Nestled within the fortress of our craniums, the human brain 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. 

This myth offers an alluring narrative — that we’re sitting on a goldmine of untapped cognitive resources, ready to transform our abilities if only we could access that dormant 90%. Yet, delving into its origins reveals a complex interplay of historical influences, media representations and deeply rooted cognitive biases. Hollywood, for example, has played a significant role in perpetuating the myth through films like “Limitless” and “Lucy,” blurring the lines between fiction and reality. Additionally, the self-help industry, driven by profit motives, often misleads individuals with promises of unlocking unused cognitive abilities.

Exploring the evolution of the brain offers tangible evidence against the 10% myth. The brain, despite comprising only 2% of the body’s weight, demands over 20% of its energy. From an evolutionary standpoint, maintaining such an energetically costly organ would be impractical if 90% remained inactive. The fallacy of the 10% myth is further highlighted by studies showing how lesions in the temporal lobe lead to memory deficits, and how damage to the frontal cortex affects executive function and decision-making. Neuroscientists and clinicians routinely observe how damage to specific regions yields consequential impairments, challenging the simplistic notion that only 10% of the brain actively contributes to our cognitive functions.

Recent advancements in neuroimaging technology have shattered the illusion of the 10% brain myth. Studies utilizing EEGs, PET scans and fMRI machines capture continuous and purposeful engagement across the entirety of the brain, dismissing the idea that significant portions remain dormant. Containing over 100 billion nerve cells, the brain has evolved through the ages to function at optimal efficiency, contradicting the idea of vast inactive regions. The promise of unlocking the other 90% of our cognitive potential may sound appealing, but scientific evidence suggests that our brains are already functioning at full capacity.

The origins of the 10% brain myth are elusive, but some clues point to William James, a Harvard psychologist and philosopher. In 1907, James wrote about humans using only a fraction of their potential, which over time transformed into the notion that we only use 10% of our brains. This misinterpretation gained momentum in the self-help movement of the 1920s, evolving into a catchy phrase that has persisted for over a century. Self-help marketers, driven by profit motives, have long tried to sell the promise that they can help you unlock a greater portion of your cognitive abilities. Unfortunately, the self-help industry merely provides the illusion of progress and not progress itself. 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. 

As we now know, the idea that we only use 10% of our brains turns out to be 100% false.  It would be nice to think that if we could just access that untapped 90%, we would find a direct route to achieving our dreams. 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.

A version of this article appeared on pg. 10 of the April 11, 2024 print edition of the Daily Nexus.