Why are there more right-handed than left-handed people?

Why are there many more people who are better right-handed than left-handed?

In this article we will analyze the struggle hypothesis that talks about left-handedness, struggle and survival, and we will draw on the most recent empirical evidence that explains why there are more right-handers than left-handers according to an interesting line of research.

Left-handed, right-handed and ambidextrous.

People with left-handedness are those who tend to use, preferentially, the left side of their body (i.e., their hands and feet).

Left-handedness is a minority phenotype in the human species.i.e. there are more right-handed people (who preferentially use their right limbs) than left-handed people.

In fact, between 8 and 13% of the world's population is left-handed; on the other hand, there are more left-handed men than left-handed women (13% vs. 9%), although it is not known why. Finally, it is worth mentioning that people who use both right and left limbs are called ambidextrous.

Why there are more right-handed than left-handed people, according to research

As we mentioned in the introduction, this article focuses on the fact that there are many more people whose dominant hand is the right hand. Why are there more right-handed than left-handed people? But before we go into this question, let's clarify why there are left-handers in the population, according to the struggle hypothesis.

According to this hypothesis, there are left-handers in the population because in the past, left-handed people had an advantage in violent intrasexual competitions.. This, according to this hypothesis, would explain why left-handedness persisted over time.

Struggle hypothesis

But what does the struggle hypothesis specifically say about left-handedness?

According to this hypothesis, there is a polymorphism (polymorphism implies the existence, in a population, of multiple alleles of a gene) in human hands, that is maintained over time by a process of natural selection; in the case of left-handed peopleIn the case of left-handed people, this process is a frequency-dependent selection.

What does this mean? That when a trait offers a certain Biological efficiency to a certain species (increasing its probability of survival), this trait remains, even if it is a minority trait (as left-handedness would be).

How does this extrapolate to the field of fighting and left-handedness? Right-handed fighters are used to fighting against other right-handed fighters.Therefore, when competing against a left-handed fighter, the latter will have a certain advantage in the fight (and therefore will probably have a better chance of winning), since the left-handed fighter is more accustomed to fighting a right-hander than the right-handed fighter is to fighting a left-hander.

Empirical evidence: study

We found different studies showing how left-handed men are overrepresented among modern professional fighters. A recent study (2019) by Richardson and Gilman, also set out to analyze the question of why there are more right-handed than left-handed and focused on the world of boxing and wrestling.

Sample

The study looked at a total of 13,800 boxers and wrestlers of different martial arts. and fighters of different martial arts, of mixed type.

That is, the sample included both men and women. However, it is worth mentioning that of the total number of boxers, 10,445 were men (8,666 right-handed and 1,779 left-handed), 1,314 were women (1,150 right-handed and 164 left-handed) and 2,100 were MMA (mixed martial arts) fighters (1,770 right-handed and 393 left-handed).

Through these data we see how left-handed men represent 12.6% of the general population, 17% of men within the boxing world, and 18.7% in the MMA sector; in the case of women, they represent 9.9% of the general population, and 12.5% of female boxers. We see how, in both cases, left-handedness is overrepresented in the fighting world..

Objectives of the study

The study aimed to verify two aspects; on the one hand, whether or not there is an overrepresentation of left-handed fighters with respect to right-handed fighters, and on the other hand, whether the latter accumulate more victories than right-handed fighters.

Results

The results of Richardson and Gilman's study revealed that, indeed, left-handed boxers and fighters had more victories (number of fights won) than right-handed boxers and fighters. This was reflected in both male and female fighters..

In addition, the fighting ability of male and female fighters was also evaluated, through an objective measure, and the results were along the same lines; left-handed fighters had better fighting ability than right-handed fighters.

Another hypothesis that was raised and analyzed in the aforementioned study is another one already suggested by previous studies, and it was the following: the fact that left-handed wrestlers show a greater variation in fighting ability.. This hypothesis could not be confirmed, since no such variation was observed in left-handed wrestlers.

Conclusions

As we have seen, analyzing the question of why there are more right-handers than left-handers, we come to the following conclusion: the fact that left-handers are in the minority (hence they are overrepresented), makes their actions and techniques more difficult for their opponents to predict..

This can be explained by the tendency of right-handed opponents to attend mostly to the right hand of their opponent (this is an attentional bias), and this tendency would appear because right-handers would be accustomed (when competing generally with right-handed opponents) to attend to that hand.

Verification of the hypothesis

Thus, what happens today in the field of wrestling and boxing, we can extrapolate to our ancestors; thus, it is likely that our left-handed ancestors, as suggested by the wrestling hypothesis, had a certain advantage. in violent combats (these being, moreover, more frequent in the past than at present), which gave them a certain evolutionary advantage.

In this way, we see how the hypothesis of the fight would be fulfilled, since the fact of being left-handed or left-handed implies an advantage in this type of sports.

Bibliographical references:

• Bejarano, M. A. & Naranjo, J. (2014) Laterality and sport performance. Arch Med Deporte, 31(3), 200-204.
• Hardyck, C., & Petrinovich, L. F. (1977). Left-handedness, Psychological Bulletin, 84, 385-404.
• Richardson, T. & Gilman, R. T. (2019). Left-handedness is associated with greater fighting success in humans. Sci Rep 9, 15402.