Teaching, or even forcing, people to become ambidextrous is a practice that has been around for centuries. Some even claim that learned "cross dominance" can improve brain function. But as the science shows, not only is this not true, it may actually harm our neural development.
Indeed, it wasn't too long ago that many parents forced their children to use their nondominant hands. My own father, who is naturally left-handed, remembers being a child and having his "wrong" hand slapped whenever he reached for a fork or pencil. Eventually, he learned to use his right hand quite proficiently, but at the cost of his left-handedness.
Aside from my grandparents' aversion to left-handedness, though, some thinkers argued that ambidextrousness could benefit society as a whole, and result in "two-brainedness".
But as cognitive neuroscientist Michael Corballis recently noted in SciAm, this is simply not the case:
This hype died down in the mid-20th century as benefits of being ambidextrous failed to materialize. Given that handedness is apparent early in life and the vast majority of people are right-handed, we are almost certainly dextral by nature. Recent evidence even associated being ambidextrous from birth with developmental problems, including reading disability and stuttering. A study of 11-year-olds in England showed that those who are naturally ambidextrous are slightly more prone to academic difficulties than either left- or right-handers. Research in Sweden found ambidextrous children to be at a greater risk for developmental conditions such as attention-deficit hyperactivity disorder. Another study, which my colleagues and I conducted, revealed that ambidextrous children and adults both performed worse than left- or right-handers on a range of skills, especially in math, memory retrieval and logical reasoning.
Corballis says the two hemispheres of the brain are not interchangeable, and that they're used for different processes and tasks. "These asymmetries probably evolved to allow the two sides of the brain to specialize," he says. "To attempt to undo or tamper with this efficient setup may invite psychological problems."
It's okay to train your nondominant hand to be more proficient, he says, just don't do it at the expense of your dominant one.
Read the entire article at SciAm.