DAYLENGTH DURING PREGNANCY AND SHYNESS IN CHILDREN - RESULTS FROM NORTHERN AND SOUTHERN HEMISPHERES

An extreme degree of shyness in young children is a temperamental trai t under modest genetic influence and characterized by distinct physiol ogical profiles. Data from both the United States and New Zealand indi cate that maternal exposure to short daylength during pregnancy, espec ially the midpoint of gestation, predicts an increased risk of subsequ ent shy behavior in children. Estimates of attributable risk indicate that approximately one-quarter of shyness prevalence can be linked to pregnancy during times of reduced daylength. This phenomenon might be mediated by changing concentrations of melatonin, serotonin, or other neurotransmitters or corticoids that are known to covary with seasonal variations in daylength. (C) 1997 John Wiley & Sons, Inc.