Prediction of hemispheric asymmetry as measured by handedness from digit length and 2D:4D digit ratio.
Hemispheric asymmetry is widely theorised as having a basis in prenatal androgen levels. However, these theories ignore a second round of asymmetrical changes in the brain, which occur at the same time as post-puberty surges in androgens. Hemispheric asymmetry in adults might therefore be explained in terms of the joint effects of prenatal and post-pubertal androgen levels. Evidence is emerging that the ratio between the length of the second and fourth digits (2D:4D) is related to prenatal androgen exposure, and that digit length is related to post-puberty levels of androgen exposure. In this study, hemispheric asymmetry is measured as handedness, prenatal androgen levels as 2D:4D, and post-puberty androgen levels as digit length. Right-handedness is associated with consistent prenatal and post puberty androgen release whereas left-handedness is associated with mixed levels of androgen release. Age, race, and sex effects were explored but were not significant.
Jackson
Chris
C
Australian School of Business, University of New South Wales, Australia. chrisj@psy.uq.edu.au
D000293:Adolescent; D000328:Adult; D000728:Androgens / Q000097:blood; D000886:Anthropometry; D001921:Brain / Q000502:physiology*; D005260:Female; D047109:Fetal Development / Q000502:physiology; D005385:Fingers / Q000033:anatomy & histology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000033:anatomy & histology; D011247:Pregnancy; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013739:Testosterone / Q000097:blood
D000728:Androgens; D013739:Testosterone