LEFT-HANDED VS RIGHT-HANDED
LEFT-HANDED VS RIGHT-HANDED
How Rare Are Lefties?
Right-handed people dominate the world, and
it’s been that way since the Stone Age. How
do we know? Researchers figured it out by
measuring the arm bones in ancient skeletons
and by examining wear patterns in prehistoric
tools. In Western countries, lefties make up
only about 10% of the population. Folks who
favor different hands for different tasks (mixed
handed) or who use both hands with equal
skill (ambidextrous) are uncommon.
Right-handed people dominate the world, and
it’s been that way since the Stone Age. How
do we know? Researchers figured it out by
measuring the arm bones in ancient skeletons
and by examining wear patterns in prehistoric
tools. In Western countries, lefties make up
only about 10% of the population. Folks who
favor different hands for different tasks (mixed
handed) or who use both hands with equal
skill (ambidextrous) are uncommon.
Genetic Roots
Scientists have long known that handedness is
partly shaped by genes. But it wasn’t until 2019
that they identified differences in parts of the DNA
of left- and right-handers. The study, which also
analyzed brain scans of 9,000 British subjects,
found that in lefties, the parts of the right and left
sides of the brain that process language work in
better tandem. Whether that makes left-handers
more fluent speakers is still to be investigated.
Scientists have long known that handedness is
partly shaped by genes. But it wasn’t until 2019
that they identified differences in parts of the DNA
of left- and right-handers. The study, which also
analyzed brain scans of 9,000 British subjects,
found that in lefties, the parts of the right and left
sides of the brain that process language work in
better tandem. Whether that makes left-handers
more fluent speakers is still to be investigated.
Handedness in the Womb
Fetuses start to move their arms around 9-10
weeks. By early in the second trimester, the
babies show a clear preference for sucking
one thumb over the other. So handedness is
probably hardwired before birth. Still, most
development experts say parents likely won’t
get a good sense of their child’s dominant
hand until age 2 or 3. Many kids continue to
switch hands for different tasks during early
childhood.
Fetuses start to move their arms around 9-10
weeks. By early in the second trimester, the
babies show a clear preference for sucking
one thumb over the other. So handedness is
probably hardwired before birth. Still, most
development experts say parents likely won’t
get a good sense of their child’s dominant
hand until age 2 or 3. Many kids continue to
switch hands for different tasks during early
childhood.
Mixed Dominant Hands
Studies show that non-right-handed students
are much more likely to struggle in school and
have ADHD symptoms. That may be particularly
true for those who are mixed-handed or
ambidextrous. One study found that children
who switch hands back and forth are about
twice as likely to have dyslexia. Researchers
don’t know exactly why. But they suspect that
having an inconsistent dominant hand may be a
bigger problem than consistent left-handedness.
Studies show that non-right-handed students
are much more likely to struggle in school and
have ADHD symptoms. That may be particularly
true for those who are mixed-handed or
ambidextrous. One study found that children
who switch hands back and forth are about
twice as likely to have dyslexia. Researchers
don’t know exactly why. But they suspect that
having an inconsistent dominant hand may be a
bigger problem than consistent left-handedness.
Superior Lefties?
Your brain’s right side controls muscles on the left
side of your body and largely drives musical and
spatial abilities. That may be why left-handers often
hold more than their share of slots in creative
professions. Mirror writing, where letters are reversed
and written backward, is almost always done with the
left hand. Some studies show that left-handed
children score higher on verbal reasoning or are
more likely to be in gifted programs. But other
research differs.
Your brain’s right side controls muscles on the left
side of your body and largely drives musical and
spatial abilities. That may be why left-handers often
hold more than their share of slots in creative
professions. Mirror writing, where letters are reversed
and written backward, is almost always done with the
left hand. Some studies show that left-handed
children score higher on verbal reasoning or are
more likely to be in gifted programs. But other
research differs.
Handedness and Age
In an interesting experiment with righthanded
seniors, researchers found that
the subjects relied less and less on their
dominant hand the older they got. As
their right hands grew slower and
unsteady, the elderly people handled
some of the tasks just as well with their
left hands. But they still all saw
themselves as strong righties.
In an interesting experiment with righthanded
seniors, researchers found that
the subjects relied less and less on their
dominant hand the older they got. As
their right hands grew slower and
unsteady, the elderly people handled
some of the tasks just as well with their
left hands. But they still all saw
themselves as strong righties.
Handedness and Athletics
Lefties appear to have an edge in sports
like boxing or fencing, where they might
surprise opponents used to facing off
against mostly right-handers. In some
years, nearly half of Major League
Baseball’s All-Star roster has been
southpaws or switch hitters. But that may
be due less to athletic talent than to
practical advantages like the fact that lefthanded
hitters stand closer to first base.
Lefties appear to have an edge in sports
like boxing or fencing, where they might
surprise opponents used to facing off
against mostly right-handers. In some
years, nearly half of Major League
Baseball’s All-Star roster has been
southpaws or switch hitters. But that may
be due less to athletic talent than to
practical advantages like the fact that lefthanded
hitters stand closer to first base.
Brain Disorders
There’s a well-established link between lefthandedness
and mental conditions like
schizophrenia, which can cause hallucinations
and impaired thinking. A large recent study in
the U.K. found a strong link between regions of
the brain involved in handedness and how likely
you are to have mood swings, restlessness,
and neuroticism, a personality type marked by
anxiety and fear that sometimes can veer into
mental disorder.
There’s a well-established link between lefthandedness
and mental conditions like
schizophrenia, which can cause hallucinations
and impaired thinking. A large recent study in
the U.K. found a strong link between regions of
the brain involved in handedness and how likely
you are to have mood swings, restlessness,
and neuroticism, a personality type marked by
anxiety and fear that sometimes can veer into
mental disorder.
Humans vs. Apes
We’re not the only animals with a handedness
trait. Researchers watching wild chimps found
they favor their left hands twice as often when
fishing for termites. And the same was largely true
for chimpanzees raised in captivity. But results
were different for nut-cracking. For that task, which
requires sheer force instead of the fine motor skills
needed for extracting insects, wild chimps were
much more likely to favor their right hands.
We’re not the only animals with a handedness
trait. Researchers watching wild chimps found
they favor their left hands twice as often when
fishing for termites. And the same was largely true
for chimpanzees raised in captivity. But results
were different for nut-cracking. For that task, which
requires sheer force instead of the fine motor skills
needed for extracting insects, wild chimps were
much more likely to favor their right hands.
Forced Right-Handedness
Cultural biases against left-handers has existed
throughout history. In the Middle Ages, the devil
was believed to be a lefty. In Japan, China, and
other Asian countries, the percentage of left-handers
is much smaller than in the West.
American teachers and doctors in the early 1900s
believed that left-handers were more prone to
mental disorders and pressured students to switch
hands.
Cultural biases against left-handers has existed
throughout history. In the Middle Ages, the devil
was believed to be a lefty. In Japan, China, and
other Asian countries, the percentage of left-handers
is much smaller than in the West.
American teachers and doctors in the early 1900s
believed that left-handers were more prone to
mental disorders and pressured students to switch
hands.
Famous Lefties
Four of the six most recent U.S.
presidents were lefties: Ronald
Reagan, George H.W. Bush, Bill
Clinton, and Barack Obama. Celebrity
southpaws include Oprah Winfrey, Bill
Gates, Tom Cruise, Paul McCartney,
Prince Charles, and his son, Prince
William.
Four of the six most recent U.S.
presidents were lefties: Ronald
Reagan, George H.W. Bush, Bill
Clinton, and Barack Obama. Celebrity
southpaws include Oprah Winfrey, Bill
Gates, Tom Cruise, Paul McCartney,
Prince Charles, and his son, Prince
William.
Tools for Lefties
If you’re a righty and ever used your left hand
to cut with scissors, you know it’s awkward.
Lefties can find a growing number of products
for the kitchen, office, and elsewhere that are
designed with them in mind. You can buy
knives with the sharpened edge on the right
side of the blade for cleaner slicing. Or a
measuring cup with unit labels that face you
when you hold it in your left hand.
If you’re a righty and ever used your left hand
to cut with scissors, you know it’s awkward.
Lefties can find a growing number of products
for the kitchen, office, and elsewhere that are
designed with them in mind. You can buy
knives with the sharpened edge on the right
side of the blade for cleaner slicing. Or a
measuring cup with unit labels that face you
when you hold it in your left hand.
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