Debunking the 10% Myth

The human brain, an intricate arrangement of neurons and synapses, stands as one of the most complex structures in the known universe. It orchestrates our thoughts, emotions, and behaviors with a level of sophistication that has inspired centuries of scientific exploration. Despite the wealth of scientific knowledge gained through decades of research, a widely circulated myth has captured the public’s imagination: the belief that humans only use 10% of their brains.

The 10% brain myth includes the idea that the majority of our brainpower goes unused, and that unlocking the other 90% could lead to enhanced cognitive abilities. This myth, while captivating, stands in stark contrast to the scientific consensus. It is well understood among neuroscientists that the brain operates as a highly efficient organ, with intricate networks and connections functioning across its entirety. Various studies on neurological processing discredit the 10% myth using neuroimaging techniques such as EEGs, PET scans, and fMRI machines, demonstrating widespread and continuous brain activity. By analyzing recent studies, this myth is easily debunked by advanced brain imaging technology that supports the idea that there is no part of the brain that goes unused.

The allure of the 10% myth lies in the promise that the human mind possesses untapped potential, waiting to be unleashed. Beneath this enticing narrative lies an interplay of historical influences, media representation, and cognitive biases. Once the myth made its way into contemporary society, the idea that humans could potentially unlock the other 90% of their brain gained popularity as an exciting storyline for fantasy films. Media and popular culture began to reinforce the notion that humans can reach their full potential if they could just figure out how to access that other 90%. Analyzing the origins and persistence of this myth goes beyond just dispelling a widely held misconception. It opens the door to broader issues such as media influence and the challenge of communicating scientific truths in a world filled with misinformation. It is important to understand why such myths persist, and more importantly, the implications they carry for broader societal understanding.

Debunking the Myth:

Containing over 100 billion nerve cells, the brain is by far the most complicated structure that nature has ever created. For over 300,000 years, natural selection has shaped the modern human brain to meet the demands of survival, producing a highly functioning and astonishingly complex organ (Neubauer et al., 2018). From an evolutionary perspective, it cannot be possible that 90% of the brain remains dormant. The brain weighs only 2% of the total body weight, but uses over 20% of the body’s energy. Therefore, brain tissue is costly to grow and use. Using only 10% of such an expensive system would be a complete waste of bodily energy, and natural selection would not favor an organ that contains such non-functional mass (Hale, 2020). When considering the mechanisms of evolutionary processes, it becomes clear that the brain unquestionably operates at 100% capacity.

Further evidence comes from the consequences of brain damage. If only 10% of the brain was actively utilized, damage to any portion beyond this small fraction should theoretically be inconsequential. However, neurological cases and clinical studies vividly demonstrate that even damage to relatively small and specific areas of the brain can result in a significant impairment (Beyerstein, 2004). For instance, lesions in the temporal lobe may lead to memory deficits, while damage to the frontal cortex can impact executive functions and decision-making (Sridhar, 2023). Neuroscientists and clinicians routinely observe how localized damage can have cascading effects throughout the entire cognitive system. These findings challenge the simplistic narrative of the 10% myth, highlighting the seamlessly interconnected network of various brain regions involved in maintaining overall cognitive health.

Tangible evidence strongly supports these logical conclusions. Neuroimaging techniques using fMRI and PET scans have shown that most brain regions are continually active over a 24 hour period (Burgess, 2023). Functional magnetic resonance imaging, or fMRI, works by detecting changes in blood flow that occur with neural activity. When an area of the brain is active, it consumes more oxygen, and therefore requires more bloodflow to that particular area (Glover, 2011). Monitoring this blood flow allows scientists to directly pinpoint which parts of the brain are active during specific tasks such as thinking, moving, learning, or remembering. Positron emission tomography (PET) is a technique that involves the injection of a radioactive tracer that travels to active parts of the brain by attaching to glucose, the primary fuel of the brain. Active areas of the brain will use more glucose than inactive areas (Tai, 2004). The scanner can then detect these active areas and create detailed images that provide information about chemical and functional changes across the brain.

Recent neuroimaging studies have unveiled the brian’s intricate processing across various timescales, emphasizing its dynamic and continuous nature. Timescales refer to the duration over which neural processes occur, impacting everything from how quickly a neuron responds to stimuli to how long it remains active. Primary sensory areas, adept at processing immediate sensory inputs, operate on shorter timescales (Cavanaugh et al., 2020). These areas swiftly process information from brief sensory encounters, suggesting a constant state of readiness and processing, even beyond our conscious awareness. For instance, the quick processing of sensory stimuli like the brief touch of a fabric or the instant perception of a light demonstrates the brain’s capacity to manage moment-to-moment information efficiently.

On the other end, the association areas of the brain work on longer timescales, crucial for the sustained attention and integration of information necessary for complex cognitive functions. This extended neural activity supports tasks requiring memory maintenance and the integration of diverse, task-relevant information. It showcases the brain’s ability to juggle multiple pieces of information, facilitating complex problem-solving, planning, and reflective thinking over more extended periods (Cavanaugh et al., 2020). The differentiation between these timescales illustrates not just the brain’s adaptability, but also its continuous engagement in a broad spectrum of cognitive tasks, maintaining baseline activity that ensures readiness and responsiveness to the environment.

Discussing brain activity in terms of shorter versus longer timescales is still a major oversimplification of the intricate arrangement of the brain’s neural networks. Brain networks are physically expensive to build and run, and are therefore organized to minimize wiring costs while maximizing adaptive value (Bullmore, 2012). As previously discussed, since natural selection has worked diligently to create a brain that operates at maximum capacity, it is logical that this brain would contain mechanisms of communication that optimizes its functional networks. These networks span the entirety of the brain, meaning that all areas of the brain are connected and constantly active. This understanding contradicts the notion of an unused 90% of the brain, emphasizing the continuous and purposeful activity involved in various cognitive functions.

Tracing the Origins of the Myth:

While there is no clear source of the origins of the 10% brain myth, there are some possible explanations. Pioneering Harvard psychologist and philosopher William James published a collection of essays in 1907 titled The Energies of Men. The book discusses the idea of willpower and how humans only use a fraction of their full potential. James writes:

“Compared with what we ought to be, we are only half awake…We are making use of only a small part of our possible mental and physical resources. Stating the thing broadly, the human individual thus lives far within his limits; he possesses powers of various sorts which he habitually fails to use.” (James, 1907)

By this, James simply meant that we are not fully aware of our true potential, and that individuals tend to operate well below their capable limits. Nonetheless, this iconic line from James’s book has been modified and distorted for the past century, often leading to the widespread belief that humans only utilize 10% of their brain capacity. However, James never specified such a percentage; he merely suggested that individuals do not reach their full potential. This misinterpretation may have found unintended support in the numerical discrepancy between neurons and glial cells within the brain. While neurons, the brain’s primary signal carriers, constitute about 10% of its cellular makeup, glial cells make up the remaining 90% (von Bartheld, 2016). A simplistic and now debunked view suggested that if neurons were directly responsible for cognition and only comprised a small fraction of the brain’s cells, then perhaps we were only harnessing a fraction of our brian’s true potential.

Contrary to previous assumptions, glial cells play active and essential roles in brain function. They provide structural support to neurons, transport nutrients, regulate neurotransmitter levels, and facilitate waste removal. Additionally, glial cells contribute to insulation of neuronal axons, boosting the speed of electrical impulse conduction. They also participate in the brain’s immune defense and promote neurogenesis, the creation of new neurons, crucial for learning and memory (Rasband, 2016). This collaborative relationship between neurons and glial cells illustrates the brain’s full capacity utilization, refuting the 10% myth. Despite mountain evidence, the persistence of this myth underscores a widespread underestimation of the brain’s complexity. Recognizing the vital functions of both neuron and glial cells provides a more accurate understanding of brain operation as a highly integrated and efficient system. This realization debunks the myth of underutilized brain potential and highlights the evolutionary sophistication of the brain’s design, optimized to utilize every aspect of its structure and function.

With the rise of the self-help movement in the 1920s, the belief that humans possess a reservoir of unused potential became a core idea for people striving for greater creativity and productivity in their lives. Somewhere along the lines of this movement, “10% of our capacity” turned into “10% of our brain.” In 1936, American writer Lowell Thomas popularized the idea when he wrote in a preface of Dale Carnegie’s How to Win Friends and Influence People that “Professor William James of Harvard used to say that the average man develops only ten percent of his latent mental ability.” Ever since, the myth has only gained traction, as more and more self-help entrepreneurs use it to sell their scientifically inaccurate ideologies to the public.

How this Affects the Public:

Considering the irrefutable logic and overwhelming evidence dispelling the 10% brain myth, one might reasonably expect that this fallacy would have long been extinguished. However, Hollywood has played a significant role in perpetuating this myth since the 1980s. In Flight of the Navigator (1986), for instance, a young boy undergoes alien experiments to explore the consequences of humans using 100% of their brains. Phenomenon (1996) portrays John Travolta’s character gaining super-intelligence and telekinesis from a mysterious light descending from the sky that allows him to use “more areas of active brain than anyone has ever tested – ever.” In Limitless (2011), Bradley Cooper’s character attains superhuman intelligence after consuming a smart drug enabling him to utilize 100% of his brain. Similarly, Luc Besson’s newest thriller Lucy (2014) follows Scarlett Johansson’s character, Lucy, who gains superhuman abilities after unintentionally ingesting a drug that unlocks the full potential of her brain. While science fiction movies are inherently fictional, their ability to captivate and blur the lines of reality often make it understandable why people can be easily misled.

Another significant factor contributing to the endurance of the 10% myth is the increasing popularity of the self-help movement. While certain self-help experts can actually offer legitimate life advice, the self-help industry is a multi-billion dollar industry that creates unrealistic expectations and is often yet another form of avoidance. What's more, is that most of it is usually not even scientifically validated. The self-help industry is driven by profit-motives to create the illusion of progress and not progress itself. One of the fantasies that these marketers try to sell is the promise that they can help you unlock a greater portion of your cognitive abilities. The reality is that every individual, assuming they do not suffer from any brain damage, has the capacity to consistently utilize all of their cognitive abilities.

Certainly, the persistence of this myth can be attributed to the inclination of many individuals to prefer believing in its truth. It would be nice to think that if we could just access that other 90% of our brains, we would find a direct route to achieving our dreams. As we now know, the idea that we only use 10% of our brains turns out to be 100% false. Believing in eventual access to untapped mental abilities is an apathetic mindset that can actually decrease productivity and have a negative impact on personal growth. Needless to say, there is no substitute for hard work and practice when it comes to success. There is no magic pill, miracle cure, or special potion that will expand one’s brain capacity and unlock their full potential. Nevertheless, understanding the scientific truth about the brain in a world of misinformation is empowering, and we can take comfort in knowing that our efforts and achievements are not limited by an arbitrary 10% cap.

Sources

Beyerstein, B (2004). Why do we only use 10 percent of our brains?. Scientific American https://www.scientificamerican.com/article/do-we-really-use-only-10/

Bullmore, E., & Sporns, O. (2012). The economy of brain network organization. Nature reviews. Neuroscience, 13(5), 336–349. https://doi.org/10.1038/nrn3214

Cavanagh, S. E., Hunt, L. T., & Kennerley, S. W. (2020). A diversity of intrinsic timescales underlie neural computations. Frontiers in Neural Circuits, 14. https://doi.org/10.3389/fncir.2020.615626

Glover G. H. (2011). Overview of functional magnetic resonance imaging. Neurosurgery clinics of North America, 22(2), 133–vii. https://doi.org/10.1016/j.nec.2010.11.001

Hale, J (2020). Why we use more than 10 percent of our brain power. Center For Inquiry. https://centerforinquiry.org/blog/why-we-use-more-than-10-percent-of-our-brain-power/

James W. THE ENERGIES OF MEN. Science. 1907 Mar 1;25(635):321-32. doi: 10.1126/science.25.635.321. PMID: 17736950.

Neubauer, S., Hublin, J. J., & Gunz, P. (2018). The evolution of modern human brain shape. Science Advances, 4(1), eaao5961. https://doi.org/10.1126/sciadv.aao5961

Rasband M. N. (2016). Glial Contributions to Neural Function and Disease. Molecular & Cellular Proteomics : MCP, 15(2), 355–361. https://doi.org/10.1074/mcp.R115.053744

Sridhar, S., Khamaj, A., & Asthana, M. K. (2023). Cognitive neuroscience perspective on memory: overview and summary. Frontiers in human neuroscience, 17, 1217093. https://doi.org/10.3389/fnhum.2023.1217093

Tai, Y. F., & Piccini, P. (2004). Applications of positron emission tomography (PET) in neurology. Journal of Neurology, Neurosurgery, and Psychiatry, 75(5), 669–676. https://doi.org/10.1136/jnnp.2003.028175

von Bartheld, C. S., Bahney, J., & Herculano-Houzel, S. (2016). The search for true numbers of neurons and glial cells in the human brain: A review of 150 years of cell counting. The Journal of comparative neurology, 524(18), 3865–3895. https://doi.org/10.1002/cne.24040