Approximately 85 percent of people are right – handed . The genetic proposal to explain hand preference states that there are two alleles, or two manifestations of a gene at the same genetic location, that are associated with handedness.
The reasons for this are not fully understood, but it is thought that because the left cerebral hemisphere of the brain controls the right side of the body, the right side is generally stronger; it is suggested that the left cerebral hemisphere is dominant over the right in most humans because in 90-92% of all humans,
Although the percentage varies by culture, in Western countries 85 to 90 percent of people are right – handed and 10 to 15 percent of people are left – handed . Mixed-handedness (preferring different hands for different tasks) and ambidextrousness (the ability to perform tasks equally well with either hand) are uncommon.
About 90 percent of people are right-handed, says Corballis. The remaining 10 percent are either left-handed or some degree of ambidextrous, though people with “true” ambidexterity—i.e., no dominant hand at all—only make up about 1 percent of the population.
The bulk of the studies included in the systematic review reported no differences in IQ scores between left – and right- handers .
So why are lefties so rare ? Scientists have long tried to answer this. In 2012, researchers at Northwestern University developed a mathematical model to show that the percentage of left – handed people was a result of human evolution — specifically, a balance of cooperation and competition.
In certain societies, they may be considered unlucky or even malicious by the right-handed majority. Many languages still contain references to left-handedness to convey awkwardness, dishonesty, stupidity, or other undesirable qualities.
Being a leftie has a genetic component, is linked to better verbal skills and is associated with a lower risk of Parkinson’s disease, according to a new study published in the journal Brain .
Lefties represent only 10 percent of the world’s population, yet they’ve been such a fascination for so long that study after study has been conducted on what makes them so unique. But while we now know that lefties are normal folks, history wasn’t always so kind to our left-handed friends.
If you’re left handed you’re more likely to be a genius, says study. A recent study has now once again linked a left-hand preference with increased mathematical skills, which makes left-handed people more likely to be a genius, reports the Indy100.
Studies suggest that approximately 10% of people are left- handed . Cross-dominance or mixed – handedness is the change of hand preference between tasks. This is very uncommon , with about a 1% prevalence. Ambidexterity, equal ability in both hands, is rare .
In baseball, “ southpaw ” has referred to left-handed pitchers since the 19th century. One origins tale notes that old ballparks were oriented with home plate to the west, so that a lefty facing west would be throwing with his “south” paw.
McManus which found that the Netherlands has one of the world’s highest prevalences of left-handedness at 13.23 percent. The United States isn’t far behind with a rate of 13.1 percent while neighboring Canada has 12.8 percent. Elsewhere, rates of left-handedness are far lower and China is a good example.
In the left – handed participants, the two halves of the brain – the left and right hemispheres – were better connected and more co-ordinated in regions involved in language. The study also showed slightly higher risks of schizophrenia, and slightly lower risks of Parkinson’s disease, in left – handed people .
Ambidexterity is the ability to use both the right and left hand equally well. When referring to objects, the term indicates that the object is equally suitable for right – handed and left – handed people.