and his team discovered did not send ripples; it sent crashing waves that would go on to change people’s lives profoundly.2
The team successfully made mind maps of the monkeys’ brains and then set the maps aside to continue on with other aspects of their work. When they returned to the mind maps, they realized the monkey’s brain networks, which they had sketched out in the mind maps, had changed. Merzenich himself reflected: “What we saw was absolutely astounding. I couldn’t understand it.”3 Eventually the scientists drew the only possible conclusion they could—the brains of the monkeys were changing and they were changing quickly. This was the birth of what came to be known as neuroplasticity.
When Merzenich published his findings, he received pushback from other scientists. Many simply would not accept an idea they had been so certain was wrong. Some scientists had believed that brains were fixed from birth, and others that brains became fixed by the time people became adults. The evidence that adult brains were changing every day seemed inconceivable. Now, two decades later, even those who were the most vehemently opposed to the evidence from neuroplasticity research have conceded.
Unfortunately our schools, colleges, businesses, and culture have, for hundreds of years, been built around the idea that some people can and some people can’t. This is why putting young students into different groups and teaching them differently made perfect sense. If individuals within a school or company weren’t reaching their potential, it was not due to teaching methods or environmental factors, but to their limited brains. But now, with decades of knowledge about brain plasticity, it is time that we eradicate this damaging myth about learning and potential.
Energized by the new evidence showing brain plasticity in animals, researchers began to look at the potential of human brains to change. One of the most compelling studies of the time came from London, the city where I had my first teaching and university job. London is one of the most vibrant cities in the world—and it is always filled with millions of residents and visitors. On any day in London you will see “black cabs” zipping around the thousands of major thruways, streets, and lanes. The drivers of these iconic taxicabs hold themselves to very high professional standards. Londoners know that if they get in a black cab and tell the driver a road to find, and the driver does not know it, the driver should be reported to black-cab authorities.
Knowing all the roads in London is quite a feat—and drivers go to huge lengths to learn them. In order to become a black-cab driver, you need to study for at least four years. The most recent cab driver I traveled with told me he had studied for seven years. During this time drivers must memorize every one of the twenty-five thousand streets and twenty thousand landmarks within a six-mile radius of the centrally located Charing Cross station—and every connection between them. This is not a task that can be accomplished through blind memorization—the drivers drive the roads, experiencing the streets, landmarks, and connections, so they can remember them. At the end of the training period, the drivers take a test that is aptly named “The Knowledge.” On average, people have to take the test twelve times in order to pass it.
The extent and focus of the deep training needed by black-cab drivers caught the attention of brain scientists, who decided to study the brains of the black-cab drivers before and after the training. Their research found that, after the intense spatial training, the hippocampus of the cab drivers’ brains had grown significantly.4 This study was significant for many reasons. First, the study was conducted with adults of a range of ages, all of whom showed significant brain growth and change. Second, the area of the brain that grew—the hippocampus—is important for all forms of spatial and mathematical thinking. Researchers also found that when black-cab drivers retired from cab driving, the hippocampus shrank back down again—not from age, but from lack of use.5 This degree of plasticity of the brain, the amount of change, shocked the scientific world. Brains were literally growing new connections and pathways as the adults studied and learned, and when the pathways were no longer needed, they faded away.
These discoveries began in the early 2000s. At around the same time, the medical world was stumbling upon its own revelations in the realm of neuroplasticity. A nine-year-old girl, Cameron Mott, was suffering from a rare condition that gave her life-threatening seizures. Doctors decided to perform a revolutionary operation, removing the entire left hemisphere of her brain. They expected Cameron to be paralyzed for many years or possibly life, as the brain controls physical movement. After the surgery, they were absolutely stunned when she started moving in unexpected ways. The only conclusion they could draw was that the right side of the brain was developing the new connections it needed to perform the functions of the left side of the brain,6 and the growth happened at a faster rate than doctors had ever thought possible.
Since then, other children have had half of their brains removed. Christina Santhouse was eight when she had the operation—performed by neurosurgeon Ben Carson, who later would run for president. Christina went on to make the honor roll at her high school, graduate from college, and go on to achieve a master’s degree. She is now a speech pathologist.
We have multiple forms of evidence, from neuroscience and from medicine, that brains are in a constant state of growth and change. Every single day when we wake up in the morning, our brains are different than they were the day before. In the next chapters you will learn ways to maximize brain growth and connectivity throughout your life.
A few years ago we invited eighty-three middle-school students to the Stanford campus for an eighteen-day math camp. They were typical students as far as their achievement levels and beliefs went. On the first day each of the eighty-three students told interviewers that he or she was “not a math person.” When asked, they all named the one student in their class whom they believed to be a “math person.” Unsurprisingly, it was usually the student who was quickest to answer questions.
We spent our time with the children working to change their damaging beliefs. All students had taken a math test in their district before coming to us. We gave them the same test eighteen days later at the end of our camp. The students had improved by an average of 50 percent per student, the equivalent of 2.8 years of school. These were incredible results and further evidence of the brain’s learning potential when given the right messages and forms of teaching.
When the teachers and I were working to dispel the negative beliefs the students held, we showed them images of Cameron’s brain, with only one hemisphere, and told them about the operation she underwent to have half of her brain removed. We also described her recovery and how the growth of the other hemisphere had shocked doctors. Hearing about Cameron inspired our middle-school students. As they worked over the next two weeks, I often heard them say to each other, “If that girl with half a brain can do it, I know I can do it!”
So many people harbor the damaging idea that their brain is not suited to math, science, art, English, or any other particular area. When they find a subject difficult, instead of strengthening brain areas to make study possible, they decide they were not born with the right brain. Nobody, however, is born with the brain they need for a particular subject. Everyone has to develop the neural pathways they need.
Researchers now know that when we learn something, we grow the brain in three ways. The first is that a new pathway is formed. Initially the pathway is delicate and fine, but the more deeply you learn an idea, the stronger the pathway becomes. The second is that a pathway that is already there is strengthened, and the third is that a connection is formed between two previously unconnected pathways.
These three forms of brain growth occur when we learn, and the processes by which the pathways are formed and strengthened allow us to succeed in our mathematical, historical, scientific, artistic, musical, and other endeavors. We are not born with these pathways; they develop as we learn—and the more we struggle, the better the learning and brain growth, as later chapters will show. In fact, our brain structure changes with every different activity we perform, perfecting circuits so they are better suited to tasks at hand.7
The Fixed-Brain Message
Let’s imagine how transformative this knowledge can be for the millions of children and