Anthropologists have found a link between human body asymmetry and right-handedness in close combat.
The reason why humanity isn't evenly divided into left-handed and right-handed people has preoccupied evolutionary biologists for decades. For the past 30 years, the "fighting hypothesis" has been dominant, but it only explains the continued existence of left-handed people, leaving the question of the overwhelming dominance of right-handed people open.
New research by an international team led by Paul Rodway from the University of Chester in Britain presents a modified theory linking the dominant hand to the anatomical location of the heart. The results of the study were published in the journal Laterality.
According to the classical hypothesis, left-handed people (approximately 10.6% of the population) persist thanks to an evolutionary advantage in close combat. The left-handed fighter benefits from the element of surprise against a right-handed opponent, as the latter is unprepared for an attack from their "uncomfortable" side. Modern martial arts data supports this theory, but it doesn't answer a key question: "If right-handed people didn't possess this advantage, why do they make up roughly 90% of the human population?"
According to Psychology Today, the revised hypothesis of the Rodway team suggests that the focus should shift from hand-to-hand combat to battles using bladed weapons, such as knives, daggers, and serrated stones, which have been common for tens of thousands of years in human history.
The scientists' main argument rests on the asymmetry of the human body. Since the heart is located on the left side of the chest, a right-handed person facing an opponent directly has a mechanical advantage: when striking with the right hand, the weapon's trajectory tends toward the left side of the opponent's chest, where the impact is more lethal. For a left-handed person, repeating the strike in reverse often hits the right side of the opponent's chest, where the damage is less severe.
The researchers offer several pieces of evidence to support their hypothesis:
Fatality of injuries: Forensic medical examination statistics show that stab wounds to the left side of the chest lead to death more quickly and frequently.
Evolutionary selection: In ongoing group conflicts during the Stone Age, right-handed users had a greater chance of eliminating an opponent with a single, precise strike, which boosted their survival rate and the transmission of their genes.
Defensive stance: It is easier for a right-handed person to protect their left side (heart) using a shield or free hand, leaving the right hand for attack.
The new hypothesis doesn't negate the old one, but rather complements it, paving the way for a model of dynamic equilibrium: right-handed users dominate thanks to their "lethal advantage" in knife fighting, while left-handed users remain a strategic minority dependent on the element of surprise. If the number of left-handed people increases significantly, this advantage will disappear, as fighters will learn to defend against left-handed attacks.
