Why are most people right handed?

[Valleygolfer]

2 hours ago, newtogolf said:

Thanks, I was going to look it up after I responded to a few posts but thought I'd throw it out there.  I went to Catholic elementary school and they tried to switch me to write right handed but it didn't take.  I wonder how many more people my age (50) and older would be left handed if not for those nuns in catholic school.  

Clearly left handed people are hell's spawn... Very simple answer....

[Lihu]

2 hours ago, newtogolf said:

Thanks, I was going to look it up after I responded to a few posts but thought I'd throw it out there.  I went to Catholic elementary school and they tried to switch me to write right handed but it didn't take.  I wonder how many more people my age (50) and older would be left handed if not for those nuns in catholic school.  

 

http://www.scientificamerican.com/article/what-causes-some-people-t/

Quote

Clare Porac, a professor of psychology at Pennsylvania State University who studies handedness, explains.

Researchers who study human hand preference agree that the side of the preferred hand (right versus left) is produced by biological and, most likely, genetic causes. The two most widely published genetic theories of human hand preference argue that evolutionary natural selection produced a majority of individuals with speech and language control in the left hemisphere of the brain. Because the left hemisphere also controls the movements of the right hand--and notably the movements needed to produce written language--millennia of evolutionary development resulted in a population of humans that is biased genetically toward individuals with left hemisphere speech/language and right-hand preference. Approximately 85 percent of people are right-handed. These theories also try to explain the persistent and continuing presence of a left-handed minority (about 15 percent of humans).

The genetic proposal to explain hand preference states that there are two alleles, or two manifestations of a gene at the same genetic location, that are associated with handedness. One of these alleles is a D gene (for dextral, meaning right) and the other allele is a C gene (for chance). The D gene is more frequent in the population and is more likely to occur as part of the genetic heritage of an individual. It is the D gene that promotes right-hand preference in the majority of humans. The C gene is less likely to occur within the gene pool, but when it is present, the hand preference of the individual with the C gene is determined randomly. Individuals with the C gene will have a 50 percent chance of being right-handed and a 50 percent chance of being left-handed.

These theories of hand preference causation are intriguing because they can account for the fact that the side of hand preference of individuals with the C gene (most left-handers and some right-handers) can be influenced by external cultural and societal pressures, a phenomenon that researchers have documented. These theories can also explain the presence of right-handed children in families with left-handed parents and the presence of left-handed children in families with right-handed parents. If the familial genetic pool contains C genes, then hand preference becomes amenable to chance influences, including the pressures of familial training and other environmental interventions that favor the use of one hand over the other. The proposed genetic locus that determines hand preference contains an allele from each parent, and the various possible genetic combinations are DD individuals who are strongly right-handed, DC individuals who are also mostly right-handed, and CC individuals who are either right-handed or left-handed. These genetic combinations leave us with an overwhelming majority of human right-handers and a small, but persistently occurring, minority of left-handers.

Those pesky left-handers!

 

http://www.sciguru.org/newsitem/13739/Shedding-Light-Southpaws-Sports-data-help-confirm-theory-explaining-left-handed-minority-general-p

Quote

Shedding Light on Southpaws: Sports data help confirm theory explaining left-handed minority in general population

Wed, 04/25/2012 -- Science News Desk

 

Lefties have always been a bit of a puzzle. Representing only 10 percent of the general human population, left-handers have been viewed with suspicion and persecuted across history. The word “sinister” even derives from “left or left-hand.”

Two Northwestern University researchers now report that a high degree of cooperation, not something odd or sinister, plays a key role in the rarity of left-handedness. They developed a mathematical model that shows the low percentage of lefties is a result of the balance between cooperation and competition in human evolution.

Professor Daniel M. Abrams and his graduate student Mark J. Panaggio -- both right-handers -- are the first to use real-world data (from competitive sports) to test and confirm the hypothesis that social behavior is related to population-level handedness.

More than 50 percent of elite baseball players, such as Sandy Koufax (pictured), are left-handed, well above the general population rate of 10 percent.

The results are published today (April 25) in The Journal of the Royal Society Interface.

“The more social the animal -- where cooperation is highly valued -- the more the general population will trend toward one side,” said Abrams, an assistant professor of engineering sciences and applied mathematics at the McCormick School of Engineering and Applied Science. “The most important factor for an efficient society is a high degree of cooperation. In humans, this has resulted in a right-handed majority.”

If societies were entirely cooperative everyone would be same-handed, Abrams said. But if competition were more important, one could expect the population to be 50-50. The new model can predict accurately the percentage of left-handers in a group -- humans, parrots, baseball players, golfers -- based on the degrees of cooperation and competition in the social interaction.

The model helps to explain our right-handed world now and historically: the 90-10 right-handed to left-handed ratio has remained the same for more than 5,000 years. It also explains the dominance of left-handed athletes in many sports where competition can drive the number of lefties up to a disproportionate level.

Cooperation favors same-handedness -- for sharing the same tools, for example. Physical competition, on the other hand, favors the unusual. In a fight, a left-hander in a right-handed world would have an advantage.

Abrams and Panaggio turned to the world of sports for data to support their balance of cooperation and competition theory. Their model accurately predicted the number of elite left-handed athletes in baseball, boxing, hockey, fencing and table tennis -- more than 50 percent among top baseball players and well above 10 percent (the general population rate) for the other sports.

On the other hand, the number of successful left-handed PGA golfers is very low, only 4 percent. The model also accurately predicted this.

“The accuracy of our model’s predictions when applied to sports data supports the idea that we are seeing the same effect in human society,” Abrams said.

Handedness, the preference for using one hand over the other, is partially genetic and partially environmental. Identical twins, who share exactly the same genes, don’t always share the same handedness.

“As computers and simulation become more widespread in science, it remains important to create understandable mathematical models of the phenomena that interest us, such as the left-handed minority,” Abrams said. “By discarding unnecessary elements, these simple models can give us insight into the most important aspects of a problem, sometimes even shedding light on things seemingly outside the domain of math.”

The James S. McDonnell Foundation supported this research.

And so uncooperative too!

 

 

[Golfingdad]

20 minutes ago, Lihu said:

Now you do. I used to write right handed but play baseball lefty. In Taiwan, we were forced to write with right hand. I was in the corner with the other struggling naturally left handed kids. The baseball coach didn't care which hand we used to play. He just wanted us to all do our best. In international school in Japan, they didn't care which hand you used.

Do you write right-handed or left-handed now?

[Lihu]

2 minutes ago, Golfingdad said:

Do you write right-handed or left-handed now?

Left.

Fortunately I broke my right wrist when I was 12 and started writing with my left hand again after 8 years using my right hand. It was natural, I was writing "normally" again within a week, just with my left hand.

[mdl]

I can't remember where I read this, but given I can't provide a link...

One of the things that interests researchers about this is that other animals, I remember dogs and other primates being mentioned, are basically 50/50 in terms of dominant side/hand.  The other piece of relevant information is that there the regions of the brain that are in charge of motor control overlap with those that control language (I believe based on fMRI studies).  There's some unknown causation here.  For instance, those could be learned overlaps based on literate modern people all having learned to write before undergoing these studies, so that link could be learned rather than innate.

But the interesting hypothesis from this was that humans developed to much more commonly be right hand dominant because we developed highly sophisticated, enlarged parts of our brains as we developed complex language – that's primarily on the left side of the brain – and those parts of the brain were potentially hijacked or expanded from parts of the brain that controlled the right side of the body, motor wise.  So we ended up with generally more sophisticated brain regions associated with right side motor control than left side motor control, on average.

[Golfingdad]

28 minutes ago, Lihu said:

Left.

I would say, then, that you weren't really a right handed writer.  However ...

28 minutes ago, Lihu said:

Fortunately I broke my right wrist when I was 12 and started writing with my left hand again after 8 years using my right hand. It was natural, I was writing "normally" again within a week, just with my left hand.

Fascinating.  Obvious question:  Do you think you'd be writing right or left handed today had you not broken your wrist?

[Lihu]

15 minutes ago, Golfingdad said:

I would say, then, that you weren't really a right handed writer.  However ...

Fascinating.  Obvious question:  Do you think you'd be writing right or left handed today had you not broken your wrist?

Probably right handed. My parents are both right handed as are my two siblings, but my mom's dad was also ambidextrous like me. A lefty forced to do things with the right hand.

My official signature is left handed, but I can sign things that meet most signature criteria with either hand. I used to play parlor tricks by writing backwards with my left hand and superimposing it with my right handed version and they look nearly identical.

[Jeremie Boop]

If I remember my history correctly, being left handed used to be frowned upon. When someone showed that they were developing as left hand dominant they had their left hand tied to their waist and forced to use their right hand until it became dominant. I don't remember the particulars, but I remember it was considered weird or abnormal. So much so that the French word for left, "gauche", was used as an insult or slight.

[Lihu]

2 hours ago, jamo said:

I wonder how the development of your dominant hand correlates to hand-eye coordination and overall athletic ability. If you developed left-handedness late, could that lead to worse hand-eye coordination?

Possibly, but I can only cite two examples. Me and my son. We both started right handed, and we both switched to lefty. It took him very little time to adjust. It took me 2-3 years to get to a swing that didn't feel like I was resisting my own motion.

 

1 hour ago, saevel25 said:

Maybe in the case if you have the predisposition to be left handed and they teach you to be right handed. I wonder if that can slow down the development of that particular sport when considering playing it left or right handed.

Like in baseball when some players hit more homeruns right handed than left handed but they can bat both ways and have a pretty decent average in both.

I think it depends upon the individual. If you have really good coordination, you can probably pick things up a lot faster.

[9wood]

I don't know why most people are right-handed but I do know that I wish I was left handed so I could take advantage of the low prices on left-handed clubs. Could save a whole lot of money if I was left-handed.

[gatsby47]

In Canada there are a lot more left handed golfers proportionally than in the USA,  A lot has to do with playing hockey.  You do not need to be left handed to put your left hand on the stick lower.  Most times it just happens and transcends itself over to golf.  Kicking a soccer ball is not quite the same but better skilled players do shoot with both feet but on a penalty kick they will use their favourite or dominant much the same as throwing.  If you get a chance, try swinging a left hand club.  or putting from the other side. you may end up cursing yourself for all the wasted rounds and years and become a cranky ex golfer yelling at little kids.

Edited March 29, 2016 by gatsby47