4 common but harmful myths about how your brain works

Psychology professor Art Markman explains why you should stop believing these things about your brain.

4 common but harmful myths about how your brain works
[Source images: tampatra/iStock; Jolygon/iStock]

The brain is endlessly fascinating. Despite the amount of time we spend thinking, few of us learn much about the way our minds and brains work. As a result, there are some persistent myths about the brain. It is worth highlighting them, because you’ll think more effectively if you work with your brain rather than against it.


1. People only use 10% of their brains

People throw this number around all the time, but what does this even mean? Up front, it’s important to note that the brain is an incredibly energy-hungry organ. It’s generally about 3% of your body weight, but it uses 20-25% of the energy you expend each day. Evolution would kill off creatures that had an organ that was that expensive to operate that wasn’t being used.

The source of this figure isn’t entirely clear. One possibility is that it refers to the proportion of the brain that consists of neurons (which are cells that send electrical signals and process the brain’s information) to supporting structure (including fluid and cells that insulate neurons and repair damage). It is true that neurons are only one of a number of different kinds of cells and structures in the brain. But, all of this structure is important for the functioning of the brain.

Another possibility is that people are referring to the capacity of the brain. That is, perhaps people are only using 10% of their potential. Again, it isn’t clear where this number comes from. A better way to think about this, though, is people’s capacity to develop any skill is a combination of practice and talent (where talent refers to the capacity a person has to achieve in that domain).

A simple rule to keep in mind is that you can get quite good at almost any skill (whether it is a thinking-based skill, a musical skill, or a physical skill) if you practice hard at it. However, if your goal is to be among the best in the world at something, you had better also have some talent for it.

2. You are either left-brained or right-brained

If you look at a picture of a brain, you’ll see that the right and left sides (called hemispheres) are mirror images. The hemispheres are connected together by a couple of bands of tissue, the biggest of which is called the corpus callosum.

Starting in the late 1950s, neuroscientist Roger Sperry studied patients who had their corpus collosum cut as a way of controlling epilepsy. Epilepsy involves electrical signals in the brain that are out of control. The aim of this surgery was to prevent that wild electrical activity from crossing from one hemisphere to the other.


Sperry did clever experiments in which information was presented to a patient’s right- or left-side, which led that information to go initially to only one hemisphere of the brain. In general, information crosses over, so information presented to the left visually crosses to the right side of the brain, while information presented to the right goes first to the left side of the brain.

In normal brains, this information quickly crosses over the corpus callosum and is processed on both sides, but in split-brain patients, it remains in the hemisphere where it goes first.

On the basis of these studies, Sperry found that a lot of language abilities (for right-handed people and many left-handers) are processed in the left hemisphere of the brain, while many spatial abilities are better when done by the right hemisphere. This work is consistent with observations from stroke patients going back to the 1800s, and similar results have been found in more recent brain-imaging studies.

From this work, people began to talk about themselves as being left- or right-brain dominant, where the left brain was supposed to be logical and algorithmic, and the right brain was supposed to be more artistic and intuitive.

There are both intuitive and more effortfully cognitive systems in the brain, and there are differences in the way that people like to think and reason. However, these abilities don’t really have anything to do with the hemispheres of the normally functioning brain. Both hemispheres of your brain are involved in all of the complex work you do.

A potential danger of labeling yourself as right-brained or left-brained is that you will ignore the information that you get from either your intuitive or effortful system. The most effective thinkers are ones who learn to rely on both their intuitive judgments (which reflect the statistics of events, objects, and people they have encountered in the past) as well as their reasoning (which reflects procedures they have learned to carry out). After all, good decisions think right and feel right.


3. Emotions prevent rational thinking

Related to this discussion is the idea that emotions just get in the way of good thinking. The idea is that emotions reflect a more primitive form of thinking and that good human thinking is coldly rational.

As the cognitive neuroscientist Joseph LeDoux has pointed out, our emotional and reasoning systems work in concert. When faced with risky decisions, for example, it is possible to talk yourself into almost anything. But, the tingle of anxiety that comes along with those risky decisions is providing valuable information that you should not ignore.

It is not just that emotions don’t always get you in trouble; sometimes, they actually save you from bad decisions.

4. Everyone has one learning style that suits them best

Finally, there has been a lot of discussion over the past few decades about “learning styles.” Many people enjoy getting information in a particular mode. Some like to hear things. Some like to read things. Some like to get visual representations of new information. Some people like to be able to touch and manipulate things they are learning about.

Based on these preferences, there was a popular proposal that there are significant differences between people in which modes let them learn best. That is, “visual learners” would learn things differently than “auditory learners” or “tactile learners.” Research by Dan Willingham and his colleagues has demonstrated consistently that any preferences people have for the way they want to take in information does not determine how well they learn when information is presented in different ways.

Instead, everyone takes away different kinds of information from different sorts of interactions with what they are trying to learn. So, rather than trying to tailor the way you learn new information to a particular style, give yourself many different exposures to new material in different modes to maximize what you learn.