Be careful of your thoughts, for your thoughts become your words. Be careful of your words, for your words become your actions. Be careful of your actions, for your actions become your habits. Be careful of your habits, for your habits become your character. Be careful of your character, for your character becomes your destiny.
—Chinese proverb
Insanity is doing the same thing, over and over again, but expecting different results.
—Albert Einstein
In February 1983, my grandparents were visiting my uncle and aunt in the small Canadian town of Peace River, Alberta. In the middle of the night there was a commotion and my grandfather ran upstairs from the guest room to my uncle’s room and said, “Mom is having a problem.” My uncle went down to find my grandma unable to move or speak properly. He carried her to the car and drove her to the local hospital. She’d had a stroke in the left side of her brain. The blood and oxygen supply to that region had been cut off, leading to the death of crucial brain cells. She was in the Peace River hospital for a month before being flown to Edmonton, where she was in a rehab hospital for several weeks. Despite this, the stroke left the right side of her body paralyzed.
The doctors and physiotherapists and her family focused on helping her to increase the use of the left side of her body. Even simple tasks are difficult with only one hand. My grandma used to love squeezing fresh oranges to make juice for breakfast. However, if you think about it, you can’t do this with one hand. You need to hold the orange with one hand, while the other hand cuts. If you can’t hold the orange, it tries to escape while you attempt to cut it. Before he died, my grandfather made her a cool cutting board with suction cups underneath and two nails poking up out of it. That way Grandma could stick the orange onto the nails and cut it in half with one hand, without either the cutting board or the orange sliding out from under her knife.
My maternal grandmother grew up on a ranch with no running water or much time to complain about it. Grandma was a tough lady and she lived on for another thirty years after her stroke, mostly in her own house. She changed from knitting, which requires two hands, to a kind of crocheting that requires only one. She crocheted rugs for each of her five remaining children and all eleven of her grandchildren with just her left hand. My rug is as long as me and depicts a Scottish soldier playing the bagpipes.
According to conventional medical thinking at the time of her stroke, my grandma’s care and rehabilitation was a success story, because she learned to function relatively well using only the left side of her body. Trying to get her to use her right hand would supposedly have been pointless, since the part of her hardwired brain that sends signals to the right side of the body was dead. Or so they thought.
Until recently, virtually all scientists believed that our brain becomes largely fixed during what are called sensitive or critical periods in childhood, at a time when brain circuits are unusually open to being shaped by sensory experiences. According to this view, each part of the brain is responsible for a specific function in the body. For example, the visual cortex (located at the back of the brain) is responsible for visual perception; the auditory cortex (located on each side of the brain just above the ears) is responsible for making sense of sounds; the motor cortex (in the top middle part of the brain) is responsible for moving limbs; and so on.
Knowing which parts of the brain were responsible for specific functions allowed scientists to create a brain map. The development of technology for brain imaging, such as computed axial tomography (CAT), magnetic resonance imaging (MRI), and functional magnetic resonance imaging (fMRI) seemed to support the view that brains were hardwired. Brain imaging showed that different parts of our brains were responsible for moving our hands, for vision, and for interpreting sounds. Since the brain was seen as hardwired, nothing could be done about the paralysis of the right side of the body in someone who had suffered a stroke in the left side of their brain, like my grandmother. End of story, right?
In fact, as is often the case in science, a story that seemed over was not. Medical conventional wisdom on the degree to which the brain can be rewired in adulthood has changed. Had my grandma had her stroke ten years later, the chances are that she would have regained control of her right arm.
In 1958, University of Wisconsin professor Paul Bach-y-Rita’s father, Pedro, suffered a stroke. As in my grandmother’s case, half of his body was paralyzed. He also lost his ability to speak. Paul’s psychiatrist brother, George, refused to believe that Pedro would spend the rest of his days in this condition and dedicated his life to helping him. George kept encouraging Pedro to try and use the paralyzed side of his body, and eventually—after a lot of hard work—he did. Pedro got to the point where he could walk and hike normally. An autopsy performed on Pedro’s body when he died revealed that he had suffered serious damage to his brain stem, which had not repaired itself after the stroke. While areas of the brain damaged by the stroke had remained so until Pedro died, other parts seemed to have taken over control of the paralyzed side of the body to allow it to move again.
His father’s recovery inspired Paul Bach-y-Rita to conduct a daring and fascinating experiment in which he tried to teach blind people to see with their tongues. Most blind people’s eyes work—it is the connection between the eyes and the brain that does not. You don’t just see with your eyes; you see with your mind and brain. The eye sends signals to a part of your brain near the back of your skull called the visual cortex. Your consciousness then perceives those signals to tell you what the thing is in the visual cortex. The same goes for what you hear, feel, and smell.
When most people go blind, what they really lose is the ability to transmit signals from the eye via the optic nerve to the visual cortex. Noting this, Bach-y-Rita sought to teach the brain how to see via the sensation of touch. In one example, he developed a device that translated images on a camera placed on the head of blind people into patterns of sensations delivered to their tongue by a special ribbon. For instance, if the camera saw something square, it would cause sensations in the shape of a square to be delivered to the tongue. The blind person would then feel something shaped like a square on their tongue and know that there was a square-shaped thing in front of them. They increased the complexity of the things people “saw” until eventually several patients were able to recognize the supermodel Twiggy. The study was all the more dramatic because the blind people in the experiments were congenitally blind, meaning they had never been able to see.
These experiments sparked a new field called sensory substitution, which is currently a hot topic leading to many potentially important clinical applications. The experiments also led to the foundation of the science of neuroplasticity. The word neuroplasticity comes from the root words neuron and plastic. A neuron is a nerve cell in the brain, and plastic is used in the sense of to mold, sculpt, or modify.
Neuroplasticity refers to the potential that the brain has to reorganize itself by creating new neural pathways. While Bach-y-Rita’s experiments all happened years before my grandma had her stroke, the results were not implemented into mainstream stroke rehabilitation. This was partly because science can move at a frustratingly slow pace, and also because the view that the brain was hardwired was difficult to overthrow. This all changed when animal experiments provided some insight into the underlying mechanisms explaining how the brain changes.
In the late 1970s and early 1980s, neuroscientist professor Edward Taub conducted some experiments on monkeys in Silver Spring, Maryland, that explained what happened when the brain was being rewired. He started by cutting the monkeys’ nerves that sent signals from one of their limbs to the brain. For example, he would cut the nerves that communicated between a monkey’s right arm and brain, so it could not move the arm. He then restricted the left arm, forcing the monkey to try to use the “bad” right arm. Eventually these animals would relearn to use their bad limbs, meaning the limbs had been reconnected to the nervous system.
Soon after his initial research, Edward Taub was charged with animal cruelty and he had to stop his experiments. Animal rights activists argued that the animals were not treated humanely. After a long and hard-fought battle, all the charges against Taub were eventually dropped. But the protestors had a point: Bach-y-Rita proved that we could have learned the same thing without inflicting what to many people was cruelty toward the monkeys. Experiments such as those carried out by Taub could not only have avoided legal and ethical issues, but also concerns about whether the results of research on monkeys apply to humans.
Taub’s work was eventually adapted for use with humans who had suffered from strokes in a kind of treatment called constraint-induced movement therapy. This involves placing the limb that can be used in a sling or a splint, or restricting its movement in some other way, for 90 percent of the patient’s waking hours for about two weeks. The therapy has been shown to be highly effective. Had the therapy been common when my grandmother first had her stroke, I have no doubt that with her determined character she would have completely recovered most of the use of her right side.
The science of neuroplasticity and how the brain changes is flourishing, and experiments have even shown that the brain can generate new neurons, and that this can happen in elderly people. It can also happen faster than was previously believed. Researchers who carried out scans on medical students before and after they studied for exams found the volume of gray matter in their brains had increased significantly over the few months that they studied for their exams.
Change can help us survive, so from an evolutionary perspective it is hardly surprising that our brain can be remolded. Humans are considered to be the most adaptable species on the planet. Even rats and cockroaches cannot live in places like Iceland, where humans have thrived for centuries. This ability to learn to survive in climates ranging from scorching-hot deserts to freezing-cold northern tundra has been a major evolutionary advantage. If our ancestors’ brains were hardwired, humans could not have learned to adapt and thrive in the climates we now inhabit.
You may recall from earlier chapters that our physiological responses to the world around us are caused not only by external stimuli but also by the way we interpret and react to them. The way we react, in turn, is determined partly by our neural networks. Let’s say two people in a room see a spider on a window. One of them is frightened of spiders and experiences a fight-or-flight response. To the other, the sight reminds them of a cuddly spider toy they had as a child, and it gives them a warm, nostalgic feeling. News of rain might upset someone planning a picnic, while bringing a smile to the face of a farmer whose crops need water. A paranoid person might think that someone looking at them is planning to rob them, whereas a more confident person might perceive the same lingering look as a sign that the person is attracted to them.
Key differences in these examples are in the ways the brains of the different individuals have learned to react. How does the perception of a spider activate the fight-or-flight response in one person and the warm nostalgic response of another? Here is what is going on within the brain. The visual cortex communicates with the amygdala (a small part of the middle of the brain that is responsible for activating the fight-or-flight response) via nervous system cells called neurons.
Neurons rarely connect randomly with other neurons. Instead, they connect via neural networks that are a bit like groups of well-worn roads. As soon as a person who is scared of spiders sees the object of their fear, the brain network that links the image to the amygdala activates. For the person who grew up with a stuffed, friendly spider toy, the perception of a spider is strongly connected to parts of the brain that generate feel-good chemicals.
The creation of neural networks based on experience is what allows us to learn. When a child puts a finger close to a flame they feel pain. This creates a neural network connecting the perception of fire and the part of the brain that warns us to stay away. This helps us to avoid getting burned. Next time you are near a candle, try to put your fingers near the flame. You can almost feel the signal in your brain applying the brakes to your hand. You don’t need to consciously think about avoiding a flame, it all happens naturally.
Other habits include looking both ways before you cross the street; driving or walking a familiar route, for example, from home to work; reaching in your pocket to get a wallet when you are paying for something; and indeed most of the things we do every day. These subconscious learned habits are useful because they free up our mind to do other, more productive things. If we had to constantly remember or relearn that flames burn, that our money is in our wallets, or that there are dangerous cars on the streets, we would have little energy left to do much else. That these neural network–based behaviors are automatic is usually useful, but it is also a double-edged sword, as we can develop patterns that are bad for us.
Eating chocolate cake gives us a dopamine high, which in turn teaches our brain that doing so makes us feel good. This is fine up to a point; however, it can lead to two problems. First, too much chocolate cake can be bad for our health, and second, it can make us falsely generalize from one emotional experience. Someone who has been hurt in a relationship might come to think that getting close to people generally leads to getting hurt, in the same way that we might react to putting our hands close to flames. The same thing can apply to sex, drugs, and emotional reactions. For example, someone who gets their own way by shouting as a child may become angry as their default reaction when people disagree with them. Neuroplasticity offers us an escape from these patterns.
Most of us now live in an era in which cardiovascular diseases (CVD), such as heart attacks and strokes, are more likely to kill us than the infectious diseases, like tuberculosis and pneumonia, that killed our ancestors. Unlike infectious diseases, cardiovascular diseases are more successfully treated by lifestyle changes in our eating and exercise habits than by medicine. Even the risk of cancer can be greatly reduced by maintaining a healthy lifestyle. The bad news is that eating less and exercising more is easier said than done. The good news is that besides helping people recover from strokes, neuroplasticity suggests that it really is possible to change our brain and our habits. Let’s look at habits in a bit more detail.
Habits are automatic behaviors triggered by cues that produce a reward. It’s automatic: the flame is the cue to pull your hand away (the behavior) to avoid getting burned (your reward). An urge to sneeze is a cue to cover your mouth with your hand to avoid people telling you off—depending, of course, on your upbringing. So the pattern is: cue → behavior → reward.
In his book about changing habits, American writer Charles Duhigg talks about how he changed his habit of eating a chocolate cookie every afternoon. His cue was that he became bored in the middle of the afternoon, so he developed a habit of walking to the cafeteria to speak with his friends. In the cafeteria, his routine was to buy a chocolate cookie. His reward was feeling refreshed because he’d had a break from work. From a neuroscientific point of view, Duhigg trained his brain to get up from his desk, walk to the cafeteria, buy a cookie, and then feel rewarded and ready for more work in the afternoon. The sense of satisfaction he got as a result was in fact a dopamine rush that he came to crave, leading him to continue performing his afternoon cookie ritual.
To change his habit, Duhigg had to interrupt the cue → behavior → reward cycle in a new way that gave him a similar reward but without the chocolate cookie. He did this by going for a walk to get a breath of fresh air when he felt the cue (feeling bored in the afternoon). This made him feel good, too, and did not involve chocolate. Until he formed a new habit, he would not have been able to go to the cafeteria and chat with his friends for a break without a cookie and still feel good about it. This is because the cafeteria provided the context that automatically triggered the cookie-buying behavior.
One problem with habits is that they are very like addictions. An important difference is that with an addiction you need more and more to get the same rush. Try to recall the buzz you got the first time you tried coffee or alcohol. A single cup or glass was probably enough to produce an effect. Then, if you carried on drinking coffee or alcohol on a daily basis, you needed more to feel the way you did that first time. You may or may not remember, but there was a time when we were all cheap dates. The neurological explanation for this is that the neural network linking the stimulus with the reward becomes strengthened and reinforced with repeated exposures. Your body becomes accustomed to the chemicals generated by drinking coffee and beer, meaning it needs more and more in order to get excited about it.
In spite of the distinction, the difference between a habit and an addiction is a matter of degree. Addictions involve more intense cravings and usually have more detrimental effects. They both involve an automatic cue → behavior → reward process. It is a thought pattern with its foundations within a neural network. More generally, the ways we react to things are also often habitual. They could be seen as emotional habits or addictions.
Someone who is easily angered will have a well-used neural network that activates the anger emotion. Compared with other people, signals travel easily along the network, meaning it does not take much to make the person angry. And just as someone who takes cocaine regularly will desensitize the reward pathways, the person who gets angry easily needs less and less provocation to become angry, or has to react more and more forcefully to feel the same emotion.
The same thing applies to other emotions like depression, sadness, and attraction. It explains why sex addicts often need harder- and harder-core pornography to satisfy their desires. These emotions are generated by neural networks that give your brain the associated chemical that it is used to. To change our habits we need to reprogram the cue → behavior → reward cycle in ways that benefit us.
Understanding that the brain is not totally hardwired can play the same motivational role as understanding that your health is not (just) due to your genes. You really can change.
This does not mean that changing habits is easy. It is not. At a deeper level, accessing your inner will or desire to change can be difficult, too. Someone might understand the science of neuroplasticity, and they might know that if they changed their thoughts about food they could eat more healthily and lose weight. But the problem many people have is that they don’t have the willpower. They know that healthy food is better for their bodies at an intellectual level, but they don’t know how to translate that into new habits.
It is a problem I can empathize with. Whereas I am very disciplined about getting enough exercise, I love sweet things, especially Nutella. If there is any Nutella in the house and there is also a spoon, the chances are that I will eat the entire jar by the end of the day. I am well aware this is not good for me, but I find it difficult to resist, as I have had a sweet tooth for as long as I can remember. Where can we get the willpower to change these difficult things? An important part of the answer to this question is simple: believe that you can change. The mere belief that you can change will give you a dopamine rush that makes you feel good, and this can help you change your habit. This connection was illustrated in the discussion of self-efficacy in Chapter 8. And if you cannot muster a real belief that you can do it, start by pretending that you can. Fake it until you make it. The good thing is that if you are reading this book, you have already proved that you have some motivation.
Think of a habit you would like to change, and write down what the cue, behavior, and reward are. Duhigg’s cue was feeling bored, his behavior was buying a cookie, and his reward was basically a sugar high. I have the same type of habit as Duhigg, and I eat too many sweet things. My cue is that I will see a sweet thing (cue), eat it (behavior), and get a reward (a sugar high). So the next time I walk past a sweet thing, I am going to take ten deep breaths and stretch.
I’m not aware of any trials that support the following exercise, but it has helped me get “unstuck” at times. Sometimes the best way to change an old habit can be to ignore it for a while and focus on something new. To create new habits and new neural pathways you have to behave in a new way. The exercise in this chapter is very simple: just do something different. Anything. It can be a big thing or a small thing. Here are some examples for inspiration:
It has to be something you would not normally do. Notice how you feel when you think of it. Chances are you might feel some resistance, some reason not to do it. And when you actually do it, chances are you will feel good. Use this as a starting point to kick an old habit and begin a new one.