Do You Believe Either Of These 2 Infamous Psychology Myths?

Although these two psychology 'facts' are wildly popular, they are entirely untrue. Have you heard them before?

By Mark Travers, Ph.D. | April 24, 2024

The human mind holds more wonders than we can imagine—so much so that, for centuries, we've dedicated ourselves to trying to understand it. It's in the very name; "psyche", meaning mind or soul, and "-ology", meaning study, come together to refer to the field we know, love and take a great deal of interest in: psychology.

Since the time of our psychological forefathers, we've come far in our attempts to grasp the essence of the human mind and brain. While there's still plenty we're not certain of, there's an equal amount of knowledge we've been able to gain. However, with this pursuit of knowledge comes the spread of mythological thought—ideas that, despite their prevalence, lack any empirical support and mislead us in our understanding of the mind.

You've likely heard these two myths before. Through actual psychological insight, you can learn the truth behind them.

1. People Are Either "Left Brained" Or "Right Brained"

The idea that people are either "left- or right-brained" is an enduring concept. The left side of the brain is personified as being the logical one, and the right side as being the creative one—and the idea suggests our personalities and skills are shaped by the hemisphere we favor. Are you a logical, analytical left-brainer or a free-spirited, creative right-brainer? It's an alluring dichotomy.

Although they are symmetrically located within the brain, it's common knowledge that the left and right hemispheres of the brain both develop and function asymmetrically. They both share nearly 100 billion neurons—close to the amount of stars in the Milky Way galaxy—that are located in identifiable regions and tuned to take on specific tasks. These two hemispheres work in tandem, but not in the way our intuition would lead us to think.

Research from the International Journal of Innovation, Creativity and Change underlines the counterintuitive way that the left and right hemispheres operate. For instance, the brain processes incoming visual information from the eyes through the occipital lobes at the back of the brain; however, the left hemisphere processes information from the right visual field, and vice versa. Similarly, the left frontal lobe typically controls the movement of the right side of the body, and also vice versa.

However, despite these asymmetries, the authors explain that there is virtually no evidence to suggest that normal cognitive functioning happens exclusively in one hemisphere or the other. The corpus callosum—the bridge between the hemispheres—allows extensive communication between the hemispheres, making sure that brain activity is coordinated across both sides.

While the idea of "left- versus right-brained thinking" may seem like a convenient framework, it ultimately falls short as a scientific reality. While some people may be more adept in analytical thinking, and while others may thrive in creative pursuits, these strengths can't be reliably attributed to the dominance of one hemisphere over the other. In reality, most of us have a diverse range of skills that can't be neatly categorized into left-brained or right-brained categories.

2. Humans Only Use 10% Of Their Brain

From the silver screen to casual conversations, the idea that humans only use 10% of their brains has made its way throughout popular culture. You might remember Scarlett Johansson's portrayal of a woman unlocking superhuman abilities as she surpasses the "10% threshold" in the movie Lucy. This idea, however, begs too many questions.

Humans are often referred to as "cognitive misers" in psychology. According to renowned cognitive scientist Keith Stanovich, animals—including humans—have evolved over time to help their genes survive and reproduce, rather than to always make perfect decisions. This means that being rational, or making decisions that perfectly match reality, isn't always the most important thing for survival. Sometimes, it's more beneficial for us to use less energy or resources, even if it means being a bit inaccurate.

Put simply, we often take the path of least resistance when it comes to thinking—and it's this notion that may have given rise to the idea that we only use 10% of our brains. However, the theory of humans being cognitive misers by no means suggests that we are incapable of using the "full capacity" of our brains. If this were the case, our reality as humans would look a lot different.

To prove this, neuroscientist Barry Beyernstein set out six pieces of evidence to debunk the "10% myth":

1. If we only use 10% of our brains, then traumatic brain injuries to the other 90% would have no effect on our functioning. In reality, however, there's virtually not a single part of the brain that can be damaged without impairing our functioning.
2. No matter what we are doing, every area in a healthy, undamaged brain is always active. While some areas might not participate as much as others, they all play a part—even when we're sleeping—in ensuring that we can function.
3. The brain uses a massive amount of resources to operate. If we didn't need 90% of our brains, humans likely would have evolved to eliminate these redundant areas to reduce energy consumption and increase survival chances.
4. Research shows distinct regions of the brain responsible for different tasks, meaning that the brain operates as a specialized network rather than a homogeneous mass. We haven't found any parts of the brain that don't serve a purpose.
5. Instruments that monitor the activity of individual brain cells reveal that most cells are always active. At all times, a majority of the brain is engaged in processing information.
6. Brain cells that no longer function will degenerate over time. If 90% of our brain cells were useless, our autopsies would persistently show large-scale neurological degeneration.

The reality is that every part of our brain serves a purpose, and in no way does one half dominate the other. So, the next time you chat with a self-proclaimed "left-brainer", or a person fantasizing about what humans would look like using 100% of their brain's potential, remember that the truth about our minds is far more detailed and fascinating than these reductive myths suggest.

Do you often accept seemingly intuitive information without seeking empirical support? Take the Intuitive Decision Style Scale to learn more about how you process information.

A similar version of this article can also be found on Forbes.com, here, and PsychologyToday.com, here.