The left hemisphere sees the world in small pictures, like the stills that make up a movie. It ignores the whole and zeroes in on the details. It breaks things into small pieces and examines them. The left brain controls the small muscles or fine motor skills; everything done with the hands and fingers, feet and toes, such as tying shoes or playing the piano, are left brain skills. The left brain moves the small muscles of the throat and mouth in rapid sequence so a child can speak. Similarly, it translates the rapidly differing sounds of letters and syllables into language. The left hemisphere is the verbal side of the brain. Everything that has to do with language resides here. Reading, writing, speaking, and interpretation all take place here. It reads individual words in a sentence and translates their meaning, letter by letter and syllable by syllable.
The left brain is the literal brain, understanding only one primary meaning of a word. Because it is attuned to words, the left is the conscious side of the brain. It is involved in every conscious move the body makes. It is also involved in conscious thoughts—a child talks to herself with the left brain. When your child is doing her homework, reading a book, doing a math problem, or memorizing a poem, they are using their left brain. It’s the linear and logical brain. It works out basic math operations, arithmetic, calculating, and remembering numbers in a sequence.The left side of the brain is also good at pattern recognition skills—figuring out what comes next in a sequence.
Language develops because of pattern recognition skills. This is believed to be the reason why young children can learn a new language so easily versus trying to learn later on in adulthood. For example, learning to play a musical instrument is a pattern skill. It also involves using fine motor skills, which are controlled on the left. Computer games and video games are all about pattern recognition skills. The left brain loves computer games because it is all about systemizing; left brain thinking is linear and logical. It likes to examine things one at a time and in order. It likes basic science and math and other logical pursuits. It is, in actuality, the thinking brain. It loves to do the same routine over and over and hates new things. However, it happens to be the more curious hemisphere; it controls seeking and goal-directed behavior.
It is responsible for intelligence, especially verbal intelligence, and is more measured by traditional IQ tests than the right brain. Behaviorally, the left brain controls what we call approach behavior. It wants to approach a situation to study all the details and figure out a pattern and remember that pattern. Emotionally, it is in charge of positive emotions, motivation and happiness– encouraging the get-up-and-go mindset. On the flip side, it also controls anger. So when anything gets in the way of achieving a goal, it reacts with frustration and anger, which helps us persist in the face of adversity.
Like the right brain, the left brain also helps control the immune system. It activates it to fight off infections and toxins. It stimulates the growth and development of immune tissue called lymphoid tissue that houses white blood cells and other immune-mediated chemicals. It activates the immune system to produce antibodies to fight off foreign invaders. And when a body is sick and has an infection, the left hemisphere mobilizes the immune system to fight it off. It also helps regulate some of the body’s automatic functions, such as heart rhythm.