Left brain vs. right brain: Fact and fiction

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The brain is a complex organ that controls all bodily processes, including thought, sensory perception, and physical action. Despite weighing only 3 pounds, the human brain contains as many as 100 billion neurons and 100 trillion connections.

Neurons are information messengers which use electrical and chemical impulses to transmit information around the central nervous system (CNS).

The brain processes information it receives through its neuron network and sends signals to all parts of the body to control bodily functions and respond to stimuli

The left and right sides of the brain.

The left and right sides of the brain have different functions and control different processes. Each half of the brain contains six different lobes.

The brain’s left half is primarily responsible for speech and abstract thinking. It also controls the right side of the body. The right side of the brain is responsible for image processing, spatial thinking, and movement in the left side of the body.

The left and right sides of the brain connect via nerve fibers. In a healthy brain, the two sides communicate with one another.

The two sides do not necessarily have to communicate, though. If a person has an injury that separates the two brain hemispheres, they can still function relatively normally.

In the 1960s, the neurobiologist Roger W. Sperry suggested that all people have one-half of their brain, which is more dominant and determines their personality, thoughts, and behavior.

Due to the different functions of the two brain hemispheres, the idea that people can be left-brained and right-brained is tempting.

According to the dated theory, left-brained people are more:

• analytical
• logical
• detail- and fact-oriented
• numerical
• likely to think in words

By contrast, the theory suggests that right-brained people are more:

• creative
• free-thinking
• able to see the big picture
• intuitive
• likely to visualize more than think in words

Research suggests that the left brain vs. right brain theory is not correct. While specific parts of the brain do dominate the processing of different mental tasks, there is typically no overall dominant side.

A 2013 study assessed 3-D pictures of over 1,000 people’s brains. They measured the activity of the left and right hemispheres using an MRI scanner. Their results show that a person uses both hemispheres of the brain and does not seem to be a dominant side.

However, a person’s brain activity does differ depending on what task they are doing.

For example, a 2020 review suggests that the left side of the brain is the dominant force in language processing, even though both sides are necessary for full comprehension.

Although people do not fall neatly into the categories of left-brained or right-brained, there are differences in what the left and right hemispheres do.

Differences in the left and right brain hemisphere function exist in:

Emotion

While the brain uses multiple areas to process and generate emotional responses, the right side of the brain is dominant in these processes. This is the case for all emotions.

Language

The left brain is more active in speech production than the right. In most people, the two main language areas, known as Broca’s area and Wernicke’s area, are in the left hemisphere.

Handedness

Left- and right-handed people use the left and right sides of their brains differently. For example, a left-handed person uses their right brain for manual tasks and vice versa.

Asymmetries such as this can even develop before birth. For example, some babies prefer to suck their left or right thumb from as early as 15 weeks.

Not everyone’s brains work in the same way. Some people may primarily process language on the left side of their brain, while others may do so on the right side or symmetrically across the hemispheres.

A large 2021 study found that left-handed people often use different sides of their brains for working memory, language, vision, and hand control compared to right-handed people.

Researchers also found that left-handed people typically had more gray matter on the right side of their brain. This may be due to the right side of the brain controlling the dominant left hand.

Staying active and engaging in mentally stimulating activities can help to improve memory and cognitive function.

• Meditation: There is growing evidence that mindful meditation can help to slow age-related cognitive decline.
• Exercise: Research shows that regular exercise can improve episodic memory in older adults.
• Sleep: According to a 2020 study, getting too little or too much sleep is associated with faster cognitive decline in adults.
• Stimulating games: Studies show that regularly using number puzzles and other mentally-stimulating games can help improve cognitive function in people over 50 years of age.
• Diet: Eating a balanced, healthful diet is a simple and effective way to slow cognitive decline from aging.

Discover 22 tips to improve memory and cognition here.

The brain is a complex organ with many parts and functions. The left and right sides of the brain operate differently and are responsible for different bodily processes.

The division of these processes can differ between people. For example, the left side of the brain is primarily responsible for language and communication in most right-handed people, while this is less common in those who are left-hand dominant.

While the two halves of the brain have different functions, people do not have a dominant side that affects their personalities and behaviors.