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 ?
Subsequently, researchers asked 120 participants to hug a mannequin to investigate the influence of handedness and footedness.
Interestingly, these past studies, just like many others, differed from each other in how handedness was measured and how participants were categorised 6 some of them simply asked people what their hand preference was in general.
It was suggested that the mechanisms of handedness do not contribute to the differences in nerve conduction velocities.
The observations don't reveal whether the cloud has a preference for one handedness over another; that will have to wait for future observations.
However, many studies have not taken the sex variable into consideration which might be one of the reasons for conflicting findings in the handedness research.
In contrast, proponents defending the nurture stance in this debate suggest that handedness can be modified by rather subtle environmental manipulation, considering that individuals may switch their hand of preference in an attempt to adapt themselves to the environment (Tang & Verstynen, 2001).
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.
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.
So the pair turned to the world of sports for data to populate their mathematical model, which tracks the rarity of left handedness.
Other studies based on prenatal ultrasounds show that handedness formation occurs prenatally, before societal influences on handedness are present.
Forcible change of handedness makes what psychologists describe as a "misplaced sinister" and these downhearted people have miserable childhoods.