Dermatoglyphic Asymmetry is Related to Perceptual Asymmetry and to Interhemispheric Transmission

Abstract

The numbers of ridges on the fingertips is asymmetrical between hands and is also sexually dimorphic. Most people have more ridges on the right hand (rightward dermatoglyphic asymmetry; R >) and men typically have more ridges than women. The direction of dermatoglyphic asymmetry has been shown to be related to patterns of cognitive abilities in men and women and to perceptual asymmetry in homosexual men. W e assessed presumptively heterosexual, right-handed men and women who had either R > (n = 35) or L > (n = 30) ridge count, on: (1) dichotic listening to words; (2) two tachistoscopic tasks sampling visual field asymmetries (dot location and letter identification); and (3) a tachistoscopic task designed to examine interhemispheric transmission. L > subjects had a smaller right-ear advantage than R > subjects, but this was accounted for by an increased incidence of an atypical left-ear advantage in the L > group. Visual field asymmetries were also smaller in the L > group but the asymmetry measures did not reach significance, with the exception of an increased incidence of an atypical field advantage (left) for letter recognition only. On the interhemispheric transfer task, L > subjects performed relatively faster on tasks requiring interhemispheric comparisons than did R > subjects. These findings confirm an association between the direction of dermatoglyphic asymmetry and aspects of brain organisation.