What Are the Functions of the Major Cerebral Hemispheres?

You think. You feel. You create. As simple as it seems, the things that make you uniquely you, exist in and because of your cerebrum. The largest part of the brain, yet only a portion of about 10 billion nerve cells weighing around three pounds, the cerebrum makes us human. There are only two hemispheres in the brain--the left and right. But between the lobes contained in each, and their cooperation, the higher functioning of humanity is found.

Functions of the Left Hemisphere

• Considered the "dominant half of the brain" in most people due to the verbal and analytical skills contained, the left hemisphere is the logical, rational hemisphere of the brain, as Enspire Press states. It controls all communication such as talking, reading and verbal awareness. The processing of information in logic and spatial perceptions--such as multiplying, using reason, typing and analyzing situations is made possible within the left hemisphere. The left hemisphere also controls the right half of the body.

Functions of the Right Hemisphere

• The right hemisphere, explains Alz Online, "is associated with 'unconscious' awareness (in the sense it is not linguistically based)." Recognition of faces, understanding of social interaction, artistic creativity, intuition and emotion are controlled by your brain's right hemisphere. However, although either hemisphere has its own specialty, communication between both occurs across the corpus callosum--the dividing matter. But, "this is not an equal partnership ... one hemisphere usually dominates over the other," as Bryn Mawr explains. Evidence of this is in people who are either left or right handed. Additionally, women have a thicker corpus callosum, explains Enspire Press, "likely giving rise to women's intuition." Even the differences between men's and women's thoughts and emotions are thought to arise from differences in the right and left hemispheres.

Hemispheric Lobe Functions

• Both of the hemispheres, right and left, contain specialized areas called lobes. The lobes are named to correspond to the section of skull plate protecting them: frontal, parietal, temporal, and occipital. Most important of these, the frontal lobe, contained in both left and right hemispheres, is associated "with what it means to be human," as Enspire Press explains. Whether in the right or left hemisphere, any damage results "in a person who is deemed emotionally shallow, listless, apathetic, and insensitive to social norms," Enspire continues. In contrast, the parietal, temporal and occipital lobes within the hemispheres regulate perception. The parietal regulates touch, pressure, pain, even temperature. The occipital processes visual information, and hearing is controlled by the temporal lobe. Thus, it is not the hemispheres at all that control emotional and physical function--but the lobes located in the hemispheres.

Lateralization or Plasticity of Hemispheric Function

• It can prove unclear which predominates--the specialization of a hemisphere and its lobes, called lateralization--or the interaction and cooperation of hemispheric regions. In the early years of psychology, the discovery of Broca's area--a small region of the right hemisphere without which speech is impossible--led psychologists to speculate that hemispheric power is all or nothing; each hemisphere has localized function, they believed, which led to "a very stereotyped understanding of the two hemispheres," as Bryn Warn College explains. In reality, while "damage to only one hemisphere of the brain may cause complete loss of such functions" if affecting very specialized areas, "most functions (such as memory) require coordination of several areas in both hemispheres," as Merck notes. Thus, in most instances, hemispheres do not work alone; the functions of the major cerebral hemispheres and their lobes work together, and for function "to be completely lost, both hemispheres must be damaged," concludes Merck.