Featured Research

from universities, journals, and other organizations

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

Date:
April 25, 2012
Source:
Northwestern University
Summary:
Lefties (only ten percent of the general population) have always been a bit of a puzzle. Researchers have now developed a mathematical model that shows the low percentage of lefties is a result of the balance between cooperation and competition in human evolution. They are the first to use real-world data (from competitive sports, including baseball, boxing and hockey) to test and confirm the hypothesis that social behavior is related to population-level handedness.

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.
Credit: Michael Ireland / Fotolia

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.

The results are published 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 paper is titled "A Model Balancing Cooperation and Competition Can Explain Our Right-Handed World and the Dominance of Left-Handed Athletes."

The James S. McDonnell Foundation supported this research.


Story Source:

The above story is based on materials provided by Northwestern University. The original article was written by Megan Fellman. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. M. Abrams, M. J. Panaggio. A model balancing cooperation and competition can explain our right-handed world and the dominance of left-handed athletes. Journal of The Royal Society Interface, 2012; DOI: 10.1098/rsif.2012.0211

Cite This Page:

Northwestern University. "Shedding light on southpaws: Sports data help confirm theory explaining left-handed minority in general population." ScienceDaily. ScienceDaily, 25 April 2012. <www.sciencedaily.com/releases/2012/04/120425140457.htm>.
Northwestern University. (2012, April 25). Shedding light on southpaws: Sports data help confirm theory explaining left-handed minority in general population. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2012/04/120425140457.htm
Northwestern University. "Shedding light on southpaws: Sports data help confirm theory explaining left-handed minority in general population." ScienceDaily. www.sciencedaily.com/releases/2012/04/120425140457.htm (accessed July 24, 2014).

Share This




More Science & Society News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Condemned Man's US Execution Takes Nearly Two Hours

Condemned Man's US Execution Takes Nearly Two Hours

AFP (July 24, 2014) America's death penalty debate raged Thursday after it took nearly two hours for Arizona to execute a prisoner who lost a Supreme Court battle challenging the experimental lethal drug cocktail. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
China's Ageing Millions Look Forward to Bleak Future

China's Ageing Millions Look Forward to Bleak Future

AFP (July 24, 2014) China's elderly population is expanding so quickly that children struggle to look after them, pushing them to do something unexpected in Chinese society- move their parents into a nursing home. Duration: 02:07 Video provided by AFP
Powered by NewsLook.com
Hundreds in Virginia Turn out for a Free Clinic to Manage Health

Hundreds in Virginia Turn out for a Free Clinic to Manage Health

AFP (July 24, 2014) America may be the world’s richest country, but in terms of healthcare, the World Health Organisation ranks it 37th - prompting hundreds in Virginia to turn out for a free clinic run by “Remote Area Medical”. Duration 02:40 Video provided by AFP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins