While left-handed people have been considered more creative and eccentric, they’re also more likely to have a slender face.
Research led by Philippe Hujoel, from the Department of Epidemiology of the School of Public Health at the University of Washington, found that people with a slender lower face are 25 percent more likely to be left-handed.
The study took information from more than 13,536 individuals who were part of three different national surveys within the United States.
Hujoel said the association has been a long time coming, but slender jaws are also linked to a susceptibility to tuberculosis as well.
“Almost 2,000 years ago a Greek physician was first to identify slender jaws as a marker for TB susceptibility, and he turned out to be right,” Hujoel said in a press release. “Twentieth-century studies confirmed his clinical observations, as slender facial features became recognized as one aspect of a slender physique of a TB-susceptible person. The low body weight of this slender physique is still today recognized by the Centers for Disease Control and Prevention as a marker for TB susceptibility.”
Lower face variability was one of the six facial types and was related to handedness using models that were adjusted for sex, ancestry, geography and income. The association between a slender, longer face and tuberculosis susceptibility could be a genetic modification finding its roots in the genes that determine left-handedness, the study said.
Individuals with slender jaws have a lower jaw that bites backward, known today as an overbite, and gives them a convex facial profile. The link between left-handedness, facial shape and TB susceptibility could help to further understand geographical similarities, Hujoel said.
For example, the United Kingdom was dubbed the tuberculosis capital of the world. The area has a population filled with slender faces and left-handed people. Eskimos, on the other hand, have rounder faces and were considered tuberculosis-resistant during the 19th century.
The Eskimo were also thought to be more right-handed than left, as their art showed right-hand dominance with tools and instruments. These kinds of developments need to be further studied, Hujoel said. He also added that slender people were known as “ectomorphs” in the early 20th century.
“In a world dominated by an obesity crisis and right-handers, ectomorphs can be different in their desires,” he said. “Popular websites suggest they commonly express a desire to gain weight or muscle mass. Their slightly increased chance of being a ‘leftie’ is an additional feature that makes them different.”
The study was published in the journal Laterality: Asymmetries of Body, Brain and Cognition.