Document Type



This study is a re-evaluation, using ridge-counts, of the relationship between finger dermatoglyphics and handedness. It shows, like earlier studies using pattern types, that the difference between left and right handers is small. Comparison of mean ridge-counts between the handedness groups produced only one significant difference in males and three in females. Comparison of variances and correlations between handedness groups show more marked differences than means. Left handers are characterized by lower variances and lower correlations between ridge-counts on different digits. This indicates that left handers show greater within group homogeneity than right handers, but higher levels of within individual variation. These findings do not permit a choice between genetic and environmental hypotheses, but they clearly show that early prenatal development plays a role in the etiology of handedness.