Tongue rolling is the ability to curl the lateral edges of the tongue upwards into a tube-like shape. This oral maneuver has long fascinated people, sparking curiosity about its prevalence and origins. It involves specific manipulation of the tongue’s muscles. For many years, it was commonly perceived as a straightforward inherited trait.
How Many People Can Roll Their Tongue
The ability to roll one’s tongue is common across the global population. Studies indicate that its prevalence typically ranges between 60% and 81% of individuals. A study in the Netherlands, for instance, reported an even higher percentage, with 83.7% of participants demonstrating this ability.
While there is no statistically notable difference in prevalence between sexes, older studies sometimes indicated a slightly higher proportion among females. However, more recent research has found similar or even slightly higher percentages in males in some populations. The ability can also increase with age, particularly during childhood. For example, a study of Japanese schoolchildren found that the proportion of tongue rollers increased from 54% at ages 6-7 to 76% by age 12, suggesting that it can be acquired over time.
Is Tongue Rolling Genetic or Learned?
Historically, tongue rolling was widely believed to be a simple Mendelian genetic trait, controlled by a single dominant gene. This idea gained prominence from Alfred Sturtevant’s work in 1940 and was frequently taught in introductory biology courses.
However, this long-held genetic theory has since been largely disproven by scientific research. Philip Matlock’s 1952 study on identical twins provided compelling evidence against simple genetic inheritance. He observed that some identical twin pairs, who share the same genetic makeup, were discordant for tongue rolling; one twin could perform the action while the other could not. This finding indicated that factors beyond simple genetics were at play, leading Sturtevant himself to later acknowledge the misconception.
Current understanding suggests that tongue rolling is a complex trait influenced by multiple genetic factors, rather than a single gene. Environmental influences and practice also contribute to the ability. The increasing prevalence with age in children supports the idea that it can be learned or developed through muscle control and coordination. AncestryDNA’s research, which identified thousands of DNA markers linked to tongue rolling, further underscores its polygenic nature.
The Anatomy of Tongue Rolling
The ability to roll the tongue relies on the intricate network of muscles within the tongue. The tongue is composed of two main groups: intrinsic and extrinsic. Intrinsic muscles originate and insert entirely within the tongue, allowing for precise changes in its shape and size. These include the superior longitudinal, inferior longitudinal, transverse, and vertical muscles. The superior longitudinal muscle, for instance, is particularly involved in curling the tongue upwards.
Extrinsic muscles originate outside the tongue and insert into it, primarily responsible for broader movements like protrusion, retraction, and elevation. While intrinsic muscles are directly responsible for forming the tongue into specific shapes like a tube, both muscle groups work in concert for complex tongue movements. The overall shape and size of an individual’s tongue, along with the strength and coordination of these muscle groups, can influence their ability to perform tongue rolling.