A 14-item questionnaire was administered to tertiary students and their families. The responses of the 508 subjects in the parental generation were compared with those of the 917 younger subjects. For every item significantly fewer older subjects gave left responses. The questionnaire identified more left-handers among subjects than writing hand did, but as only 5.9% of these were classed as left-handed, compared with 11.8% of the younger generation, it seems unlikely that ascertainment was complete in the parental group. Using data from an additional 69 non-right-handers, item analyses indicated that writing and drawing were unsuitable items for older subjects and that, of the items tested, toothbrush and hammer use and pouring would be the best indicators of left-handedness.
From a population of 512 4-year-olds attending preschools, 41 children were identified as left-handed and 23 as lacking definite hand preference. Using the McCarthy Motor Scales and a fine-motor scale designed by the investigator, these children were compared with right-handers matched for age, sex, and preschool attended. T tests indicated no difference between left-handers and right-handers of either sex, but the children lacking hand preference had lower scores than right-handers. Implications for the education of children lacking handedness and possible sex differences are discussed.
From a population of 512 4-year-olds attending preschools, 41 children were identified as left-handed and 23 as lacking definite hand preference. Using the McCarthy Motor Scales and a fine-motor scale designed by the investigator, these children were compared with right-handers matched for age, sex, and preschool attended. T tests indicated no difference between left-handers and right-handers of either sex, but the children lacking hand preference had lower scores than right-handers. Implications for the education of children lacking handedness and possible sex differences are discussed.
The handedness of 942 subjects (305 tertiary students, 591 of their siblings and 46 of their children) was ascertained by a 14-item questionnaire. The mothers of the subjects supplied information about maternal age at birth, birth weight and the presence or absence of twelve conditions likely to be associated with birth stress for each subject. No increase in left handedness was found among fourth or later born children. A significant decrease occurred in first-borns of both sexes, although these had more stressful births than the other subjects. No relationship between maternal age, birth weight or reported birth stress and left handedness was found. Thus the hypothesis that birth stress is a major cause of left handedness in normal subjects was not supported. Acknowledgements. We are particularly grateful to the students from the Institute for Early Childhood Development and their families, who provided the data for this study. We also wish to thank Dr John L. Bradshaw for his very constructive comments during the preparation of this paper.
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