“Internalizers may have an exceptionally alert nervous system from birth. Some research has found that differences in babies’ levels of attunement to the environment can be seen at a very early age (Porges 2011). Even as five-month-old infants, some babies show more perceptiveness and sustained interest than others (Conradt, Measelle, and Ablow 2013). Further, these characteristics were found to be correlated with the kinds of behaviors children engaged in as they matured.”