Reason most humans are right-handed explained in violent theory

Ever wondered why around 85 to 90 percent of us are right-handed?

Researchers have been unable to explain why there is such a large difference between the number of righties and lefties for decades - but a study published last month has put forward a new theory.

Experts were confused as they hadn't found any health disadvantages which would explain why there are significantly fewer lefties than righties knocking about.

Scientists from Lund University in Sweden and Chester University in the UK have now proposed a new theory which might explain why it's an evolutionary disadvantage to be left-handed.

Matz Larsson, Astrid Schepman, and Paul Rodway contend in an article in the journal Symmetry that though lefties are better fighters, they're also more likely to be mortally wounded in combat.

They reckon the left-handed population is so small in comparison to those with a dominant right hand because of the position of the heart and the way early humans fought with sharp, pointed tools.

Essentially, the heart is three-quarters into the left hemithorax, which means that the left side of the chest vulnerable to a fatal blow if exposed.

The researchers noted that whichever hand holds the weapon changes the way the chest is exposed when fighting.

For instance, a left-handed grip rotates the left side of the chest, which turns almost all of the heart toward an opponent, but a right-handed grip will rotate it away.

Not only does a right-handed grip rotate the heart away, but then there is the left hand free to act in defence of the vulnerable space when in combat.

The researchers noted: "Consequently, right-handed early ancestors, with a preference for using the right forelimb in combat, may have had a lower risk of a mortal wound, and a fighting advantage.

"This would explain their greater frequency."

Even though this is all still a hypothesis and based on speculation from behavioural and physiological facts, it still gives food for thought when understanding the large disparity between the number of lefties and righties around the world.