Abstract
This special section of Developmental Psychology contains articles on the interplay of biology and the environment, broadly defined, that have the potential to change or challenge how developmental psychologists think. Topics include how experience affects gene expression; how genes affect how the environment is experienced and what effect the environment has; interactions between the environment and the presence or absence of early brain damage; motor neurons and the understanding of others' beliefs and intentions; the effect of physical fitness on cognition and the brain; evidence that our brains work and develop differently from the way traditionally thought; misconceptions that can arise from treating children as if they are simply small adults; and how research with adults can provide insights into developmental processes in children. Each of the 16 articles in the special section forges new territory and crosses disciplinary boundaries. They suggest that investigators look at variables not typically considered, or look at them from perspectives not usually taken, and especially that they pay more attention to interrelations among variables.