BRAIN RULES. Copyright © 2008 by John J. Medina. All rights reserved. Printed in the United States of America. No part of this book may be used or reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles or reviews. Requests for permission should be addressed to: Pear Press P.O. Box 70525 Seattle, WA 98127-0525 U.S.A. This book may be purchased for educational, business, or sales promotional use. For information, please visit www.pearpress.com. First Pear Press trade paperback edition 2009 Edited by Tracy Cutchlow Designed by Greg Pearson Library of Congress Cataloging-In-Publication Data is available upon request. ISBN-10: 0-9797777-4-7 ISBN-13: 978-0-9797777-4-5 10 9 8 7 6 5 4 3 2 1 To Joshua and Noah Gratitude, my dear boys, for constantly reminding me that age is not something that matters unless you are cheese. contents introduction 1 exercise 7 Rule #1: Exercise boosts brain power. Our brains love motion ~ The incredible test-score booster ~ Will you age like Jim or like Frank? ~ How oxygen builds roads for the brain survival 29 Rule #2: The human brain evolved, too. What’s uniquely human about us ~ A brilliant survival strategy ~ Meet your brain ~ How we conquered the world wiring 49 Rule #3: Every brain is wired differently. Neurons slide, slither, and split ~ Experience makes the difference ~ Furious brain development not once, but twice ~ The Jennifer Aniston neuron attention 71 Rule #4: We don’t pay attention to boring things. Emotion matters ~ Why there is no such thing as multitasking ~ We pay great attention to threats, sex, and pattern matching ~ The brain needs a break! short-term memory 95 Rule #5: Repeat to remember. Memories are volatile ~ How details become splattered across the insides of our brains ~ How the brain pieces them back together again ~ Where memories go long-term memory 121 Rule #6: Remember to repeat. If you don’t repeat this within 30 seconds, you’ll forget it ~ Spaced repetition cycles are key to remembering ~ When floating in water could help your memory sleep 149 Rule #7: Sleep well, think well. The brain doesn’t sleep to rest ~ Two armies at war in your head ~ How to improve your performance 34 percent in 26 minutes ~ Which bird are you? ~ Sleep on it! stress 169 Rule #8: Stressed brains don’t learn the same way. Stress is good, stress is bad ~ A villain and a hero in the toxic-stress battle ~ Why the home matters to the workplace ~ Marriage intervention for happy couples sensory integration 197 Rule #9: Stimulate more of the senses. Lessons from a nightclub ~ How and why all of our senses work together ~ Multisensory learning means better remembering ~ What’s that smell? vision 221 Rule #10: Vision trumps all other senses. Playing tricks on wine tasters ~ You see what your brain wants to see, and it likes to make stuff up ~ Throw out your PowerPoint gender 241 Rule #11: Male and female brains are different. Sexing humans ~ The difference between little girl best friends and little boy best friends ~ Men favor gist when stressed; women favor details ~ A forgetting drug exploration 261 Rule #12: We are powerful and natural explorers. Babies are great scientists ~ Exploration is aggressive ~ Monkey see, monkey do ~ Curiosity is everything acknowledgements 283 index 285 introduction go ahead and multiply the number 8,388,628 x 2 in your head. Can you do it in a few seconds? There is a young man who can double that number 24 times in the space of a few seconds. He gets it right every time. There is a boy who can tell you the precise time of day at any moment, even in his sleep. There is a girl who can correctly determine the exact dimensions of an object 20 feet away. There is a child who at age 6 drew such lifelike and powerful pictures, she got her own show at a gallery on Madison Avenue. Yet none of these children could be taught to tie their shoes. Indeed, none of them have an IQ greater than 50. The brain is an amazing thing. Your brain may not be nearly so odd, but it is no less extraordinary. Easily the most sophisticated information-transfer system on Earth, your brain is fully capable of taking the little black squiggles on this piece of bleached wood and deriving meaning from them. To accomplish this miracle, your brain sends jolts of electricity crackling through hundreds of miles of wires composed of brain cells BRAIN RULES so small that thousands of them could fit into the period at the end of this sentence. You accomplish all of this in less time than it takes you to blink. Indeed, you have just done it. What’s equally incredible, given our intimate association with it, is this: Most of us have no idea how our brain works. This has strange consequences. We try to talk on our cell phones and drive at the same time, even though it is literally impossible for our brains to multitask when it comes to paying attention. We have created high-stress office environments, even though a stressed brain is significantly less productive. Our schools are designed so that most real learning has to occur at home. This would be funny if it weren’t so harmful. Blame it on the fact that brain scientists rarely have a conversation with teachers and business professionals, education majors and accountants, superintendents and CEOs. Unless you have the Journal of Neuroscience sitting on your coffee table, you’re out of the loop. This book is meant to get you into the loop. 12 brain rules My goal is to introduce you to 12 things we know about how the brain works. I call these Brain Rules. For each rule, I present the science and then offer ideas for investigating how the rule might apply to our daily lives, especially at work and school. The brain is complex, and I am taking only slivers of information from each subject—not comprehensive but, I hope, accessible. The Brain Rules film, available at www.brainrules.net/dvd, is an integral part of the project. You might use the DVD as an introduction, and then jump between a chapter in the book and the illustrations online. A sampling of the ideas you’ll encounter: • For starters, we are not used to sitting at a desk for eight hours a day. From an evolutionary perspective, our brains developed while working out, walking as many as 12 miles a day. The brain still craves that experience, especially in sedentary populations like 2