NcuraFsycholo@. \‘oi. 16. ,,p 743 to 746 c Perpamon Press Ltd 1978. Printed in Great Brutal

NOTE

INCIDENCE OF LEFT-HANDERS WITH INVERTED WRITING POSITION IN A POPULATION OF 5910 ELEMENTARY SCHOOL CHILDREN

MICHAEL PETERS* and KRIS PEDERSES

Department of Psychology. University of Guelph. Guelph, Ontario, Canada. N1 G 2W 1

(Received 5 June 1978)

Abstract-A survey of writing positions of left-handers in a sample of 5910 school children was conducted. There were significantly more male than female left-handers with an inverted writing position. There was a significant change in the incidence of left-handers with an in- verted writing position over the six elementary school grades sampled with a much higher incidence in grades five and six than in the lower grades. The incidence of left-handers with an inverted writing position over all grades was 40% for males and 29% for females. For grades 5 and 6 the incidence was 59 0/0 for males and 43 0/O for females.

INTRODUCTION

LEFT-HANDED writers are known to adopt a number of different writing positions of which two are very common and easily identified. The first resembles the position normally seen in right-handers. The second is described by CLARK [l] as “the hook, where the hand is actually above the line of writing” (p. 83). Tradi- tionally, this latter writing position has been considered to arise as an adaptation to technical aspects of writing in the left-hander, such as avoiding smudges while writing with a straight pen or avoiding the occlusion of written words by the hand. Recently, LEVY and REID [2] have suggested that the different writing positions reflect underlying differences in the cerebral organization of left-handers with the two different writing positions. Specifically, Levy and Reid suggest that an inverted writing position in the left-bander reflects specialization of the hemisphere ipsilateral to the writing hand for language processes. A non- inverted writing position presumably reflects such a specialization for the hemisphere contralateral to the writing hand. If this relationship holds, it should be possible to gain some understanding of the incidence of left-handers with either type of lateral specialization by measuring the incidence of left-handed writers with the two principal writing postures in the general population. Below, we report on the results of a survey of writing positions of left-handed school children.

METHOD

Questionnaires were distributed to elementary schools in three different school districts.+ There was one questionnaire for each class and teachers were asked to indicate the total number of children in the class and the number of boys and girls in each class and the number of boys and girls writing with the left hand. The questionnaire also contained drawings of left-handed writing positions similar to those given by LEVY and REID [2] and teachers were asked to categorize left-handed writing positions as either inverted, noninverted or unclear. The “unclear” category allowed teachers to classify children who could not be included under the other two categories. An attempt was also made to collect information about right-handers with an inverted writing position. Finally, the questionnaire also encouraged teachers to express their opinions as (0 what a desirable writing position for the left-hander should be.

RESULTS As the trends from the three separate school districts were very similar, the data from these districts were

*Supported by University of Guelph RAB Grant No. 80806.

iSchool district No. 24. British Columbia. Canada: Wellington County separate and public school boards. Ontario. Canada.

743

744 Nol~

Table 1. Incidence of left-handers with inverted, noninverted and unclear writing positions

Males Grade NT NL IN NIN U ~___.

I 518 62 17 33 12 2 469 63 19 38 6 3 588 58 19 27 12 4 479 60 19 26 15 5 510 57 34 :; 4 6 456 60 35 5:

3020 360 143 164

NT = Total number of subjects.

NL = Left-handers. IN = Inverted writing position. NIN = Noninverted writing position U = Unclear writing position.

Females Grade NT NL IN NIN U

1 521 40 6 26 8 2 411 41 11 26 4 3 622 50 12 34 4 4 439 58 14 38 6 5 468 50 24 25 1 6 429 50 19 25

2890 289 86 174 2:

collapsed. Table 1 provides a summary of the total number of children in the sample. The left-handers represent ca 11% of the population with a higher incidence of left-handed males (11.9 %) than females (10%). The difference reached significance (~2 = 5.57, @I, P < 0.02). The proportion of writers having the inverted and noninverted writing position was different for males and females (~2 = 13.85, @2. P < 0.001). The difference was clearly due to larger numbers of males with the inverted writing position and females with the noninverted writing position.

The incidence of writing positions changed drastically over grades bz for sexes combined = 36.3. df 10. P <O.OOl). For males the average incidence of the inverted writing position in grades 1-4 was 31% while in grades 5 and 6 it was 59 %. For females the corresuondina figures were 22 and 43 X

The questionnaire resilts did not allow any -statem&-as to the incidence’ of right-handers with the inverted writing position. With regard to teacher attitudes towards writing positions, little can be said. Very few teachers expressed any views and of these all but two felt that left-handers should write in whatever way felt most comfortable. The two teachers who differed felt that the noninverted writing position was the only correct position.

DISCUSSION

LEVY and NAGYLAKI [3] and LEVY and REID [2] have suggested that the writing position of about 90% of alI left-handers can be identified as being either inverted or noninverted. The remaining 10% cannot be classified. In addition, they suggest that the majority of all left-banders write with the inverted writing posi- tion. It appears that their estimates apply only to the male left-handers in grades 5 and 6 in our sample. The majority of male left-handers in grades l-4 and the majority of all female left-handers write with the non- inverted writing position.It is not possible to discuss the discrepancy between Levy and Reid’s estimates and our figures without reference to the change in the incidence of the inverted writing position over the six school grades sampled in this survey.

Three different but not necessarily independent hypotheses may be entertained in order to account for the drastic increase in the frequency of left-handers with the inverted writing position in grades 5 and 6. First, it may be assumed that the cerebral organization underlying the different writing positions becomes fully established only at ages 10-12. Second, and more plausible, it may be assumed that the inverted writing position is related to rapid cursive writing. While acquiring the skill of writing, children tend to use arm rather than hand and finger movements in order to draw or shape letters. As the writing skill progresses, the graphemes are shaped more and more through hand and finger movements while arm movements largely Serve to transport the writing hand laterally to allow smooth progression. Rapid and fluid writing requires the integration of hand and finger movements with arm movements. The supporting movements of the arm in the right-hander are abductive while they are adductive in the left-hander. VAN DER STAAK [4] has sug- gested that adductive arm movements tend to be guided through a contralateral system while abductive movements are guided by a system which can act either contra- or ipsilaterally. The right-hander presum- ably guides hand and finger and arm movements through the contralateral hemisphere. The left-hander with the noninverted writing position can, in principle, also guide all writing movements through the contra- lateral hemisphere. The left-hander with the inverted writing position (as well as the right-hander with the inverted writing position), however, presumably guides the fine movements of hand and fingers through the ipsilateral hemisphere (LEVY and NAGYLAKI 131). The supporting arm movements may either be guided through the ipsilateral or the contralateral hemisphere. It may be suggested that in someunspecified way the demands ‘of integrating ipsilateral control of fine movements with supporting arm movements encourage

NOTE 745

the inverted wrning position. A critical element is perhaps the role of the hand and fingers in lateral transport movements. In the right-hander, the continuous production of graphemes is interrupted only when Aexion of the fingers and lateral movement of the wrist reach their limit and repositioning of the entire arm is required.

In left-banders. however, lateral progression is accomplished by extension of the fingers with minimal involvement of the wrist. This limits the range of lateral movement and results in much more frequent lateral transport arm movements for the left-hander than the right-hander. The left-hander with an inverted writing position has an even more limited lateral range than the left-hander with a noninverted writing position and depends almost entirely on arm movements for lateral progression. Could it be that the inverted writing position serves tominimize thenumber of simultaneously active motor elements, an adaptation needed because of inherent limitations of ipsilateral control of movement? To summarize. it is argued here that the inverted writing position is an adaptation to the demands of integrating shaping and lateral transport movements during writing and that these demands become increasingly severe as the speed of writing in- creases. For this reason, one might expect an increase in the incidence of the inverted writing position at a time when school children begin to become proficient at rapid cursive writing.

The third hypothesis concerns social pressures. While very few of the teachers expressed their views as to what the appropriate writing position of left-handers should be, interviews with principals and perusal of curriculum manuals indicate a general trend towards discouragement of the inverted writing position. Clearly, older views “there is nothing normal about this position” (Clark [l, p. 831) are being revived. This trend is fairly recent and it may well be that the older children in grades 5 and 6 grew up under the more permissive philosophy which allowed a left-handed child to hold a pen in a way which feels comfortable rather than in the “correct” way. Thus, the low incidence of inverted left-handers in the lower grades may reflect both the emphasis of arm movements in the earlier stager of writing and a relatively recent return to emphasis of “proper” penmanship. An explanation of an unequal distribution over grades of the writing positions in terms of social pressures has the advantage of accounting at least partially for the observed sex differences. Social pressures tend to bear more strongly on females than males and it may be for this reason that the proportion of females with the inverted writing position was lower over all grades. However, in the absence of any positive proof that social pressures are indeed responsible for the observed sex differences one must allow for the possibility that these differences reflect underlying differences in brain organization between males and females. In terms of Levy and Reid’s model this would suggest a higher incidence of right hemisphere specialization for language processes in female left-handers than in male left-handers.

In view of the fact that the inverted writing position tends to be discouraged, a certain number of persons with the noninverted writing position are probably misclassified. The converse is not likely to be the case. Thus, if LEVY and REID’S [2] suggestion is valid, one would expect a proportionately larger number of non- inverted left-handers with left hemisphere specialization for language than inverted left-handers with right hemisphere specialization.

The results of this survey suggest that at least for children of the ages sampled the incidence of the inverted and noninverted writing position is not a simple indicator of types of cerebral organization as was suggested by Levy and Reid to be the case for adults.

I. 2.

3. 4.

REFERENCES

CLARK, M. M. Left-Handedness. University of London Press, London, 1957. LEW, J. and REID, M. Variations in writing posture and cerebral organization. Scierzce 194, 337-339. 1976. LEVY, J. and NAGYLAKI, T. A mode1 for the genetics of handedness. Generics 72,117-128,1972. VAN DER STAAK, C. Intra- and interhemispheric visual-motor control of human arm movements. Neuro- psvchologiu 13, 439-448, 1975.

746 NOTE

RCSUrnL --

On a Etudii :a position de la main dam I’lcrieure dcs s”.~ets rv~-i;crs

dam “ne population de 5910 enfants d’Pge scolaire. On constatait significntivfnent

plus de gar$ons que de filies gnuchera prdsentant “ne position inversie dans l’kri-

t”re. La friquence des gauchers avec “ne position d’dcriture invers6e se mdifiait

significativement s”r les 6 degris scolaires ilimentaiees avec “ne plus grande

frfequence dens ies degres 5 et 6 que dam les degre% les plus bas. La frEq”ence des

gauchers avec “ne position inverse% de l’kriture Etait s”r l’ensemble de 40% pour

les gargcms et de 29% pour les filles. Pour les degrBs 5 et 6, les pourcentages

Ptnient de 59 pour les gargms et de 43 pour les filles.

Deutschsrrachiqe Zusammenfassung:

Zin Uberblick ;_iber Schreibpositionen von Linkshsndern in einer

Stichprobe von 5910 Schulkindern xurde durchkefii?nrt. 2s fanden

sich signifikant mehr m#nnliche als weibliche Linkshander nit.

einer umgekehrten Schreibposition. Auch fand ain signifikanter

Wandel im Vorkommen von Linkshdndern mit einer umgekehrten

Schreibposition fiber 6 Grundschuljahre hinweg statt mit .einem

gehauften Vorkommen im 5. und 6. Schuljahr im Vergleich au den

ersten Klassen. Das Auftreten von Linkshandern mit einer umge-

kehrten Schreibposition tiber alle Schulkiassen betrug 40 % fiir

Junqen und 29 5: fiir.X#dchen. In den Xlassen 5 und 6 betrug die

i?;ufigkeit 59 r6 fiir Jungen und 43 ';: fiir i,i$$dchen.