Th e human brain reflects developments that have occurred during the course of evolution. It consists of three superimposed layers, all of which are highly developed enough to control various functions and work together.

The cerebellum dates from the reptile era. Th e oldest part of the brain, it controls our primary needs of self-preservation, such as establishment of a food supply, self-protection, defense of personal territory, and sexuality. Spontaneous reactions take place in the cerebellum. Th e ability to make instinctive decisions “from the gut” resides here, and this area of the brain has little ability for further development. The interbrain, the so-called limbic system, developed during the era of early mammals, and it wraps around the cerebellum. The emotions governing our interpersonal relationships are based here. This system has enough storage capacity for further evolution resulting from external influences  The cerebrum can influence the structure of the cerebellum and interbrain. It consists of two physiological hemispheres that are connected by a complex network, the corpus callosum. Professor Roger Sperry, a neurophysiologist at the California Institute of Technology, discovered that the two halves of the brain differ from one another significantly and that different mental activities can be ascribed to each hemisphere. In 1981 he was awarded the Nobel Prize in Medicine for this discovery.

Since then, the left half of the brain has been considered the one responsible for rational thought processes dealing with logic, language, analysis, linearity, sequencing, numbers, and so on. It is responsible for activities such as solving mathematical problems and is also where facts such as historical dates or telephone numbers are stored.

On the other hand, the right brain is primarily responsible for emotions, creativity, mimicry, gestures, musical ability, and spatial orientation. According to Sperry, this half of the brain controls the imagination and daydreams, things like the perception of color, space, dimension, and rhythm, overall impressions; and images.

Science now assumes that the brain’s performance is far more all-encompassing than was originally theorized by Sperry. With the assistance of current methods using computers connected to ultrasound and magnetic resonance tomography equipment, researchers are able to virtually “watch” people thinking, different parts of the brain are activated by different types of tasks, and the stimulated sections appear in different colors on a computer screen. Given the results of investigations, it has been conjectured that although the left and right halves of the brain are responsible for different activities, they have not become completely specialized. This means that, depending on the task, a specific area of the brain is activated and various areas of the other hemisphere are also involved to a lesser extent. Th is research has also shown that activating both hemispheres at the same time has a beneficial effect on the development of their individual brain functions and therefore increases the performance capacity of the cerebrum.