Left-handed minority in general population explained

   Apr 26, 11:35 am

Washington, Apr 26 (ANI): Left-handers, who represent just 10 percent of the general human population, 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 behaviour is related to population-level handedness.

"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 favours same-handedness - for sharing the same tools, for example. Physical competition, on the other hand, favours 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," Abrams added.

The results have been published in The Journal of the Royal Society Interface. (ANI)

Why 'blind' bats never collide while flying at night Sep 2, 1:54 pm
Washington, Sept 2 (ANI): A new study has showed that bats emit "echolocation sounds" and they are equipped with a spatial map that represents different echo delays that helps them to adapt to external factors.
Full Story
Indian students successfully build first low cost 3-D printer Sep 2, 1:20 pm
New Delhi, September 2 (ANI): A group of engineering students have successfully built and tested their first low cost 3-D printer.
Full Story
United Nations' 'reports from future' predicts climate hell by 2050 Sep 2, 11:55 am
London, Sep 02 (ANI): United Nation recent initiative called 'weather reports from the future' predicted the disastrous climate change by 2050 with imagined weather forecasts.
Full Story
Neanderthals may have shared humans' artistic abilities Sep 2, 10:57 am
Washington, Sept 2 (ANI): Scientists have studied rock engraving in Gorham's Cave in Gibraltar that may have been created by Neanderthals, suggesting that they may have shared humans' artistic abilities.
Full Story
Comments

LATEST STORIES
TOP VIDEO STORIES
PHOTO GALLERY