Manual proficiency in Cattle's Intelligence Test in left-handed male and female subjects.
The relationship between nonverbal intelligence (spatial reasoning) and manual proficiency was studied in male and female left-handers. Manual proficiency was assessed by measuring the speed and accuracy in performing the dot-filling test. Nonverbal intelligence was assessed by Cattle's Culture Fair Intelligence Test. Females were found to be better than males in left-hand performance, and were more lateralized than males in manual proficiency. No significant sex difference could be established in right-hand performance. The right-hand skill was positively correlated to test intelligence (p less than 0.001). There was a negative correlation between the left- minus right-hand skill difference and the scores for nonverbal intelligence (p less than 0.001). The left-hand skill did not show any correlation with nonverbal IQ. It was concluded that the left-hemisphere is of utmost importance even for nonverbal intelligence; strong cerebral lateralization is disadvantageous for spatial reasoning.
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Atatürk University, Medical Faculty, Institute of Physiology, Erzurum, Turkey.
D000328:Adult; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D011597:Psychomotor Performance; D012737:Sex Factors