Why are there (almost) no left-handers in China?

Howard I. Kushner*

Emory University, Department of Behavioral Sciences & Health Education, Rollins School of Public Health and Program in

Neuroscience & Behavioral Biology, 1518 Clifton Road, NE, 5th floor, Atlanta, GA 30322, United States

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Surveys of Chinese students since the 1980s reportthat less than 1% are left-handed. This is an extraordi-narily low number given the generally accepted viewthat between 10 and 12% of humans are left-handed.Are there actually very few left-handers in China and,if so, why? A number of sometimes overlappingreasons have shaped Chinese attitudes toward left-handedness. Some of these reflect the transcendenthuman reactions to biological laterality. Others havebeen shaped by Chinese historical and cultural experi-ence. What is true in China can be identified in othersocieties: attitudes and practices toward left-handershave been and continue to be shaped by over-determined forces, which at the same time transcendspecific cultures, while they respond to historical andcultural pressures. Like the Chinese, many North andEast African peoples attempt to ‘cure’ left-handednessby a combination of restraints and severe punish-ments. Religion has often reinforced these practices.In China, we can see how a combination of traditionalvalues and practical considerations seems to havemerged to reduce both the actual and reported preva-lence of left-handedness. When we add in the popula-tion of India, and much of the remaining Islamic world,we can conclude that for two-thirds of the world’spopulation, being born left-handed exposes one todiscrimination and stigma.

It is said amongst the old Zulus that no person ofimportance ever counted with his left hand. [1] (p. 296)

The superior man ordinarily considers the left handthe most honorable place. [2] (31:1)

A 1980s survey of more than 20,000 mainland Chinesestudents and professionals reported that only 0.23% wereleft-handed, an astoundingly low number [3]. Thirty yearslater, the numbers hadn’t changed much. In 2008 aChinese university professor wrote that he had ‘beenteaching in universities in China for the past 12 years.Literally thousands of students. Only one has been left-handed. This compares with 10 percent of students when Iwas teaching in London. I’m sure that the genetic ratio isprobably the same but children are forced to use their righthands – as they were in the UK (and the US, I guess) notthat long ago’ [4]. Across the straits in Taiwan the numberswere similar. For instance, in their 1977 study of 4143

Corresponding author: Kushner, H.I. (hkushne@emory.edu).*Tel.: +1 404 727 9523.Available online 30 January 2013

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Taiwanese elementary and college students, a California/Taiwanese team found that ‘18 percent reported havingexperienced frequent requests to change hand use from leftto the right.’ As a result ‘a scanty 0.7 percent of the subjectsstill used the left hand for writing and 1.5 percent still usedthe left hand for eating’ [5] (p. 193). A more focused studyeight years later of adults and school children in Taiwan’scapital of Taipei reported that the ‘prevalence rate of left-handers was about 3.5% for both schoolchildren and adults’[6] (p. 143). In contrast, a study of Chinese-American schoolchildren in Berkeley, California, found that 6.5% of 538Asian-American school children used their left hands forwriting [5] (p. 1149). While lower than the non-AsianBerkeley students whose left-handed prevalence was9.9% (n = 7146), the Chinese-American rate was hugecompared to that of mainland China and Taiwan. Inter-estingly, a similar study, more than a half a centuryearlier, found no significant difference in the prevalenceof left-handedness between 317, 12-year-old Chinese-American elementary mission school children and 1000University of California, Berkeley, freshmen and sopho-mores. While 7.6% of the Berkeley students threw withtheir left hands, so did 6.9% of the Chinese-Americanchildren [7] (pp. 40–41).

Despite the scientific evidence that Homo sapienshave been 90% right-handed since the Upper Paleolithicperiod (late Stone Age 40,000–10,000 BP) (Groenen,1997) [8,9] (p. 146) [10], there are great disparities inthe reported prevalence of left-handedness in differentpopulations and cultures ranging from .06 to 19.8% [11](p. 282). In general the highest rates (15–20%) arereported in the U.S., Canada, Britain, and WesternEurope, with the lowest (.06–2.8%) in the Congo, China(including Hong Kong), and Taiwan. The general findingis that the prevalence of left-handers is significantlylower in Asia and Africa than in the West and (non-aboriginal) Australia [12] (p. 296).

In India the reported rates of left-handedness arehigher than those in China, but significantly lower thanthose found among European, Canadian, and Americanchildren of the same age. In their two large surveys ofhandedness in India, Singh and Bryden found a signifi-cantly ‘lower prevalence of left-handedness in the Indianpopulation’ when compared to a similar North Americansample [13]. A 2001 follow-up study of ten unimanualactivities by 718 New Delhi (India) private school stu-dents, ages 4–11, found a left-hand prevalence of 3.2% [14](pp. 233–235). A second study of 400 6- to 18-year-oldIndian students at another private school, north of NewDelhi, examined handedness, footedness, eye domination,use of hand in space, and absolute and relative hand skill.

d. http://dx.doi.org/10.1016/j.endeavour.2012.12.003

1 Chichewa is a Bantu language, and along with English, it is the national languageof Malawi.

2 The Chinese use directions rather than using left and right. Where in English wemay say, ‘turn right at the crossroad,’ the Chinese will say ‘go westward, etc.’ I thankmy friend and China expert Lydie Mepham for this information.

3 One might conclude that the taboos and prejudices against left handers arosesimply because humans used their non-dominant hand for removal of human feces.That is, to avoid disease and unpleasant odors, early humans favored their right handfor eating. Although this interpretation is plausible, it is not fully persuasive becausethe practice of discriminating against the left-handers is more ancient than theconnection between odor and disease. Especially when it comes to handedness, theoverwhelming evidence is that human ritual is more powerful in shaping attitudestoward handedness than the desire to reduce the risk of disease in traditional cultures[16,17] (pp. 10–13). Moreover, we should not assume that our current abhorrence toodors has been uniformly so throughout human history. In fact, for most of ourexistence, humans have lived with odors we could not continence today. Finally,miasma theories – connecting dirt and odor with disease– came rather late in humanhistory and often were, as was the case of cholera in Britain, misleading.

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This study reported a 4.25% left-handed prevalence [14](pp. 235–237).

A number of investigations have found that left–hand-edness declines as a population ages, a trend seen even insecondary school children. For instance, a French/IvoryCoast team developed ‘a 20-item manual preference ques-tionnaire’ in order to determine the handedness of 382secondary school students (ages 12–22) in Abidjan, thelargest city of the Ivory Coast. They found a higher preva-lence of left-handers at the younger end of the age spec-trum (14% of 12–15 year-olds) that declined dramaticallyto 1% among 18–22 year-olds [15] (pp. 151, 155–157). Asecond study by the same research group, but using adifferent 25-item questionnaire, of 759 Khartoum (Sudan)18–33 year-old undergraduates reported a 5% ‘left manualpreference’ [15] (pp. 151, 157–163).

Why are there so few left-handers in China – or for thatmatter in India and much of Africa? The answer seems tosupport French anthropologist Robert Hertz’s conclusionthat the pre-eminence of the right hand and subordinationof the left has been determined by culture rather thanbiology [16]. Specifically, there are a number of overlappingfactors that have shaped the reported less than expectedprevalence of left-handers. Some of these reflect the tran-scendent human reactions to biological laterality as out-lined by Hertz in 1909 [17]. Others have been shaped bylocal, regional, ethnic, and national environmental andcultural forces. Still others result from the variety ofdefinitions and categorizations of handedness that havebeen used by different investigators over the last twocenturies, making it difficult to compare the findings ofdifferent investigations or interpretation of the data col-lected in different studies. Although these influences andpressures often overlap, it is nevertheless useful to exam-ine them separately. I begin with the transcendent atti-tudes, then move to the role of specific cultural pressures,and finally examine the role of definitions and classifica-tion of left-handedness.

Transcendent attitudesThroughout human history there has been a sustained andtranscultural abhorrence of left-handedness. Despite thefamous claim of Italian criminologist Cesare Lombrosothat traditional peoples were naturally left-handed[18,19], Hertz’s opposite conclusions have been borneout by archeological and anthropological studies. De-scribed by Hertz, the stigmatizing of left-handednesscan be found imbedded in cultural assumptions and prac-tices, such as the tendency among humans to view theworld often in a binary framework in which the right hasbeen associated with positive attributes and the left withnegative ones. This opposition is so much a part of ourlanguage and social practices that even when the specificlocal and cultural and environmental factors that restrictleft-handers are neutralized, as they increasingly seem tobe, deeper antipathies continue to influence reactions toleft-handedness [17].

Negative attitudes toward left-handedness are fixedin the meanings given to the words ‘left’ and ‘left-hand’ inalmost all the world’s languages. As many observershave pointed out, the words for ‘left’ generally have

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had a negative connotation associated with being defec-tive in most languages such as ‘gauche’ in French or‘sinistra’ in Latin and Italian. The word ‘left’ in Englishcomes from the word ‘lyft’ for broken, while in German,‘linkisch’ is associated with awkwardness [20] (pp. 60–65). Labeling some as left-handed (levja) in Russian is asynonym for being seen as deceptive or untrusworthy[21] (pp. 1–3); also see [22]. In Chichewa, the traditionallanguage for the majority of Malawians,1 the word for‘left’ implies inferior, female, and weaker, while the righthand is often called the male hand [23,24]. In Mandarin(Chinese) the character for left, zou, is variously trans-lated as weird, unorthodox, wrong, incorrect, different,contrary, or opposite. Taking the left path means usingunorthodox or immoral means. In contrast, the Manda-rin character for right indicates that one should eat withthe right hand.2

These meanings attached to the left hand reflect andreinforce the history of human practices aimed atrestricting the use of the left hand to the most distained,but necessary, human tasks such as cleaning oneselfafter elimination of waste. For the Zulu of South Africaleft-handedness was a tabooed behavior that requiredearly and powerful interventions. A Zulu child, wroteBritish anthropologist Dudley Kidd in 1906, ‘is taughtnever to give anything with the left hand. When a childoffers something to another with the left hand the oldpeople hit the hand without speaking to the child; andthey go on hitting the hand till the child sees its mis-take.’ When the child drops ‘the article through pain, theold people pick the thing up and give it to the child intoits right hand, as a sort of prompting suggestion.’ Eatingwith the left hand was also taboo. ‘If a child should eatporridge with its left hand,’ reported Kidd, ‘the peopleplace both of the hands of the child into the hot porridgeas an object lesson.’ For the Zulus ‘the left hand is usedfor mean purposes, such as scraping away dirt, and so itmust not be used for other purposes.’ For those childrenwho, nevertheless, ‘seem to be naturally left-handedthe people pour boiling water into a hole in the earth,place the child’s left hand in the hole, ramming the earthdown around it; by this means the left hand becomes soscalded that the child is bound to use the right hand’ [1](p. 296).3

4 As Lydie Mepham reminded me, one of the difficulties in dealing with this issue ofleft and right in China is the fundamental principle in Chinese philosophy of theduality of yin and yang that has permeated Chinese thinking for over 2000 years.Everything is yin or yang. Water is yin; mountains are yang. But different sides of amountain are yin or yang. Foods are yin or yang. So is Chinese medicine. Yang is themasculine, positive element. The sun is yang. Yin is the feminine, negative principle.The moon is yin. And the left hand is yin and the right one is yang.

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Like the Zulus many North and East African peoples,according to University of Pennsylvania anthropologistHeinz Wieschhoff (1906–1961), had ‘an outspoken right-preference’ and actively attempted to ‘cure’ left-handednessthroughout much of the African continent [25] (pp. 216–217). Similar practices have been identified by anthropolo-gists in many aboriginal cultures on every continent [26].

Religion has often reinforced these practices. The holytexts of Judaism, Christianity, and Islam all stigmatize left-handers. According to the early medieval Persian scholarand historian Abu Ja’far Muhammad ibn Jarir al-Tabari(828–923), ‘Allah has nothing left-handed about him, sinceboth his hands are right hands’ (al-Tabari, quoted in [27] (p.240). ‘Among the Arabs and in Islam, this marked prefer-ence for the right,’ according to French anthropologist J.Chelhod, ‘gives rise to all kinds of beliefs, customs, andinjunctions’ [27] (p. 240). Similar to other societies, writesChelhod, ‘the right hand is the organ of possession andpower. . . and is made the object of careful and attentivetraining.’ In contrast, ‘the left is regarded as evil because it issynonymous with ill omen’ (p. 242). Thus, among Islam’s 1.8billion people, left-handedness continues to be discouragedand the forced transformation of left-handers into right-handers is widely practiced [28] (pp. 254–258).

‘The predominant importance of the concept of right isquite obvious,’ wrote Wieschhoff in his 1938 comprehen-sive review of the attitudes and practices of a number of

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North and East African societies. ‘Scattered over mostparts of the African continent are indications that the rightis considered as the superior side and is associated withsuch beliefs as are understood to be good and favorable.’Although Wieschhoff admitted that his survey, thoughextensive, was incomplete, he concluded that the ‘distribu-tion of right-preference’ pointed to ‘outside influences.’That is, beliefs in the superiority of right-handedness werestrongest in North and East African cultures ‘which hadmore or less close cultural contacts with Arabs and Islam. . .going back at least for a period of a millennium.’ This ‘longlasting influence,’ he concluded, ‘cannot be overestimated’[25] (p. 216). Wieschhoff also suggested these ‘culturalinfluences may even have reached the tribes of the Congoarea’ where ‘a culturally confined right-preference’ proba-bly ‘had a considerable influence’ on attitudes toward left-handedness (p. 216).

The persistence of these cultural influences has beenvalidated by Malawian University physiologist Y.P.Zverev in his studies of handedness among 21st centuryMalawi students in Blantyre, the nation’s second largestcity. ‘In the Malawian culture,’ writes Zverev, ‘it is offen-sive to greet somebody with the left hand. It is also taboo,especially among Muslims and tribes affiliated with ori-ental traditions, to eat in public with the use of the lefthand’ [12] (p. 297). Zverev reported that 87.6% of thosesurveyed (n = 440) believed that left-handers should beforced to use their right hand for habitual activities,including writing, tool use, and throwing. This beliefreflected practices and the study found that ‘all mix-hand-ed children and 90% of left-handers reported that they hadexperienced a pressure to change the hand.’ When askedwhy they believed left-handers should be forced to switchto right-handedness, 38% responded that ‘the left hand isdirty, or it is disrespectful and unwelcome to use the lefthand in public.’ A majority were convinced that they‘expected inferior performance’ from left-handers, whothey assumed were less skilled than right-handers [12](pp. 299–300).

Exceptions and ambiguitiesDespite the examples above and Hertz’s claim that discrim-ination against the left was universal, there are exceptions,even in China. Although current Chinese practices advocateforcible switching of left-handed children, in ancient Chinagood fortune was attributed to the left hand [29] (pp. 176–177). ‘On occasions of festivity to be on the left hand is theprized position; on occasions of mourning the right hand,’wrote Lao Tse, in the most widely read Chinese book in theworld, the Tao te Ching (ca 6th century BCE), ‘the superiorman ordinarily considers the left hand the most honorableplace, but in time of war the right hand,. . To consider thisdesirable would be to delight in the slaughter of men and hewho delights in the slaughter of men cannot get his will inthe kingdom’ [2] (31.1).4

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These attitudes were not restricted to China. According toWieschhoff, the Khoisans of South Africa seemed ‘indifferenttoward the question of right or left’ (p. 217). Writing in theAmerican Anthropologist in 1898, Daniel Brinton foundgeneral tolerance toward left-handers in Native Americancultures. ‘Left-handed persons were not infrequent,’ wroteBrinton, and the terms for ‘left’ and ‘left-handed’ in NativeAmerican languages do not have ‘the sinister sense attachedto them’ that is found in most European and Arabic lan-guages. For instance, ‘in Cree, namatinisk, ‘‘the left hand,’’ isevidently from the radical, nama, no, not, a simple negation.’The Mayan term for the left, ‘dziic,’ is the same as ‘the wordfor soldier, brave, etc., dziic, dziicil, singularly enough arefrom that root’ [29] (p.176). Combining his examination ofNative American language with tool use and painting, Brin-ton concluded that it ‘seems justifiable that the aboriginalrace of North America was either left-handed or ambidex-trous to a greater degree than the peoples of modern Europe’(p. 180). In pre-Columbian Peru, writes Michael Barsley, ‘oneof the Inca chiefs, a man renowned for his good deeds,was called Lloque Yupanqui – which means left-handed’[22] (p. 30). Even today, among the Paiute of the AmericanSouthwest, being left-handed is viewed positively [30] (p. 50).

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Dutch anthropologist Albert C. Kruyt described ambig-uous attitudes and practices in his 1941 study of theToradja of central Celebes (Indonesia). Kruyt noted thata superficial examination of Toradja society would seem toaffirm Hertz’s conclusion that the ‘complete subordinationof the left hand to the right, whereby the former is not onlyleft undeveloped but is also less regarded than the right,must be sought in causes lying outside the human organ-ism’ [31] (p. 74). However, a closer examination of Toradja‘daily life’ suggests a disconnect between theory and prac-tice. Thus, while the Toradja refer to persons who use theirleft hand as ‘stupid,’ one of their divine heroes, GumaNgkoana, which translates into ‘he who wears his swordon the right side of his body,’ was clearly left-handed (p. 75).Generally, the right is associated with life and the left withdeath, to the extent that the dead are presumed to be left-handed. Thus, in respect of the dead, ‘the living employ theleft [hand] whenever they do anything for or in connectionwith the dead’ (p. 80). Kruyt’s observations lend support toHertz’s general claims that right and left serve as binaryopposites [16]. Thus, according to Kruyt, ‘the left and theright play a great part in all important circumstances oflife; in order to ensure life, one must do everything with theright, because the left means death’ [31] (p. 83). However,as Kruyt’s study reveals, while left and right are employedas proxies for wider constructs of life and death among theToradja, their meaning varies in other societies and cul-tures. One need go no further than Hertz’s 1907 essay ondeath to discover that among the Maori death is not thebinary opposite of life, nor is it connected to handedness,but rather it is a ritual that enables a transition from onestate to another [32]. This raises the question of whether ornot, as Hertz insisted, the left and the right are essentiallysynonymous with cultural constructions of the profane andsacred, or are only sometimes convenient proxies thatauthorize discrimination against difference.

This ambiguity is reflected in French sociologist MarcelGranet’s 1933 study, ‘Right and Left in China.’ Displayingthe conventional deference, Granet recalled ‘the fine workof the late and lamented Robert Hertz on the pre-eminenceof the right hand.’ Granet, nevertheless, found that ‘thediametric opposition or polarity of which Hertz spoke is notfound in China’ [33] (p. 44). Contrary to Hertz, Granetnoted that only in ‘certain respects’ were the Chinese‘obligatorily right-handed.’ Most important, wrote Granet,‘whereas the Chinese are right-handed, the honorable sidefor them is the left’ (pp. 43–44, italics in original). Hertz hadsuggested the reason for this contradiction might be foundin China’s agricultural technology, but he never elaboratedhow or why this might be so. Granet demurred, writingthat the explanations ‘might perhaps be better sought, notin the techniques of agriculture but in military techniques,’which he also does not elaborate. ‘The Chinese,’ accordingto Granet, ‘attribute values to left and right which areunequal, and relative to circumstances, but are alwayscomparable.’ Rather than ‘absolute pre-eminence’ whatone finds is ‘an alteration,’ where attitudes and practicestoward right and left are governed by rules of etiquette.According to Granet, ‘instead of absolute oppositions,’ inChinese thought and mythology, ‘there are only correla-tions’ and no ‘strict taboos.’ Thus ‘everything is a matter of

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convention, because everything is a matter of fitting’ (p. 44,italics in original).

‘In China, etiquette’ writes Granet, ‘expresses the struc-ture of the world.’ Thus, Granet concludes that it is ‘theanatomy of the world which will explain the alternatepreeminence of the right and of the left’ [33] (p. 44). Thisdeference to etiquette is underlined by American statisti-cians Avery N. Gilbert and Charles J. Wysocki who suggestthat ‘strictures on left-handed writing (perhaps driven bychopstick use) are stronger in China and Japan than inWestern societies.’ This explains to them why ‘consistentwith this observation, the prevalence of the left-handedwriting phenotypes among Asian respondents was one-third less than among whites, blacks and AmericanIndians’ [34] (p. 606).

What these examples suggest is that attitudes and prac-tices toward left-handers have not ‘evolved’ from discrimi-nation to tolerance. Rather, a more complex picture emergesin which examination of early human cultures reveals anambivalent attitude toward left-handedness, whereby evenextreme suppression of left-handers in one culture wascontradicted by admiration of left-handers in another.5 Asin the case of China, discrimination can follow tolerance andtolerance can exist even where rhetoric and custom seem tostigmatize left-handedness. From this perspective, the sup-pression of left-handed behaviors should be viewed as serv-ing both deep-seated human responses to difference and toparticular cultural and political agendas.

Environmental pressures‘Cultural and environmental factors,’ write French re-searcher Maria De Agostini and her colleagues, ‘change‘‘natural’’ hand preference in three ways.’ First, they mightonly affect one activity, such as eating or writing, but notinfluence other common unimanual tasks [15] (pp. 151,162–165). Second, those who experience temporary inju-ries to their dominant hands tend to become ‘ambi-handed’rather than totally shift to their non-injured hand. [15] (p.152). Finally, attitudes toward left-handedness can direct-ly influence left-handed prevalence in different cultures[15] (pp. 151, 162–165).

The first and third of these environmental influenceshave shaped Chinese practices toward handedness, butthese forces are more dynamic than usually portrayed.Not least of all is the social and economic cost of makingadjustments for 10% of the population. As the China Dailyrecently reported, ‘in China kids are all taught to write withtheir right hands. If they pick up a pencil with their lefthand, the teacher will put it in their right. It is really just amatter of practicality. In the US, you have left-handeddesks, left-handed guitars, and all sorts of other left-handeddevices, but in China we have none of the sort.’ However, a

5 One might read these exceptions and ambiguities in China as suggesting thathistorical and current practices toward left-handedness are less severe than incultures where discrimination against left-handers is reinforced by religious practices,such as in India and in Islamic societies. Thus, one might attribute Chinese practices,as suggested in the China Daily report above, as more practical than ideological.Nevertheless, the prevalence reported in China and Taiwan is exceptionally low and,to the extent that these reports are accurate, they suggest a vigorous effort to maintaina right-handed society. Thus, the impact on those switched may be no less devastatingthan in societies where restriction of left-handedness is driven by religious beliefs.Also, whatever the reasons for forced hand switching, its practice, especially whenofficially sanctioned, serves to reinforce negative attitudes toward left-handers.

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number of reports agree with the observation that there are‘a lot more lefties here in 2007 Shanghai than’ in Guang-dong. Thus, the report concluded that ‘forced switching isslowly being phased out, at least in the city’ [4].

‘Of course,’ writes China expert Lydie Mepham, thereare ‘left handers in China, but maybe not in the past. In factbeing a left hander nowadays is a good thing when playingping pong, tennis, etc. [as] it must be true in our westernsphere also today.’ But, Mepham concedes, that forcingleft-handers to write with their right hands persists. ‘AChinese friend,’ writes Mepham, ‘tells me that all the left-handers he knows, actually can also write. . . with theirright hand!’ (personal correspondence, 28 July 2011).

The renowned Indian/American geneticist Krishna R.Dronamraju uncovered a higher than expected left-handedprevalence among Andhra Pradesh tribals. This persuadedDronamraju that pressures to switch left-handers to right-handedness were more recent in India than generallysupposed. Dronamraju urged ‘that similar quantitativestudies of left-handedness should be made in other tribaland aboriginal populations before they are culturally con-ditioned to right-handedness’ [35] (p. 161).

As researchers from Hertz to Zverev have insisted, thereis ‘a lot of evidence that cultural and environmental pres-sures play a significant role in the variability of left-handedpreference in communities especially for well-trainedtasks’ [12] (p. 296). According to psychologist Clare Poracand colleagues, prevalence differences between and amongsocieties worldwide are more strongly correlated withcultural rather than biological pressures.6 Nevertheless,within cultures ‘the largest percentage of variability inhandedness scores’ must be attributed to neurologicaland genetic forces [11] (p. 285).

Technological innovations, from early human tools tocontemporary scissors, can openers, and student desks,have provided additional pressures on natural left-handersand resulted in reduced left-handed prevalence [36] (p.196). The spread of literacy, especially of writing also, as Iwill discuss below, initially increased the pressures on left-handers to become right-handed writers [37]. It probably

6 They find that cultural pressures account for 8% of the handedness variabilityamong adults and 23.5% of cross-cultural variability, while biological factors accountless than 2% of the variance [11], (p. 285).

8 Moreover, these surveys weigh all their categories as equally contributing to left-handedness, which Dragovic and colleagues have found to be invalid [45,46]. The sameteam have found Annett’s questionnaire to be reliable, but antiquated in its categoriessuch as sweeping and shoveling [47]. These limitations do not address the even morecomplex issue of whether or not these surveys are conflating weak right-handedness

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played a role in the decline of prevalence of left-handers inthe U.S. and Britain in the 19th century, described by anumber studies and discussed in depth below [36] (pp. 216–217), [34] (pp. 603–605), [38] (pp. 186, 205). One factor thatrecently has tended toward an increased prevalence of left-handedness is the worldwide sports craze in which left-handed athletes have an advantage in a number of sportsincluding American baseball, tennis, football (soccer); andin China left-handed ping-pong players have increased thetolerance for left-handers.

Measuring left-handednessHistorically, the reported prevalence of left-handednesshas been strongly influenced by the definition of whatconstitutes left-handedness. ‘Differences in the prevalenceof left-handedness,’ writes Zverev, can reflect a ‘discrepan-cy of methods used for the assessment of handedness ortype of a criterion used for categorization of handedness’[12] (p. 296). The prevalence of left-handedness has beenand continues to be determined by the criterion adopted fordetermining handedness. Thus, it is difficult to determinethe reason for the differences in left-handed prevalence, ifresearchers do not agree on the definition of what consti-tutes left-handedness.

The prevalence of handedness historically has relied onone of three criteria: observation, self-reporting, and/or asurvey questionnaire, administrated either by an observeror filled out by the subjects themselves.7 Of the three,observation alone, with its well-recognized observer bias,is the least reliable. Self-reporting has the advantage ofallowing the collection of large samples, but, similar toobserver reports, suffers from well-documented unreliabil-ity [41]. The third, and most reliable method, because allrespondents answer the same questions, is a survey inven-tory. The most widely used in Britain and the U.S. is theEdinburgh survey developed in 1971 by psychologist R.C.Oldfield (1909–1972) reproduced below consisting of 10non-weighted questions [42].

Edinburgh Handedness InventoryPlease try and answer all of the questions, and only leave a blank if you have no experience at all with the object or task.

Left Righ t1. Writing2. Drawing3. Throwing4. Scissors5. Toothbrush6. Knife (without fork)7. Spoon8. Broom (upper hand)9. Striking Match (match)10. Opening box (lid)TOTAL(count checks in both columns)

Difference CumulativeTOTAL

Result

7 There is a fourth method – tests of skill for relatively less-practiced acts of the kindused by Marian Annett, Michael Peters, and other researchers. Because these aremore time-consuming to administer, they have been used less frequently in estimatingthe prevalence of handedness subtypes [39,40].

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Developed around the same time was British psycholo-gist Marian Annett’s 12-question survey [43]. Althoughboth of these surveys are reliable, in that they each mea-sure the same things, they may not be valid [44]. That is, itis uncertain that they are actually measuring left-handed-ness, rather than proxies assumed to be signs of left-handedness.8

In China, the studies of prevalence of handedness dis-cussed in this article were obtained by measuring thehanded activities that were most essential to the Chinesewhen they were being measured. In earlier epochs, whatmattered most was what hand one used for eating [5]. Bythe late 20th century writing and drawing had becomethe test for handedness. As University of Hong Kongresearcher R. Hoosain pointed out in 1990, because naturalleft-handers were routinely made to write and draw withtheir right hands, little attention was paid to the fact thatthese people continued to rely on their left hand for othertasks [48].

As in China the definition of handedness has oftenproven unstable, reflecting changing social values. Thuswhen in 1997 De Agostini and her colleagues asked theirIvory Coast and Sudan subjects to indicate any pressure tochange hands, they found that in both societies ‘the targetactivity against left-hand use was eating’ but not throwingor writing, even though all the interviewees were students[15] (p. 151).

Despite the low reported prevalence rates reported inthe world’s two most populous societies, China and India,most current experts, nevertheless, seem to agree thatbetween 10 and 12% of humans are left-handed and prob-ably have been since the beginning of our species [20] (p.151); [49].9 Nevertheless, depending on the definition,geographic location and historical period, studies have

with right lateralization.9 All studies consistently have found that males were more likely to be left-handed

than females by a ratio of 5:4 [50], (pp.267-81). Sedden and McManus’s meta-analysisof over 100 studies ‘found the sex difference to be constant across many societies andhistorical periods’ [51,52]. Similar sex ratios have been noted worldwide. Also see themore recent meta-analysis of Papadatou-Pastou, M., et al., [53].

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reported a frequency of left-handedness of between 5 and26% of the human population [54] (p. 882). With such apotentially large margin of error, developing robust statis-tical claims about the prevalence of left-handedness isproblematic. A similar range of 5 to 25% was reported ina review of 81 reports of throwing (by a combined total ofmore than 1.2 million persons) in 14 countries for theperiod 1922–1998. The study’s authors were optimisticthat the ‘geographical variation in handedness’ that theyuncovered presented ‘an opportunity to identify the selec-tive forces’ that influence handedness [10] (p.47). Whatthese and other recent studies indicate is that there is noconsensus on the prevalence of left-handedness in largepart because there is no agreement on the phenotype to bemeasured. Unlike in developed countries where handed-ness is generally measured using the writing hand, studiesof traditional cultures have relied on eating, acts of throw-ing or tool-use. Thus, Raymond and Pontier’s review of 81studies, found a range of 2–25.9% left-hand use for throw-ing or hammering [10]. This range is almost twice thatfound in studies of hand use for writing. For instancePerelle and Ehrman, who surveyed subjects from 17 coun-tries, reported a range from 2.5 to 12.8% [55]. The implica-tion would seem to be that for acts less likely to come undersocial-cultural control and/or to be the target of specialtraining, left-handedness is more prevalent than it is foracts, prominently eating and writing, more likely to comeunder social-cultural control.

Even where there is a consistent phenotype, the preva-lence data raises as many questions as it answers. Corenand his colleagues, who claim a consistent left-handedprevalence of 10% throughout human history, found ‘thatthe percentage of left-handers in the population grewsteadily smaller’ when they ‘looked at older groups ofindividuals’ [21] (p. 50). They found that 15% of 10-year-olds were left-handed, but only 5% of 80-year-olds. WhileCoren and colleagues admitted that the decline could beinterpreted as evidence that ‘older individuals more fre-quently switched to right-handedness,’ they ultimatelyread the data as evidence ‘that the rarity of older left-handers is due to reduced longevity,’ [56] (p. 1) [57,58].10

Coren’s finding contradicted those of a French team led bypsychologist Georges Dellatolas who had reported thattheir 1991 survey of left-handed in Algeria, Greece, Italy,France and Spain, found ‘no systematic decrease in thefrequency of left-handedness with age,’ despite the factthat left-handed writing ‘was common in the youngest agegroup and rare after 40 years of age.’ The decrease in adultleft-handed writing, according to Dellatolas and collea-gues, was ‘not easily explained by variations in the socialpressure against left-hand use, differential mortality, orinformation bias’ [60] (p. 225). Of course, both the Corenand Dellatolas findings could be accurate because they areprobably measuring different definitions of what they labelas left-handedness, which unfortunately for those seekingto uncover the prevalence of left-handedness seems often tobe the case. Nevertheless, even if the reported data is oftenunreliable, it still can tell us something important about

10 Most researchers reject Halpern and Coren’s claims of the putative higher earlymortality of left-handers [59] (pp. 235–47).

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the experience of left-handers. That is, it can serve as anindicator of the intensity of discrimination against left-handers.

Reported prevalence as an indicator of discriminationThe reported prevalence of left-handers in any societyserves as an indicator of the extent of discriminationagainst or tolerance of left-handers. Reported rates ofleft-handers that are significantly lower than 10% suggestsustained discrimination against left-handers. Some nat-ural left-handers may either through shame or fear under-report their left-handedness. Others may successfully passas right-handers as they voluntarily shift to their right-hand reliance. Other natural left-handers may have beenforced to switch to use of their right hands. To the extentthat handedness has a genetic substrate, the rejection ofleft-handers as marriage partners would result in an actu-al diminution of left-handers. From these perspectivescontemporary China with its incredibly low prevalencewould represent a high level of discrimination, wherebythe United States, Canada, and Western Europe wouldrepresent a high level of tolerance.

Practices resulting in the reduction of left-handers in apopulation have been referred to as ‘the cultural pressurehypothesis.’ Psychologist John L. Dawson found ‘support(for) the culture pressure hypothesis’ in his comparison ofthe Temne of Sierra Leone with Arunta aboriginals ofCentral Australia: The ‘conformist Temne culture,’reported Dawson, was 3.4% left-handed, ‘while the morepermissive Arunta’ [were] ‘10.5% left-handed’ [26] (pp. 219,222). This meshes with Zverev’s assertion that ‘contrary towestern countries, cultural and environmental pressuresagainst expression of left-handedness in the African popu-lations remain strong. These pressures are likely to biasthe incidence of left-handedness and underlie persecutionof left-handers in African communities’ [12] (p. 297).

The methods used to persuade left-handers to switchare not always negative. For instance, Bryden and collea-gues reported that among the Tucano adolescents of theAmazon region of Colombia, right-hand preference wasincreased ‘through positive reinforcement’ [61] (p. 301).‘Explicitly forcing a child to develop skill with one handfor a particular activity,’ Bryden reminds us, ‘does notnecessarily lead the child to prefer the same hand for otheractivities.’ However, ‘by making the use of the right handinteresting and rewarding, and by providing these rewardsat an early age, they have created a situation in which theirchildren prefer to use the right hand.’ Thus, the Tucanohave been more successful than other cultures in trans-forming [left-handed] children to right-handers [61](p. 306).

When we discuss handedness in ‘China’ or ‘India,’ (oreven more problematic, ‘Africa’) we are obviously paintingwith a very broad brush. These are all diverse and compli-cated societies that ultimately must be examined in moredetail with the recognition that even the most careful androbust local studies should be generalized only with thegreatest of caution. Thus in India or China, not to mentionthe diverse African continent, the prevalence of left-hand-edness can vary regionally and within the same regions, byethnicity and religious practice. For example, writing in

11 A ‘more direct index of this change,’ he wrote, ‘is through a cross-generational, or‘‘secular trend,’’ analysis. That is, if we assume the prevalence of left-handedness in aparticular age cohort. . . reflects cultural practices pertaining to handedness in opera-tion for that cohort, then by comparing cohorts, we can chart temporal changes,including starting and finishing points’ [36] (pp. 217–218).

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1975 Dronamraju found a high left-handed prevalenceamong Andhra Pradesh tribals of 15.49% for males and7.79% for females compared to a 6.9% and 4.65% of Hindumen and women in Andhra Pradesh [35]. Whether or notDronamraju’s data have borne out, his observations arereinforced by the recent growth of Web-based sites such as‘The Association for Left-handers’ in Mumbai calling forthe cessation of the practice of forcing left-handers toconvert to right-handedness, a typical cultural practicein much of India [62].

As we have learned, both traditional values and thebeginnings of modernization can equally depress the prev-alence of left-handers. The role of traditional factors iswidely acknowledged and we have examined these forcesextensively. Throughout this article we have also exam-ined a number of studies that revealed that the centrali-zation of resources that drives urbanization can also have aprofound impact on rates of left-handedness. This effect isespecially visible in educational institutions where theinflux of first-generation children has strained resourcesand required sustained conformity in order to teach stu-dents basic skills, especially to read and write. From thisperspective, allowing 10% of the students to write withtheir left hands has been seen as wasteful and inefficient,especially in societies that already have a deep antipathytoward left-handedness. This is reflected in data fromChina, Africa, and South Asia that have shown as studentsbecome more integrated into educational institutions, themore likely that their prevalence of left-handednessdeclines. Thus, secondary education students became moreright-handed than their younger siblings in elementarygrades. As the developing world emerges into a collection ofdensely populated urban centers, where dispirit ruralmigrants are integrated into modern society, diversity,including encouraging 10% of the population to developtheir left-handed skills, is inefficient.

Recent studies suggest that a similar scenario, of in-creased public education resulting in a decrease in left-handers, took place in 19th century America, Canada,Britain, and Australia. University of Melbourne research-er C. J. Brackenridge reported a 2 to 13% increase in ‘left-handed writers of high socio-economic status born inAustralia or New Zealand. . . from 1880 to 1969.’ Brack-enridge attributed the increase in left-handers to what hedescribed as ‘cultural relaxation in promoting an increas-ing proportion of sinistrals with time.’ He suggested that asimilar increase in left-handers would also be found in theUnited States, but that it would occur slightly later there.[63] (p. 459). A similar pattern, but somewhat later, wasfound in the Netherlands, where researchers reported thata cross-sectional examination of respondents ages 4 to 86,revealed that ‘the percentage of left-handers writing withtheir left hand increased from 0% for people of 40 yr andover, to 100% for 14 yr and younger’ [64] (p. 301). Theauthors attributed these results to changing attitudestoward left-handers by Dutch educators.

This conclusion was supported in 1990 by MichiganState University psychologist Lauren Julius Harris whopointed to a heightened debate among American educatorsbeginning approximately in the mid teens to early 1930s[65,66] [67] (pp. 63–65). These disputes, which I have

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examined in greater detail in a recent article [68], had,according to Harris, resulted in more toleration of left-handed writing in American and British elementaryschools and as a result, in an increased reported populationof left-handers: ‘In the case of Great Britain and the UnitedStates,’ wrote Harris, ‘we traced the beginnings of thechange of practice to the period from approximately1915 to the early 1930s, largely on the basis of statementsof psychologists and educators of that era’ [36] (pp. 216–218).11

Harris’s argument was affirmed by American statisti-cians Avery N. Gilbert and Charles J. Wysocki who ana-lyzed data on left-handed writing and throwing that wascollected as part of the 1986 National Geographic ‘SmellSurvey’ of 1.78 million American men and women, ages 10to 86, from all regions of the country [69]. Employingsophisticated statistical methods and a novel set of vari-able phenotypes, that included a spectrum of strong left-handed preference to weaker mixed handed behaviors,Gilbert and Wysocki reported that their findings were‘consistent with a model that posits an historical reductionin socially mediated sanctions on left-handed writing be-ginning early in this century’ [34] (p. 605). Based on theirvariable phenotype model, they claimed that the datarevealed ‘a record of the historical lifting of the repressionof left-handed writing in the United States. That is, morerecent birth cohorts show greater expression of intrinsicleft motoric bias (higher prevalence of L,L, and L,R,), andreduced evidence of repressed left-handed writing (lowerprevalence of R,L,).’ This ‘more gradual increase in preva-lence of L,R, (in comparison to L,L,) would reflect theweaker intrinsic left motoric bias of this group. Based onthis hypothesis, the repression of left-handed writing in theUnited States would appear to have eased first around1917, and been fully lifted by 1937’ [34] (p.603). Gilbert andWysocki pointed out that ‘these dates correlate well withhistorical trends in the scientific attitude toward sinistral-ity as summarized earlier by Harris.’

Gilbert and Wysocki also noted that increasing numbersof publications in the second decade of the 20th century‘suggested that forcing left-handed children to write withtheir right hand interfered with the normal development ofspeech.’ Along with Harris they noted that these concerns‘spread from psychologists and educators to the generalpublic, as evidenced by articles in popular magazines from1917 to 1922’ (pp. 605–606).

The implication of all of these findings for Chris McMa-nus and his colleagues is that in the 19th century theprevalence of left-handers was artificially low; as low ascontemporary China, and that there was an actual declinein left-handers in late nineteenth-century North Americaand Britain, followed by a significant increase in preva-lence in the 20th century. Combining the Gilbert andWysocki data with a number of other studies, includinga large 1953 BBC data set collected from 6549 viewerpostcards, the McManus team conducted a meta-analysis.

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Using a modified Wiebull function probability distributiontest enabled McManus to extrapolate backwards in time:‘The rate of left-handedness in the eighteenth century wasprobably about 10%, with the decline beginning in about1780, and reaching around 7% in about 1830,’ and contin-ued to decline, to ‘almost 3% by about 1896’ [38] (pp. 186,205). McManus and colleagues found that ‘the rate of left-handedness is probably at its nadir for those born betweenabout 1880 and 1900, then begins to rise fairly quickly untilit reached a plateau between about 1945 and 1950.’ Thus,they concluded that ‘there seems little doubt that the rateof left-handedness rose dramatically during the twentiethcentury’ [38] (p. 205).

Here and in other publications, McManus insists thatthe decline in left-handers represents an actual geneticdecline rather than a reflection of left-handers passingthemselves off as right-handers or having been switchedto right-handedness by 19th-century parents, teachers,and other accumulated social forces. While this may beso, most of the data about 19th-century Anglo-Americanleft-handedness is based on self-reporting. Given thestrong social stigma toward left-handedness in the 19thcentury, many natural left-handers may have purposelymisrepresented their handedness; others may have forgot-ten that they were switched. In either case, many of thoseswitched to right-handed writing would most likely seethemselves as right-handed if they used their right handfor writing. It is possible that as people aged they tended touse their right hand more for writing and throwing becausethis population had been under greater pressure to usetheir right hand than previous or subsequent populations.But, McManus could be correct in asserting that there werefewer actual natural left-handers; and he has proposed agenetic model that supports such a conclusion that couldsupport the theory that discrimination against left-han-ders made them less desirable mates, marry later or lessfrequently, and have fewer off-spring. This would reducethe transmission of the gene implicated in left-handedness[20,50].

But whatever the explanation, the fact remains thatreduction of numbers of left-handers (whether real ormerely reported) resulted in great measure from switchingleft-handed writers to right-handed writers. Finally, espe-cially in North America, the period of the putative declineof left-handers maps on to the period of greatest immigra-tion. As a number of studies have shown, immigrants,especially those that arrived from the 1880s to WorldWar I who were typically from Southern and EasternEuropean cultures, would have been the most likely torestrict their children’s left-handed behaviors, as well as bethe most vulnerable to having others impose right-handedwriting on them.

By the mid-20th century, the prevalence of left-han-ders increased dramatically in North America and Brit-ain and, soon after in much of Western Europe. In their1997 study of the hand-writing habits of 700 Frenchmenand women between the ages of 16 and 80 Dellatolas andcolleagues reported that while only 9% of natural left-handers over 40 used their left hand for writing, 80% ofthose under 40 wrote with their left hand [15] (p. 152),[70]. Similar findings have been reported for Germany,

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Italy, and Spain, suggesting that by the late 20th centu-ry, earlier educational practices had become more toler-ant toward left-handers writing with their left hands [15](p. 152).

Although McManus and colleagues find it ‘indis-putable. . . that rates of left-handedness fell during mostof the nineteenth century, only subsequently to rise in thetwentieth century,’ they admit to having ‘no robust evi-dence to suggest how and when that occurred’ [38] (pp. 186,205). One possible source of evidence may be foundthrough an examination of the push back from educatorsand nascent child development researchers of the early20th century. This push back came from two directions.The first can be seen in the ‘ambidextrous movement’ ofthe late 19th and early 20th century in North America andBritain [17] (pp. 13–15), [71,72] (pp. 130–136). The secondand more substantial reaction was the debate over theputative risks of learning and speech disorders, especiallystuttering, that some researchers believed resulted fromconverting natural left-handers [68].

ConclusionThe question raised at the outset, ‘Why are there so fewChinese left-handers?’ has a number of possible answers,including that there are and always have been many left-handers in China, but that the way they were measureddetermined their prevalence. Alternatively, the differencescould be real because as we saw with China, a combinationof traditional values and practical considerations seem tohave merged to reduce the reported prevalence of left-handedness. The question remains whether or not thesefactors reduced the actual prevalence of left-handers. Butwhat seems indisputable is the impact of negative atti-tudes toward left-handers. If to China we add in thepopulations of India, and much of the remaining Islamicworld, we can conclude that for two-thirds of the world’spopulation, being born left-handed exposes one to discrim-ination and stigma.

The connection between left-handedness and mentaldeficiency has deep mystical and superstitious origins.Although current researchers reject the traditional neg-ative and stigmatizing rhetoric, many have employedmodern scientific and statistical tools to connect left-handedness with an increased risk of mental illness,learning disabilities [73] (p. 281), [74] (p. 591), [19] andeven autoimmune disease [75]. Teasing out the validity ofthese connections is the focus of my current research.Similar claims in the early and mid-twentieth centuryjustified a number of putative ‘cures’ for left-handedness,including forcing left-handers to become right-handers.Training of left-handers to become right-handers was acommon practice in American and Europe until recently[76] and continues today in China, India, and much of thedeveloping world. As early as the 1930s there was per-suasive evidence that such interventions may have them-selves resulted in a number of learning disabilities,including stuttering [68]. Thus, sorting out the reasonsfor the reported and actual prevalence of left-handers inChina may have important implications for the diagnosisand treatment of learning and language disorders on therest of the planet.

80 Feature Endeavour Vol. 37 No. 2

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