Misconceptions about Brains, Part 1: You’re not left-brained or right-brained, you’re front-brained

There are many misconceptions about the brain, but perhaps the most pervasive are the many myths about the structure of the brain and how it relates to function.

Many people have made claims about which area of the brain is associated with which actions. It is true that the brain is partitioned into different structures, but the divisions are very broad. The brain contains three main structures: the hindbrain (which handles involuntary actions such as breathing and heartbeats), the midbrain (which handles reflexes), and the forebrain (which handles thoughts, senses, and voluntary motion)1.

Most people’s visualization of the brain is limited to the forebrain. The forebrain is divided into four lobes on each of two hemispheres. A particularly widespread myth is that the right hemisphere is associated with creativity while the left is associated with logic. This is completely false2.

Source: xkcd.com

The only substantial differences between the hemispheres of the brain are the crossing-over of sensory and motor nerves (the left hemisphere handles sensory information motor functions from the right side of the body and vice-versa) and the Broca’s area, which handles language and is usually located exclusively in the left hemisphere2.

In truth, the human brain cannot distinguish between logic and emotion, only between abstract thought and basic impulses. Simple emotions (happiness, anger, fear, etc.) are controlled by the hypothalamus, found under the fissure between the hemispheres. Complex emotions (love, spite, anxiety, etc.) are controlled by the frontal lobe, the same place as logic and all other forms of advanced cognition1.

Thus, the idea that left-brained people are good at math and science while right-brained people are good at art and language is false; all of those things are located in both hemispheres, except for language, which is in the left hemisphere.

The partitioning of lobes is also exaggerated; each lobe is named for the bone of the skull around that region of the brain3. There is no clear delineation between the lobes in the brain itself, which can lead to disagreements such as whether the Broca’s area is in the frontal or parietal lobe. In general, advanced cognition is in the frontal lobe (front), tactile senses and motor functions are in the parietal lobe (top), vision is in the occipital (back), and hearing is in the temporal lobe (sides)1.

Any regions more specific than this are usually false. Specific parts of the parietal lobe are linked to specific parts of the body, but there is no part of the brain associated with specific actions or thoughts (such as eating a sandwich, listening to Mozart, or remembering a embarrassing childhood incident). There are only regions associated with broad categories of actions (such as taste, hearing, or memory).

The human brain can be thought of like a smartphone: finding the neuron associated with as specific task is like finding the wire associated with a specific app. A single wire cannot run an application; similarly, the entire brain is necessary for any action. The entire brain is associated with all of human behavior.

Bibliography

1“Brain Basics: Know Your Brain”, National Institute of Neurological Disorders and Stroke, 17 April 2015, www.ninds.nih.gov

2Corballis, Michael C., “Left Brain, Right Brain: Facts and Fantasies”, Public Library of Science Biology, National Center for Biotechnology Information, 21 January 2014, www.ncbi.nlm.nih.gov

3“Cranial Structures”, MedlinePlus, U.S. National Library of Medicine, 2 September 2015, medlineplus.gov

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