For most of human history, scientists believed the brain was fixed and unchangeable after childhood. If you were born with certain abilities, you were stuck with them for life. This view shaped everything from education to medicine to how we understood human potential.
Neuroscience has completely overturned this belief. Your brain can rewire itself throughout your entire life. This ability is called neuroplasticity, and it explains why London cab drivers develop larger memory centers, how stroke victims can recover lost abilities, and why your habits (good and bad) become so deeply ingrained. Read on to discover how this remarkable process works and what it means for your capacity to learn, change, and grow.
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What Is Neuroplasticity?
The brain possesses a remarkable ability called neuroplasticity: the capacity to reorganize itself and create new neural pathways throughout our entire lives. Neuroscientist Andrew Huberman (Huberman Lab) explains that neuroplasticity is a fundamental process that allows the brain to adapt and change in response to learning, environmental influences, and even psychological stress. This discovery means that our intelligence and ability levels are determined more by our environment than by our genes—a paradigm shift with profound implications for how we understand human potential.
How Neuroplasticity Was Discovered
Ryan A. Bush (Designing the Mind) argues that the brain’s neuroplasticity developed through evolution. Our ancestors frequently had to adapt to changing conditions, so their brains had to restructure and adjust to support their survival. Even today, by default, we’re constantly creating new neural pathways through our experiences—pathways that are strengthened or weakened as we learn and practice different thought processes and behaviors.
Even though it’s now understood that neuroplasticity has existed for ages, it wasn’t always considered valid in the field of neuroscience or related fields such as psychology and biology. According to Doidge, the concept of the brain as plastic wasn’t taken seriously in the scientific community until around the 1960s. Instead, the brain was thought of as a machine with distinct parts designated for different functions. This was called localizationism and suggested the brain wasn’t capable of significant structural changes.
| Harmful Worldviews Stemming From Localizationism While some of the principles of localizationism—for example, that certain functions tended to be controlled by certain parts of the brain—were correct, the belief that localizationism was universal and inflexible is what led to the dismissal of neuroplastic concepts. Additionally, it led to the founding and validation of the pseudoscience of phrenology, or the belief that brain function can be examined by studying a person’s skull. This was based on the assumption that the structure of the brain shaped the skull. The concepts of phrenology have been debunked, but before that it was often used as a justification for racism, particularly in the United States. In the 1800s, certain scientists used studies of phrenology to claim that Africans’ brains made them inherently more prone to subservience and caused them to need a master to control them. Others used it to argue that white people were a separate species from other races like Native Americans and used this claim to justify land theft, colonization, and genocide of Native American tribes. |
As Shawn Achor observes in The Happiness Advantage, for most of the 20th century, the scientific community broadly believed that human brains grow only from birth through adolescence, after which the brain’s capacity is fixed. But, over time, new studies started to challenge that assumption.
The Physical Mechanisms of Neuroplasticity
These studies were possible because scientists began understanding the brain’s underlying architecture and how it enables change. According to neuroscientist Tara Swart (The Source), the brain consists of 86 billion neurons (brain cells) that are interconnected. These connections are responsible for all our brain’s functions, including all our thoughts and behaviors. But how do these neurons actually communicate?
(Shortform note: With its 86 billion neurons, the human brain has as many as triple the number of neurons as the brains of other primates. However, while this number is staggering, research suggests that the number of neurons in a human’s brain isn’t a predictor of intelligence; rather, according to additional research, it’s the size and speed of neurons that determines intelligence. Additionally, while the brain’s neuroplasticity can help you make significant, desirable changes, not all neuroplastic change is positive: Maladaptive plasticity is when the brain changes in a way that produces unwanted symptoms, such as phantom pain. Being aware of how neuroplasticity works can help you both produce desirable changes and avoid maladaptive plastic changes.)
Psychiatrist and psychoanalyst Norman Doidge (The Brain That Changes Itself) provides a detailed explanation of this process. The brain is made up of neurons (nerve cells) that send signals to each other to produce every one of the brain’s functions. These neurons are separated by tiny spaces called synapses. When one neuron sends a signal to another neuron, it releases a chemical called a neurotransmitter into the synapse. The neurotransmitter then travels to the next neuron and delivers it a message. Neurosurgeon Sanjay Gupta (Keep Sharp), adds another crucial detail: dendrites are the parts of a neuron that receive these electrical signals from other neurons.
Neural Connections Can Change
The crucial insight, as Swart points out, is that these neural connections aren’t set in stone; they can change according to our experiences and our responses to those experiences. These changes include forming new neural connections, strengthening and speeding up existing connections, pruning away old neural connections that are no longer needed, and even creating new neurons through a process called neurogenesis. Gupta notes that plasticity is the brain’s ability to create new dendrites, and this ability remains with us throughout our lives.
(Shortform note: The brain’s neuroplastic potential bodes well for people who’ve experienced trauma: Trauma causes changes in the brain, such as heightening your stress response and impeding your higher-level brain functions. However, through trauma-informed therapy, you can learn to strengthen or form neural connections that help your brain respond appropriately to stress and let it prune away those that developed as a result of trauma.)
Pathways Form Through Repetition
Doidge explains that neuroplastic change occurs when a specific type of signal is sent between neurons again and again so that a pathway is formed between them, which makes them more likely to fire in that same way in the future. Neurons can send and receive two types of messages: signals that cause other neurons to fire and signals that make other neurons less likely to fire. Through repetition, these pathways become established and increasingly efficient.
Researchers recognize that this neuroplastic process manifests in two distinct forms. Structural plasticity occurs when the brain’s structure changes in response to which parts get used the most—exactly what happens when repeated signals strengthen certain pathways. Functional plasticity, on the other hand, describes how the brain adapts to disease or injury, enabling healthy parts to take on the functions of damaged portions. The brain accomplishes both feats through the same fundamental mechanism: strengthening the neurons we use most while allowing unused connections to deteriorate. Those unused neurons might even die and get reabsorbed by the body in a process called synaptic pruning.
| The Second Step of Neuroplasticity: Insulating Our Brain’s Pathways Doidge’s description of the role of neurons in neuroplasticity is extensive, but it might be only part of the neuroplastic picture. The new neuronal pathways created by learning new information or skills are like uninsulated electrical wires—they can successfully transfer their electrical signals, but research suggests this transference isn’t made efficient until a sheath of a fat called myelin forms around the pathway. This sheath insulates the pathway so that energy doesn’t leak out as electricity travels through it. The more myelin that forms around the pathway, the more efficient it becomes. This process—called myelination—is responsible for the development of what we call muscle memory, which is when a skill becomes so ingrained that you can do it without consciously thinking about it. This is how your new skills and ideas become long-term or permanent memories, or how you might go from consciously forcing yourself to use your non-dominant hand to being fully ambidextrous. Because myelination occurs on such a large scale in the brain but consists of so many micro-components, it’s very difficult to study, so its role in neuroplasticity has only recently been recognized. |
Evidence for Neuroplasticity
Achor cites an experiment that revealed that the brains of London cab drivers actually grew in a way that reflected their special skill sets. London’s streets are difficult to navigate because they’re not based on a grid system as other big cities are, so cab drivers develop an intricate mental map of the city. Researchers discovered that the part of the brain in charge of this mental map—the hippocampus, which manages spatial memory—was significantly larger among cabbies than in average people.
Achor writes about another experiment: A man who had become blind as a teenager developed greater sensitivity and sophistication in his braille-reading finger than the average person would have. When scientists probed his braille-reading finger, it activated a much larger area of the brain than when they did the same on another finger.
Perhaps the most dramatic evidence for neuroplasticity comes from cases of extreme brain adaptation. Computer scientist, futurist, and inventor Ray Kurzweil (How to Create a Mind) points to the brain’s plasticity as compelling evidence for his theory that all regions of the neocortex use the same pattern recognition algorithm. Because of this uniformity, he argues, different areas can substitute for each other when necessary.
This flexibility manifests in remarkable ways. People born blind can use their visual cortex for language processing. Stroke victims can sometimes recover lost functions by having other brain regions take over the work of damaged areas. Perhaps most astounding, children who have an entire brain hemisphere removed can still develop normal intelligence, with the remaining hemisphere handling functions typically spread across both sides.
(Shortform note: While brain regions substituting for each other sounds almost magical, neuroscientist Jill Bolte Taylor’s My Stroke of Insight reveals how this process works. When Taylor had a stroke that destroyed much of her left brain, she had to rebuild neural pathways synapse by synapse—relearning everything from vocabulary to emotions over eight years. Brain plasticity doesn’t see regions suddenly switching roles, but requires the strengthening of new neural connections while weakening old ones. This explains why stroke survivors such as Taylor need years of repetitive practice to regain function, gradually reconstructing their brain’s wiring.)
Kurzweil argues that the ability of one brain region to substitute for another would be impossible if different regions used fundamentally different processing methods. The fact that a brain area “designed” for vision can successfully handle language suggests that both vision and language rely on the same underlying pattern recognition principles.
(Shortform note: While Kurzweil uses neuroplasticity to argue that all brain regions work the same way, research shows that neuroplasticity itself involves different mechanisms across the brain. In “upward neuroplasticity,” the brain builds new connections between nerve cells and makes existing connections stronger. In “downward neuroplasticity,” it weakens or eliminates connections by dismantling or disconnecting synapses. The brain also grows new branches on nerve cells, shifts which areas handle specific tasks, and builds new nerve cells. Yet the extent to which any one brain region is adaptable depends on supporting systems such as immune cells, blood vessels, and chemical messenger networks that vary significantly across the brain.)
The Speed and Scope of Neuroplastic Change
Neuroplasticity operates across multiple scales and timeframes. Huberman notes that this plasticity ranges from individual neuron pathways making new connections to larger-scale adjustments like cortical remapping or neural oscillation. The changes can be both subtle and profound, occurring at the microscopic level of individual synapses or at the macroscopic level of entire brain regions.
Perhaps most encouraging is the speed at which neuroplastic change can occur. Gupta points to research from 2006 showing that the brain evolves more rapidly than previously thought: the process of creating and reconfiguring neural networks can occur in the span of just a few hours. This rapid adaptability means that experts can use this information to find ways to work around certain neural pathologies.
Equally important is the fact that neuroplasticity is a lifelong capacity. While Huberman contends that the developing (younger) brain exhibits higher plasticity, Gupta emphasizes that the capacity for neuroplasticity remains throughout life. No matter how old you are, you can take steps to strengthen and preserve your brain. The ability to create new dendrites and form new neural connections doesn’t diminish with age—meaning we retain the power to learn, adapt, and grow throughout our entire lives.
Neuroplasticity’s Competitive Nature
Neuroplasticity isn’t just magical brain improvement—it’s a competitive system that rewards what we practice, for better or worse. Competition is a fundamental feature of how the brain optimizes itself, creating both opportunities and challenges.
The Benefits
The discovery of neuroplasticity has profound practical implications across multiple domains. In education, evidence suggests teaching children they have the power to change their own brains helps them learn better—particularly at-risk students. Understanding that intelligence is malleable rather than fixed can fundamentally change how students approach learning and challenges.
In the medical realm, Gupta argues that the plasticity of our brains may allow us to fight off cognitive decline. This information is key because it suggests that we might be able to slow down, reverse, or even stop degenerative brain diseases by strengthening our neural connections. Gupta points out that experts can use knowledge of neuroplasticity to find ways to work around certain neural pathologies, opening new therapeutic possibilities.
Gupta explains that another significant aspect of neuroplasticity is the way it can be used to build stronger memories and skills simply by focusing our attention. Because the brain is constantly shaping and reorganizing itself in response to stimuli, what we choose to pay attention to literally shapes our brain’s circuitry.
The Tradeoffs
Doidge explains that, when one area of the brain becomes unused, it’s likely to be taken over by other functions that are used regularly. This can make it difficult to break bad habits because using the pathways involved with those habits not only strengthens them but weakens the pathways that are not used by the bad habit.
(Shortform note: This pattern of engaging in a bad habit, strengthening that habit, and weakening good habits can create a harmful feedback loop: Any time a habit is triggered, you’re more likely to engage in that habit, which further reinforces the association of that habit with that same trigger. To break this loop and the bad habits it entails, experts recommend quitting bad habits cold turkey so you stop reinforcing them and then replacing them with good habits so those pathways get strengthened instead. If quitting cold turkey is too difficult or dangerous, you can still replace the bad habits with good ones using incremental steps.)
This also applies to learning a second language: The reason adults have more trouble learning a second language than children do is that the areas of their brain that process language are already being used to process their first language. It therefore takes more practice for an adult than for a child to create new pathways in that area to correspond to a second language. It’s easier to learn a second language while you’re acquiring your first language because the map of neural pathways for language widens to include both languages as they develop at the same time. However, when you’re learning a second language as an adult, that new language has to develop a brand new neural map rather than incorporating it into the first language’s map.
(Shortform note: Other research suggests that learning a language in childhood may be easier because of brain lateralization—the tendency of the brain to use either the left or right hemisphere more than the other in certain processes. Experts say that, during the critical period in childhood, the brain is able to use both hemispheres in learning language because it’s more plastic—whereas, in adulthood, that learning would likely be specialized to the left hemisphere, which might reduce its connection to other parts of the brain and thus make learning harder.)
A Cause of (or Cure for) Anxiety
Doidge also suggests that neuroplasticity could be responsible for excessive worry and disorders such as obsessive-compulsive disorder. As your brain continually plays through anxiety-inducing scenarios, those pathways become stronger, which means you worry about them even more.
Though this could be the cause, Doidge also says that neuroplasticity could be the cure for excessive worry and obsessive-compulsive disorder. Therapy that entails reframing the worrisome thoughts into something positive or distracting yourself with something positive can help weaken the worry pathways that have become so strong.
(Shortform note: Other research into obsessive compulsive disorder suggests that distraction from worry might not be as effective as thinking about your worry through metacognition. Rather than diverting your attention away from your obsessive thoughts, metacognition based on doubt therapy is designed to make you more comfortable with the uncertainty underlying those thoughts. For example, if you compulsively wash your hands because you always doubt they’re fully clean, this therapy would give you step-by-step instructions for becoming more comfortable with the idea that your hands might not be fully clean. While the approach is different, this method would also weaken the brain pathways entailed in worry.)
Explore Further
Understanding neuroplasticity fundamentally changes how we think about human potential. Our brains remain capable of remarkable change throughout our lives, continuously reshaping themselves based on what we practice and experience. By understanding how this process works—including its competitive nature—we can make more informed choices about which neural pathways we want to strengthen and which we want to allow to fade away. Take a look at our article about increasing neuroplasticity to learn how to harness this ability.
To learn more about the broader context of the brain and mental health, check out Shortform’s guides to the books and podcast episode referenced in this article:
- Huberman Lab: “LIVE EVENT Q&A: Dr. Andrew Huberman Question & Answer in Toronto, ON” (Andrew Huberman)
- The Brain That Changes Itself by Norman Doidge
- The Source by Tara Swart
- Keep Sharp by Sanjay Gupta
- Designing the Mind by Ryan A. Bush
- The Happiness Advantage by Shawn Achor
- How to Create a Mind by Ray Kurzweil
