The "fighting hypothesis" suggests left-handed people are more successful in some competitive sports.

A new study has found that left-handed people show higher levels of hypercompetitive orientation.

Competitiveness may help explain the evolution of left-handedness.

Most people are right-handed, but 10.6 percent are left-handed. There is a long-standing debate on why this specific 90-to-10 pattern between right-handedness and left-handedness has been pretty much stable across centuries and countries. One perspective from evolutionary psychology is that both right-handedness and left-handedness have evolutionary advantages.

The 'fighting hypothesis' and the evolution of handedness

Right-handers may have an advantage in some cooperative behaviors, such as learning to craft something based on somebody else modeling how to do it. As most teachers are likely right-handers, right-handed learners may have an easier time picking up a new task. Left-handers, in comparison, are thought to have an advantage in competitive situations, such as fighting, because they are much rarer than right-handers, making their attacks in a combat situation more surprising than those of right-handers.

Indeed, studies have shown that left-handers have an advantage in some sports like fencing and badminton (see my post on this research). However, for left-handers to actually benefit from their surprise advantage in sports or fighting situations, they should be highly competitive and actively search for conflict situations or sports competitions. However, until now, there had been no study on competitiveness and handedness.

A new study on handedness and competitiveness

New research published in Scientific Reports focuses on investigating the link between left-handedness and competitiveness (Prete et al, 2026). In the study, the research team led by scientist Giulia Prete from the Department of Psychology at the University of Chieti-Pescara in Italy conducted two experiments.

In the first experiment, the scientists collected data from more than 1100 volunteers. Each volunteer filled out the Edinburgh Handedness Inventory, a well-known test to assess hand preference. Based on these data, the scientists identified 50 strongly left-handed volunteers and 483 strongly right-handed volunteers. The volunteers filled out several questionnaires on personality, competitiveness, depression, and anxiety. The statistical analysis showed that stronger right-handedness was linked to stronger anxiety-driven competition avoidance. It also showed that stronger left-handedness was linked to stronger self-developmental competitive orientation. Moreover, left-handers showed higher levels of hypercompetitive orientation. Thus, taken together, the results of the first experiment show that right-handers tend to avoid competition to a larger extent than left-handers, while left-handers showed higher competitiveness than right-handers. In the second experiment, a subset of volunteers from the first experiment were re-invited to perform the pegboard task, a common measure of hand skill. However, no association with competitiveness emerged.

Taken together, the study provided an important puzzle piece for understanding the evolution of left-handedness: Left-handers indeed are more competitive than right-handers.

Prete, G., Marascia, E., Di Crosta, A., Malatesta, G., & Tommasi, L. (2026). Assessing the link among laterality, sex and competitiveness to verify the evolutionarily stable strategy of handedness. Scientific reports, 10.1038/s41598-026-38170-x. Advance online publication. https://doi.org/10.1038/s41598-026-38170-x

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