The origins of the myth
The left/right brain myth holds that a right-brain dominant person is generally creative, intuitive, artsy, while a left-brain dominant person is more of a problem-solver, more linear, logical. The myth arose from genuine science, but new imaging technology has shown that the brain is more interdependent than once thought.
The myth probably took root in the 1800s, when scientists discovered that an injury to one side of the brain often caused a loss of specific abilities. For example, spatial abilities seemed to reside in the right side of the brain, with language in the left. The myth gained ground from the Nobel Prize-winning research of Roger Sperry in the 1960s. Sperry’s research team studied epilepsy patients who had surgery to sever the connection between the two hemispheres. In particular, patients were treated with a surgical procedure that cut the brain along a structure called the corpus callosum. Because the corpus callosum connects the two hemispheres of the brain, the two sides of these patients’ brains could no longer communicate and were unaware of one another – and even respond differently to stimuli. For example, when one patient was asked what he wanted to do, his left brain responded with “draftsman” but his right brain with “automobile racer.”
Sperry and other researchers, through a series of clever studies, determined which parts, or sides, of the brain were involved in language, math, drawing and other functions in these patients. But then popular-level psychology enthusiasts ran with this idea, creating the notion that personalities and other human attributes are determined by having one side of the brain dominate the other.
Does science support this notion?
Recently, brain scan technology has revealed that the hemispheres’ roles are not quite so cut-and-dried as once thought. The two hemispheres are in fact highly complementary. For example, language processing, once believed to be left- hemisphere-only, is now understood to take place in both hemispheres: the left side processes grammar and pronunciation while the right processes intonation. Similarly, experiments have shown that the right hemisphere does not work in isolation with regard to spatial ability: the right hemisphere seems to deal with a general sense of space, while the left hemisphere deals with objects in specific locations.
Research evidence of debunking the myth
Scientists at the University of Utah have evidence from more than 1,000 brain scans showing absolutely no signs of left or right dominance in people.
The preference to use one brain region more than others for certain functions, which scientists call lateralization, is indeed real, said lead author Dr. Jeff Anderson, director of the fMRI Neurosurgical Mapping Service at the University of Utah. For example, speech emanates from the left side of the brain for most right-handed people. This does not imply, though, that great writers or speakers use their left side of the brain more than the right, or that one side is richer in neurons.
There is a misconception that everything to do with being analytical is confined to one side of the brain, and everything to do with being creative is confined to the opposite side, Anderson said. In fact, it is the connections among all brain regions that enable humans to engage in both creativity and analytical thinking.
“It is not the case that the left hemisphere is associated with logic or reasoning more than the right,” Anderson told LiveScience. “Also, creativity is no more processed in the right hemisphere than the left.”
 “Left Brain vs. Right: It’s a Myth, Research Finds” by Christopher Wanjek on September 2, 2013 at Live Science.
If you want to know more about the left/right brain myth and the research behind it, read this article by The Centre for Educational Research and Innovation (CERI). In case your laziness is not prone to read more information or you are a visual person, there is a TEDx Talk called “The left brain vs. right brain myth” by Elizabeth Waters that might be ideal for you.