Transmission and Gymnastic Ability

HOWARD H.

Learning of

HIRSCHHORN

BRIEF COMMUNICATION

Tongue

Hofimann-LaRoche Inc., and New York University

ABSTRACT Observations were made for two weeks on the ability to roll, twist, and fold the tongue in the four members of an American family of northern European background. Photographs and questions were mailed to relatives, thus providing data for a total of 13 persons in three generations. It was found that ample time and example must be provided for learning tongue tricks, even if they be genetically determined. Also, there was evidence for the independent transmission of folding and rolling, and of transitory intermediate positions of the tongue before full expression of the abilities appeared.

Is the ability to do any one of various tongue “tricks” linked to the ability to do any other one?

Liu and Hsu (’49) concluded from a study of a Chinese population that “in those persons who can fold up the tongue tip, the structure of the tongue muscle can also meet the requirements of the rolling process.” Gahres (’52) reported that his study of Caucasians in the eastern U. S., mostly of mixed European ancestry, con- firmed the hypothesis of Liu and Hsu that there is an “epistatic interaction between the rolling and folding genes,” and that there is an absence of a roll-but-not-fold class. Lee, (’55) however, reported evi- dence for fold-but-not-roll and roll-but-not- fold categories; he presented evidence sug- gesting independence between rolling and folding .

Some insight into the ability to do three tongue “tricks” - by learning, by heredity, or both - might be gained from this two- week observation on the ability to roll up the lateral edges of the tongue into a tube, twist it, and fold it, in an American family (father, mother, 2 daughters) of northern European background. Data for other than immediate family members was also ob- tained.

MATERIALS AND METHODS

Figures 1, 2 , and 3 illustrate what is meant here by roll, twist, and fold.

The study was made in the subjects’ home, where discussion of the trait (s) and demonstrations were done in short sessions over a period of two weeks. Data for the

AM. J. PHYS. AXTHROP., 32: 451-454.

parents of the mother and father, and the siblings of the mother were obtained by mail; figures 1, 2, and 3 were sent to family members, who, by return mail, in- dicated which of the movements depicted they were able to do. Data for 13 persons in three generations were thus obtained in this study.

OBSERVATIONS

The mother can roll in the edges of her tongue without the aid of the teeth or the lips. She can also twist (right and left) the apex 90” from the plane of the blade. Just after the start of this observation, she could also fold up the apex momentarily with the aid of the teeth. She appeared to have learned this movement after ten min- utes practice (preceded by a week of dis- cussion of the trait), while watching her husband demonstrate folding his tongue. She averred she had been unable to fold her tongue prior to this practice. TWO weeks later she was able to fold like her husband.

The father can fold the apex back upon the blade (fig. 3 ) with the help of the teeth. He cannot roll or twist his tongue.

The eight-year-old daughter can roll (fig. 1) and twist (fig. 2 ) her tongue, but the twisting is only to the right and with the aid of the teeth. At first, although she could not fold her tongue back as her father does, she was barely able to bend up the margin of the tip. Like her mother, she seemed to learn to do this by imitation

1 Address communications to: 5 Virginia Lane, Mil- ton, New Jersey 07438.

451

452 HOWARD H. HIRSCHHORN

Fig. 1 Roll.

Fig. 2 Twist.

LEARNING AND INHERITED TONGUE ABILITIES 453

Fig. 3 Fold.

during the course of this observation. After two weeks of intermittent practice, the eight-year-old daughter was able to fold back her tongue like her father and mother.

The six-year-old daughter can roll her tongue like her mother and sister; unlike them, she cannot twist or fold. She can- not imitate her father’s folding at all, not even to the bare extent of her sister’s first efforts.

The following pedigree (fig. 4, 13 peo- ple) shows the distribution of tongue gym- nastics in the parents and siblings of the mother and father observed in this study.

Fold ing . The eight-year-old’s maternal grandfather folded, as did two of his three daughters; none of his three sons folded. Also, the eight-year-old’s paternal grand- mother folded, as did her only son (the 8- year-old’s father); he cannot do any other tongue tricks. It will be interesting to see if he eventually learns any other, unless, perhaps, there might be an educability limit to acquiring this kind of ability; he

CONCLUSIONS AND COMMENTS

is 38 years old. (His wife learned to fold during this study, a t the age of 29 years.) Also, it will be interesting to see if the six- year-old daughter eventually learns to twist or fold.

The transitory intermediate positions (between full fold and lack of any fold- ing ability) exhibited by the mother and the eight-year-old daughter are noteworthy. Comparison of pedigrees for any individ- uals who exhibit only an intermediate posi- tion, never achieving the full trait, might be rewarding.

Rol l ing . The paternal grandfather, and the father, are the only non-rollers. Two of the mother’s brothers rolled only, as did one of her two children.

T w i s t i n g . Both grandmothers twisted, as well as the mother and her two sisters; one of the mother’s brothers was the only male in this genealogy of 13 people who twisted.

The one male twister, as well as the small number of persons investigated here, impede any statement or suggestion con- cerning sex-linkage or sex-influenced in-

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FOLD

HOWARD H. HIRSCHHORN

ROLL ROLL ROLL ROLL ROLL ROLL TWIST TWIST TWIST TWIST FOLD FOLD

ROLL TWIST FOLD I TWIST FOLD

ROLL ROLL TWIST FOLD

Fig. 4 Pedigree for tongue gymnastics. The arrow points to the father, the only one of the folders who was unable to do any other tongue tricks.

heritance. This study does indicate what seems to be independent transmission of folding and of rolling.

This study also illustrates a possible source of error in rapidly conducted sur- veys of tongue abilities: subjects may not have sufficient practice, or example to imi- tate, to perform what might be genetically possible. (Also, and quite simply, some strictly polite or sensitive people may abhor sticking out and manipulating the tongue.) Studies which report that a monogenic in- heritance with dominance of ability over inability is insufficient to explain the find- ing that parents who cannot do the tricks have progeny who can (Sturtevant, ’40; Vogel, ’57), may not have given the sup- posedly negative parents ample time or ex- ample for “developing” their potential. Knowledge of whether the parents’ parents and other relatives were able to do the tricks affords some control over this source of error, Liu and Hsu (’49) write that in

tests those few persons who need practice to acquire ability are erroneously included in the inability group, and that these errors “obscure the data, but the effect seems very slight and may be neglected.” (This state- ment was associated with the examination of 1,043 students.) These errors can well obliterate the whole sense of smaller studies, however; and studies may occa- sionally have to be small (or smaller than 1,043), especially if adequate genealogical controls (vide supra) are to be established.

LITERATURE CITED Gahres, E. E 1952 Tongue rolling and tongue

folding. J. Hered., 43: 221-225. Lee, J. W. 1955 Tongue-folding and tongue-

rolling. J. Hered., 56: 289-291. Liu, T. T., and T. C. Hsu 1949 Tongue-folding

and tongue-rolling. J. Hered., 40.: 19-21. Sturtevant, A. H. 1940 A new inherited charac-

ter in man. Proc. Nat. Acad. Sci. U. S., 26: 100-102.

Vogel, F. 1957 Wber die Fahigkeit, die Zunge urn die Langsachse zu rollen. Acta Genet., 6: 225-230.