Human handedness and scalp hair whorl direction: No evidence for a common cause

Perelle, Ira B.; Chanza, Melissa

doi:10.1080/13576500802387692

Cited by 7 publications

(3 citation statements)

References 15 publications

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“…The number is too small to justify a separate category. Although alternative cutoff points have been empirically validated and recommend for handedness classification [4], there remains no consensus regarding the best classification method among researchers who use the EHI [52]. Furthermore, one of the purposes of this study is to compare prevalence of handedness based on preference and performance measures, and a consistent classification criterion, i.e.…”

Section: Discussionmentioning

confidence: 99%

Prevalence and heritability of handedness in a Hong Kong Chinese twin and singleton sample

Zheng

McBride

et al. 2020

BMC Psychol

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Background: Left-handedness prevalence has been consistently reported at around 10% with heritability estimates at around 25%. Higher left-handedness prevalence has been reported in males and in twins. Lower prevalence has been reported in Asia, but it remains unclear whether this is due to biological or cultural factors. Most studies are based on samples with European ethnicities and using the preferred hand for writing as key assessment. Here, we investigated handedness in a sample of Chinese school children in Hong Kong, including 426 singletons and 205 pairs of twins, using both the Edinburgh Handedness Inventory and Pegboard Task. Results: Based on a binary definition of writing hand, we found a higher prevalence of left-handedness (8%) than what was previously reported in Asian datasets. We found no evidence of increased left-handedness in twins, but our results were in line with previous findings showing that males have a higher tendency to be left-handed than females. Heritability was similar for both hand preference (21%) and laterality indexes (22%). However, these two handedness measures present only a moderate correlation (.42) and appear to be underpinned by different genetic factors. Conclusion: In summary, we report new reference data for an ethnic group usually underrepresented in the literature. Our heritability analysis supports the idea that different measures will capture different components of handedness and, as a consequence, datasets assessed with heterogeneous criteria are not easily combined or compared.

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Section: Discussionmentioning

confidence: 99%

Prevalence and heritability of handedness in a Hong Kong Chinese twin and singleton sample

Zheng

McBride

et al. 2020

BMC Psychol

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show abstract

Section: Discussionmentioning

confidence: 99%

Prevalence and Heritability of Handedness in a Hong Kong Chinese Twin and Singleton Sample

Zheng¹,

McBride²,

Ho³

et al. 2019

Preprint

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Left-Handedness prevalence has been consistently reported at around 10% with heritability estimates at around 25%. Higher left-handedness prevalence has been reported in males and in twins. Lower prevalence has been reported in Asia, but it remains unclear whether this is due to biological or cultural factors. Most studies are based on samples with European ethnicities and using the preferred hand for writing as the key assessment. Here, we investigated handedness in a sample of Chinese school children in Hong Kong, including 426 singletons and 205 pairs of twins, using both the Edinburgh Handedness Inventory and Pegboard Task. Based on a binary definition of writing hand, we found a higher prevalence of left-handedness (8%) than what was previously reported in Asian datasets. We found no evidence of increased left-handedness in twins, but our results were in line with previous findings showing that males have a higher tendency to be left-handed than females. Heritability was similar for both hand preference (21%) and laterality indexes (22%). However, these two handedness measures present only a moderate correlation (.42) and appear to be underpinned by different genetic factors. In summary, we report new reference data for an ethnic group usually underrepresented in the literature. Our heritability analysis supports the idea that different measures will capture different components of handedness and, as a consequence, datasets assessed with heterogeneous criteria are not easily combined or compared.

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“…Klar et al [9][10][11][12] published a number of research papers on the presence or the absence of relevance between dominant handedness and PW. One of their studies reported that PW was associated with hemispheric language dominance and homosexuality [13,14]. Further, numerous studies investigated PW.…”

Section: Discussionmentioning

confidence: 99%

Predicting the Permanent Safe Donor Area for Hair Transplantation in Koreans with Male Pattern Baldness according to the Position of the Parietal Whorl

Park

Moh

et al. 2014

Arch Plast Surg

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BackgroundThe most crucial factor in hair transplantation for male pattern baldness (MPB) patients is the efficient utilization of the donor-recipient ratio. However, there is no known factor that scientifically predicts the rate of progression of alopecia or indicates a permanently safe donor area.MethodsThe study considered 1,008 Korean adult males with MPB; of these, it excluded 56 males with an absence of parietal whorls (PWs). The authors investigated the distance from the vertical bimeatal line (VM) to the PW, from the PW to the upper border of the helical rim (HR), and the distance from the PW to the occipital fringe (OF) in 952 subjects with a PW. Furthermore, we examined the distance from the PW to the OF considering the duration of alopecia and age in 322 subjects with vertex alopecia.ResultsThe distance between the VM and PW varied from 1.5 to 11 cm, with an average distance of 6.25 cm. The PW-HR distance ranged from 3.4 to 17.5 cm, and the average distance was 7.79 cm. The PW-OF distance ranged from 0.5 to 5.5 cm, and the average distance was 2.37 cm.ConclusionsFor the PW, very large variations existed in the vertical direction. The position of the PW could predict the progression range of the total alopecia of the vertex. Alopecia mostly progresses within 6 cm of the PW toward the occipital side.

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Human handedness and scalp hair whorl direction: No evidence for a common cause

Cited by 7 publications

References 15 publications

Prevalence and heritability of handedness in a Hong Kong Chinese twin and singleton sample

Prevalence and heritability of handedness in a Hong Kong Chinese twin and singleton sample

Prevalence and Heritability of Handedness in a Hong Kong Chinese Twin and Singleton Sample

Predicting the Permanent Safe Donor Area for Hair Transplantation in Koreans with Male Pattern Baldness according to the Position of the Parietal Whorl

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