The tendency of a person to rely more heavily on and to be more easy and proficient at using one hand than the other; also called chirality. The preference for one hand over the other is believed to reflect the dominance of one side of the brain over the other, but why this occurs is unknown. About two-thirds of the population—with males and females in equal proportions—are right-handed for fine motor skills, with as many as 90 percent writing right-handed. Some people are ambidextrous, or able to use both hands equally well. Though few parents and teachers any longer force left-handed children to use their right hands for writing and other fine motor activities, social pressure is still great to use the right hand. The equipment in this technological world is generally geared to right-handed people, so many left-handed people come to use their right hand a good deal. No special artistic or intellectual abilities are clearly linked with left-handedness. Lefthanders do have a higher proportion of accidents—due, many people feel, to the right-handed orientation of the things around them. Parents of left-handed children may well want to select left-handed versions of various tools and equipment, commonly available in special catalogs.
Preference to use either the left or the right hand for writing and other delicate manipulations. Handedness is thought to be hereditary and is related to cerebral dominance, with left-handedness being associated with dominance of the right hemisphere of the brain and vice versa. Of 100 persons, usually about 67 are right-handed.
The tendency to use one hand in preference to the other. Preferential use of the left hand is called sinistrality and of the right hand dextrality.
Handedness refers to an individual’s preference for using either the right or left hand. Approximately 90% of adults favor the right hand for writing, and two-thirds prefer using it for most coordinated and skillful activities. The remaining individuals are either left-handed or ambidextrous, meaning they can use both hands with equal proficiency.
The reason why all humans aren’t naturally ambidextrous remains unclear. Until about the age of 12, it’s possible to alter one’s dominant hand, for instance, if the dominant hemisphere of a person’s brain has sustained damage.
Handedness is associated with the brain’s division into two hemispheres, each controlling movement and feeling on the opposite side of the body. In most right-handed individuals, the speech center is located in the left hemisphere of the brain. Genetic factors likely play a significant role in determining an individual’s handedness.