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.
Australian School of Business, University of New South Wales, Australia. chrisj@psy.uq.edu.au
Chris
C
Jackson
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