Brain Rules

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Brain Rules
John Medina
John medina
Star Star Star Star Star
5 out of 5
Short Summary:
A great, clear walk-through of latest neuroscience research on memory, learning, stress and effects of exercise as well as history of development of the brain,  gender differences and evolution. Author does a great job of summarizing how we can apply the knowledge to our everyday life without unnecessary academic jargon.
Terry's Notes:

Chapter 1: Exercise

By doing aerobic cardio exercise 2 times a week, even 20 minutes walk, you will decrease your lifetime risk for stroke, dementia, and Alzheimer’s by 50-60% (those three are leading causes of mental disability in adults). For anxiety and depression, regular exercise can be even more effective than medication

Exercise --> More Blood --> More Blood to Brain

Exercise improves bloodflow into body’s tissues. Blood carries important nutrients, glucose and oxygen to cells. More you exercise, more tissues you can feed with more blood à which means more food, water and oxygen that gets ride of toxic waste or free radicals. Exercise strengthens existing bloodstream structures and also adds new ones, like adding new roads in a highway. Brain needs a lot of blood. Exercise causes increased blood volume (thus more glucose and oxygen) to brain’s memory formation function and also brain’s growth hormones. It encourages neurogenesis which means more neurons connecting with each other.

Evolutionally, human beings are still designed to walk up to 12 miles a day. We are not programmed to sit eight hours a day in school or office. To improve thinking, creativity, memory, problem-solving, exercise + MOVING is KEY.

How well you age is almost directly proportional to how much you exercise


Chapter 2: Survival

Apes became masters of the world by adapting to change itself – while others died off because they only adapted to one environment.

Brain takes up only 2% of body weight but consumes 20% of our entire glucose energy supply.

Prefrontal cortex, or frontal lobe, just behind the forehead controls below:

The Neo-Cortex separates humans from animals by ability of symbolic reasoning. Our intelligence in language, mathematics, art and music may have come from powerful need to predict our neighbor’s psychological interiors. Knowing their motivations, interests, shared goals and fulfilling their needs were immensely helpful to creating bonds – which were very important because in order to survive in the jungle, you either cooperate with others to fend off cheetahs and elephants, or you die. Those who bonded with others most effectively are ones who survived through the ages.

Everyone’s brain is wired differently à we all store things in different regions, even the functions, language, memory, information

Brain has

1) Basic wiring à hard-wired

2) Experience Expectant wiring à Language

3) Completely flexible experience-dependent wiring à Jennifer Aniston neuron

IQ tests measure very little à since IQ has very little to do with musical, spatial, rhythmic, lingual, interpersonal ability, intelligence cannot be captured by just problem solving and logic.

Left Brain is logical, critical, analytical and lingual

Right Brain is creative, artistic and subjective


Chapter 3: Attention

What we focus on depends on culture and memory habit. Asians pay great attention to context of what they see and relationships between what is being seen in the foreground and what’s going on in the background. Americans focus much more on what they see in the foreground and their perception of context is much weaker

Multi-tasking is a myth. Brain can’t process two tasks simultaneously

               Step 1: Attention shift alert and blood shifts to frontal cortex

               Step 2: Brain finds neurons responsible for executing certain task

               Step 3: Those specific neurons get activated – this all takes 1/10 of a second

               Step 4: Another task interrupts, step 1 repeats again

A person who’s interrupted during a task takes 50% longer to accomplish a task AND makes 50% more errors.

80% of all accidents happen due to distraction while driving like talking on cell or reaching for something à raises risk of accident by 9 times

Try creating interruption-free time zones for your tasks (Pomodoros) à Turn off FB, email, music, phone

Expertise doesn’t guarantee good teachers.


Chapter 4: Memory

We remember patterns, meaning, connections more than detail, factual, declarative information

Emotional arousal helps learning.

Audiences check out 10 minutes after a lecture or a class or a presentation. You can grab interest and attention by hooks, stories, events rich in emotion.

EVERY 10 MINUTES, supply a hook à after doing 3-4 hooks, you don’t need to do hooks as often for the rest of the speech

Use hierarchies for organizing your information and presenting it to the audience. Brain loves hierarchy. General. Gist. Central. Core. Any details need to be clearly explained to why it links to that general core, central idea or it will get lost.

Sensory Integration

1) People learn better from words and pictures than from just words

2) Words and pictures should be shown simultaneously, not separately

3) Words/Pictures should be close together

4) When extra info is excluded, it’s better

5) Animation + narration is better than animation and on-screen text

Enrich encoding at the moment of learning and information is much easily comprehended

PROUST EFFECT à smell evokes memory and enhances retrieval

               Memory increases by 10-20% when smell is introduced.

               Smell is special in that it’s the only sense that directly communicates to the amygdala and bypasses the thalamus. Amygdala controls formation of emotional experiences and memory. Smell directly stimulates emotions.

               Smell of chocolate and vanilla increased nearby chocolate/ice cream business sales by 50%. Even for retailers, certain smells evoke positive responses among its customers according to gender.

2 people can perceive event very differently.

Our senses evolved to work together à we learn best by stimulating several senses at once à tasting, smelling, seeing, touching, feeling, hearing

TIP: Stimulate smell, hearing, vision and touch when you are learning something and it will be easier to recall later à stronger memory because stronger encoding.


Oral and text presentations are way less efficient than pictures and animation for retaining information

               10% retained for oral or text

               65% if you add pictures à pictures are worth a 1000 words

People can remember 2500 pictures with 90% accuracy for days --> mostly because pictures are rich in encoding with colors, curves, symbolic reasoning, objects etc

Text is cumbersome to remember because each letter itself is a PICTURE and takes repetitive processing with little obvious symbolic representation

Vision is the dictator and king of all senses. Even when we read text, we try to visualize the scene in our heads. When wine experts taste a white wine with red coloring, they start to taste red wine.

50% of all brain’s resources goes to VISION.

Learning/Teaching/Lectures/Presentations/Comedy Routines/Blogs/Articles should use pictures, motion, colors, videos, diagrams, images and less written/spoken words.

Pictures are just more efficient delivery of information than text. Eyes go to pictures first à which caused success stories of many magazines like USAtoday


Chapter 5: Short-Term Memory

We forget 90% of what we learn within 30 days. Majority of forgetting happens first few hours after learning.

Movies have to hook audience in first 3 minutes. Public speakers have to hook audience in first 30 seconds. That’s the time and time again proven rule of success in grabbing attention of people.

First few seconds of learning determines memory – more elaborately we encode a memory during initial moments, stronger it becomes à drawing, listening, seeing the words, seeing a picture, smelling, touching, tasting

Improve your chances of remembering something by reproducing the environment where you first  put it into your brain … Ex) if you lost your key somewhere in the kitchen, go back to the kitchen and think about it

REPEAT information in timed intervals. Massed learning is not as effective as time interval learning … Ex) IF you spend 3 hours cramming for a test the night before, or you spend 1 hour studying in three separate nights before the test, you will do much better by the timed-interval method because sleep helps consolidate your memory over sleep and you want to take full advantage of your sleep memory consolidation and neuron growth as possible.


Chapter 6: Long Term Memory

Remember to REPEAT what you want to put into your long term memory

Most memories disappear within minutes but those who survive the fragile period strengthen with time

Incorporate new information gradually and repeat in timed intervals


Chapter 7: Sleep Well and Think Well

Naps matter. Public speakers know giving a talk in mid-afternoon is the worst. Accidents happen most in mid-afternoon.

Naps are supposed to represent waking energy (neurons/hormones) and sleeping energy (neurons/hormones) clashing in a delicate balance about 8 hours after you have woken up and 8 hours before you will go to deep sleep. Mid-afternoon makes brain tired because you’ve been up for a long time.

30-minute biological drive for afternoon nap is universal. Nap improves pilot performance by 34%, cognitive performance increases. 30 minute nap prevents negative effects of an all-nighter.

Sleep loss affects learning by 200 to 300%.  Sleep deprivation of 6 hours or less affects your next day cognitive skills decrease by 30%. If you continue this, debt adds up and continues to affect you. Sleep deprivation accelerates aging, affects mood, memory, attention, math skills, problem-solving, motor skills and learning

During sleep, your memories are replayed 1000x inside your brain à the neurons that just grew out of your day’s experience will get solidified à if this solidification process gets interrupted, your learning is interrupted as well.

If you sleep after being exposed to a problem that requires great thought and processing, your ability to solve it increases by 300% by sleeping on it and waking up the next day.


Chapter 8: Stress

Brain remembers, retains and recalls stressful memories very strongly. Our body needed to do this so we retain good memories of attacks, vicious animals and survival situations.

Prolonged Stress decreases our cognitive ability, memory, situational adaptation skills, concentration, math/language abilities. Stress stops generation of new neurons.

People’s responses to stress varies. A girl can blossom into a popular honor student despite stressful childhood. Some people are born with genetic defenses against stress.

People are often emotionally distracted, upset and preoccupied by the drama of their lives involving family, friends and work so that the stress makes them unable to concentrate and learn to 100% of their max intelligence capacity, especially young kids in school.

Stress/depression kills innovation, creativity, problem-solving and memory. Stress also attacks immune system à making you more likely to get sick

77% of workforce report being burned out. 80% of medical expenditures are stress-related.

Incredible stress has a tendency to evoke “learned helplessness” where people do absolutely nothing, stay at rest, oversleep, do not venture to social opportunities, avoid people and escape into imagination. Might be a biological hard-wiring that tries to save on energy expenditure as much as possible until something external changes à almost like hibernation mode or starvation mode.



46 chromosomes in DNA à 2 of them are SEX chromosomes

23 come from Dad and 23 come from Mom

Basic default setting of mammalian embryo is to become FEMALE.

The two SEX chromosomes are called X chromosome and Y chromosome.

If a kid inherits two X chromosomes, she becomes a girl

If a kid inherits One X chromosome from the mom and one Y chromosome from Dad, then he is a boy.

Y can only come from a male sperm. Thus, if a woman is having trouble having a son, it is completely the man’s sperm problem and the woman has nothing to do with it.


Under stress, men activate right hemisphere of “top-down” gist big idea processing/memory

Under stress, women activate left hemisphere à details/memory à and have more information to which they are capable of reacting

Male and Females have different brain types.

Men have bigger amygdalas than women meaning bigger emphasis on the 4 Fs à fighting, fleeting, feeding and fucking. Competition, survival and replication.

Men are more hierarchial and produce serotonin faster. Meaning better fight against depression, better regulation of mood, appetite and sleep, and faster wound healing. Men are more likely to suffer from schizophrenia, and be addicted to alcohol or drugs

Females have more diverse genetic makeups than men. The two X chromosomes have many genes inside of them and prevents DNA defects especially in the brain.

Women remember emotional memories better with greater intensity à first date, arguments, weddings, sad movies à Women feel with more intensity. Women are driven by nurturing, survival and finding suitable mate.

Women are twice more likely to experience depression and anxiety



When we watch others do something, mirror neurons are activated in our brains. We can learn by observing and then imitating

We lose 30,000 neurons per day but gain new ones as well

Brain is constantly changing its structure in response to experience à creating, expanding throughout old age.

Brian craves to be expanded. It craves exploration and is curious à when the brain structures expand and gain new neurons, it brings you joy in the form of reward hormones, endorphins and dopamine. As you gain mastery of skills and solidify your neural connections and strengthen your brain structure, you will lead a much larger life than others who rot their brains and don’t care about expanding.

People who play instruments like violin or guitar who need to coordinate fine left-hand movements with right-hand movements have very different brain structures from other normal people who don’t play those instruments.

TIP: When you feel stuck or uninspired or lethargic, just get up and do SOMETHING à a ritual that gets you “doing something” and anything at all.


Make the promise that from today, you will activate important neurons in your brain everyday. Day by day, add new neurons, solidify your important existing ones and take charge of your neural expansion and retention. 

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