Critical Thinking and Pop Sci: We Use More Than 10% of Our Brains!

By Nick Fontaine


There are many pseudoscientific factoids that get passed around until they become general public knowledge. As a person interested in neuroscience, perhaps there is no more infuriating a scientific myth than “we only use ten percent of our brain.” This myth is so widely believed that I can remember being taught it during elementary school. It’s also very prevalent in pop culture, which tends to take it a step farther with the added bonus that if we could use more than 10%, we could have super powers (looking at you Bradley Cooper and Scarlett Johansson). Despite its pervasiveness, this idea has been shown many times over to be completely unfounded.


Firstly, let’s look at it from a logical standpoint using minimal scientific data. The human brain makes up for just about 2% of our body mass on average, but uses a whopping 20% of the body’s oxygen and 25% of its glucose (Bélanger, Allaman, & Magistretti, 2011). To give such a disproportionate amount of our limited energy reserves to something that is 90% unused makes little to no sense. While evolution isn’t a perfectly efficient process, it would likely never lead to such a comical level of waste.


The myth of 10% brain usage has really been put to bed by functional magnetic resonance imaging (fMRI) research. Since this technique was created in the 1990s, many different studies have shown that we use every part of our brain. In short, fMRI measures brain activity based on neurons requiring more oxygen as they become more active in response to certain stimulation. Below, I took images fMRI data from many different studies and pasted them on top of each other: in this you can see that every region of the brain is used in one way or another.


I should also mention that in able to obtain the activation images they want, fMRI researchers have to set a very high activation threshold, because the entire brain is more or less active at all times, and these thresholds allow for examinations of specific, statistically significant, changes.

A collection of data from a cursory search of fMRI studies (Bzdok et al., 2016; Calhoun, Maciejewski, Pearlson, & Kiehl, 2008; Hartogsveld et al., 2018; Jamison, Roy, He, Engel, & He, 2015; Krishan, Alexopoulos, & Najm, n.d.; Svolgaard et al., 2018)

While the belief that we only use 10% of our brain is far from the most dangerous science myth (anti-vaxxers and climate change deniers probably take the cake there), the widespread, unquestioning acceptance of this falsehood may be indicative of larger societal problem. With the increasing presence of social media and smartphones, we are constantly bombarded with information. If we do not think critically about what we are taking in, more falsehoods like this could spread much faster than ever before.

While it can be easy to write off “facts” like this as something an expert said once and tacitly accept it, it is important for everyone— including scientists— to really consider the logic behind the information they are given. And please, find a better plot point for sci-fi movies.


References:


Bélanger, M., Allaman, I., & Magistretti, P. J. (2011). Brain Energy Metabolism: Focus on Astrocyte-Neuron Metabolic Cooperation. Cell Metabolism, 14(6), 724–738. https://doi.org/10.1016/j.cmet.2011.08.016


Bzdok, D., Hartwigsen, G., Reid, A., Laird, A. R., Fox, P. T., & Eickhoff, S. B. (2016). Left inferior parietal lobe engagement in social cognition and language. Neuroscience & Biobehavioral Reviews, 68, 319–334. https://doi.org/10.1016/j.neubiorev.2016.02.024


Calhoun, V. D., Maciejewski, P. K., Pearlson, G. D., & Kiehl, K. A. (2008). Temporal Lobe and “Default” Hemodynamic Brain Modes Discriminate Between Schizophrenia and Bipolar Disorder. Human Brain Mapping, 29(11), 1265–1275. https://doi.org/10.1002/hbm.20463


Hartogsveld, B., Bramson, B., Vijayakumar, S., van Campen, A. D., Marques, J. P., Roelofs, K., … Mars, R. B. (2018). Lateral frontal pole and relational processing: Activation patterns and connectivity profile. Behavioural Brain Research, 355, 2–11. https://doi.org/10.1016/j.bbr.2017.08.003


Jamison, K. W., Roy, A. V., He, S., Engel, S. A., & He, B. (2015). SSVEP Signatures of Binocular Rivalry During Simultaneous EEG and fMRI. Journal of Neuroscience Methods, 243, 53–62. https://doi.org/10.1016/j.jneumeth.2015.01.024


Krishan, B., Alexopoulos, A., & Najm, I. (2015, January 1). EEG-Correlated fMRI: A Promising Tool in the Multimodal Evaluation of Refractory Epilepsy – Consult QD. Retrieved April 1, 2019, from https://consultqd.clevelandclinic.org/eeg-correlated-fmri-a-promising-tool-in-the-multimodal-evaluation-of-refractory-epilepsy/


Svolgaard, O., Andersen, K. W., Bauer, C., Madsen, K. H., Blinkenberg, M., Selleberg, F., & Siebner, H. R. (2018). Cerebellar and premotor activity during a non-fatiguing grip task reflects motor fatigue in relapsing-remitting multiple sclerosis. PLoS ONE, 13(10). https://doi.org/10.1371/journal.pone.0201162

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