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

Apr 25, 2012

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 that shows the low percentage of lefties is a result of the balance between cooperation and competition in .

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 is related to population-level handedness.

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 will trend toward one side," said Abrams, an assistant professor of engineering sciences and applied mathematics at the McCormick School of Engineering and . "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 .

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."

Explore further: Why plants in the office make us more productive

More information: The paper is titled "A Model Balancing Cooperation and Competition Can Explain Our Right-Handed World and the Dominance of Left-Handed Athletes." The paper is available at: rsif.royalsocietypublishing.or… 04/24/rsif.2012.0211

add to favorites email to friend print save as pdf

Related Stories

Different bodies, different minds

Feb 14, 2012

We like to think of ourselves as rational creatures, absorbing information, weighing it carefully, and making thoughtful decisions. But, as it turns out, we're kidding ourselves. Over the past few decades, scientists have ...

Lefties more likely to look before they leap

Feb 08, 2012

(Medical Xpress) -- New research from the University of Abertay Dundee has found evidence that left-handed people may be better decision makers than their right-handed counterparts.

Recommended for you

Precarious work schedules common among younger workers

Aug 29, 2014

One wish many workers may have this Labor Day is for more control and predictability of their work schedules. A new report finds that unpredictability is widespread in many workers' schedules—one reason ...

Girls got game

Aug 29, 2014

Debi Taylor has worked in everything from construction development to IT, and is well and truly socialised into male-dominated workplaces. So when she found herself the only female in her game development ...

Computer games give a boost to English

Aug 28, 2014

If you want to make a mark in the world of computer games you had better have a good English vocabulary. It has now also been scientifically proven that someone who is good at computer games has a larger ...

Saddam Hussein—a sincere dictator?

Aug 28, 2014

Are political speeches manipulative and strategic? They could be – when politicians say one thing in public, and privately believe something else, political scientists say. Saddam Hussein's legacy of recording private discussions ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Smashin_Z_1885
1 / 5 (1) Apr 26, 2012
Left handed people are, in general, far more intelligent than the majority (right handers). Spacial awareness in Lefties FAR exceeds right handers, so much so in fact, that to a Lefty, many right handed people may be perceived as "mildly to profoundly retarded", according to a recent European study of the brains of both types of people. One example given involved Sports, and another involved Map Reading skills. In the case of sports, Lefties demonstrated an odd ability to "know" where a ball, or player, was located in 3 dimensional space and calculate predictions of future locations with incredible speed, and without conscious thought. When reading a map, it was demonstrated that Lefties are capable of reading the overall 'big picture' of a map nearly instantly, and apply the resulting visual memory of the map to the real world with incredible speed and accuracy. It is hypothesized that such is a result of superior communication between brain hemispheres.