Speaker 1: Welcome to brain Stuff production of I Heart Radio, Hey
Speaker 1: brain Stuff Lauren Bogelbaum. Here, the world is made up
Speaker 1: of about right handed people and ten percent left handed people.
Speaker 1: Folks who are truly ambidexterous those who use their right
Speaker 1: and left hand equally well make up a negligible sliver
Speaker 1: of the population. But is ambidexterity inherited or learned? And
Speaker 1: if learned, can it be learned as an adult? We
Speaker 1: spoke by email with Dr Sebastian Aucklenberg, a professor of
Speaker 1: psychology at Rural University in Bochum, Germany. He said a
Speaker 1: little bit of both. Handedness is determined by about twenty
Speaker 1: percent genetic factors and non genetic factors like environmental influences.
Speaker 1: It clearly runs in families, so it is somewhat inherited,
Speaker 1: but learning might also affect it. I think ambidexterity for
Speaker 1: a specific task like hitting a tennis ball with a racket,
Speaker 1: is possible, but full ambodexterity for all tasks is unlikely. Handedness,
Speaker 1: being the skill and comfort of person feels using one
Speaker 1: hand or the other, is considered a complex genetic trait,
Speaker 1: and since genes are involved, hand preference develops before a
Speaker 1: person is even born, But like other complex traits, handedness,
Speaker 1: including ambedoxterity, doesn't have a simple pattern of inheritance. Yes,
Speaker 1: there is a greater chance that children of left handed
Speaker 1: parents will also be left handed than children of rights,
Speaker 1: but remember the chance of being a lefty is just
Speaker 1: ten percent overall, so most children of lefties are still
Speaker 1: right handed, and identical twins are more likely than non
Speaker 1: identical twins to both be either right or left handed,
Speaker 1: but many of both types do have opposite hand preferences.
Speaker 1: And that's before we even talk about whether a child's
Speaker 1: handedness is allowed to develop naturally or whether parents and
Speaker 1: teachers interfere. Hand dominance typically develops around age three and
Speaker 1: is fully developed by age four to five, but it
Speaker 1: can be influenced by insisting a child uses their other
Speaker 1: hand or by happenstance. For example, when he was four
Speaker 1: years old, former Major League baseball pitcher Billy Wagner broke
Speaker 1: his right elbow and spent the summer in a cast.
Speaker 1: In his memoir, Wagner vividly recalls being a natural righty
Speaker 1: at the time and already mad for baseball, but for
Speaker 1: the next six weeks he threw only left handed. When
Speaker 1: the cast came off, he was in for a surprise
Speaker 1: when he tried throwing with his right The ball went nowhere.
Speaker 1: Had lost not just strength but coordination for throwing with
Speaker 1: his right arm and gained it in his left. Wagner wrote,
Speaker 1: I was a natural righty then and still am. I
Speaker 1: do everything right handed, eat hold tools, right to start
Speaker 1: the lawnmower, everything except pitch. Wagner wouldn't be considered ambidextrous,
Speaker 1: though he certainly managed to have an incredibly successful career
Speaker 1: working with his non dominant hand. Base all is full
Speaker 1: of players who switch hit, meaning they hit equally well
Speaker 1: from either the left or right side and are comfortable
Speaker 1: facing left or right handed pitchers. Some like Hall of
Speaker 1: famers Eddie Murray, Mickey Mantle, and Chipper Jones, were very successful,
Speaker 1: but they, like Wagner, weren't truly ambidexterous, which is something
Speaker 1: that's very difficult to do. But why. Aucklenburg said, handedness
Speaker 1: is something that is generated in the brain, not the hands.
Speaker 1: As such, the half of the brain contralateral to the
Speaker 1: hand is better in controlling fine motor movements. For example,
Speaker 1: the left brain hemisphere in right handers. The strength of
Speaker 1: this preference varies between individuals. Some people have a very
Speaker 1: strong preference for one hand and resulting from that greater
Speaker 1: issue in using the other for specific tasks. So it's
Speaker 1: the brain that sets the barrier. But if the brain
Speaker 1: sets the barrier, the brain can also remove it. Take
Speaker 1: the case of Billy McLaughlin. McLoughlin is an award winning
Speaker 1: guitarist known for a unique style of play, placing both
Speaker 1: hands on the fretboard. He was originally predominantly a right
Speaker 1: handed guitar player, but in the late nineteen nineties, but
Speaker 1: despite having a record at number seven on the Billboard Charts,
Speaker 1: he was struggling with control problems. He was missing notes
Speaker 1: when he played, and experienced muscle spasms to the point
Speaker 1: that he was unable to perform. Finally, in two thousand one,
Speaker 1: McLoughlin was diagnosed with vocal dystonia, a movement disorder causing
Speaker 1: muscles to contract involuntarily. Though advised to find another career,
Speaker 1: McLoughlin opted to teach himself to play left handed, and
Speaker 1: he succeeded. So this begs the question, can we teach
Speaker 1: ourselves to become ambidextrous as adults. A two thousand seven
Speaker 1: study found that as we age, we actually become more
Speaker 1: ambidextrous without even trying, in part because the hand that
Speaker 1: we use more loses its dominance. The study was small.
Speaker 1: It included sixty participants, all wrongly right handed according to
Speaker 1: the Edinburgh Handedness Inventory. The participants completed various computerized dexterity tests,
Speaker 1: which included line tracing and aiming task and tapping. The
Speaker 1: youngest group, average age twenty five years, performed all the
Speaker 1: skills proficiently using their right hand. The middle aged participants,
Speaker 1: average age fifty years, performed well using either hand on
Speaker 1: the aiming task, while the two oldest groups, average ages
Speaker 1: seventy and eighty years, performed just as well using either
Speaker 1: hand on all tasks except one. However, overall performance appeared
Speaker 1: to decline with increasing age, especially for the participants dominant
Speaker 1: right hand, leading researchers to believe that quote we become
Speaker 1: more ambidexterous as we get older because our dominant hand
Speaker 1: loses its superior dexterity and becomes more like our weaker hand.
Speaker 1: Some people have wondered whether attempting to become ambidexterous could
Speaker 1: strengthen the brain and potentially slow or fight the effect
Speaker 1: of aging or dementia. Aucklandberg said that's a myth. While
Speaker 1: it is true in general that brain training is a
Speaker 1: good idea when aging, research has shown that what gets
Speaker 1: strengthened is what is trained. So if I trained to
Speaker 1: write with my non dominant hand, this would affect the
Speaker 1: motor brain areas of the contralateral half of the brain,
Speaker 1: but not the areas involved in memory. Thus a specific
Speaker 1: memory training would make more sense in aging and dementia.
Speaker 1: Today's episode was written by Patty Resmusin and produced by
Speaker 1: Tyler Clang. For more on this and lots of other topics,
Speaker 1: visit how stuff works dot com. Brain Stuff is production
Speaker 1: of I Heart Radio. For more podcasts my heart Radio,
Speaker 1: visit the i heart Radio app, Apple Podcasts, or wherever
Speaker 1: you listen to your favorite shows.