In the late 1960s, research in the US was done by Roger Sperry and Robert Ormstein into the brain and its functions. They found that we have two brains (cortices) or, to be more accurate, two sides of the brain which is linked by a nerve structure called the corpus callosum. These two different hemispheres function in different ways and serve different mental processes.
The left side, which controls the right side of the body, is predominantly engaged with academic activities such as logical thinking, mathematics and numbers, words, analysis and reasoning, whereas the right side of the brain, which controls the left side of the body, is the artistic part which deals with images, imagination, rhythm, colour, orientation in space, music, humour and dreams, and recognition of faces, patterns and maps.
(Source: Energize Yourself! by Vera Peiffer)