The left brain vs. right brain myth - Elizabeth Waters

Summary

The brain’s left and right sides do handle some functions differently, but the familiar claim that the left side governs logic while the right governs creativity is a myth unsupported by scientific evidence.

Left–right organization

The brain is divided into two sides, including in its outer cortex and several internal regions. Each side controls movement on the opposite side of the body.

Vision

Each eye receives information from both visual fields. Information from the left visual field is processed by the right side of the brain, while information from the right visual field is processed by the left. Both sides therefore contribute to a complete view.

Why visual pathways cross is uncertain. One proposed explanation is that crossing may have helped animals react more quickly to threats.

How the myth arose

In the mid-1800s, neurologists Paul Broca and Carl Wernicke linked damage to patients’ left temporal lobes with communication difficulties, suggesting that language was controlled by the left side. The idea of opposing logical and emotional hemispheres was later popularized by Robert Louis Stevenson through Dr. Jekyll and Mr. Hyde.

What later evidence shows

People who had one hemisphere missing or whose hemispheres were separated displayed a wide range of both logical and creative behaviors. Research does find that some functions are more strongly associated with one side—language more with the left and attention more with the right—but this varies by function, not by person.

There is no evidence that individuals have a generally dominant brain side or that logic and creativity are split between hemispheres. Complex math can involve creativity, and art can have logical structure; both rely on the brain working as a whole.

Researchers and sources mentioned

• Paul Broca
• Carl Wernicke
• Robert Louis Stevenson
• Elizabeth Waters (named in the video title)