I came across this article when I was reading Yahoo news...so interesting...enjoy. =]
Lefties VS Righties
The mysteries of lefthandedness
"Plato and Aristotle puzzled over lefthanders, as did Charles Darwin. What determines "handedness"? Why are only 10 percent of us lefthanded, and why did the ratio seem to change over the last century? Are lefties somehow different - less healthy, more creative?
With brain scanning and the latest genetic technology, scientists are finally starting to crack the mysteries. Lefthanders really are special, and the ways they differ are yielding insight into human diversity - especially how one person's brain differs from another's.
"Lefthandedness is connected to a lot of neurodevelopmental disorders," says Daniel Geschwind, a UCLA expert in what is known as neurobehavioral genetics. People with autism and schizophrenia are more likely to be lefthanded, he says. "But with that risk, there is also gain."
Look at MIT professors or musicians or architects, he suggests, and you'll see a slightly higher percentage of lefthanders than in the general population. Neuroscientists are beginning to figure out why.
The brains of lefthanded people develop more freely in utero, they say, allowing the organization to stray more from the standard design.
In most people, experts say, the left hemisphere of the brain specializes in tasks that are performed in sequence, such as reading and speaking; the right does more holistic processing, like that needed for visual perception. Most people have a dominant left hemisphere, and since each hemisphere controls the opposite side of the body, most of the population is righthanded.
A large body of research shows the majority of righthanders follow the typical pattern, using the left hemisphere for language. Lefthanders' brains appear less predictable: About half have language abilities concentrated in the left, 10 percent in the right, and 40 percent make use of various regions on both sides.
In humans, handedness runs in families, though not in an easily predictable way. Lefthanders are about twice as likely as righties to produce lefthanded children, but most of their offspring will still be righthanded.
Other scientists are examining how LRRTM1 and other genes might tie lefthandedness loosely with all sorts of characteristics. Various studies have found weak but statistically significant associations between lefthandedness and schizophrenia, autism and even homosexuality.
Psychologist Ronald Yeo of the University of New Mexico thinks the common link is a kind of flexibility known as developmental instability. Roughly, this describes the tendency to get off track during development, he says, freeing some brains to vary from the majority design, with each component in its place.
That may allow for novel ways of arranging the brain. Perhaps only an unusual configuration can produce an artistic and scientific genius like Leonardo da Vinci, who was reportedly both lefthanded and gay.
Lefthandedness studies, Yeo says, "have proven to be an avenue into understanding more general issues in how human beings develop and where variation comes from." In doing that, they sometimes overturn long-held beliefs.
Yeo reanalyzed a study that relied on death records to show that lefthanders died an average of seven years younger than righthanders but found that its conclusions were based on the incorrect assumption that the percentage of lefthanders has remained steady over time. ------------------------------------------------------------------------------------ I hope what I fear is just a fear, not the truth.
