Formally it’s “lateralization of brain function.” More commonly people refer to their left and right brain. Whichever name you choose, you need both parts of your brain to write well.
Left brain, right brain
Read Kendra Cherry’s article, “Understanding the Myth of Left Brain and Right Brain Dominance” and you’ll learn why you’re probably not “left-brained” or “right-brained.” Even though that’s true, you still have two halves of your brain and they specialize in different things.
Creative connections from the right brain
It’s your right brain that makes those leaps to connect bits of information and generate new ideas. We call that creativity. Connecting things that weren’t connected before. Assembling new ideas from pieces of old ideas. You need that kind of thinking to make your writing unique.
Logical progression from the left brain
You left brain is where language and logic live. That’s important because writing is linear. And when you start stringing ideas together to make an article or book, you discover gaps in your thinking.
You’ll write better if you use all of your brain. Catch creative ideas and make new connections. Then set them down in order and attach words to them.