An important thing to keep in mind is that while split brain patients have divided abilities, those are not present in people who have an intact corpus callosum. These split brain studies led to the ideas of left or right brained people, which isn’t really a thing. We use both sides of our brain, all the time, seamlessly. I’m going to direct you to a great article in the Yale Scientific Magazine about this myth: http://www.yalescientific.org/2012/04/left-brain-right-brain-an-outdated-argument/
An excerpt: “I am definitely a left-brained person — I am not very artistic.” How many times have we characterized ourselves as either left-brained and logical people or right-brained and creative people? This popular myth, which conjures up an image of one side of our brains crackling with activity while the other lies dormant, has its roots in outdated findings from the 1970s, and it seems to imply that humans strongly favor using one hemisphere over the other. More recent findings have shown that although there are indeed differences between the hemispheres, they may not be as clear-cut as we once thought.
Our personalities and abilities are not determined by favoring one hemisphere over the other — that much is certain. Many other functions, however, such as response to danger and language generation, are lateralized in the brain. Researchers hypothesize that these differences arose from early vertebrates. Originally, it seems that the right hemisphere began to respond more quickly to danger. In fact, when we are suddenly confronted by a dangerous stimulus, we will respond more quickly with our left hand, which is controlled by the right hemisphere. The left hemisphere, on the other hand, has developed to handle more common, routine tasks, such as feeding and hand control. Since this hemisphere controls the right hand, a strong right-handed preference has arisen in most of us, providing one explanation of why most people are right-hand dominant.