Why do we use one hand more than the other? (Thinkstock)
Why do we use one hand more than the other?
Lexile

You asked us, why do we use one hand more than the other?

By the age of 2 or 3, most of us have started to prefer using one hand, and it is typically the right.

Only about 10 percent of us end up as lefties. If you are a lefty, you've probably been called a southpaw. They are basically all of the evil, witchy, criminal-type people out there. Just kidding! I'm just trying to mess with you, because we don't believe in that crazy talk anymore.

But why do we develop into righties and lefties? That question has more than a few scientists scratching their heads - with their dominant hand of course. (It's going to get worse.)

Handedness in humans probably goes way back, maybe as far as our Neanderthal ancestors or even earlier. Some researchers suggest the trait evolved as our tools became more sophisticated. 
 
But why the right hand came to dominate the left is anybody's guess. We do know that genetics plays a role in handedness. It's possible hundreds of genes are involved.
But, a person's environment is important, too. Just ask your grandma. In the past, lefties often had to learn how to write with their favored hand tied behind their back.
 
And even today, we basically live in a right-handed world, which forces many a lefty's hand when it comes to using scissors, writing at a desk or even zipping up a jacket. 
 
Until, that is, you get a lefty into the boxing ring or at home plate. That's when an element of surprise gives them the upper hand.

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CRITICAL THINKING QUESTION
Why are some people left-handed?
Write your answers in the comments section below


COMMENTS (279)
  • ethanm-4-bar
    4/28/2016 - 09:11 p.m.

    Some people are left handed because of our genes. However, we do not yet know why only 10%of people are left handed. Having a primary hand started when humans started using tools, and we don't know if being left handed was around then too.
    I was very surprised to learn that being right or left handed can be in our genes or our surroundings, like being forced to write with the opposite hand. I had never thought about that. I was also very surprised that we don't know why most humans are left handed.

  • sheilah-6-bar
    4/28/2016 - 09:32 p.m.

    Some people are left-handed. The article states,"But why the right hand came to dominate the left is anybody's guess. We do know that genetics plays a role in handedness. It's possible hundreds of genes are involved. But, a person's environment is important, too. Just ask your grandma. In the past, lefties often had to learn how to write with their favored hand tied behind their back. And even today, we basically live in a right-handed world, which forces many a lefty's hand when it comes to using scissors, writing at a desk or even zipping up a jacket." People who are left-handed may be because genetics. There are many genes that show how genetics can change a person's preference for one hand. Another idea is that the environment changes people's tendency to use their left hand. Many items used in daily life are made for right-handed people. This article surprised me because I didn't know that only 10% of people are left-handed. I thought half of people were left-handed.

  • gabriellek-1-bar
    4/28/2016 - 09:32 p.m.

    Some people are left-handed because of genetics and the environment that person lives in. This article is interesting because I did not know that where you live may make an impact on what hand you are most dominate. I was surprised because only 10% of the population are lefties.

  • colbys-3-bar
    4/28/2016 - 09:38 p.m.

    Some people are left because they are taught to as a kid or they use it because it is their natural born dominant hand. When some kids grew up they were forced to use their left hand. Only ten percent of people have left as their dominant hand. I thought this article was interesting because I only have one lefty friend and i wondered what makes people lefty.

  • ellans-1-bar
    4/28/2016 - 09:46 p.m.

    Some people are lefties, because of their genetics and genes. This article states, "Handedness in humans probably goes way back, maybe as far as our Neanderthal ancestors or even earlier. Some researchers suggest the trait evolved as our tools became more sophisticated. " This shows that left-handed people are rare, because we live in a right-handed society. I think this article is interesting, because a lot of people aren left-handed in a right-handed society.

  • simonak-3-bar
    4/28/2016 - 10:07 p.m.

    Some people are left handed because different variables will cause for them to be left handed. The passage states,"It's possible hundreds of genes are involved. But, a person's environment is important, too." This sentence directly states in the text that people can be left handed (or right handed) because of their genes and/or environment.
    I found this article interesting because I am right handed like most people and I wanted to know why.

  • aliciac-4-bar
    4/28/2016 - 10:13 p.m.

    Some people are left handed, typically because of our genes. Beyond that, the only reason some are left handed is because they chose to practice writing with their left hand in preschool. Practice makes perfect, and by practicing such small, precise movements and exercising the motor muscles in one hand rather than the other, you train one hand to be stronger than the other.

  • zeusr-3-bar
    4/28/2016 - 10:18 p.m.

    Handedness in humans probably goes way back, maybe as far as our Neanderthal ancestors or even earlier. Some researchers suggest the trait evolved as our tools became more sophisticated.

    My opinion on this topic is that I always wondered why this phenomenon happened.

  • jennaw-1-bar
    4/28/2016 - 10:29 p.m.

    In this article The reader learns about left and right handed people and why they write with the hand they write with. The reason that some people right with left hand is because when they were around age 2 they only used this specific hand the most. This article was interesting to me because the hand we write with has stuck with us our whole lives.

  • aidanp-1-bar
    4/28/2016 - 10:31 p.m.

    Some people are left handed for a number of reasons. Genetics can play a role because early humans may have singled out lefty's and the family tree made all of the children became rightys. Just like it says on paragraph 6, "But why the right hand came to dominate the left is anybody's guess. We do know that genetics plays a role in handedness. It's possible hundreds of genes are involved.But, a person's environment is important, too. Just ask your grandma. In the past, lefties often had to learn how to write with their favored hand tied behind their back.

    I liked this article because it was interesting.

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