Psychologist and neuroscientist Dr. Nim Tottenham highlights evidence showing how early social experiences may influence development through learning and modification of developmental pathways. These age-related changes will be discussed in terms of potential developmental sensitive periods for environmental influence. Compared to other species, human brain development is very slow, thus maximizing its chances of being influenced by environmental factors. In fact, it is this prolonged development that optimizes human brain development for learning from its environment. Variations in early experiences and environments reveal the profound effects of these influences on emotional development and associated neurobiology.