Functional specialisation explains how the two cerebral hemispheres are specialized in different types of mental activity.
Explanation:
The nervous systems of all animals have in common a number of basic functions, the most notable of which are control of movement and analysis of sensation. What sets the human brain apart is the variety of more specialized activities it is capable of learning and the integration and control of the different functions. In 90% of the population the left cerebral hemisphere specializes or controls the ability to speak and write, and the ability to understand spoken and written language. In the remaining 10%, the right hemisphere or both hemispheres dominate spoken or written language. The right cerebral hemisphere perceives tactile stimuli and spatial vision relationships better than the left hemisphere. Another area, the posterior-parietal lobe is related to the tactile abilities, it is particularly involved in the abilities to name and point out the parts of the body, one's own and of others, as well as in the abilities to name, distinguish, recognize or draw the fingers of the hand. The parietal lobe is particularly involved in perceptual accuracy in locating stimuli, in estimating line orientation (parietal-frontal lobe) and in the ability to estimate the number of stimuli presented in the central visual field.
