Right-handed
From Wikipedia, the free encyclopedia
One who is right-handed is more dextrous with one's right hand than with one's left hand: one will probably write with their right hand, and probably also use this hand for tasks such as personal care, cooking, and so on. According to different studies, 85% to 90%[1] of the population is right-handed, while most of the remaining are left-handed. A very small percentage of the population can use both hands equally well; a person with this ability is deemed to be ambidextrous.
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[edit] Why is the population right-hand dominant?
It is not known with any degree of certainty why the population is right-hand dominant.
According to scientific theory, the right-side of the body is controlled by the left hemisphere of the brain, and vice-versa. In right-handed people, the left hemisphere of the brain is the dominant hemisphere.[1]
A recent study found that right-handers use the right side of the brain to focus on an entire image, but the left side of the brain to focus on details within an image.[2]
Being right-handed does not always mean that the favoured foot is also on the right side. When playing football for instance, many people prefer using their left foot rather than the right, despite being right-handed.[3]
[edit] Theories explaining right-hand dominance
- Warrior and his shield theory: This theory attempts to explain right-handedness by the position of a warrior's shield and his heart. Basically, since the heart is slightly nearer to the left side of the body, a right-handed warrior (who holds his shield with his left hand to free the right hand for a weapon) would be better able to protect his heart and therefore more likely to survive.
- Brain hemisphere division of labor: The premise of this theory is that since both speaking and handiwork require fine motor skills, having one hemisphere of the brain do both would be more efficient than having it divided up.
[edit] Right-handedness in society
In the past, many schools around the world forced left-handed children to write right-handed.[4] In Islam, one is required to use the left hand for tasks such as wiping oneself after using the bathroom and the right hand for eating.[5]
A good number of technological devices are made primarily for right-handers; examples of everyday objects primarily designed for right-handers include refrigerators, scissors, microwaves, can-openers, button-down shirts, and padded kitchen mittens (padded on one side only). Musical instruments such as guitars are also set up for right-handers. Military rifles designed to be shot only from the right shoulder have resulted in injuries from spent cartridge casings hitting left-handers in the eye and head.[6]
[edit] References
- ^ a b Psychology for A-level second edition, page 309
- ^ BBC website
- ^ Toddler Today website
- ^ Scientific American website
- ^ Muslim Restrooms
- ^ http://news.bbc.co.uk/2/hi/health/4242419.stm
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