Difference Between Left Handed and Right Handed

Ever wonder why there are people who prefer to use their right hands, while others prefer to use their left hands? There are still others that can use both hands in writing and doing things. Well, here are some things that you might want to know about how and why people choose one hand over the other.

The left handedness or right handedness of a person is best manifested in his hand preference in writing. Left handed people also use their left hands in everyday activities and it is believed that 8 to 15 percent of the world’s population is left handed.

Seventy to ninety percent of the world’s population is right handed.  The reason for this is not known but it all has to do with the difference between the two parts of our brain that control each side of our bodies. A person who has his right hand impaired can also become left handed even after the right hand has healed.

One of the theories created to explain left handedness is the vanishing twin theory which states that the left handed person is actually part of an identical twin. The other twin fails to develop causing the other twin to become left handed. Can you believe that?

What is more plausible is the idea that it is caused by exposure to high rates of testosterone (Geschwind theory) before birth and that it is in a person’s genes. It all begins while the person is still a foetus and is determined by observing which hand the foetus is always held close to his mouth.

Norman Geschwind, a neurologist suggested that the levels of testosterone during pregnancy shape the development of the brain.  Testosterone can suppress the growth of the left cerebral hemisphere so that more neurons go to the right hemisphere.

This makes the right hemisphere suited to function as the center of a person’s language and handedness. Since the right hemisphere controls the left part of the body, the person will become left handed.

This testosterone exposure can also lead to an increased risk of auto-immune and learning disorders, dyslexia, stuttering and increased spatial ability and it is believed that more left handed people are prone to mental disorders. A study also suggests that most paedophiles are left handed.

But then, although the left hand is associated with all things negative, it is important to note that in a study on the earning capacity of certain individuals, it has been found that left handed people usually earn more than right handed people.

Since they live in a world dominated by right handed people, their ability to adapt is noteworthy. Everyday things and tools are usually made to cater to right handed people and left handed people have learned to use these things despite their hand preference.

Summary:

1. 70-90 percent of the world’s population is right handed, while only 8-15 percent is left handed.
2. Right handed people prefer to use their right hands in doing things, while left handed people prefer to use their left hands.
3. Right handed people were exposed to lesser testosterone levels as foetuses, while left handed people were exposed to more.
4. Left handed people are most likely to develop mental disorders than right handed people.