. As you know, males have no backup X. If their X gets damaged, they have to live with the consequences. If the female’s X is damaged, she can often ignore the consequences.

Mental health professionals have known for years about sex-based differences in the type and severity of psychiatric disorders. Males are more severely afflicted by schizophrenia than females, by more than 2 to 1. Women are more likely to get depressed and then, a figure that shows up just after puberty and remains stable for the next 50 years. Males exhibit more antisocial behavior. Females have more anxiety. Most alcoholics and drug addicts or male. Most anorexics or females.

Women recall more emotional autobiographical events, more rapidly and with greater intensity, than men do.  Women consistently report more vivid memories for emotionally important events such as a recent argument, a first date, or a vacation. Other studies show that, under stress, women tend to focus on nurturing their offspring, while men tend to withdraw. This tendency in females has sometimes been called “tend and befriend.”

Language and reading disorders occur approximately twice as often in little boys as in little girls. Women also recover from stroke-induced verbal impairment better than men. Women tend to use both hemispheres when speaking and processing verbal information. Men primarily use one. Women tend to have thick cables connecting the two hemispheres. Men’s are thinner. It’s as though females have a backup system that is absent in males.

Girls seem verbally more sophisticated than little boys as they go through the school system. They are better at verbal memory tasks, verbal fluency tasks, and speed articulation. When these little girls grow up, they are still champions at processing verbal information.

When girl best friends communicate with each other, they lean in, maintain eye contact, and do a lot of talking. They use their sophisticated verbal talents to cement relationships. Boys never do this. They really face each other directly, preferring either parallel or oblique angles. They make little eye contact, their gaze always casting about the room. They do not use verbal information to cement relationships. Instead, commotion seems to be the central currency of a little boy’s social economy. Doing things physically together is the glue that holds the relationship intact.

In her research, Deborah Tannen found that high-status males give orders to the rest of the group, verbally or even physically pushing the low-status boys around. The leaders maintain their fiefdoms not only by issuing orders but by making sure the orders are carried out. Other strong members try to challenge them, so the guys at the top learned quickly to deflect challenges. This is often done with words as well. The upshot is that the hierarchy is very evident with boys. And hard. The life of a low-status male is often miserable. Independent behavior, which is a characteristic of control at the top, tends to be highly prized.

Tannen found different results with girls who also have high status and low-status roles. Girls use strikingly different strategies to generate and maintain the hierarchies. They spend a lot of time talking. This communication is so important that the type of talk determines the status of the relationship. To whom you tell your secrets determines best friend status. The more secrets revealed, the more likely the girls identify with each other as close. Girls tend to deemphasize the status between them in these situations. Using their sophisticated verbal ability, the girls tend not to give top-down imperial borders. Various members of the group give suggestions, then discuss alternatives. Eventually, a consensus emerges.

Any boy who gives orders is perceived as a leader. Any girl who gives orders is perceived as bossy. By college age, most of these styles were deeply entrenched.

Rule #12 – We Are Powerful and Natural Explorers.

Researchers have shown that some regions of the adult brain stay as malleable as a baby’s brain, so we can grow new connections, strengthen existing connections, and even create new neurons, allowing us all to be lifelong learners.

Our learning abilities don’t have to change as we age.

Babies are the model of how we learn – not by passive reaction to the environment up by active testing to observation, hypothesis, experiment, and conclusion.

Specific parts of the brain allow the scientific approach. The right prefrontal cortex looks for errors in our hypothesis, and an adjoining region tells us to change behavior.

We can recognize and imitate behavior because of mirror neurons scattered across the brain.