Brain laterization and handedness
http://www.apa.org/monitor/2009/01/brain.aspx
According to the American Psychological Association, about 90 % of people are right handed, and the remaining 10% are left handed or ambidextrous. Handedness is based off of brain lateralization. Those who are right handed have a dominant left hemisphere and those who are left handed have a dominant right hemisphere. If a majority of the worlds population have strongly lateralized brains, then there must be a genetic or evolutionary explanation.
In this article, the authors use Albert Einstein as an example because he is a famous figure popularly known for being left handed. The article clears up the misconception that Einstein was left handed because myriad photo's show him writing with his right hand. Autopsies suggest that his brain's hemispheres were more symmetrical, a trait of left handed and ambidextrous people.
The left hemisphere of the brain is responsible for language processing and the right hemisphere handles emotion and image processing. 20% of lefties divide these responsibilities equally throughout the brain. As we discussed in class, popular culture exaggerated the effects of brain laterization on individuals personality and mental abilities. The brain specialist, Michael Corball, PhD, says " There's an advantage to cerebral dominance because it localizes function to one hemisphere," he says. "Otherwise, information has to cross back and forth across the corpus callosum, and that can sometimes cause problems."
The researchers found that a strongly symmetrical brain could lead to mental dysfunction, or it could lead to creative thinking, like Einstein. Less laterized brains, like those of people who are ambidextrous, are linked with lower IQ scores, especially in dealing with memory and reasoning. In 2007, the Journal of Mental and Nervous Disease found that most musicians, painters and writers are left handed. Studies also show that left handed college educated men earn 15% more than right handed men. But there are over 20% of left handed individuals who do not fit the creative stereotype.
The researchers hypothesize that through evolution, our brains became laterized because we were capable of doing things, such as processing language, effectively with one hemisphere, so that free'd up the other hemisphere to do other things, like processing the emotional content of the language.
In 2007 genetics identified a gene on chromosome 2 called LRRTM1 that is present in most lefties and in those with schizophrenia. But the researchers theorize that the brain encounters faulty neuronal connections when the information it's processing goes back and forth between both hemispheres.
The conclusion of this article is a little confusion because the researchers don't really come to a conclusion. The brain hemisphere specialist stated that finding a balance between asymmetrical and symmetrical brains is part of the human condition. The information presented in this article doesn't stray far from what we learned in class, but I did learn interesting facts about those who are left handed. I was hopping to get a more in depth explanation of the genetic or evolutionary reasons behind handedness. More research should be conducted to find the significance of handedness and its relations to brain laterization.
According to the American Psychological Association, about 90 % of people are right handed, and the remaining 10% are left handed or ambidextrous. Handedness is based off of brain lateralization. Those who are right handed have a dominant left hemisphere and those who are left handed have a dominant right hemisphere. If a majority of the worlds population have strongly lateralized brains, then there must be a genetic or evolutionary explanation.
In this article, the authors use Albert Einstein as an example because he is a famous figure popularly known for being left handed. The article clears up the misconception that Einstein was left handed because myriad photo's show him writing with his right hand. Autopsies suggest that his brain's hemispheres were more symmetrical, a trait of left handed and ambidextrous people.
The left hemisphere of the brain is responsible for language processing and the right hemisphere handles emotion and image processing. 20% of lefties divide these responsibilities equally throughout the brain. As we discussed in class, popular culture exaggerated the effects of brain laterization on individuals personality and mental abilities. The brain specialist, Michael Corball, PhD, says " There's an advantage to cerebral dominance because it localizes function to one hemisphere," he says. "Otherwise, information has to cross back and forth across the corpus callosum, and that can sometimes cause problems."
The researchers found that a strongly symmetrical brain could lead to mental dysfunction, or it could lead to creative thinking, like Einstein. Less laterized brains, like those of people who are ambidextrous, are linked with lower IQ scores, especially in dealing with memory and reasoning. In 2007, the Journal of Mental and Nervous Disease found that most musicians, painters and writers are left handed. Studies also show that left handed college educated men earn 15% more than right handed men. But there are over 20% of left handed individuals who do not fit the creative stereotype.
The researchers hypothesize that through evolution, our brains became laterized because we were capable of doing things, such as processing language, effectively with one hemisphere, so that free'd up the other hemisphere to do other things, like processing the emotional content of the language.
In 2007 genetics identified a gene on chromosome 2 called LRRTM1 that is present in most lefties and in those with schizophrenia. But the researchers theorize that the brain encounters faulty neuronal connections when the information it's processing goes back and forth between both hemispheres.
The conclusion of this article is a little confusion because the researchers don't really come to a conclusion. The brain hemisphere specialist stated that finding a balance between asymmetrical and symmetrical brains is part of the human condition. The information presented in this article doesn't stray far from what we learned in class, but I did learn interesting facts about those who are left handed. I was hopping to get a more in depth explanation of the genetic or evolutionary reasons behind handedness. More research should be conducted to find the significance of handedness and its relations to brain laterization.
After reading this, my mind wonders in several different directions based off of the information presented. I have always known about cerebral dominance it the theories that correlate with it. However after reading this information, It makes it seem as though people are born either left handed or right handed based on the points made about mental disorders. Also along those lines, it seems as though the author is saying that because of the transfer of information in a symmetrical brain, which is correlated with left handed and ambidextrous people, between hemispheres, left handed people are more likely to develop mental and neural disorders than right handed people. In my opinion if that is the case, why would we not promote right handedness in an effort to take preventative measures against the possibility of these things happening? I would also argue that based off of this information, it would be a good idea with schizophrenics to encourage left hemispherical dominance in an effort to combat the effects of the LRRTM1 gene and see if that makes a difference. It seems as if the author of the article just threw a lot of information around and did not have a clear cut direction with it so I agree with your conclusion about it being confusing. I think more research should be done on hemisphere dominance to see how exactly it effects functioning especially in the presence of mental disorder and handedness.
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