This article was contributed by guest blogger Rosemary Sears. It's always interesting to read about a new, research-based point of view.
Understanding Handedness Using Sport
Being left handed has always caused scientists a bit of a quandary. Left handed people form only 10% of the general human population. Historically, people who are left handed have always been regarded suspiciously and often have been the subject of persecution and torment. In ancient times it was even seen as being a sign of the devil and the word "sinister" is derived from "left or left handed".
However, recent researched conducted at a US university reports that left handedness today has more to do with social factors than something peculiar or different. The researchers at Northwestern University-McCormick School of Engineering and Applied Science believe that society's high degree of cooperation is what leads to left handedness being so uncommon. They have developed a mathematical model that demonstrates that the low volume of left handed people has links to the balance of cooperation versus competition.
Using sports data
The full study published last month in The Journal of the Royal Society Interface used data from competitive sports to try out their theory. In essence it states that it is social behavior that dictates how many left handed and right handed people there are in the population.
The two scientists Professor Daniel M. Abrams and his graduate student Mark J. Panaggio are somewhat ironically both right handed, however their research demonstrates that desire to be social animals means that more cooperate with the majority and are right handed.
Of the research Abrahms says: "The more social the animal -- where cooperation is highly valued -- the more the general population will trend toward one side. The most important factor for an efficient society is a high degree of cooperation. In humans, this has resulted in a right-handed majority."
The research finds that if cooperation and competition were in equal proportion then so would the handedness of society and that if it was only cooperation that motivated humans then they would all be same handed, in today's case right handed. This is due to the sports data used showing that where competition is more important then left handedness increases. The data demonstrated that left handedness is more prevalent in sports based on the degrees of competition involved.
Right handed world
Abrahms continues: "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."
The research supported by the James S. McDonnell Foundation used a model which accurately predicted the number of left handed sportspeople in a variety of sports including basketball, boxing, fencing and table tennis. In basketball the model correctly predicted that there are more than 50% of left handed professional players where there is high competition. It also told of the low percentage of PGA golfers at just 4% where competition is less and there is more cooperation towards right handed play due to availability of equipment.
"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.
Nothing to declare
So it is unlikely that this research means that society is going to have to start declaring left or right handedness for car or bicycle insurance, or on passports and other documentation, but insight into what causes a preference for using one hand gives knowledge about how the human brain works.
Genetics has already been dismissed as a reason for handedness as there has been no proven pattern from generation to generation. Even identical twins aren't necessarily automatically predisposed to have the same handedness.
Abrahms concludes: "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."
For the last 5000 years left handedness has remained at a 10% minority. Research surrounding left handedness is few and far between as studies often exclude left handed participation because results will skew research.
© 2012 Rosemary Sears