10% of fetuses preferably used left-hand movements
-The beliefs that left-handers have greater artistic skills or more difficulties for learning is not underpinned by methodologically valid data
Barcelona, April 2012.- what Barack Obama and Hugo Chavez have in common? and Messi or Iker Casillas? All of them are left-handed. Only 15% of the world’s population is left-handed. Spain the latest statistics show there about 12% of left-handers.
Formerly, false beliefs surrounding persons that unfolded better with the left hand, but today things have changed and be left-handed is treated as one feature again, as that is tall or thin.
Says Dr. Roberto BelvÃs, Coordinator of the Neurology of USP Dexeus, normality is to be right-handed, but being left-handed is not an abnormality if not a variant of normal reporting a 15% of the world population and that has motivated them dangerous situations in various cultures throughout the history of the humanity. ”
how the right dominance – left? All workplaces and nerve pathways in the right hemisphere of the brain also exist in the left hemisphere. The right-left dominance in some functions like hearing (ear that we put on the clock), vision (eye we put into the telescope), the manual handling (the hand with which we write) or foot (the foot that chutamos a ball) is determined by genetic and environmental factors and laying in the lathe to the five years:
-factors genético: some populations such as the Asian have higher percentage of left-handed people. On the other hand, ultrasound in pregnant women studies show that 10% of babies already use preferably the left hand movements (and babies still not been subject to any environmental factor).
-environmental factors: if the parents of the baby the pacifier with his right hand, the baby will receive it in a natural way with the right and vice versa. For this reason, usually a son presents the dominance of their parents. A practical example is the castle of the clan Fernieshirst left-handed Scottish built Kerr to be defended by lefties in the 15th century be left-handed with the sword could be an advantage in combat as today it is for a footballer.
Being left-handed does not imply any problem while there is uniformity in the dominance (hand-foot – eye-ear). Homogeneous lefties are no more problems of learning than homogeneous right-handers. The problem appears when the dominance is not homogeneous if not cross because learning calculus, writing and reading problems may occur in the child according to the DRA. Virginia Trèmols, USP Dexeus child psychologist: the laterality presupposes not a learning disability. While it is true that at the beginning of the learning of reading and writing left-handed tend to do more investment (type B instead of D) this is part of the normal process of learning which over time is corrected spontaneously. I.e., there are no disorders caused by having laterality non homogeneous. ”
beliefs that left-handers are more artistic or intellectual capacities have prompted all kinds of pseudoscientific publications that do not sustain in methodologically valid data – points Dr. Belvis. in the same sense, the belief that lefties die before by accident in a world designed for right-handers is based in the percentage of left-handed seniors is lower than the left-handed young, but this is because they were forced to correct ” its dominance and not to deaths premature. ”
