Handedness trends across age groups in a Japanese sample of 2316.
Hand-preference data of 2316 Japanese were analyzed by age groups, sex, and familial sinistrality. Right-hand preference increased across age groups at least up to 30 years for men, while women showed relatively stable and stronger preference for right-hand use. Unlike some Western studies, no linear trends across age groups were found for both sexes. Declining cultural censorship against left-handedness would not be responsible for the trends, since there was no evidence indicating such a decline in Japan. Hypotheses of reduced longevity and life-long adaptation to the right-handed world are not satisfactory either, since both hypotheses assume a linear trend spanning the entire life span. Thus, it seems that a single-factor hypothesis which explains all the results by resorting to a single cause does not account for the complex results found in this and other studies.
Iwasaki
S
S
Department of Humanities and Social Sciences, Fukushima Medical College, Japan.
Kaiho
T
T
Iseki
K
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000523:psychology*; D002648:Child; D005006:Ethnicity / Q000235:genetics* / Q000523:psychology; D005260:Female; D007839:Functional Laterality / Q000235:genetics; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D010641:Phenotype; D012737:Sex Factors