Right-Handedness

RIGHT-HANDEDNESS, the preferential use of the right hand characteristic of the majority of people when performing such motor acts as writing, drawing, etc. Similar to left-handedness, right-handedness can be congenital or forced. Forced right-handedness occurs when a left-handed person is compelled to use the right hand due to an acquired disability of the left hand. Right-handedness is observed in the overwhelming majority of the population (see Left-Handed). According to Schafer, right-handed people constitute 95.73% of the population (94.56% among males and 68.86% among females - Note: OCR says 96.86%). Other authors cite different figures (see Left-Handed). In newborns, functional dominance of either hand is not noticeable; only in the second half of the first year does the preferential use of one of the hands begin to emerge, as can be observed when grasping a rubber nipple, a teaspoon, etc. Many researchers, such as Gegenbaur, Griesbach, Lüddekens, Kapustin, and others, view the predisposing cause of the preferential use of one hand or the other in the functional dominance of one of the cerebral hemispheres: in right-handed people, the left hemisphere (left-brain type); in left-handed people, the right hemisphere (right-brain type). The existence of one type or the other, i.e., the left- or right-brain type, can be regarded as one of the manifestations of human body asymmetry. Pfister, by weighing children's brains in 302 cases, found a difference in weight between the right and left cerebral hemispheres reaching from 5 to 15 g in favor of the left hemisphere. Some researchers recognize right-handedness as an inherited constitutional phenomenon, which, according to Schott, is in some cases a dominant trait and in others a recessive one. There is an opinion that primitive humanity was characterized by right-handedness; left-handedness as an abnormal phenomenon appeared only in modern Europeans. According to Bardeleben, the gibbon and orangutan are predominantly right-handed, whereas the chimpanzee and gorilla are left-handed. The identification of right-handedness, apart from inquiry into the preferential use of the right hand when performing habitual actions, can be aided by: hand dynamometry, measurement of hand length (Bardeleben), mirror-writing test (Schafer), blood pressure measurement, and indications of heredity (Steiner, Schafer, Stier). It must be said that functional superiority on the preferred side has been found by many researchers.