Sex Differences in Left-Handedness: A Meta-Analysis of 144 Studies

Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
Psychological Bulletin (Impact Factor: 14.76). 10/2008; 134(5):677-99. DOI: 10.1037/a0012814
Source: PubMed


Human handedness, a marker for language lateralization in the brain, continues to attract great research interest. A widely reported but not universal finding is a greater male tendency toward left-handedness. Here the authors present a meta-analysis of k = 144 studies, totaling N = 1,787,629 participants, the results of which demonstrate that the sex difference is both significant and robust. The overall best estimate for the male to female odds ratio was 1.23 (95% confidence interval = 1.19, 1.27). The widespread observation of this sex difference is consistent with it being related to innate characteristics of sexual differentiation, and its observed magnitude places an important constraint on current theories of handedness. In addition, the size of the sex difference was significantly moderated by the way in which handedness was assessed (by writing hand or by other means), the location of testing, and the year of publication of the study, implicating additional influences on its development.

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    • "Approximately 90% of humans are right-handed, with the rest made up of left-handed and ambidextrous individuals. It is well established as to singletons that the prevalence of left-handedness in males is slightly higher than that in females (Papadatou-Pastou et al., 2008). There has been a long-standing debate on the complex correlation between the development of human hand preference and brain lateralization. "
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    ABSTRACT: There has been a long-standing debate on the complex correlation between the development of human hand preference and brain lateralization. Handedness, used as a proxy for cerebral lateralization, is a topic of considerable importance because of its potential to reveal the mechanisms of the underlying pathophysiology of problems related to brain development or cognitive systems. Twin studies, which represent an important method of research in human genetics, would provide valuable suggestions to the studies on the relationship between lateralization and cognitive systems. Many studies have been performed using twin subjects; however, the results are inconsistent, partly because of sample size, background assumptions, data limits or inaccuracies, incorrect zygosity classification, and/or lack of birth histories. In summary, within the long history and large number of twin studies performed on handedness, a surprisingly large number of controversial findings have been reported, suggesting the complicated nature of this phenotype. In this mini review, the wide variety of twin studies on human handedness performed to date are introduced.
    Frontiers in Psychology 01/2014; 5:10. DOI:10.3389/fpsyg.2014.00010 · 2.80 Impact Factor
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    • "Humans exhibit sidedness preferences when performing many routine tasks (see Damerose and Vauclair 2002; Lalumière et al. 2000; Papadatou-Pastou et al. 2008). In most cases, limbs and digits on the right side are utilized more than those on the left (Carey et al. 2001; "
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    • "The aforementioned sex differences, together with observations that females are more strongly right-handed,32 males have a greater tendency toward left-handedness,33 and that the torque is anatomically more pronounced in males,34 implicate a sex chromosomal locus for the right shift. Further evidence of an X/Y homologous sex chromosomal locus for cerebral asymmetry comes from cases of sex chromosomal aneuploidies; individuals with Turner's syndrome, who have only one X chromosome, or individuals with an extra X (triple X and Klinefelter's [XXY] syndromes) or an extra Y (XYY syndrome). "
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