Possible organizational effect of sex steroids on the stabilization of manual preference in female common marmosets (Callithrix jacchus).

Handedness has been widely studied in nonhuman primates. However, few studies investigate this behavior throughout ontogenetic development. To determine the influence of developmental stage in common marmoset (Callithrix jacchus) females, we used six animals, which were observed in food-reaching tests involving hand-use preference from the infantile to the adult phase. During this period, fecal samples were collected for sexual hormone analysis (estrogen and progesterone). The results point to correlations between age and stabilization of manual preference across the developmental phases. A relationship between progesterone and the intensity of hand use asymmetry was observed during the pubertal period, when the data was grouped into three phases: prepubertal, pubertal, and postpubertal. These data show increasing strength of hand preference during ontogenetic development and that sexual hormones may be involved in females.