|RSA ANIMATE: Left Brain, Right Brain|
People who identify as left-brain thinkers might feel that they have strong math and logic skills. Right-brain thinkers feel that their talents are more on the creative side of things. The theory of left-brain or right-brain dominance states each side of the brain controls different types of thinking. Additionally, people are said to prefer one type of thinking over the other. A person who is "left-brained" is often said to be more logical, analytical, and objective. A person who is "right-brained" is said to be more intuitive, thoughtful, and subjective.
In psychology, the theory is based on the lateralization of brain function. The brain contains two hemispheres that each performs several roles. The two sides of the brain communicate with one another via corpus callosum. The left hemisphere controls the muscles on the right side of the body. The right hemisphere controls those on the left. Damage to the left side of the brain might influence the right side of the body.
So, does one side of the brain control specific functions? Are people either left-brained or right-brained? Like many popular psychology myths, this one grew out of observations of the human brain that were then dramatically distorted and exaggerated.
The right-brain left-brain theory originated in the work of Roger W. Sperry. He was awarded the Nobel Prize in 1981. While studying the effects of epilepsy, Sperry discovered that cutting the corpus callosum (the structure that connects the two hemispheres of the brain) could reduce or eliminate seizures.
However, these patients also experienced other symptoms. This is after the communication pathway between the two sides of the brain was cut. For example, many split-brain patients found themselves unable to name objects that were processed by the right side of the brain. They could name objects that were processed by the left-side of the brain. Based on this information, Sperry suggested that the left-side of the brain controlled language. The left side of the brain tends to control many aspects of language and logic. The right side tends to handle spatial information and visual comprehension.
Later research has shown that the brain is not nearly as dichotomous as once thought. Research has shown abilities in subjects. Math is strongest when both halves of the brain work together. Today, neuroscientists know that the two sides of the brain collaborate to perform a broad variety of tasks. The two hemispheres communicate through the corpus callosum.
No matter how lateralized the brain can get, though, the two sides still work together. Science writer Carl Zimmer explained this in an article for Discover magazine. The pop psychology notion of a left brain and a right brain doesn’t capture their intimate working relationship. The left hemisphere specializes in picking out the sounds that form words and working out the syntax of the phrase, for example, but it does not have a monopoly on language processing. The right hemisphere is more sensitive to the emotional features of language, tuning in to the slow rhythms of speech that carry intonation and stress.
In one study by researchers at the University of Utah, more than 1,000 participants had their brains analyzed to determine if they preferred using one side over the other. The study revealed that while activity was sometimes higher in certain critical regions, both sides of the brain were essentially equal in their activity on average.
It’s true that some brain functions occur in one or the other side of the brain. Language tends to be on the left, attention more on the right. However people don’t tend to have a stronger left- or right-sided brain network.