handedness


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handedness,

habitual or more skillful use of one hand as opposed to the other. Approximately 90% of humans are thought to be right-handed. It was traditionally argued that there is a slight tendency toward asymmetrical physiological development favoring the right side of the body, and that the center of gravity is to the right of the body's midline. This, however, would seem to be the consequence of greater dependence upon the right hand rather than the cause of right-handedness.

The neurological argument holds that since the right and left sides of the body are controlled by the opposite hemispheres of the brain, the greater development of the left hemisphere results in right-handedness. Anatomical studies have demonstrated that Broca's center, the area of the cerebral cortex that controls speech and muscular coordination, is almost always better developed in the left hemisphere in right-handed individuals; in 70% of left-handed individuals these centers are located in the right brain. Psychologists have raised the possibility of a cultural explanation. Although young children can be trained to prefer the right hand against a natural inclination, there is evidence that handedness is hereditary and that denser neurological connections extending from one side of the brain or the other are present from birth. A cultural explanation is also challenged by the evidence that some other vertebrates demonstrate a preference for one hand or paw over the other.

Although it is not clear that culture is a causative agent in handedness, it is certain that the high incidence of right-handedness has shaped human society in almost every conceivable aspect. Tools, machinery, and even clothing are largely designed for the right-handed, and until fairly recently, many left-handed individuals were strongly encouraged to switch to right-handedness. In some cultures the left-handed were thought to be evil or to bring bad luck.

handedness

[′han·dəd·nəs]
(physics)
A division of objects, such as coordinate systems, screws, and circularly polarized light beams, into two classes (right and left), which distinguishes an object from a mirror image but not from a rotated object.
References in periodicals archive ?
Wood published a letter in Nature (14): "It has been suggested that handedness influences life expectancy--the influence being that left-handers really are more gauche and maladroit than their more dexterous counterpoints.
Experiment 1: A total of 47 music students and faculty (21 right-handed and 26 dNRH) were tested for handedness and then given two questionnaires.
It is also possible that the biblical authors merely noted left-handed Benjamites because of the irony of the handedness and the meaning of their name.
Results showed children who had clear early hand preference performed better on language skills tests than those who did not develop handedness until toddlerhood.
According to Reuters the European Union's executive European Commission has warned national regulators to guard against heavy handedness with respect to their dealings with banks from elsewhere in the bloc.
For example, in studies of monozygotic (MZ) and dizygotic twins, there is little difference between the concordance and disconcordance rates for handedness (Neale, 1988).
What are lefties' perceptions of their handedness and their thoughts on the accommodations they need to make in school?
Jeanne Shami's "Anti-Catholicism in the Sermons of John Donne" cites evidence from sermons throughout Donne's career to show him as a man of integrity who genuinely regarded "papist and puritan extremes as equal menaces" (162), even after the Jacobean political moment for such rhetorical even handedness had passed.
Although handedness exists in animals other than humans, its prevalence in invertebrate animals hasn't been studied very much.
KARACHI -- Secretary Home Department Sindh, Dr Niaz Ali Abbasi has ordered inquiry against the police officers allegedly involved in extortion and high handedness on transporters, passengers on the Hub River Road.
Tran also added that "US neurologists Norman Geschwind and Albert Galaburda first argued that testosterone levels may influence handedness in the 1980s.
The study was unable to find a strong genetic factor in determining handedness.