A Hand Test: Genetical, Psychological and Social Analysis to Being Left-Handed
The preferred usage of one hand over the other is called handedness. Approximately 90 percent of the world’s populations are right-handed and these were passed on from one generation to other, although learning and culture could be the other possibilities to these phenomena (Lexicon University Encyclopedia, 1988). According to the New Encyclopedia Britannica (1993), laterality is the development of specialized functions in each of the hemisphere in our brain or the side of our body it controls. Handedness is the most obvious example of laterality, which uses one hand to perform activities over the other. It can be classified as right-handed, left-handed or ambidextrous. In anatomy, our hands are mirror images. The vast majority of the right-handers use their right hands exclusively for tasks requiring dexterity and mastery (Hockenbury, 1997). This also goes the same for the people who use their left hands or the so-called “left-handers.”
Left-handers are the people who use their left hands in writing or most of their usual activities rather than their right hands. One person in ten is a left-hander. Anywhere you look, left-handedness is something of a rarity (de Kay, 1979). Almost ten percent (somewhat more among males, somewhat less among females) of the human population is left-handed. Judging from the cave drawings and the tools of the prehistoric humans, this veer to the right occurred a long way back in the development of our species (Myers, 1986). Men are twice as many as women who were left-handed. They believe that this is due to the fact that males are exposed to higher testosterone levels during pregnancy (Hockenbury, 1997).
For most left-handers, living in a right-handed world may sometimes difficult for them. Most tools used in our daily lives are designed primarily for the right-handers. For left-handers, handwriting shows an obstacle. Adapting specifically to right-handed tools for music, business education and physical education should be done and mastered for some left-handers (Lance, 2006).The physical environment we are living today are specifically designed for the right-handers, but this should not be linked to a small percentage of left-handed elderly in our society. Most tools, equipments and machines in school and workplaces are designed for the convenience and safety of the right-handers. And these inconveniences are hazardous to health and safety of the left-handers. This can only be prevented if the machines, tools and equipments are to be made “user-friendly,” meaning ideally suited for both left-handers and right-handers (Kassin, 1989).
Researchers hypothesized that a gene in a person’s DNA might confer to his handedness, specifically right-handedness. They theorized that people who lack this gene might display a random handedness, one-half being right-handed and the other half being left-handed. The problem with this theory that the other studies show that there is 30%-40% chance of having a left-handed child, when both parents are left-handed. Further studies are conducting to full gene map to this single gene theory (Jansen, 1998). But just recently, the scientists from the Wellcome Trust Centre for Human Genetics at Oxford University have lately discovered the gene LRRTM1, which they believe that increases the person’s chances to become left-handed. Over 40 scientists from 20 research centers revealed that this gene, the LRRTM1, is the first to be discovered which has an effect on handedness. Although little is known about LRRTM1, the Oxford team suspects that it modifies the development of asymmetry in the human brain. They also discovered that LRRTM1 might the risk to become schizophrenic, a brain disorder which results to impaired perception and thoughts. Yet, Dr. Clyde Franck, the leader of the Oxford team said that,” people really should not be concerned by this result. There were many factors...
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