In general the right side of the brain controls visual and spatial information, while the left controls logic and language, says About.com. However, recent research suggests that both sides of the brain work together and that individuals do not err more strongly towards one side.
Lateralization of brain function in which certain activities are controlled by one side or the other may, evolutionarily, provide the advantage of allowing an individual to complete two important tasks at the same time, reports Dr. Janet Fitzakerley of the University of Minnesota Medical School. Evidence suggests that the left brain often controls the right field of vision and right handedness and vice versa. It is also understood that the left brain functions more in grammar, syntax, writing and speech, while the right brain controls the meaning of language and words, and spatial analysis such as face recognition.
A new study, however, calls into question the idea of right-brainers and left-brainers, says the University of Utah. This study looked at the brain scans of 1,011 people from 7 to 29 years of age and searched for connections between thousands of brain regions. The results showed that certain processes resulted in higher brain activity in critical regions, but that both sides of the brain were used equally by all individuals.